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The tcpCO2 handbook - Radiometer America

1. 49 7 mmHg and PaCO 6 29 kPa 47 3 mmHg Open arrow indicates episode 923 tcoCO 8 09 kPa 60 8 mmHg and PaCO 7 39 kPa 55 6 mmHg tcoCO with in vivo calibration and tgoCO without in vivo calibration Copyright obtained from Eur Respir J 78 Acute Respiratory Distress Syndrome ARDS In a study on patients with various respiratory conditions it was concluded that tcoCO provides a better indication of ventilation status than end tidal pCO The authors write that this is due to an increased dead space ventilation or ventilation in excess of perfusion Under these circumstances high V Q mismatch the carbon dioxide may be inadequately removed trom the bloodstream and the PaCO will increase without an equivalent increase in the end tidal pCO The discrepancy be tween arterial and end tidal pCO is particularly large in ARDS patients 83 Non invasive ventilation Increasing evidence of the benefits of Non invasive Positive Pressure Ventilation NPPV in a variety of pulmonary disorders has led to its widespread use tcoCO was shown to be in excel lent agreement with PaCO in hemodynamically stable adults Also the time for a change in ventilation to be detected by tcoCO measurements was shown to be compatible with the aim of clinical monitoring of patients under NPPV 22 Leaks during non invasive positive pressure ventilation It has been documented that many non invasively ventilated patients
2. Back Forearm Abdomen Bottom Medial prox leg 40 C 104 F 41 C 106 F 42 C 108 F 43 C 109 F 44 C 111 F 45 C 113 F The diagram is based on market experience and should not be used as general rule Adult Respiratory med OR ICU Conscious veep lab step down sedation Shock warning tc Sensor E5480 O76 O tc Sensor E5280 O7G O tc Sensor 92 Sp0 CO tc Sensor E5260 CO tc Sensor 54 CO tc Sensor E5250 O tc Sensor 84 CG O ACUTE CARE TESTING
3. 1 29 35 Poets CF Stebbens VA Detection of movement artefact in recorded pulse oximeter saturation European Journal of Pediatrics 1997 156 10 808 11 Hickson VM Mathews GR Pulse oximeter sensor accuracy Poster presenta tion from the ISAMOV 2007 conference 15 17 Mars 2007 Duke University Durham North Carolina Senn O Clarenbach CF Kaplan V et al Monitoring carbon dioxide tension and arterial oxygen saturation by a single earlobe sensor in patients with critical illness or sleep apnea Chest 2005 128 1291 96 Bloch KE Tosca selected case reports Adipositas hypoventilation syn drome 2005 Patient 1 Figure 2 5 Linde Medical Sensors AG Austrasse 25 Ch 4051 Basel Switzerland Jablonka DH Aymen A Stout RG What is the optimum site to measure the effect of spontaneous ventilation on the pulse oximeters waveform ASA annual meeting abstracts 2004 A 191 Awad AA Stout RG Ghobashy AM Analysis of the ear pulse oximeter wave form Journal of Clinical Monitoring and Computing 2006 20 3 174 84 General TC application advice Practical application An ideal TC measuring site is an area of skin over a homoge neous capillary bed with no large veins skin defects or hair Placing the sensor directly on top of a bone or a scar may cause erroneous results because of locally impaired perfusion of these sites Severe edema may also lead to unreliable results because of the reduction of blood flow caused by a compres s
4. COPD Chronic Obstructive Pulmonary Disease COPD is a major cause of respiratory morbidity The European Commission for Public Health characterizes COPD as a leading cause of chronic morbidity and the US National Institutes of Health list it as the fourth leading cause of death in the US 78 COPD patients are often old and hospitalized repeatedly for longer or shorter periods of time and it is therefore impor tant to minimize the interventions and use non invasive sur veillance Monitoring of the carbon dioxide tension level by a combined tcoCO SpO probe is according to the studies mentioned below often the right choice Carbon dioxide monitoring in COPD and other respiratory patients A study compared PaCO with arterialized capillary blood PacCO tcoCO end tidal pCO and physiological respirato ry dead space to tidal volume VD VT ratio in COPD patients postoperative cardiac surgery patients and healthy control subjects Patients were evaluated at three mechanical ventila tor patterns PaCO tcoCO end tidal pCO correlated well with VD VT and PaCO 0 99 0 97 and 0 87 However other studies have demonstrated that end tidal pCO is inaccurate in patients with ventilation perfusion mismatch 21 27 79 COPD exacerbation during oxygen therapy Hypoxic patients with acute exacerbation of COPD are ac cording to studies and the guideline The ABC of oxygen ther apy at risk of carbon dioxide retention when they
5. 156 15 2219 26 Franker KL Tullis E Sasson Z et a Pulmonary hypertension and cardiac function in adult cystic fibrosis Chest 1999 115 1321 28 Alswang M Friesen RH Bangert P Effect of preanesthetic medication on carbon dioxide tension in children with congenital heart disease J Cardio thorac Vasc Anaesth 1994 8 4 415 19 Zin W Y Clinical study on hemodynamics blood gases and hemorheologic monitoring of patients with cor pulmonale Zhong xi yi jie he za zhi 1989 9 9 522 14 Shoemaker WC Wo CCJ Demetriades D et a Scientific reviews Early physiologic patterns in acute illness and accidents Toward a concept of circulatory dysfunction and shock based on invasive and noninvasive hemo dynamic monitoring New Horizons 1996 4 4 395 12 Dalbec R Batool S Levin Y et a Transcutaneous pCO monitoring in a ventilator weaning unit AARC 51st International Respiratory Congress Program from the open forum no 1 2005 OF 05 116 70 Rowley D Walsh BK Young BS et a Evaluation of a new digital transcuta neous tcoCO amp SpO combination sensor and its correlation to ABG PaCO AARC 51st International Respiratory Congress Program from the open forum no 1 2005 OF 05 106 69 Evans EN Ganeshalingam K Ebden P Changes in oxygen saturation and transcutaneous carbon dioxide levels in patients undergoing fibreoptic bronchoscopy Respiratory Medicine 1998 92 739 42 Pulmonary respiratory medicine laboratory or wards
6. 3 Use the black arrow keys to adjust the volume 4 Press OK Note The setting of this option is common to pCO pO and SpO3 1 Press Setup Technical enter password 19100 gt Enter gt Date time 2 Adjust the date and time 3 Press OK Press Setup Technical enter password 19100 gt Enter Units pCO pO kPa mmHg 2 Adjust the units 3 Press OK Adjust the default values e g the unit kPa mmHg the alarm limits the curve ranges and the temperature in order to match your local needs Note Under technical setting it is possible to choose standard values By pressing this button many of your settings param eter limits measuring time curve view etc can be changed For complete instructions see the operator s manual or play the totorials in the monitor Conversion factors TmmHg 1 Tom 0 133322 kPa 93 How to apply tc sensors Sensors in fixation rings 1 Calibrate the tc sensor 2 It is recommended to clean the selected measuring site with alcohol or other skin preparation solution and if necessary shave the area This will help the ring to stick better to the skin or prevent air from leaking into the fixation ring Dry the site well Take a fixation ring Remove the fixation ring from the protective film Om KR W Apply the fixation ring to the measuring site as follows e Press the center of the fixation ring onto the measur ing site wi
7. 76 Endoscopy A randomized controlled trial evaluated the ability to de tect carbon dioxide retention purely by clinical observation or pulse oximetry in patients receiving supplemental oxy gen 395 patients were followed with these two methods and with tcoCO during Endoscopic Retrograde Cholan gloPancreatography ERCP Neither clinical observation nor the SpO surveillance technique reliably detected carbon dioxide retention It was concluded that additional tcoCO monitoring prevented severe carbon dioxide reten tion more effectively In 10 of the patients who received supplemental oxygen SpO did not indicate desaturation even though tcoCO increased by more than 20 mmHg Furthermore tcoCO monitoring facilitates a slightly deeper mean sedation and a significantly shorter duration of inadequate sedation The overall doses of sedative and analgesic drugs were the same irrespective of the chosen surveillance technique This indicated that transcutaneous carbon dioxide tension monitoring provided a more precise titration and timing of these drugs during ERCP 77 20 21 22 24 25 27 42 60 Hill KM Klein DG Transcutaneous carbon dioxide monitoring Crit Care Nurs Clin N Am 2006 18 211 15 Palmisano BW Severinghaus JW Transcutaneous pCO and pO a multi center study of accuracy J Clin Monit 1990 6 189 95 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critical
8. 97 Pulse oximetry Pulse oximetry allows monitoring of systemic oxygenation The technique is widespread and easy to use Motion like tremors may interrupt the SpO signal and the measuring site should be without sores breaks and birthmarks Finger or toe measurements in patients with poor peripheral circu lation may also be problematic Skin pigmentation and nail polisher may give bias Most oximeters are accurate within the range of 3 5 and are considered to be unreliable at levels below 70 Due to the flat shape of the oxygen dissocia tion curve at high oxygen levels it is not possible to estimate PaO to detect hyperoxia The staff should be aware that SpO readings might not be accurate due to elevated levels of car boxyhemoglobin changes in pH temperature 2 3 DPG and pCO levels or abnormal hemoglobin levels If these factors are taken into consideration the technique is valuable cheap and easy to use However SpO only shows the oxygenation level and not the carbon dioxide level Weaning from mechan ical ventilation tidal volume reduction in patients with acute respiratory distress syndrome and management of patients with brain edema require carbon dioxide tension monitoring 98 9 40 19 21 Gastric tonometry and sublingual capnometry Gastric tonometry and sublingual capnometry are based on the principle that tissue carbon dioxide is elevated in patients with poor perfusion The gastric tonometry technique requires
9. ICU were evaluated It was concluded that Non invasive measurements identify early circulatory problems reliably and provide objective criteria for physiological analysis as well as definition of therapeu tic goals and titration of therapy Transcutaneous oxygen and carbon dioxide tensions were used to assess tissue perfusion and oxygenation The authors refer to several Studies that have documented experimentally and clinically that tcoO changes with alterations in oxygen metabolism The authors found that hypotensive shock usually was pre ceded by episodes of high flow which was then followed by a period of low flow and inadequate tissue perfusion The latter was detected by a reduced tcpO 74 Please note that even if transcutaneous oxygen significant ly correlates with arterial values the agreement between tcpO PaO indicates that it should not be used as a solo estimation of PaO in adult patients however as docu mented above it can be an early warning of a shock 20 27 Conscious sedation during diagnostic surgery Conscious sedation In a state of moderate or deep sedation during diagnostic or therapeutic procedures regular breathing will often be disturbed by moving squeezing coughing or changes between nose and mouth ventilation causing leakage and therefore artifacts or misin terpretation of the data obtained with end tidal oCO5 These prob lems often restrict the use of side stream capnography although t
10. an insertion of the specialized nasogastric tube The method is de scribed as difficult and therefore not often used e g it requires long equilibration time ideally 90 minutes if the tube balloon is fluid dependent and nearly 20 minutes for the gas dependent type Histamine type 2 blockers are routinely required to limit the intraluminal generation of carbon dioxide from the gastric acid and enteral nutrition has to stop 2 hours prior to each measurement The sublingual oCO monitoring has been used in conditions in which the gastrointestinal system has been de prived of adequate perfusion e g early stages of shock It is non invasive and provides near instantaneous information However there is limited clinical experience with this technique So far both methods show close relation to decreases in arterial pressure and cardiac index during circulatory or septic shock They only provide intermittent measurements and they need a nurse to use a probe to acquire each data point Due to the limited use these techniques will not be discussed any further 4 64 99 End tidal pCO End tidal pCO monitoring refers to non invasive measurement of exhaled carbon dioxide concentrations at end expiration It is used mainly to verify the endotracheal tube ETT position and during cardio pulmonary resuscitation CPR It has become standard of care in the operating room in some ICUs and is now being increasingly used in the emergency departme
11. and low costs and when the limitations of the oxygen saturation technique are taken into consideration the results are easy to interpret SoO measure ment in combination with tcoCO provides a continuous esti mation of the patient s arterial oxygen saturation and of pulse rate together with information on the carbon dioxide tension in the skin and thereby the body s ability to oxygen uptake and to eliminate carbon dioxide via the cardiopulmonay system All together this provides valuable information of the patient s cardio respiratory status as an adjunct to decision making on the patient s care 10 11 12 13 14 15 16 17 Haymond S Oxygen saturation a guide to laboratory assessment Clinical Laboratory News 2006 Feb 10 12 Reprint on the AACC website www aacc org Clinical Laboratory News Series Articles Nellcor Puritan Bennett Inc A technology overview of the Nellcor oximax pulse oximetry system Web information G thgen IH Siggaard Andersen O Kokholm G Variations in the hemo globin oxygen dissociation curve in 10 079 arterial blood samples Scand J Clin Invest 1990 50 suppl 203 87 90 Poets CF Pulse oximetry vs transcutaneous monitoring in neonates practi cal aspects www bloodgas org 2003 October Neonatology Richards NM Giuliano KK Jones GJ A prospective comparison of 3 new generation pulse oximetry devices during ambulation after open heart surgery Respiratory Care 2006 51
12. and transcutaneous monitoring of carbon dioxide and oxygen tension trends allows non invasive respira tory surveillance Respiratory support Transcutaneous blood gas monitoring is an important adjunct to detect the need for and to guide assisted ventilation In addition it helps to detect complications such as obstruction either in the ventilation equipment or in the upper airways Obstructive sleep apnea and other sleep related breathing disorders During polysomnography for evaluation of pediatric obstructive sleep apnea OSA and sleep related hypoventilation tcoCO as well as end tidal pCO can been used Several studies have shown that gas exchange is efficiently monitored with tcpO tcpCO in children with COPD during sleep tcoCO is particularly useful for children who do not tolerate a nasal sampling tube and for those with moderate to severe partial airway obstruction tachypnea or increased physiological dead space where end tidal pCO underestimates the arterial pCO level tcoCO has been shown to provide an accurate estimation of PaCO over a wide range of carbon dioxide values in young and older pediatric patients with respiratory failure 23 51 52 53 Asthma WHO estimates that 300 million people children and adults suffer from asthma and 2 550 000 people died of asthma in 2005 Asthma is the most common chronic disease among children and the numbers are increasing One example From 1980 to 1994 the prevalence of a
13. by oscillation technique Rint the interrupter technique for measuring respiratory resistance sRaw Whole body plethysmography for measuring the specific airway resistance FEV forced expiratory volume in 1 second FEV1 vital capacity VC Xrs5 respiratory reactance measured by oscillation technique Methacolin was used as pharmacological test agent 57 58 Exercise testing Hemodynamic studies during heart catheterization in children are usually performed at rest This could result in exercise induced right to left shunts being missed tcoO monitoring during exercise testing is a non invasive means of detecting these shunts 59 More indications for TC monitoring Please refer to the neonatal part of this handbook as most topics in that part are just as relevant for children as for neonates 23 28 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Berkenbosch JW Lam J Burd RS et al Noninvasive monitoring of carbon dioxide during mechanical ventilation in older children End tidal versus transcutaneous techniques Anesth Analg Pediatric Anesthesia 2001 92 1427 31 Lundstr m KE Continuous blood gas monitoring in neonates and infants Radiometer Medical ApS Akandevej 21 2700 Br nsh j Denmark 2005 928 408 200502B 1 16 www tc monitoring com Lagerkvist A L Sten G Redfors S et a Repeated blood gas monitoring in healthy children and adolescents b
14. by pulse oximetry Whole body plethysmography measurements for specific airway resistance Transcutaneous tcpCO3 tcpO gt tcpCO O03 UV VDNT V O Xrs5 Transcutaneous pCO Transcutaneous pO Transcutaneous pCO and O Ultraviolet light Physiological respiratory dead space to tidal volume ratio Ventilation perfusion ratio Respiratory reactance measured by oscillation Complementary techniques The following is a summary of different monitoring techniques that complement transcutaneous monitoring Arterial blood gas samples Assessment of the alveolar ventilation and arterial oxygen sat uration in critically ill patients requires frequent arterial blood gas samples 21 Arterial blood gas analyses are the gold standard in the ICU and step down units However it is invasive painful and it can in very rare situations result in serious complications like nerve in jury arterial thrombosis and ischemia leading to necrosis Fur thermore a blood sample only provides a momentary picture of the PaCO PaO status if free of preanalytical errors it does not show continuous gas values For neonatal patients it is advisable to minimize the amount of blood samples due to the patient s small blood volume to reducing the need for blood transfusion that may lead to severe complications Despite this arterial blood samples do provide an exact gas status which may be necessary for the optimum patient surveillance 96
15. chronic respiratory failure Chest 2005 127 1 98 04 Reprinted in Tosca Selected case reports Adipositas hy poventialtion syndrome 2005 Patient 1 Figure 2 5 Linde Medical Sensors AG Austrasse 25 Ch 4051 Basel Switzerland Jennum PJ T nnesen P Rasmussen N et al Savnrelaterede respirations forstyrrelser definition forekomst patofysiologi og konsekvenser Ugeskr Leeger 2005 167 22 2380 85 Blanchette T Dziodzio J Transcutaneous pCO and end tidal pCO in venti lated adults Respiratory Care 1992 92 3 240 47 Teschler H Stampa J Ragette R et a Effect of mouth leak on effectiveness of nasal bilevel ventilatory assistance and sleep architecture Eur Respir J 1999 14 1251 57 85 86 Fontana GA Lavorini F Boddi V et a Comparison of dose response slopes obtained by simultaneous assessment of changes in FEV1 and transcutane ous oxygen partial pressure during methacholine challenges in asthmatic patients Journal of Asthma 1995 32 4 301 407 Fontana GA Cardellicchio S Camiciottoli G et al Changes in transcutane ous oxygen partial pressure as an index of response to inhaled methacholine in asthmatic patients Chest 1993 103 5 1375 80 E Sleep laboratories Sleep apnea Sleep apnea affects people worldwide According to a WHO estimations 5 20 million people in Europe and 15 20 million in the US are affected by this disease and 11 of the US obstructive sleep apnea patients also have COPD If
16. have clinically relevant mouth or other air leaks and this should therefore be measured routinely The leaks are especially seen if nasal resistance is high if treatment is not optimum or if sleep architecture appears to be impaired A study on awake control subjects has confirmed that a large mouth leak is very distressing and is a likely cause of severe Sleep disruption Sleeping patients with a mouth leak during nasal bi level ventilatory assistance have been found to have an increased tcoCO 84 One lung ventilation Several studies have shown that transcutaneous monitoring of carbon dioxide tension provides a more accurate estima tion of the PaCO during one lung ventilation OLV than end tidal pCO measurements The table below taken from one of these studies shows a significantly larger difference between the end tidal pCO and PaCO compared with the difference between the tcoCO and PaCO in patients with 1 hour of OLV during thoracic anesthesia relative to PaCO peas 0 2 2 3 6 6 3441 13496 The values are expressed as difference SD significant difference P lt 0 05 72 This study also found this significant difference in the two lung ventilation technique end tidal pCO PaCO 7 1 4 6 mmHg versus tcoCO PaCO 1 4 4 3 mmHg 68 69 Respiratory testing For asthma patients some doctors find that measurement of non specific bronchial hyperreactivity caused by inhaled bron choconstrictor a
17. in neonates has been shown to have a close correlation with PaCO at a sensor tempera ture of 40 44 C 100 111 F However transcutaneous oxy gen is best measured at a higher sensor temperature of 42 44 C 108 111 F 27 A switch on Smart Heat function which increases the temper ature by 1 C 1 8 F for the first five minutes of measuring can only be recommended for infants with a weight above 1 000 g 28 Note The physiological stabilization time of the sensor is 15 20 minutes for the tcoO reading and 3 7 minutes for the tcoCO reading During this time the sensor will slowly heat the skin making the arteries dilate Longer stabilization time may indicate a need for changing the membrane of the sen sor Other reasons could be an incorrect attachment of the sensor a poorly selected measuring site or an old sensor Adults On adults the optimum tcoCO tcpO temperature and measur ing time is 44 45 C 111 113 F for up to 4 hours However when there is a need for longer measuring periods of tcoCO only the literature often refers to temperatures around 43 C 109 F depending on patient skin condition Many sleep labo ratories use temperature settings of 42 43 C 108 109 F 30 A study has shown that a sensor temperature of 43 C 109 F was well tolerated for 5 8 hours of continuous monitoring 30 Single tcpCO combined tcpCO SpO earlobe sensor Please note that with a single tcoCO or comb
18. nm light The two absorption peaks represent oxygenated O Hb and deoxygenated HHb hemoglobin Because O Hb absorbs less red light than infrared light the underlying blood flow at high saturation values has less influ ence on the detected red signal than on the infrared one At low saturation values this situation is reversed and far more red than infrared light is absorbed Thus the arterial oxygen saturation can be derived from the ratio of the red and infra red light absorption SoO measurements indicate how much oxygen is actually bound to the available hemoglobin in the blood but it does not show the hemoglobin or dyshemo globin concentration Therefore SpO might not always show the actual blood oxygen status 8 Red LED Spectrum IR LED Spectrum Wavelength nm FIG 3 LED emitted light spectrum Overlapping of typical LED emitted light spectra and relative light absorption spectra of oxygenated and deoxygenated hemoglobin The dashed purple line indicates the spectrum of 50 saturated blood with the relative absorbance in the red and infrared indicated by the black circles Figure and text is reprinted by permission of Nellcor Puritan Bennett Inc Pleasanton California 8 The relation between SpO and pO The oxygen dissociation curve describes the relationship be tween oxygen tension pO and oxygen saturation SpO at standard conditions Fig 4 This relationship can be used with some restrictio
19. sensor placement on the patient Follow these steps to enable disable SmartHeat 1 Press Setup Parameter pCO or pO 2 Use the blue arrow key to select the SmartHeat option 3 Use the black arrow keys to set the option to ON or OFF 4 Press OK Note The setting of this option is common to pCO and pO Adjustment of 1 Press Setup Parameter pCO or pO pCO and pO Alternatively just Press on the alarm limits required Parameter 2 Use the blue arrow key to select the Alarm high low options 3 Use the black arrow keys to adjust the values 4 Press OK Adjustment of 1 Press Setup Parameter gt SpO Pulse SpO and pulse Alternatively just press Parameter alarm limits 2 Use the blue arrow key to select the SpO alarm high low and Pulse alarm high low options 3 Use the black arrow keys to adjust the values 4 Press OK Settings for 1 Press Setup Parameter SpO SatSeconds Pulse for TCM40 2 Use the blue arrow key to select the SatSeconds option 3 Use the black arrow keys to adjust the value 4 Press OK For a description of the SatSeconds function see the TCM4 40 operator s manual Silencing of Press Alarm silence to silence the alarm for alarm for all 2 minutes parameters Follow these steps to disable the alarm con tinuously 1 Press Setup gt Parameter pCO or pO or SpO Pulse To be continued page 74 2 Use the blue arrow
20. to the monitor which must be turned on Remove the old membrane retainer ring assembly using the V shaped notch in the base of the membraning tool The cable has to point downwards under the membraning tool Press the membraning tool down while the electrode is kept in place with the other hand and the old membrane is rejected Note A new sensor is delivered without mem brane In this case start with step two 2 Clean the sensor surface with a tissue soaked in clear wa ter This will also remove the spacer Dry the sensor surface and make sure that no fibers remain from the tissue Note Do not leave an unprepared sensor in air Proceed immediately with the next step SENSOR 3 This message appears on the REMEMBRANED monitor Leave unanswered YES until step eight NO Lift up the cover of the membraning tool and place two drop of electrolyte solu tion that match the sencor numbers into the center of the retainer ring assembly Insert the sensor with its surface pointing down wards into the prepara tory base until it is slightly locked Do not apply pres sure Close the cover of the membraning tool and press down until the new retainer ring clicks into place Open the cover remove sensor and discard membraning tool CALIBRATING 38 mmHg CAL Gas 0 100 7 Clean excess electrolyte from the side of the sensor Wt Ww Press on the monitor to co
21. 3 288 95 Griffin J Terry BE Burton RK et al Comparison of end tidal and transcuta neous measures of carbon dioxide during general anaesthesia in severely obese adult Br J Anaesth 2003 91 4 498 501 Tatevassian RWC Transcutaneous oxygen and CO as early warning of tissue hypoxia and homodynamic shock in critically ill emergency patients 2000 Crit Care med 28 7 2248 53 Brown BJ Richardson C Ellis Stoll C et al Transcutaneous CO monitoring versus end tidal CO during Propofol sedation Poster present at the annual ASA meeting October 2006 M nnle C Herth FJ Becker HD et al Controlling of high frequency jet ventilation by measurement of the Transcutaneous carbon dioxide tension tcpCO during rigid bronchoscopy Chest 2003 124 4 125S Sivasothy P Smith IE Shneerson JM Mask intermittent positive pressure ventilation in chronic hypercapnic respiratory failure due to chronic obstruc tive pulmonary disease Eur Respir J 1998 11 34 40 Tobias JD Noninvasive carbon dioxide monitoring during one lung ventila tion End tidal versus transcutaneous techniques Journal of Cardiothoracic and Vascular Anesthesia 2003 17 3 306 08 Oshibuchi M Cho S Hara T et a A comparative evaluation of transcutane ous and end tidal measurements of CO in thoracic anesthesia Anesth analg 2003 97 776 79 Petersen JR Gallae AM Graudal NA Intet grundlag for behandling af pulmonal hypertension med vasodilatation Ugeskr L ger 1994
22. O pCO sensor Radiometer A S Denmark 1990 ISBN 87 88138 283 TOSCA 500 Operating Manual Radiometer Basel AG Radiometer Medical ApS 2006 Publ No 520 81001 3 issued Jan Part No 520 0910 Combined measurements of tcpCO and SpO3 Combined tcpCO and SpO sensor Pulse oximetry provides instant and continuous information about oxygen saturation and pulse rate It does not howev er Indicate how much hemoglobin is available in the blood Oxygen saturation measurement is often used together with tcoCO as they compliment each other and provide a wider perspective of the patient s blood gas status Pulse oximetry is widely accepted because of its non invasive character ease of use and low cost It is also considered easy to interpret how ever the technique has certain limitations that are important to keep in mind in order to obtain optimum patient monitor ing SpO methodology A pulse oximeter sensor typically contains two light emitting diodes LEDs one with red light and one with infrared light The light passes through a blood perfused tissue to a photo detector on the other side of the finger earlobe foot or toe or is reflected by bone and other structures The more light absorbing blood that is present at the moment of measure ment the less light reaches the photodetector 7 The illustration next page shows a spectrophotometric meas urement of blood with an overlap of the red 660 nm and infrared 900
23. RADIOMETER AR The tcpCO3 handbook A Author Scientific Advisor Annette Melhedegaard Thomsen Radiometer Medical ApS Contributor Prof Dr Konrad E Bloch Universitats Spital ZUrich With input from Kevin Bage Radiometer LTD Franz von Wirth Radiometer GmbH and Phil Lazzara Radiometer America Inc Copyright 2012 Radiometer Medical ApS Denmark Contents may be reproduced if the source is acknowledged Printed in Denmark by Radiometer Medical ApS Akandevej 21 2700 Br nsh j Denmark 2011 ISBN 978 87 91026 09 6 939 049 201201E 0459 Data subject to change without notice Radiometer the Radiometer logo ABL AQT TCM RADIANCE AQURE PICO CLINITUBES and QUALICHECK are trademarks of Radiometer Medical ApS Introduction to transcutaneous monitoring tEoC OFC POs MONMMIONING 2 2240 2200ceoudidwnedosiesuadbendus TC methodology n n nananana sume wu bees eueepaaan nines Combined measurements of tcoCOz SpO 05 General TC application advice 0 eee eee eee Choice of measuring sites 2 0 6 eee eee eee Choice of measuring temperature 0 eee eee Transcutaneous monitoring applications Neonatology secaupsas even croaees lt pees erent reese moe eee Pediatrics 2 2 cc0ddiesdaetbccavedarwtdbadiabeddeseabawaienawa Operating room ICU and step down units 05 Conscious sedation during diagnostic surgery Pulmonary respiratory medici
24. are only analyzed intermittently End tidal pCO is a poor predictor of PaCO as it normally underestimates PaCO The relationship between the two values varies largely depending on the ventilation perfusion ratio and cardiac out put Thus tcoCO monitoring is an alternative way of nonin vasive estimation of arterial carbon dioxide tension without the drawbacks of end tidal pCO 4 21 tcpCO PaCO correlation studies Many TC studies focus on the tcoCO PaCO correlation however the major advantage of the tcpCO technique is that it is non invasive and follows the trends of PaCO with less than 1 minute of delay A number of different TC correlation studies are quoted in the following pages A major study tested the tcoCO PaCO correlation in a wide range of arterial carbon dioxide tension values 26 71 mmHg 3 4 9 4 kPa The authors found a close correlation r 0 968 p lt 0 0001 mean bias was 0 75 mmHg 0 1 kPa limits of agreement 4 5 to 6 mmHg 0 6 to 0 8 kPa This study also included a review of 16 other tcoCO PaCO correlation studies In general these studies showed good correlation The authors state that some errors seemed to be related to e A particular capnograph in sleep studies e Lack of calibration before every measurement e Not allowing sensor sufficient stabilization time e Inadequate cutaneous perfusion It was concluded that tcoCO in hemodynamically stable pa tients was in excellent agr
25. changes in pH These pH changes alter the voltage between the glass sensor and the reference sensor The measured pH is converted into a carbon dioxide reading by the Henderson Hasselbalch equation and is shown as a tcoCO value in either mmHg or kPa 5 6 Oxygen measurement Oxygen from the skin passes through the sensor membrane It reaches the cathode which consists of platinum Here oxygen is reduced as a result of the current generating process O 2H O 4e gt 40H The silver ring surrounding the platinum cathode is the anode where the following oxidation reaction takes place AAg 4CL gt 4AgCl 4e The reduction of oxygen generates a current that is converted by the monitor into a voltage and a digitized tcpO value in mmHg or kPa 5 6 Severinghaus JW Astrup P and Murray JF Blood gas analysis and critical care medicine Am J Respir Crit Care Med 1998 vol 157 nr 4 114 22 Wimberley PD Frederiksen PS Witt Hansen J et a Evaluation of a trans cutaneous oxygen and carbon dioxide monitor in a neonatal intensive care department Acta Paediatr Scand 1985 74 352 59 Wimberley PD Pedersen KG Olsson J et a Transcutaneous carbon dioxide and oxygen tension measured at different temperatures in healthy adults Clin Chem 1985 31 10 1611 15 Hill KM Klein DG Transcutaneous carbon dioxide monitoring Crit Care Nurs Clin N Am 2006 18 211 15 Larsen J Linnet N tc 110 Solid state transcutaneous combined p
26. cy jet ventilation HFJV high frequency oscillatory ventilation HFOV and other novel acute care therapeutic modalities Together these changes have led to an increased need for continuous focus on the patient s carbon dioxide CO status Transcutaneous CO monitoring meets these requirements non invasively This handbook is primarily a guide to transcutaneous car bon dioxide tcoCO monitoring from a clinical perspective However as transcutaneous oxygen tcoO monitoring is sometimes relevant for the same patients e g neonates on oxygen the handbook also contains information on this pa rameter For more in depth information on tcoO monitoring of patients with peripheral arterial disease PAD e g critical ischemia please refer to The tcoO handbook Thomsen A Wirth FV Bryde Jacobsen J The tcpOz handbook Radiometer Medical ApS Akandevej 21 2700 Br nsh j Denmark 2003 As measurement of oxygen saturation by pulse oximetry SpO is often used in combination with tcoCO and some times also tcoO monitoring this technique is described as well The handbook is based on scientific literature and the opera tor s manuals of Radiometer TCM monitors According to the findings in clinical studies the handbook provides suggestions on patient categories for which TC monitoring can be used References are found at the end of each section For a more detailed presentation of technical issues and troubleshooti
27. diffusing through the skin As the TC technique does not use light as used in SpO measurements it can be used for patients of all races without any bias caused by different levels of skin pigmenta tion 21 Age influences the respiration The aging process is associated with an increased risk of hy percapnic respiratory failure in patients with pneumonia con gestive heart failure or exacerbation of chronic obstructive pul monary disease COPD The increased PaCO may be related to the age related decrease in both respiratory muscle strength and compliance of the respiratory system as well as to a lower response of the respiratory center etc A tcoCO study on res piratory patients aged 66 97 years has shown a high correlation with PaCO and a low bias The authors write the limit of agreement was compatible with clinical use 8 3 8 5 mmHg 1 1 kPa Furthermore the heat 43 C 109 F from the sensor was shown to be well tolerated by older patients even after recordings at the same measuring site for up to 8 hours 27 Neonatal TC correction factor Some doctors recommend that the metabolic correction fac tor on the TC monitor is changed from the standard 4 or 5 mmHg 0 5 or 0 65 kPa to 8 or 10 mmHg 1 or 1 3 kPa for neonatal measurements This is due to the infant skin structure The difference in skin structure Is also the reason why transcutaneous carbon dioxide and especially transcutaneous oxygen have a
28. dults patients Intensive Care Med 2006 134 309 12 Rodriguez P Lellouche F Aboab J et al Transcutaneous arterial carbon dioxide pressure monitoring in critically ill adults patients supplementary material http dx doi org 10 1007 s00134 005 0006 4 Strauss MB Winant DM Strauss AG et a Cigarette smoking and transcuta neous oxygen tensions A case report Undersea Hyperbaric Medical Society 2000 27 1 43 46 Janssens J A Laszlo A Uldry C et al Non invasive transcutaneous monitor ing of pCO tcoCO in older adults Gerontology 2005 51 174 78 Choice of measuring sites Optimum measuring sites Optimum transcutaneous measuring sites are areas with good Skin perfusion Generally the best reflection of central arterial pCO pO is obtained with a chest position of the sensor and with high temperature settings max 44 45 C Preparing the measuring site The selected site should be without large veins skin defects hair or fat from oil cream or fetal fat If necessary shave and wash the site with alcohol Placing the sensor directly over a bone may cause erroneous results Severe edema will also result in unreliable results Do not place the sensor directly on previous operation sites e g on patients who have had heart lung or breast surgery Local perfusion at these sites is lower due to scar tissue It is not recommended to use TC sensors on patients with severe dermatological problems such as seen in areas o
29. e time of a heated combined tcoCO SpO earlobe sensor is faster than that of an unheated finger probe As a result the detection of the beginning and end of the desaturation happens 20 30 seconds earlier by the earlobe sensor and the obtained amplitude is nearly two times greater indicating a larger speci ficity This is important for patients with rapid and transient changes in SpO for example sleep apnea As not only the number of desaturation events but also the degree of these events correlate with the impairment of the cognitive function and with cardiovascular complications A short response time is essential in order to detect fast changes of the oxygen saturation 15 The combined tcpCO SpO sensor The combined tcoCO SpO sensor pictured below gives fast information of these parameters together with the pulse rate LEDs photodiode arterialized capillaries arteries ear lobe vens attachment clip SS FIG 7 The tcpCO SpO sensor tcpCO SpO is measured by an earlobe sensor attached by a clip The technique is a combination of the above shown TC technique and a spectrophotometric pulse oximetry measurment This TC sensor contains a gold shield that protects the membrane thereby allowing the sensor to provide reliable measurements for up to 14 days without membrane change Recommended measuring tempera ture 42 C 108 F SpO Is widely accepted due to the non invasive character of the method its ease of use
30. easuring surface carefully two or three times to remove the thin layer of silver that has precipitated on the sensor 6 Apply two drops of the electrolyte solution on the surface of the tc sensor Note Check that the elec trolyte solution covers the entire surface without air bubbles 7 Place the membrane unit on a hard and stable surface e Turn the sensor slowly so that the measuring surface faces downwards If the electrolyte solution drops off go back to step five e Insert the sensor head into the top of the TC membrane unit Changing the membrane on the E5480 sensor 1 Apply two drops of electrolyte solution to the membraning tool Note Ensure that there are no air bubbles in the electrolyte solution If air bubbles are present wait a few seconds and check again 2 Place the sensor without the protection cap in the sensor slot 3 To remove the old mem brane grip the membraning tool firmly at both ends Pull in the direction of the ar rows until only one arrow is visible in the sensor slot To click on the new membrane pull forcefully in the direc tion of the arrow until the tool is locked and no arrows are visible in the sensor slot 4 Remove the sensor and wipe off the surplus sensor solution with cleaning paper Calibrate the sensor twice before use Changing membrane on the tc sensor 54 tc sensor 84 and tc sensor 92 1 Ensure that the sensor is con nected
31. eement with PaCO and that the response to change In ventilation was compatible with the aim of clinical monitoring of non invasively mechanically ventilated patients 22 Two recent studies found a similar correlation with an even wider range of carbon dioxide values 21 85 mmHg 2 8 11 33 kPa 38 165 mmHg 5 22 kPa 60 61 So far no studies have evaluated normal or reference tcoCO values for different patient groups This is probably because transcutaneous monitoring is a tool for monitor ing carbon dioxide trends 62 Transcutaneous carbon dioxide monitoring has shown to pro vide a better estimate of PaCO than end tidal pCO during general anesthesia in patients with a body mass index greater than 40 kg m 63 Transcutaneous trends in critically ill patients A new study focused on tcoCO trends in critically ill patients which vary more than 8 mmHg 1 06 kPa from the corre sponding PaCO value The purpose was to evaluate if rel evant carbon dioxide changes were indicated in the tcoCO trend shift A trend shift was defined as A difference between tcoCO and PaCO that was more than 8 mmHg 1 06 kPa They found the following Positive predictive value negative predictive value The patients in the study had septic shock cardiac arrest car diogenic shock and other diagnoses It was concluded that tcoCO provides a safe and reliable trend monitoring tool if there is no major vasoconstriction 24 25 Susta
32. end table view current values as well as historical values are presented In Trend curve view the high and low values of the ranges can be changed with the arrow keys next to the actual parameter Cursor in Trend In Trend curve view press Cursor to add a curve view Gas status Change of cursor to the screen The cursor values oCO pO Power SpO3 Pulse Time and Date are shown in the lower right part of the screen whereas current values are shown in the upper right part of the screen When the cursor is moved all the way to the left the time axis changes and it is possible to go back in time When there is 10 or less gas left in the gas cylinder the present gas level is shown in a bar during calibration It is recommended to change the gas cylinder when the bar appears 1 Unscrew the old gas cylinder by turning it gas cylinder counter clockwise 2 Remove the white protection cap on the new gas cylinder and screw the new gas cylinder clockwise as far as possible into the socket Battery Alarm sound level Adjustment of date time Change units between kPa and mmHg Adjustment of default values If the monitor is running on battery the remaining power is indicated at the top of the screen by the following symbols full almost full low G and critically low i l 1 Press Setup Parameter pCO or pO or SpO Pulse 2 Use the blue arrow key to select the Alarm sound level option
33. er the measured blood gas values must be typed into the TC monitor In a study of 8 hours of continuous monitoring of tcoCO with this TC sensor the author concludes that the measurements gave reliable results during the 8 hours without any significant drift In this study they changed the membrane every 48 hours Therefore this is a possibility but this is however not according to the above recommendations for that sensor As an alternative one could also use the TCM TOSCA CombiM sensors that only has to be calibrated every 8 12 hours 94 In the literature there have been discussions about the need for in vivo calibration In patients with severe head and brain injury the increase in PaCO level may lead to increased cerebral blood flow and augmenting brain edema In these patients one author recommends performing an in vivo calibration at the beginning of the monitoring period and stresses the need to check it regu larly However other authors prefer not to use in vivo calibration when they work with tcoCO monitoring The study only had 12 COPD patients enrolled The authors concluded tcoCO values and variations accurately reflected PaCO values and that this seems to be restricted to patients with PaCO values below 56 mmHg However the study only had one patient with PaCO readings up to 56 mmHg which makes this part of the conclusion questionable This might also be the reason why this limited correlation was not confir
34. erinarians used a clean but not sterilized tcoO sensor with a new membrane They used a sterile glove where they cut a hole for the head of the sensor so the sensor could be placed directly on the moving intestine without contact gel or liquid The measur ing temperature was low to avoid burns This method ena bled them to decide where the tissue had sufficient levels of oxygen and where the oxygenation was too low The operation went well afterwards the horse was treated with antibiotics and it did not show any signs of infection Not published material 90 91 92 68 Hartmann M Montgomery A J nsson K et al Tissue oxygenation in hemor rhagic shock measured as transcutaneous oxygen tension subcutaneous oxygen tension and gastrointestinal intramucosal pH in pigs Critical care Medicine 1991 19 2 205 10 Ramos Cabrer P Weber R Wiedermann D et a Continuous noninvasive monitoring of transcutaneous blood gases for a stable and persistent BOLD contrast in fMRI studies in the rat NMR in Biomed 2005 18 440 46 Rocbat MC Pope ER Payne JT et al Transcutaneous oxygen monitoring for predicting skin viability in dogs Am J Vet Res 1993 53 3 468 75 Use of the TCM4 40 TOSCA CombiM monitors A short overview of TCM4 40 TOSCA CombiM monitors This section of the handbook gives a short overview of how to work with the TCM4 40 TOSCA CombiM monitors For fur ther information please refer to the operator s
35. f skin damage due to Prednisolone treatment burns or allergic reactions etc tcpCO and tcpO measuring sites e Earlobe Single tcoCO or combined tcoCO SpO sensor e Face e Laterally on the neck seldom used e Chest in the intercostal space provides the best reflec tion of PaO PaCO e Lateral abdomen on skinny adults or on children and neonates e Back mostly on neonates e Ventral side of the upper arm and forearm e Seat mostly on neonates or for ischemia patients e Thigh for tcoO measurements on babies or PAOD patients e Legs only for diagnosis of PAD ischemia Change measuring sites Because the sensor is heated this may cause local hyperemia of the skin which may disappear within 5 15 minutes How ever on patients with delicate skin this local hyperemia may last for up to 24 hours or longer If the sensor is left on the same site too long there is a risk of burns Therefore it is nec essary to change measuring site regularly For more informa tion refer to the section on choice of measuring temperature on page 29 TC monitoring on neonates and children Neonates and small children have very thin skin that allows measuring on the back and on the bottom with good results At the same time they are more vulnerable to the heat from the sensor Therefore it is important to either lower the measuring temperature or to change sensor site more frequently especially when measuring on very preterm infa
36. from the TC sensor dilates the capillary and increases local blood flow As part of the metabolic reaction there will be some oxygen consumption and an additional carbon dioxide production sor is not only determined by the arterial PaCO but also in fluenced by local blood flow and the skin metabolism The cells metabolic s pCO addition is temperature dependent this influence is minimized by applying a temperature specific constant and a metabolic factor however there will still be some difference between the tcoCO value and the carbon dioxide tension in the arterial blood Generally tcoCO would be higher than PaCO 2 3 tcpCO tcpO measures skin pCO pO tcoCO tcoO monitoring is an easy and non invasive method that reflects the trends of changes of arterial blood gases It provides assessment of the tissue s oxygenation and carbon dioxide removal via the cardio pulmonary system This infor mation can indicate if an arterial puncture is required 4 TC Methodology Measurement of carbon dioxide tension tcoCO measurement is in fact a pH measurement pCO from the skin diffuses through the membrane of the sensor into an electrolyte solution Here it reacts with water forming carbonic acid that immediately dissociates into HCO and H according to the following equation H O CO H CO3 SHt HCO As HCO in the electrolyte solution is kept at a fixed level changes in the H concentration will always be equivalent to
37. g media resources media_kit asthma_statistics stm http Avww who int int respiratory asthma en kilde Holmgren D Redfors S Wennergren G et a Histamine provocation in young awake children with bronchial asthma using a fall in oxygenation as the only indicator of a bronchial reaction 1999 Acta Paediatr 88 545 9 Klug BH Evaluation of some techniques for measurements of lung function in young children L geforeningens forlag K benhavn 2002 1 21 Doctor s thesis Quanjer PH et a Become an expert in spirometry 2006 http Avww spirx pert com indices 7 htm59 Holmgren D Redfors S Solymar L Transcutane ous pO monitoring for detection of exercise induced right to left shunts in children with congenital heart defects A case report Acta Paediatr 2001 90 816 8 Holmgren D Redfors S Solymar L Transcutaneous pO monitoring for detection of exercise induced right to left shunts in children with congenital heart defects A case report Acta Paediatr 2001 90 816 8 Operating room ICU and step down units Carbon dioxide in critically ill adult patients In Intensive Care Units ICU it is vital to continuously monitor arterial carbon dioxide tension This is commonly performed by analysis of arterial blood gas samples or derived from end tidal pCO measurement Arterial blood samples require an arterial puncture or insertion of a catheter with the associ ated risks and inconvenience for the patients In addition blood gases
38. gents provides important research and diag nostic aid tcoCO monitoring has proven to provide a useful and reli able tool for analysis of the slope of dose response curves to inhaled methacholine in asthmatic adult patients 85 86 21 22 27 36 61 67 68 69 76 77 78 79 80 81 82 83 84 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critically ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 Janssens J P Howarth Frey C Chevrolet J C et al Transcutaneous pCO to monitor noninvasive mechanical ventilation in adults Assessment to a new transcutaneous pCO device Chest 1998 113 768 73 Janssens J A Laszlo A Uldry C et a Non invasive transcutaneous monitor ing of pCO tcoCO in older adults Gerontology 2005 51 174 78 Wilson J Russo P Russo JA et al Noninvasive monitoring of carbon dioxide in infants and children with congenital heart disease End tidal versus trans cutaneous techniques J Intensive Care Med 2005 20 5 291 95 Cox M Kemp R Anwar S et a Non invasive monitoring of CO levels in patients using NIV for AECOPD Thorax 2006 61 363 4 Sivasothy P Smith IE Shneerson JM Mask intermittent positive pressure ventilation in chronic hypercapnic respiratory failure due to chronic obstruc tive pulmonary disease Eur Respir J 1998 11 34 40 Tobias JD Noninvasive carbon dioxide monitori
39. he American Society of Anesthesiologists and the American Soci ety of Gastrointestinal Endoscopy suggest in their guidelines that external monitoring with capnography should be considered for patients in conscious and deep sedation 60 65 In recent years new anesthetic drugs and advanced interven tional techniques have been used increasingly During mod erate sedation e g during colonoscopy some patients may unintentionally be sedated to a level of general anesthesia These patients may develop respiratory depression or airway obstruction In two studies on patients undergoing colonos copy SpO tcoCO and end tidal pCO were used to monitor patient status Because of supplemental oxygen supply the pulse oximeter did not show early signs of hypoventilation while tcoCO monitoring did indicate prolonged hypoventila tion It was concluded that during moderate sedation tcoCO monitoring might provide a better monitoring of the ventila tion than end tidal pCO however airway obstruction was indicated earlier by end tidal pCO 60 65 Bronchoscopy and COPD exacerbation Studies have shown that tcoCO often increases while patients are on assisted ventilation during bronchoscopy Monitoring tcoCO assists ventilator adjustments and is very helpful in as sessing patients during the initial periods off the ventilatior The authors further states that trending carbon dioxide levels is also relevant in patients with COPD exacerbation 75
40. idelines for 3100A HFOV chapter 8 1 version 0595H Lundstr m KE Pryds O Greisen G Oxygen at birth and prolonged cerebral vasoconstriction in preterm infants Arch Dis Cild 1995 73 F81 F86 American Association for Respiratory Care Transcutaneous blood gas monitoring for neonatal amp pediatric patients 2004 revision and update American Association for Respiratory Care www guideline gov Pediatrics Transcutaneous pCO pO monitoring in children Transcutaneous monitoring of carbon dioxide and oxygen ten sion has shown to be clinically relevant in respiratory ill new borns as well as in children in all ages 45 46 47 The cerebrovascular carbon dioxide reactivity in young chil dren is comparable to that of the newborn and the risk of hypo capnia induced cerebral ischemia in children is similar to that in neonates Because of this continuous monitoring of carbon dioxide tension is necessary in both patient groups 28 48 Respiratory Syncytial and other Virus infections Among small children Respiratory Syncytial Virus infections pose a risk of serious respiration insufficiency and it is the most frequent cause of hospitalization in many countries 49 50 Many children are uncomfortable or even afraid of the staff and equipment in hospital It is well known that this fear can persist for a long time after leaving hospital Therefore in chil dren s wards it is even more important to minimize the in vasive surveillance
41. in pigmentation Motion artifact is often a problem for pulse oximetry and may result in false readings or alarms A study that compared fin ger saturation probes and the number of false alarms showed significantly fewer false alarms on the middle finger compared with measurements on the index finger which is most often used as measuring site SpO measurements may also exhibit erroneous readings due to high patient skin pigmentation or nail polish Some sensors may even show a small bias when measuring on women Fur thermore correct sensor fixation is very important to ensure optimum light tissue interaction and thereby reliable measure ments 11 12 Earlobe sensors vs finger SpO sensors A study showed that a combined earlobe tcoCO SpO sen sor detects changes in oxygen saturation significantly earlier than a finger SpO sensor This can be explained by a differ ence in the lung to ear vs lung to finger circulation time and by differences in the vascularization of the monitored tissue The signal processing technique and the use of a heated sensor affect the response time of pulse oximetry as well Other studies have shown that the earlobe is less affected by systemic vasoconstriction which also makes the earlobe a good site for transcutaneous carbon dioxide measurement 131415 16 171 100 90 80 70 60 1min e 50 SpO Standard finger FIG 6 SpO response time The respons
42. ined elevated tcpCO in trauma patients High tcoCO values within the first hour of hospital admis sion were shown to correlate well with mortality in trauma pa tients The patients were monitored with tcoCO immediately after admission Early signs of poor tissue perfusion within the first hour could be related to survivors and non survivors Sus tained elevated tcoCO levels for more than 30 minutes were associated with a 100 mortality rate 4 64 High Frequency Oscillatory Ventilation and non invasive positive pressure ventilation A combined tcoCO SpO measurement is relevant in clini cal settings of non invasive positive pressure ventilation and high frequency oscillatory ventilation HFOV where end tidal pCO measurement and clinical assessment can be difficult or impossible tcoCO was also shown to be a useful tool for ad justment of the driving pressure in the jet ventilator for rigid bronchoscopy patients during high frequency jet ventilation HFJV This is especially relevant in overweight patients with pulmonary diseases and during long lasting procedures with endobronchial interventions 66 76 Since only the proximal airway pressure is monitored during HFOV and HFJV no alarm will occur in the event of obstruc tion or restriction of the airways The technique also induces a risk of hyperventilation resulting in hypocapnia HFOV manu facturer guidelines recommend tcoCO tcpO and SpO are measured during treat
43. ined tcoCO SpO earlobe sensor it is possible to obtain reliable adult carbon diox ide estimation at 42 C 108 F for more than 8 hours without changing measuring sites or calibrating the sensor 21 3 Wimberley PD Pedersen KG Olsson J Transcutaneous carbon dioxide and oxygen tension measured at different temperatures in healthy adults Clin Chem 1985 31 10 1611 15 21 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critically ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 27 Janssens J A Laszlo A Uldry C et a Non invasive transcutaneous monitor ing of pCO tcoCO in older adults Gerontology 2005 51 174 78 28 Lundstr m KE Continuous blood gas monitoring in neonates and infants Radiometer Medical ApS Akandevej 21 2700 Br nsh j Denmark 2005 928 408 200502B 1 16 www tc monitoring com 29 R diger M T pfer Hammer H et al A survey of transcutaneous blood gas monitoring among European neonatal intensive care units Neonatal Intensive Care 2007 20 3 37 40 30 Frederiksen PS Wimberley PD Melberg SG et a Transcutaneous pCO at different temperatures in newborns with respiratory insufficiency Compari son with arterial oCO gt In Continuous transcutaneous blood gas monitor ing Huch R Huch A New York Marcel Dekker inc 1983 p 233 40 Transcutaneous monitoring applications A wide range of patients Transcutaneous monitori
44. ion of the capillary loops and a longer diffusion pathway For more information refer to the section on measuring sites on page 26 The sensor The sensor must be in contact with the skin through the con tact liquid or gel This is to avoid bias from atmospheric air between tissue and sensor If there are air bubbles they will affect the measurement resulting in too high oxygen and too low carbon dioxide levels For more information refer to the section on how to apply the TC sensor on page 78 Initiation of TC monitoring involves sensor stabilization time It takes about 3 7 minutes after the sensor has been placed on the skin for the tcoCO values to stabilize and it may take a further 10 17 minutes to obtain reliable tcoO values Preheat ing the skin may reduce this time to 3 6 and 5 16 minutes respectively tcoCO tcpO is considered stable when TC val ues during stable patient conditions do not change more than about 2 mmHg 0 25 kPa within 1 minute tcpCO lag and response time A study in healthy subjects evaluated tcoCO lag time and defined it as The time from the initiation of an intervention of the gas status to the initial response of the sensor The mean lag time for tcoCO during hypercapnia was 16 8 1 3 seconds When the subjects resumed breathing room air from hypercapnia the mean lag time was 14 2 1 4 seconds The response time may be defined as The initiation of an intervention in the gas status t
45. ion such as CPAP Bi PAP HFOV During weaning from ventilator or change in ventilation strategy After extubation 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 Lundstr m KE Continuous blood gas monitoring in neonates and infants Radiometer Medical ApS Akandevej 21 2700 Br nsh j Denmark 2005 928 408 200502B 1 16 www tc monitoring com Rudiger M T pfer Hammer H et al A survey of transcutaneous blood gas monitoring among European neonatal intensive care units Neonatal Intensive Care 2007 20 3 37 40 Frederiksen PS Wimberley PD Melberg SG et a Transcutaneous pCO at different temperatures in newborns with respiratory insufficiency Compari son with arterial oCO In Continuous transcutaneous blood gas monitor ing Huch R Huch A New York Marcel Dekker inc 1983 p 233 40 Graziani LJ Spitzer AR Mitchell DG et a Mechanical ventilation in preterm infants Neurosonographic and developmental studies Pediatrics 1992 90 515 22 Greisen G Vannucci RC Is periventricular leucomalacia a result of hypoxic ischaemic injury Hypocapnia and the preterm brain Biol Neonate 2001 79 194 200 Ambalavanan N Carol WA Hypocapnia and hypercapnia in respiratory management of newborn infants Clinics in Perinatology 2001 28 3 517 31 Roll C HUning B Kaunicke M et al Umbilical artery catheter blood sampling decreases cerebral blood volume and o
46. itoring Crit Care Nurs Clin N Am 2006 18 211 15 G thgen IH Siggaard Andersen O Kokholm G Variations in the hemo globin oxygen dissociation curve in 10079 arterial blood samples Scand J Clin Invest 1990 50 suppl 203 87 90 Myers CS Measured results Pulse oximetry is proving the simple solution to many COPD disease management programs success The Journal for Respiratory Care Practitioners 1996 Aug Sep RT 83 86 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critically ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 Janssens J A Laszlo A Uldry C et al Non invasive transcutaneous monitor ing of pCO tcoCO in older adults Gerontology 2005 51 174 78 Wilson J Russo P Russo JA et al Noninvasive monitoring of carbon dioxide in infants and children with congenital hart disease End tidal versus trans cutaneous techniques J Intensive Care Med 2005 20 5 291 95 Poets CF Pulse oximetry vs transcutaneous monitoring in neonates Practi cal aspects www bloodgas org 2003 October Neonatology Nosovitch MA Johnson JO Tobias JD Noninvasiv intraoperative monitoring of carbon dioxide in children endtidal versus transcutaneous techniques Paediatric Anaesthesia 2002 12 48 52 Marik PE Regional carbon dioxide monitoring to assess the adequacy of tissue perfusion Curr Opin Crit Care 2005 11 245 51 Tobias JD Noninvasive carbon dioxide monito
47. key to select the pCO pO SpO or Pulse alarm option 3 Use the black arrow keys to set the option to ON or OFF 4 Press OK Alarm symbols The alarm symbols in Normal view have the Site time following meanings Alarm is off Alarm is on The site timer is typically activated when the sensor is affixed to the patient The site time function can be used to indicate that the sensor must be moved to another site that medication should be given or that a monitor ing period is finished The site timer will count down to zero at 1 minute intervals and when it reaches zero the message Site time end will be displayed on the screen Follow these steps to adjust the Site time 1 Press Setup Parameter pCO or pO 2 Use the blue arrow key to select the Site time option 3 Use the black arrow keys to set the timer 4 Press OK Note If Site time heat is set to OFF in the setup the sensor heat is switched off when the site timer reaches zero and the TCM4 40 monitors stops monitoring if set to ON the heat continues Note The setting of this option is common to pCO and pO gt Marking of event Views Press Event OK to mark an event for instance when giving medicine The event number will be added in the Normal Trend table and Trend curve views In order to view the desired data format on the monitor press Setup Normal or Trend table or Trend curve OK In Tr
48. liable measurements at lower temperatures than on adults tcoCO tcoO values can be obtained at low temperatures like 37 38 5 C 99 101 F but the measured values do not reliably reflect arterial blood gases and these low meas uring temperatures are therefore only used in special pharmaceutical research settings Reducing risks of skin reactions To reduce the risk of burns it is necessary to change the measur ing site regularly and or use a lower sensor temperature A good correlation of the measurement can still be obtained by choosing a high initial temperature of 43 45 C 109 113 F for the first 5 minutes a feature that is automatic in some monitors This will increase the dilatation of the underlying capillaries and the gas diffusing through the lipid structure in the skin This will be the case also after the temperature automatically has been lowered again when using a smart heat function 3 Patients with the following clinical conditions have higher risk of getting burns from the electrode e Shock e Very low blood pressure e Distinct systemic vasoconstriction e Very sensitive skin Neonates and children On neonatal and children s wards it is common to choose a tcoCO tcoO sensor temperature of 42 5 43 C 108 109 F for 2 4 hours or 44 C 111 F for a maximum of 2 hours For very preterm neonates a temperature as low as 42 C 108 F may be the optimum choice 28 29 Transcutaneous carbon dioxide
49. lso developed and introduced to the market in the early 1980s 1 The sensor on the skin Arterial end of a Venous end of a capillary loop i capillary loop CO FIG 1 Transcutaneous pCO O monitoring TC The heat from the sensor dilates the capillary and increases local blood flow and the diffusion of CO O through the skin to the sensor tcoCO tcpO is measured electrochemically inside the sensor Are tcpCO tcpO identical to arterial blood gases It is a misconception that tcoCO tcpO are the same as arte rial blood gases The purpose of monitoring transcutaneous gas tensions is to obtain information on the cardio respiratory condition of a patient without the need to repeatedly draw arterial blood samples for analysis However the transcutane ous partial pressure of oxygen reflects the underlying dermal pO level that is influenced not only by the arterial pO but depends on local blood flow oxygen release from hemoglobin and skin metabolism Living skin will always consume some oxygen and tcpO will therefore always be lower than the ar terial pO irrespective of the sensor measuring temperature Similarly dermal pCO measured by a transcutaneous sen O gt 145 mmHg O gt 100 mmHg FIG 2 Example of the different levels of gases in blood to tissue Illustration of the physiological oxygen and carbon dioxide contents in a healthy sub ject s arterioles capillaries and skin cells when the heat
50. ly ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 Janssens J P Howarth Frey C Chevrolet J C et al Transcutaneous pCO to monitor noninvasive mechanical ventilation in adults Chest 1998 113 768 73 Rodriguez P Lellouche F Aboab J et al Transcutaneous arterial carbon di oxide pressure monitoring in critically ill adults patients Intensive Care Med 2006 134 309 12 Rodriguez P Lellouche F Aboab J et a Transcutaneous arterial carbon dioxide pressure monitoring in critically ill adults patients supplementary material http dx doi org 10 1007 s00134 005 0006 4 Janssens J A Laszlo A Uldry C et al Non invasive transcutaneous monitor ing of pCO tcoCO in older adults Gerontology 2005 51 174 78 User s manual for SensorMedics Critical Care Clinical Guidelines for 3100A HFOV chapter 8 1 version 0595H Heuss LT Chhajed PN Schnieper P et a Combined pulse oximetry cutane ous carbon dioxide tension monitoring during colonoscopies Pilot study with a smart ear clip Digestion 2004 70 152 58 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 Cox M Kemp R Anwar S et al Non invasive monitoring of CO levels in patients using NIV for AECOPD Thorax 2006 61 363 4 Nelson DB Freeman ML Silvis SE et al A randomized controlled trial of transcutaneous carbon dioxide during ERCP Gastrointestinal endoscopy 2000 51
51. manual for these monitors Measurements During monitoring the results can be viewed as current nu meric results curves and trend tables The monitor stores data up to 48 hours of monitoring data It is possible to print out the data or send it to an external computer Menu structure of the TCM4 40 TOSCA CombiM monitors Setup View LEMAS LECON Printer Technical pCO SmartCal Time Enter pO Cal status interval password SpO Pulse L Sensor Time span Not TCM4 remem Report type Blood gas braned Curve ranges Printer type Trend table Normal Trend curve View Time Time span Time span interval Curve ranges Curve ranges pCO 2 pO 70 pCO Power pO SpO Pulse TCM40 only Power TCM4 only Screen saver Select curves Technical i EE Service Default settings menu values Date time For service settings personnel Date format only Fig 12 Menu structure of the TCM4 40 TOSCA CombiM monitors Only on the TCM TOSCA CombiM monitors Short form support for the TCM4 40 TOSCA CombiM monitors J Please consult the operator s manuals for instructions This short form support provides only a brife overview when using the device please consult operator s manuals Applicable for The following short form instructions are valid Start up Shutdown Calibration SmartCal for monitors with base unit model 391 876 or later Turn on the power supply on the rear of
52. med in any of the larger studies mentioned earlier in this handbook The authors explained the incidence by a too low electrode temperature and they advise the readers to perform an in vivo calibration when they use TC monitoring 78 95 Please note that in vivo calibration does not make the TC monitor read arterial values nor does it eliminate the blood flow or any other determinants that TC values depends on Although an arterial blood gas in many situations is the gold standard there is always a risk of a preanalytical error in the blood sample that is used for the in vivo calibration Fur thermore an in vivo calibration requires a new blood sample with every change of measuring site or sensor temperature and the sensor still needs regular calibration due to sensor drift TC measurements show trends not absolute values initially the trends show an actual arterial blood gas value but it might not be accurate in the end of the measuring period For more information please refer to the operator manuals 21 7S 95 21 78 93 94 95 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critically ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 O Donoghue FJ Catcheside PG Ellis EE et a Sleep hypoventilation in hy percapnic chronic obstructive pulmonary disease Prevalence and associated factors Eur Respir J 2003 21 977 84 www concert me com en conver
53. ment This is particularly important in older children and adults who have more dead space and a greater metabolic demand on ventilation 42 Hypercapnic respiratory failure and oxygen therapy A study evaluating intermittent positive pressure ventilation recommends that patients with hypercapnic respiratory failure in oxygen therapy are assessed with initial arterial blood gases and continual pulse oximetry plus tcoCO monitoring during Sleep 67 One lung ventilation Various factors may influence the difference between PaCO and end tidal pCO during thoracic anesthesia Many thoracic Surgical patients have some degree of preoperative lung dys function and a history of smoking One lung ventilation is of ten used to improve surgical exposure during thoracic proce dures However one lung ventilation impairs the ventilation perfusion matching Several studies have concluded that pa tients undergoing one lung ventilation are significantly better monitored by tcoCO than by end tidal pCO 68 69 Secondary pulmonary hypertension Patients with COPD obstructive sleep apnea and cystic fibro sis sometimes develop secondary pulmonary hypertension tcoCO tcpO and SpO are sometimes used as part of the evaluation of the respiratory status of these patients neo nates children as well as adults 70 71 72 73 Hypotensive shock diagnosed by tcpO In one study more than 300 acute episodes of circulatory dysfunction and shock in the
54. much higher PaCO O correlation in neonates than in adults The operational conditions It is recommended to have standard conditions in order to get reliable results e Ambient temperature of 5 40 C 41 104 F e Relative humidity of 20 80 18 19 20 21 22 23 24 25 26 27 Kesten S Chapman KR Rebuck AS Response characteristics of a dual transcu taneous oxygen carbon dioxide monitoring system Chest 1991 5 1211 14 Myers CS Measured results Pulse oximetry is proving the simple solution to many COPD disease management programs success The Journal for Respiratory Care Practitioners 1996 Aug Sep RT 83 86 Palmisano BW Severinghaus JW Transcutaneous pCO and pO a multi center study of accuracy J Clin Monit 1990 6 189 95 Bendjelid K Sch tz N Stotz M et al Transcutaneous pCO monitoring in critically ill adults Clinical evaluation of a new sensor Crit Care Med 2005 33 10 2203 06 Janssens J P Howarth Frey C Chevrolet J C et al Transcutaneous pCO to monitor noninvasive mechanical ventilation in adults Chest 1998 113 768 73 Berkenbosch JW Lam J Burd RS et al Noninvasive monitoring of carbon dioxide during mechanical ventilation in older children End tidal versus trans cutaneous techniques Anesth Analg Pediatric Anesthesia 2001 92 1427 31 Rodriguez P Lellouche F Aboab J et al Transcutaneous arterial carbon di oxide pressure monitoring in critically ill a
55. n to esti mate pO from SpO The position of the dissociation curve is however shifted either to the left or the right by changes in pH temperature 2 3 DPG pCO level and the presence of dyshemoglobins A multicenter study of these variables resulted in the curves shown in Fig 5 When oxygen saturation is read from this curve with a PaO of 8 kPa 60 mmHg the corresponding SpO value ranges from 69 7 to 99 4 At SpO level of 90 the PaO values ranges were 3 82 and 18 3 kPa 29 and 137 mmHg Beside this inac curacy In some patients It is also important to realize that SpO cannot differentiate between hypoxemia caused by ventilation perfusion mismatch and that caused by alveolar hypoventilation These examples illustrate that oxygen saturation does not always provide a precise estimate of hypo and hyperoxia In terms of oxygen transport how ever the oxygen saturation technique together with the hemoglobin measurements is quite important 9 10 i pO 20 40 60 80 mmHg O 2 4 6 8 10 12 kPa FIG 4 Oxygen tension vs saturation The Oxygen Dissociation Curve Psp is defined as the oxygen tension of half saturation SO 50 pO kPa 0 5 10 15 20 25 FIG 5 Oxygen tension vs saturation The curve from a multicenter study shows the measured oxygen tension vs the saturation in 10 079 arterial blood samples 9 SpO bias due to motion level of sk
56. ne laboratories or wards Sleep laboratories 2 4 2cennctenccavahade lacnecntanas tunct hes Veterinary hospitals laboratories 0 0 0 0 cece eee Use of TCM4 40 TOSCA CombiM monitors Menu structure of TCM4 40 TOSCA CombiM monitors Short form support for The TCM4 40 TOSCA CombiM monitors oaan How to apply TC sensor 2xucictcies ceearedgakueeaeunnewawden Calibration ean ond kde ocaewleseetndndiaodnbbs baba R6haheos Cleaning ane dtaks neanegua sane cesuhase ceanea eee E E Maintenance of the sensor 0 0 000 c cee eee eee List of abbreviations 0 ccc eee eee een eee aey Complementary techniques Choice of sensor site and temperature 008 Introduction to transcutaneous monitoring The transcutaneous carbon dioxide and oxygen measuring techniques were first developed in the nineteen seventies Since then major further advances have been made and sig nificantly improved the technology and practical application Today monitoring of transcutaneous gas tension is not only valuable for the respiratory and ventilatory status of neonates but also highly relevant for the ventilatory care of children and adults with chronic respiratory failure This develooment has followed the change in hospital care Trends go in two direc tions towards an increased application of non invasive acute and long term ventilation and towards a more frequent use of techniques like high frequen
57. nfirm the new sensor remembraning The date is stored in the sensor memory Lift up the lever of the cali bration chamber and insert the sensor with its surface pointing downwards as far as it will go Release the le ver The message calibrat ing sensor appears When the calibration is completed the message ready to use appears The sensor is now ready for measurements List of abbreviations AARC ARDS BMI a CPAP COPD End tidal CO F HFJV HFOV HHb ICU IR kPa LED mm Hg NPPV NPV Nm O Hb PaCO PaQ3 PcaCO BIPAP PPV Prs Rint SpO sRaw TC American Association of Respiratory Care Acute respiratory distress syndrome Body mass index kg m Degrees Celsius Continues positive airway pressure Chronic obstructive pulmonary disease End tidal concentration of CO Degrees Fahrenheit High frequency jet ventilation High frequency oscillatory ventilation Deoxygenated hemoglobin Intensive care unit Infrared Kilo Pascal Light emitting diode Millimeters of mercury the same as Torr Non invasive positive pressure ventilation Negative predictive value Nanometer Oxygenated hemoglobin Arterial CO tension Arterial O tension Capillary CO tension Bi level positive airway pressure ventilation Positive predictive value Respiratory resistance measured by oscillation Interrupter technique for measuring respira tory resistance Saturation measured
58. ng of transcutaneous monitors please refer to the operator s manuals of these products Each section contains blank pages for the reader to make rel evant notes and modifications according to local policies and procedures Note The validity of any measurement must be carefully examined by a clinician healthcare professional and related to the patient s clinical condition before any decisions are made on the basis of the measurement tcpCO tcpO monitoring Continuous non invasive monitoring Patients with respiratory and cardiovascular disease during anesthesia and surgery depend on having their carbon dioxide and oxygen status surveyed Hypercapnia and hypoxia can re sult in acidosis requiring treatment if undetected hypercapnia and hypoxia may lead to acidosic hyperkalemia myocardial depression arrhytmias arterial hypotension or hypertension intercranial hypertension narcosis and organ damage Hypo capnia and hyperoxia may also have adverse and even severe damaging effects on the brain and other organs due to the vulnerability of cells and organs to changes in blood pH level and their dependence on oxygen Continuous non invasive transcutaneous monitoring of carbon dioxide and oxygen may be obtained in various ways and combinations e tcoCO e tcpO e SpO e tcoCO tcpO e tcoCO SpO e tcoCO tcpO SpO Transcutaneous measurement of carbon dioxide and oxygen Transcutaneous carbon dioxide and oxygen m
59. ng can be used in a number of dif ferent patient segments Historically the technique has grown from a reliable and beneficial tool for monitoring the carbon dioxide and oxygen situation of neonates to a method that is applicable for many cardiovascular and respiratory patients of all ages Apart from wound care and hyperbaric medicine where the main focus is on local tcoO measurement a grow ing number of physicians have become aware of the benefit of reliable tcpoCO measurements In this part of the handbook the use of tcoCO monitoring and to some extent tcoO in the following clinical setting applications is described e Neonatology e Pediatrics e Operating room ICU and step down units e Pulmonary respiratory medicine laboratory or wards e Sleep laboratories e Veterinary hospitals laboratories Neonatology Why it is essential to monitor arterial pCO pO Continuous monitoring of both carbon dioxide and oxygen is essential in ill neonates Changes may occur fast With intermit tent monitoring or repeated blood gas analysis these changes can go undetected and may eventually result in organ damage 28 Decreased arterial carbon dioxide Decreasing PaCO results in decreased cerebral blood flow and several studies on neonates have demonstrated a strong cor relation between low PaCO and adverse cerebral outcome At values of 22 5 mmHg 3 0 kPa or less damage can oc cur within a few minutes but also exposure to sligh
60. ng during one lung ventila tion End tidal versus transcutaneous techniques Journal of Cardiothoracic and vascular Anesthesia 2003 17 3 306 08 Oshibuchi M Cho S Hara T et a A comparative evaluation of transcutane ous and end tidal measurements of CO in thoracic anesthesia Anesth analg 2003 97 776 79 Rowley D Walsh BK Young BS et a Evaluation of a new digital transcuta neous tcoCO amp SpO combination sensor and its correlation to ABG PaCO AARC 51st International Respiratory Congress Program from the open forum no 1 2005 OF 05 106 69 Chaouat A Weiltzenblum E Krieger J et a Association of chronic obstruc tive pulmonary disease and sleep apnea syndrome Am J Respir Crit Care Med 1995 151 1 82 86 O Donoghue FJ Catcheside PG Ellis EE et a l Sleep hypoventilation in hy percapnic chronic obstructive pulmonary disease Prevalence and associated factors Eur Respir J 2003 21 977 84 Xie X B Liu Y Application of bedside monitoring with arterized capillary blood transcutaneous and end tidal carbon dioxide during mechanical ventilation Zhonghua jie he he hu xi za zhi Zhonghua jiehe he huxi zazhi Chinese Journal of tuberculosis and respiratory diseases 1993 16 2 98 100 English abstract 124 5 Bateman NT Leach RM Clinical review ABC of oxygen Acute oxygen therapy BMJ 1998 317 798 801 Brack T Senn O Russi EW Bloch KE Transtracheal high flow insufflation supports spontaneous respiration in
61. noghe Fj Chatcheside PG Ellis EE et a Sleep hypoventilation in hyper capnic chronic obstructive pulmonary disease Prevealence and associatiod factors Eur Respir J 2003 21 977 84 Bloch KE Tosca Selected case reports Adipositas hypoventialtion syn drome 2005 Patient 1 figure 2 5 Linde Medical Sensors AG Austrasse 25 Ch 4051 Basel Switzerland Teschler H Stampa J Ragette R et al Effect of mouth leak on effectiveness of nasal bilevel ventilatory assistance and sleep architecture Eur Respir J 1999 14 1251 57 Mullory E McNicholas WT Ventilation and gas exchange during sleep and exercise in severe COPD Chest 1996 109 2 387 94 Milross MA Piper AJ Norman M et al Predicting sleep disordered breathing in patients with cystic fibrosis Chest 2001 120 1239 45 Piper AJ Sullivan CE Effect of long term nocturnal nasal ventilation on spontaneous breathing during sleep in neuromuscular and chest wall disor ders Eur Respir J 1996 9 1515 22 Veterinary hospitals laboratories Animals Although transcutaneous monitoring was originally developed for human use the literature has shown several examples of its use on animals Before TC measurement it is necessary to prepare the skin in order to optimize the conditions for car bon dioxide and oxygen diffusion through the skin Removing the hair and the upper layer of dead skin cells is therefore advised Do not use any kind of chemicals for hair removal as they
62. nt The sig nificant inaccuracy introduced into end tidal pCO monitoring by the presence of intrapulmonary shunting and dead space ventila tion is a problem with the technique This inaccuracy is also found in patients with intrinsic lung disease ventilation perfusion mis match or in patients with small tidal volumes e g neonates and infants Studies have shown that in all these patients end tidal pCO Is less accurate than tcoCO Several studies have shown that while end tidal pCO significantly increases during one lung ventilation neither tcoCO nor PaCO show the same changes 21 27 36 46 68 69 100 101 While both end tidal and TC measurements are most fre quently used instead of PaCO they indirectly monitor dif ferent elements of carbon dioxide production transport and elimination In a comparison study the authors conclude that end tidal pCO values may not always accurately reflect PaCO however end tidal pCO measurement still provides information that can be derived from the carbon dioxide waveform and it has a rapid response time 21 102 tcpCO tcoCO monitoring and for neonates also tcoO monitor ing provides nearly instant and continuous information on the body s peripheral circulation and ability to remove carbon dioxide via the cardiopulmonary system and deliver oxygen to the tissue The technique accurately estimates PaCO in case of significant cardio respiratory dysfunction The monitor can be moved aro
63. nts This may be done Some doctors do not want to use this site because of the risk of skin reactions by attaching two or three fixation rings to the infant and then change sensor position between these rings Remember to dry the fixation well and refill it again before use Altogether this will disturb the infants as little as possible The fixation rings should however be removed from the skin every 12 24 hours depending on the condition of the skin 19 Avoid direct pressure on the sensor Direct pressure should never be placed on the sensor while it is on the patient and the patient should never lie on the sensor Direct pressure may cause invalid measurements and or cause Skin necrosis 19 Myers CS Measured results pulse oximetry is proving the simple solution to many COPD disease management programs success The Journal for Respiratory Care Practitioners 1996 Aug Sep RT 83 86 Choice of measuring temperature Optimum transcutaneous measuring temperature The optimum transcutaneous measuring temperature is 42 45 C 108 113 F However measuring time and skin diffusion con ditions are important when choosing the temperature e The best reflection of central arterial 0O pCO is obtained with a high sensor temperature i e 44 C 111 F e The higher the temperature the shorter the response time e Skin diffusion depends on the patient The thin skin of neonates and children makes it possible to obtain re
64. o the maximum 100 re sponse of the sensor The 90 response time was 77 9 6 7 seconds tcoCO has a shorter response time compared with tcpO This is most likely due to a hypercapnia induced increased cardiac output capillary perfusion and faster carbon dioxide diffusion through the epidermis 18 mmHg 90 pCO ee alveolar pCO l tcoCO 70 Log time 60 50 f 40 30 20 0 50 100 150 200 250 Time sec Lag time Response time FIG 8 The tcpCO response and lag time UV light Measurements of tcoCO and SpO may be affected by bright light from an UV lamp e g used for jaundiced neonates un dergoing light therapy Some sensors are better shielded from UV light than others however additional shielding is still rec ommended 19 MRI scanning To minimize the risk of an electromagnetic field interfering with the TC measurements the TC monitor must always be placed in a safe distance to the MRI scanner For TC measure ments during MRI scanning the relevant length for the sensor extension cable can be calculated with support from the TCM operator s manual Vasoconstriction There is some disagreement about the reliability of tcoCO tcpO in cases of epidermal vasoconstriction caused by vaso constricting agents toxins in sepsis patients hypothermia or elevated cutaneous vascular resistance as seen in patients with hypovolemic or cardiogenic hypotension and low car diac output Several studies have doc
65. onitoring is a non invasive way of continuously measuring the tension of these gases in the skin A combined Clark type and Sever inghaus type sensor also called Stow Severinghaus sensor is placed on the skin and heated The sensor heat dilates the underlying capillaries and increases the gas diffusion through the lipid structure of the skin thereby allowing carbon diox ide and oxygen to diffuse up to 20 times more quickly from the capillaries through the skin to the sensor The oxygen generates a current and the carbon dioxide a potential in the sensor These signals are converted by the monitor and showed as tcoCO and tcpO values on the screen In the literature the pCO sensor is generally known as a Severinghaus type sensor However Richard Stow originally invented the gas measuring technique and described it in 1954 Later that year Leland C Clark Jr designed an arterial blood gas pO sensor In 1958 John W Severinghaus developed a complete blood gas apparatus by combining his more practical version of Stow s pCO sensor with Clark s pO sensor This is the reason why the pCO sensor is also known by the name Stow Severinghaus sensor Dietrich Lubbers Albert and Renata Huch demonstrated together with Patrich Eberhard in 1972 that heating the skin to 42 45 C creates vasodilatation which makes the cutaneous surface pO value reasonable close to PaO especially in newborn babies After that were the transcutaneous pCO sensor a
66. prove patient outcome Unfortunately this diag nosis is often made rather late A study showed that the me dian time from onset to clinical diagnosis was 127 minutes An elevated tcoCO without any change in oxygenation may be an indicator of this condition As tcoCO tcpO continually fol lows the changes in carbon dioxide and oxygen tension with only a short delay faster intervention is made possible 28 36 tcpCO vs end tidal pCO A study that compared end tidal pCO PaCO and tcoCO showed that the difference between end tidal pCO and PaCO significantly increased during one lung ventilation as one lung ventilation impairs ventilation perfusion matching The study showed that tcoCO reflected PaCO better than end tidal pCO 37 In infants with cardiopulmonary disease end tidal pCO has been shown to have a poor correlation with arterial values and should therefore not be used These patients are according to several studies more effectively monitored by tcoCO 37 38 39 Note In patients with Patent Ductus Arteriosus and right to left shunt tcpO will be higher on the upper part of the thorax than on the lower part In these patients the sensor should be placed on the lower back or abdomen or on the thigh Futhermore arterial blood samples for validation should always be drawn from the same side of the shunt as the tcoCO value is being measured 40 41 High Frequency Oscillatory Ventilation HFOV Since only the pro
67. r ring just enough to slightly wet it Remove the sensor from the calibration chamber and insert it into the retainer ring of the clip Press slightly until it snaps in Twist the sensor into the best position Make sure that the sensor cable is loose and will not be stretched during monitoring Route the sensor cable properly to avoid strangulation To ensure prober fixation of the sensor twist the sensor carefully a quarter of a turn Calibration When to calibrate Radiometer recommends performing a calibration on the TCM4 40 monitors e prior to each monitoring period e when changing measuring sites e every 4 hours TCM4 40 or every 8 12 hours TCM TOSCA CombiM e every time an sensor has been remembraned After a membrane change and after the TC monitor is switched on it is recommended to calibrate the sensor twice with a 30 minute break between the two calibrations before a new measurement This will minimize the sensor drift In vivo calibration In vivo calibration is an adjustment of the initial tcoCO tcpO values to the initial arterial blood gas values This is done by moving the shown TC values up or down to the initial meas ured PaO CO levels In order to perform an in vivo calibra tion it must be selected in the setup Draw an arterial blood gas sample at the beginning of a stable TC monitoring period and press the blood gas button When the sample has been analyzed on a blood gas analyz
68. receive oxygen therapy A combined tcoCO SpO measurement has shown to be useful in clinical settings of non invasive positive pressure ventilation where end tidal pCO measurement and clinical assessment can be difficult In Fig 9 an example of monitoring of a COPD patient is shown 76 80 ntact we a ak 2L min 15U min 100 O 37 0 gt 62 100 140 oi ra 120 6 0 j Aa hg ees i SLF a m 9 8 Sad z p S u 58 96 to o h the a 80 7 3 O Nn Q Q 5 gt 56 ail PAA 94 Nn 60 amp Maw N l min 40 92 O p Pulse Rate FIG 9 COPD patient during high flow oxygen in sufflation A COPD patient monitored by continuous tcoCO SpO and pulse rate during delivery of a transtracheal high flow oxygen insufflation The ventilation was measured by means of a respiratory inductive plethysmograph Vt change of lung volume 81 Ventilator manipulation according to tcpCO A study found tcoCO measurements was appropriate for es timating the ventilatory response to Non Invasive Ventilation NIV in patients with hypercapnic ventilatory failure due to acute exacerbation of chronic obstructive pulmonary disease AECOPD 61 Nocturnal oxygen desaturation in patients with COPD Nearly 80 of patients with severe chronic COPD experience nocturnal oxygen desaturation due to hypoventilation The consequence is an increased arterial carbon dioxide tension and it may result in nocturnal and daytime
69. ring during one lung ventila tion End tidal versus transcutaneous techniques Journal of Cardiothoracic and Vascular Anesthesia 2003 17 3 306 08 Oshibuchi M Cho S Hara T et a A comparative evaluation of transcutane ous and end tidal measurements of CO in thoracic anesthesia Anesth analg 2003 97 776 79 Wallach SG Cannulation injury of the radial artery Diagnosis and treatment algorithm Critical care techniques American Journal of Critical Care 2004 7 1 Dar K Williams T Aitken R et a Arterial versus capillary sampling for analy sis blood gas pressures BMJ 1995 310 24 25 Hamilton AM The importance of trained staff in pulse oximetry AARC Times 2005 29 12 39 43 Marik PE Regional carbon dioxide monitoring to assess the adequacy of tissue perfusion Curr Opin Crit Care 2005 11 245 51 Blanchette T Dziodzio J Transcutaneous pCO and end tidal pCO in venti lated adult Respiratory Care 1992 92 3 204 47 Bhende MS End tidal carbon dioxide monitoring in pediatrics Concepts and technology J Postgrad Med 2001 46 153 56 Hiller SC Schamberger MS Editorial Transcutaneous and end tidal carbon dioxide analysis Complimentary monitoring strategies Journal of Intensive Care Medicine 2005 20 5 307 09 Choice of sensor site and temperature SENSOR SITE SENSOR TEMPERATURE Neonatal Pediatric Below Above 2000 g 2000 g 1 3 years 3 16 years Forehead cheak Ear lobe Neck Chest
70. s Patients with advanced cystic fibrosis may develop hypoxia and hypercapnia during sleep particularly during REM sleep Elevated evening levels of PaCO were found to be associated with both sleep related desaturation and the rise in tcpCO in periods of NREM to REM sleep in these patients 88 Patients undergoing long term non invasive ventilation Long term nocturnal non invasive ventilation improves day time symptoms of hypoventilation sleep quality and respira tory failure even when patients are not on ventilatory support tcoCO monitoring is an important tool to evaluate effective ness of treatment and adjust ventilator settings 89 Leaks in ventilation As mentioned in the section on pulmonary medicine patients On noninvasive positive pressure ventilation often have leaks from the mask or through the mouth This may disturb the Sleep architecture The associated increases in the carbon di oxide level can be detected by tcoCO monitoring 82 76 77 78 81 82 86 88 89 Rowley D Walsh BK Young BS et a Evaluation of a new digital transcuta neous tcoCO amp SpO combination sensor and its correlation to ABG PaCO AARC 51st International Respiratory Congress Program from the open forum no 1 2005 OF 05 106 69 Chaouat A Weiltzenblum E Krieger J et a Association of chronic obstruc tive pulmonary disease and sleep apnea syndrome Am J Respir Crit Care Med 1995 151 1 82 86 O Do
71. sthma in the US increased more than 160 in children under 5 years of age and a total of more than 9 million US children under 18 have been diag nosed with the disease 1998 In these patients a challenge test of the lung function may be necessary 54 55 Lung function measurements A 20 fall in tcoO can be used as the only indicator for a bronchial reaction during a histamine bronchial provocation test In awake young children Ventilation changes evaluated by tcoCO measurements makes it possible to distinguish be tween a fall in oxygen tension due to an early false reaction as aresult of hypoventilation and a true bronchial reaction 56 A study on lung function measurements in awake 2 to 6 year old children has documented that lung function can be as sessed by transcutaneous measurements forced oscillation technique Rrs5 whole body plethysmography sRaw res piratory reactance Xrs5 and interrupter technique Rint All these techniques provide reliable tools for monitoring the re sponse during bronchial challenge test with pharmacological agents The reproducibility of the measurements and the sen sitivity in detecting changes in the airway function are good and favorable compared with standard techniques like the forced expiratory maneuver FEV in small children Small children do not have the ability to perfome the FEV manoeu vre correctly 57 58 Rrs5 Respiratory resistance measured
72. stic and thera peutic interventions as evidenced by tcoCO and tcpO values The guidelines point out that tcoCO tcpO is appropriate for continuous and prolonged monitoring e g during mechanical ventilation continuous positive airway pressure C PAP and supplemental oxygen administration Furthermore tcpO can be used for diagnostic purposes as in the assessment of func tional shunts e g in neonates with persistent pulmonary hy pertension or persistent fetal circulation or to determine the response to oxygen challenge in the assessment of congenital heart disease 41 44 Please note that during ventilation studies the sensor site and an arterial sampling site in patients with functional shunts should be on the same side of the shunt 41 44 Transcutaneous blood gas monitoring should be applied continu ously to develop trending data So called spot checks intermit tent short measuring periods are not appropriate 41 44 Conclusion To sum up transcutaneous carbon dioxide and oxygen tension monitoring should be applied in neonates whenever there is a risk of sudden changes in carbon dioxide or oxygen status for example in the following conditions Asphyxia germinal layer hemorrhage meningitis or head trauma Respiratory Distress Syndrome RDS Persistent pulmonary hypertension or pneumothorax During surfactant treatment During treatment with various forms of assisted ventila tion positive pressure ventilat
73. symptoms of res piratory failure cor pulmonale etc These patients might ben efit from tcoCO monitoring during the night when started on oxygen therapy Continuous non invasive assessment of carbon dioxide ten sion is crucial in the sleep lab for diagnosis and treatment of patients with severe COPD A study has shown a strong cor relation between daytime levels of PaCO and the severity of hypoventilation during the night i e high daytime levels of carbon dioxide are more likely to lead to hypercapnia during the following night A similar relationship between night and daytime hypoventilation was seen in a randomized controlled multicenter trial where many patients hypercapnia was de tected by a tcoCO measurement This study documents that stable COPD patients daytime PaCO levels can be improved by tcoCO based adjustments of the nocturnal non invasive ventilation An example of a patient measurement from this Study is shown in figure 10 67 78 82 a REM s D O Sleep stage UJ b kPa 9 31 7 98 j ae 6 65 Joos ari i 5 32 f 3 99 2 66 1 33 0 200 400 600 800 1000 FIG 10 A nocturnal patient measurement a Sample hypnogram showing the patients stage of sleep b Nocturnal tc oCO recordings Note the correlation between an elevated tcoCO and REM rapid eye movement sleep The time is indicated on the x axis in periods of 30 sec duration The closed arrow shows episode 55 tcoCO 6 61 kPa
74. t units pressure pressure mm mercury en html Janssens JP Perrin E Bennani I et al Is continuous transcutaneous monitor ing of pCO tcoCO over 8 h reliable in adults Respiratory Medicine 2001 95 Cuvelier A Grigoriu B Molano LC Muri J F et al Limitations of transcutane ous carbon dioxide measurements for assessing long term mechanical ventilation Chest 2005 127 1744 48 Cleaning Cleaning Wipe the following parts gently with a soft cloth moistened with skin antiseptic e g 70 alcohol e sensor head e cable Note Use of hand lotion containing isopropanol propy lalcohol and alcohol prior to handling the sensor may dam age the cable To avoid transferring lotion to the cable dry your hands before handling the sensor Cleaning the exterior When cleaning the monitor e Shut down the monitor e Use a cloth that has been lightly dampened with soapy water or a mild detergent e Do not use abrasive cleansers or pads the finish may be come damaged e Do not use ethanol based substances or aggressive deter gents Extensive use may cause the plastic to become brit tle and cracks may occur Cleaning the touch screen A dry or lightly dampened soft lint free cloth may be used to clean the monitor s touch screen Simply wipe the screen gently to remove fingerprints and or dirt To avoid streaking on the screen an approved screen cleaner is recommended Disinfection Immerse the sensor and the cable in a 2 3 aq
75. th a finger e Runa finger around the rim circumference Note It is important to press firmly to avoid introduction of atmospheric air under the fixation ring Because of the difference between physiological tcoO and tcoCO and atmospheric concentrations of 20 93 O and 0 03 CO the tcoO tcoCO values are easy to differentiate 7 Fill the well in the fixation ring with 3 5 drops of the contact liquid or one drop of contact gel 8 Affix the sensor into the fixation ring by aligning the ar row on the sensor with one of the marks on the fixation ring Turn the sensor 90 clockwise to fasten it in the fixation ring E5250 E5480 or click in the sensor 54 TOSCA92 Wait for a stable reading after the sensor has been affixed to the patient By choosing SmartHeat on the TCM4 40 monitors the physi ological stabilization time will fall to 5 16 minutes for the tcpO and to 3 6 minutes for the tcoCO At sea level and at a pressure of 1 atmosphere How to place the ear clips and earlobe sensors 1 Clean the ear lobe with alcohol swab Alcohol 2 Take an attachment clip and remove the white cover 3 Attach the clip to the fleshy part of the ear lobe with the retainer ring pointing outwards Squeeze gently to ensure that the adhesive area sticks firmly to the ear lobe Make sure that no air is under the adhesive area Apply two drops of contact gel to the visible skin area in the center of the retaine
76. the monitor and then press the D button on the front of the monitor Press the ch button on the front of the moni tor Then press OK on the screen Note If the power switch on the rear is ON the battery will be recharged when needed Insert the sensor in the calibration chamber and press Calibrate Note Make sure the sensor Is placed cor rectly in the chamber and that the arm is positioned horizontally across the sensor The SmartCal function makes sure the moni tor is always ready for monitoring by calibrat ing when needed To be continued page 72 SmartHeat Follow these steps to enable disable SmartCal 1 Press Setup Calibration SmartCal 2 Use the blue arrow key to select the SmartCal ON OFF option 3 Use the black arrow keys to set the option to ON or OFF 4 Use the blue arrow key to select the SmartCal duration option 5 Use the black arrow keys to select the duration of the SmartCal period 6 Press OK Note Although the option is enabled it is necessary to press Calibrate to start a new SmartCal period Note If SmartCal is not activated the monitor is calibrated manually by pressing Calibrate The SmartHeat TCM4 40 function increases the sensor temperature by 1 C 1 8 F NB max temp 45 C in a period of five minutes after the sensor has been removed from the calibra tion chamber As a result the tcoO tcoCO values can be read within 8 12 minutes after
77. tly higher partial pressures mmHg for a longer period of time may be dangerous Therefore it is important to monitor carbon diox ide levels 28 31 32 33 Reducing the number of blood samples Analysis of arterial blood samples provides accurate estimates of blood gases However they provide a momentary picture of the status only Repeated sampling may not only disturb and stress the neonate it may also cause the need for a blood transfusion A significant change in cerebral circulation and thereby oxygenation is documented in relation to sampling from umbilical artery catheters The number of blood samples should therefore be reduced to an absolute minimum and be combined with transcutaneous monitoring of carbon dioxide and oxygen The TC technique provides continuous informa tion on the neonate s ability to supply oxygen to the tissue and remove carbon dioxide in the tissue via the cardiopulmonary system The TC technique follows the trend and changes of these gases 28 34 Hypocapnia and lung damage Hyperventilation results in hypocapnia Low pCO before sur factant treatment as well as during ventilation treatment has shown to correlate with the development of chronic lung dis ease in the preterm infant In the ventilated preterm infant it is therefore recommended to monitor pCO continuously to minimize the risk of lung damage 28 35 Ventilation Ventilation may cause a pneumothorax and an early diagnosis is likely to im
78. ueous solution of active dialdehydes Warning Do not immerse the sensor plug in the disinfec tion solution as this will cause the sensor to fail Warning Do not heat sterilize as the sensor cannot toler ate temperatures exceeding 70 C 158 F as this will cause the sensor to fail Maintenance of the sensors Manufacturer s recommendation for the sensor For optimum measurements with the E5250 O E5260 CO E5280 O CO and E5480 neo O CO sensors a weekly change of the sensor membrane is recommended The TC sensor 54 CO TC sensor 84 O CO3 and TOSCA sensor 92 CO SpO must be remembraned every 14 days Changing the membrane on the E5250 80 sensors 1 Remove the old O rings Slide the O ring remover under the O ring just above the arrow on the sensor house 2 Turn the O ring remover clockwise and counter clockwise to release the two O rings It is easiest when the sensor is supported against a table However in one study the authors write that by more frequent membrane change i e after a maximum of two continuous 8 hour recordings or when the calibra tion process is unusually long the agreement between PaCO and tcoCO values increases even more 27 Peel off the old membrane Note that there are two membranes if it is a com bined tcpCO O sensor Clean the sensor surface Absorb the old electrolyte solution with the cleaning paper in the groove Rub the sensor m
79. umented that vasoactive substances like dopamine tolazoline isoproterenol nitroprus side aminophylline hydralazine epinephrine dobutamine phenylephrine and norepinephrine did not affect tcoCO tcoO measurements 20 21 22 23 In a coexisting study that confirms that the above mentioned catecholamines did not affect TC measurements the authors conclude However in cases with profound skin vasocon striction or shock the correlation between tcpCO and PaCO is low In these situations low tcpO may be the first warn ing of a developing hypotensive shock 22 24 25 Smoking and chewing nicotine gum have been observed to decrease the tcoO value for up to 50 minutes while tcoCO remained unaffected 26 Skin temperature A relatively large tcoCO to PaCO bias has been observed un der hypothermic conditions defined as patients with a rectal temperature lower than 36 C 97 F 24 Body mass index Some studies suspect that skin thickness in severely obese adults affect the permeability for carbon dioxide diffusion and the vasodilatation of the underlying capillaries from the heat ing element in the TC sensor However several studies have confirmed that tcoCO is not influenced by body mass index on the contrary ttoCO has been reported to be the same in both obese and lean individuals 21 22 27 Pigmentation tcoCO tcoO measurement is based on an electrochemical measurement of carbon dioxide and oxygen
80. und together with the patient However the sensor requires heating and regular calibration the measuring site should frequently be changed and the sensor must regu larly be remembraned On the other hand TC is non invasive easy to use needs short calibration time and does not involve intubation Measurements of transcutaneous carbon dioxide during HFJV HFOV are recommended by manufacturers of these techniques And tcpCO trending can validate or limit the need for more costly and higher risk monitoring technol ogy such as arterial blood samples 4 21 102 Summary All techniques have specific advantages and disadvan tages In some patients the non invasive transcutane ous technique is the most simple and the best choice It offers relevant and continues non invasive monitoring of patients with cardio respiratory disease of any age In other segments the best way to monitor can be obtained by combining one or more techniques TC ABG SpO or end tidal pCO For example when transcutaneous carbon dioxide monitoring combined with pulse oximetry enhance intermittent invasive arterial blood gas samples All in all these four techniques complement rather than exclude each other in reaching the important goal of Optimizing patient s ventilatory and respiratory status 19 21 27 36 40 46 64 68 69 96 97 98 99 100 101 102 Hill KM Klein DG Transcutaneous carbon dioxide mon
81. untreated these patients suffer from excessive daytime sleepiness and impaired cognitive performance There is also an increased risk of causing traffic accidents and suffering from cardiovascular diseases Continuous non invasive monitoring of the SpO lev els and trends have proven to be crucial in the sleep laboratory for diagnosis and treatment of these patients Correspond ingly tcoCO monitoring is useful to detect hypoventilation 76 77 78 Episodes of hypoventilation In order to avoid potentially dangerous hypoventilation or suboptimum nocturnal ventilatory assistance a combined tcoCO SpO measurement is useful in clinical settings using non invasive positive pressure ventilation Episodes of hy poventilation lasting as little as 30 seconds were detectable by the tcoCO monitoring 76 78 22 00 23 00 00 00 1 00 2 00 3 00 4 00 5 00 6 00 100 spO 75 p 50 f tcoCO SAP mmHg 48 a j 44 i 120 Pulse Rate bpm tad kibia 22 00 23 00 00 00 1 00 2 00 3 00 4 00 5 00 6 00 FIG 11 Nocturnal recording An example of nocturnal recording in a patient with obesity hypoventilation and sleep apnea syndrome Recordings were done between 6 pm and 6 am with a combined tcoCO SpO earlobe sensor The arrows illustrate how well SpO tcoCO and the pulse rate reflects events of hypoventilation and resump tion of normal ventilation respectively 81 Cystic fibrosi
82. will affect the measurements On larger animals like pigs some authors recommend that the relevant skin area Is carefully rubbed with sand paper to prepare the skin for the measurement after the hair has been removed 90 tcpCO PaCO correlation in mice and rats A linear relationship between tcoCO and PaCO was seen in mice and different races of rat 91 Skin viability in dogs A study concludes that transcutaneous oxygen is useful for assessing skin viability in dogs 92 Hemorrhagic shock in pigs Twelve week old pigs were used for evaluating the severity of hemorrhagic shock Together with measuring pH in the intramu cosal wall transcutaneous monitoring of oxygen indicated blood volume loss more rapidly than for example cardiac output 90 Not all animal studies show good results Some animal studies have shown suboptimum results This may be due to improper preparation of the animal s skin or limitations of the TC technique It is therefore recommended to conduct a validation of the measurements before new kinds of animal studies or clinical uses are initiated Experimental use of the TC technique Experimental use of the TC technique sometimes requires new ways of thinking An example of this is an unpublished case story based on TC intestinal oxygen measurement in a horse undergoing ileus surgery As the intestine is wet and moving it is impossible to use fixation rings for attaching the sensor during surgery The vet
83. ximal airway pressure is monitored during high frequency oscillatory ventilation HFOV no alarm will oc cur if there are either an obstruction or restriction of the airway The technique also induces a risk of hyperventilation resulting in hypocapnia Therefore many manufacturers of HFOV recom mend continuous measurements of tcpCO tcoO and SpO during this form of treatment This is particularly important in larger children who have more dead space and a greater meta bolic demand when on ventilation 42 Hyperoxia in infants In newborn preterm infants hyperoxia reduces cerebral blood flow for hours after oxygen status has normalized At the same time hyperoxia has a toxic effect on the lungs and may possibly cause retinopathy in preterm infants Monitor ing tcoO provides a method of early detection of hyperoxia which may not be detected by transcutaneous SpO measure ment 28 43 29 Clinical guidelines on TC measurements The relevance of transcutaneous monitoring is substantiated by the American Association for Respiratory Care AARC guidelines and the National Clearinghouse Guidelines US AARC guidelines and National Clearinghouse Guideline US According to the AARC practice guidelines transcutaneous blood gas monitoring of neonatal and pediatric patients should be used if there is a e need to monitor the adequacy of arterial oxygenation and or ventilation and or e need to quantitate the response to diagno
84. xygenation in very low birthweight infants Acta Paediatr 2000 89 862 66 Garland JS Buck RK Allred EN et al Hypocarbia before surfactant therapy appears to increase bronchopulmonary dysplasia risk in infants with respira tory distress syndrome Arch Pediatr Adolesc Med 1995 149 6 617 22 McIntosh N Becher JC Cunningham S et al Clinical diagnosis of pneumo thorax is late Use of trend data and decision support might allow preclinical detection Pediatr Res 2000 48 3 408 15 Wilson J Russo P Russo JA et al Noninvasive monitoring of carbon dioxide in infants and children with congenital heart disease End tidal versus trans cutaneous techniques J Intensive Care Med 2005 20 5 291 95 Short JA Paris ST Booker PD et a Arterial to end tidal carbon dioxide ten sion difference in children with congenital heart disease Br J Anaesth 2001 86 3 349 53 Carter BG Wiwcazaruk D Hochmann M et a Performance of transcuta neous PCO and pulse oximetry monitors in newborns and infants after cardiac surgery Anaesth Intensive Care 2001 29 260 65 Poets CF Pulse oximetry vs transcutaneous monitoring in neonates Practi cal aspects www bloodgas org 2003 October Neonatology Sitting SE AARC clinical practice guideline transcutaneous blood gas monitoring for neonatal amp pediatric patients 2004 revision amp update Respiratory Care 2004 Sep 49 9 1069 72 User s manual for SensorMedics Critical Care Clinical Gu
85. y the transcutaneous route Paediatric Pulmonology 2003 35 274 79 Nosovitch MA Johnson JO Tobias JD Noninvasive intraoperative monitoring of carbon dioxide in children endtidal versus transcutaneous techniques Paediatric anaesthesia 2002 12 48 52 Simonds AK Ward S Heather S et a Outcome of paediatric domiciliary mask ventilation in neuromuscular and skeletal disease Eur Respir J 2000 16 476 81 Berkenbosh JW Tobias JD Transcutaneous carbon dioxide monitoring dur ing high frequency oscillatory ventilation in infants and children Crit Care Med 2002 30 5 1024 27 Nielsen LM Halgrener J Hansen BVL Respiratorisk syncytialvirus infektioner hos b rn i almen praksis Ugeskrift for l ger Videnskab og praksis 2003 165 27 2747 49 Hall CB Respiratory syncytial virus and parainfluenza virus N Engl J Med 2001 344 1927 28 Gaultier C Praud JP Cl ment A et al Respiration during sleep in children with COPD Chest 1985 87 2 168 73 Morielli A Desjardins D Brouillette RT Transcutaneous and end tidal carbon dioxide pressures should be measured during pediatric polysomnography Am Rev Respir Dis 1993 148 6 1599 1604 Tobias JD Meyer DJ Noninvasive monitoring of carbon dioxide during respiratory failure in toddlers and infants End tidal versus transcutaneous carbon dioxide Anesth Analg 1997 85 55 58 Center for Disease Control Surveillance for Asthma US 1960 1995 MMWR 1998 SS 1 http Avwww AAAAI or

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