Home

1 Know the flow… © Copyright 2006-2011. Hemedex, Inc. All Rights

1. GRAYOUT A fully developed thermal field in the interrogation volume provides the highest level of accuracy in the perfusion calculation Before this field is fully developed the perfusion value as presented in the top left corner of the screen blinks This two minute blinking period is referred to as grayout The noted number is approaching that which will be presented when the thermal field is fully developed and it can be used as a stat value After the grayout period perfusion values are graphed on the screen and the numeric value no longer flashes OVERVIEW MENU Some of features discussed previously are grouped in the Overview Menu which is accessed from the Options Level 1 menu All other features not found in Overview Menu occur automatically in the phases of the Bowman Perfusion Monitor 11 Know the flow SECTION 4 MEASUREMENT CYCLE The BPM measurement cycle has three phases temperature stabilization calibration and perfusion measurement These transitions happen automatically It takes 2 7 minutes on average for the monitor to go through the temperature stabilization and calibration phases During these two phases no perfusion measurement will be taken Recalibration happens automatically at the end of the preset perfusion measurement time The message line at the top of the screen will indicate which phase of the measurement cycle the monitor is in Phases of the Measurement Cycle Temperature S
2. The data are properly interpreted The following sections should aid in this process AUDIENCE This guide is intended for use by anyone involved in the care of neurosurgery patients who are being monitored with the Bowman Perfusion Monitor Basic knowledge of neuroanatomy and procedures is assumed BACKGROUND Hemedex has developed thermal diffusion technology that continuously and accurately measures real time absolute blood flow in soft tissue The Bowman Perfusion Monitor BPM system consists of a patient monitor an umbilical cord and a minimally invasive flexible microprobe measuring 1 mm in diameter The following is a brief overview of how the BPM system uses thermal diffusion technology to quantify perfusion The probe is inserted into the target tissue approximately 25 mm below the dura The surface of the sensor at the tip of the probe is heated a small increment above the tissue baseline temperature while a second sensor 8 mm proximal to the sensor at the tip monitors and compensates for baseline tissue temperature changes The total heat transfer from the probe into the tissue consists of a thermal conduction component represented by the K value and the thermal convection component which is related to tissue blood flow Through multiple complex algorithms and the information from the sensors the BPM determines the K value and quantifies the absolute blood flow in the spherical volume of tissue interrogated by the sensor a
3. As perfusion is rather steady Fig 35 middle the increase in K is not a consequence of increased vascular volume but likely due to extra vascular water edema Middle demonstrates the value of probe placement in non pulsatile brain capillary bed The insert illustrates an extreme case that contrasts high PPA versus zero PPA perfusion data Low PPA perfusion data is characterized by a high degree of reproducibility high PPA perfusion data can be erratic Bottom is a record of the brain temperature through out the monitoring period This patient was cooled to approximately 34 8 C At approximately 10 00 on 2 15 the patient was re warmed The steady perfusion values during the 2 hour re warming period demonstrates the ability of the BPM to accurately track perfusion through large temperature changes The inset captures the last 3 high PPA 10 and the first 6 zero PPA perfusion runs of 2 13 after the probe was repositioned to avoid the artifact in k thus perfusion associated with the higher PPA s 47 Know the flow CBF CASE HIGH FEVER AND PERFUISON MONITORING The Bowman Perfusion Monitor automatically suspends perfusion measurement when the tissue temperature reaches 39 5 C or above Perfusion measurements is automatically resumed when the tissue temperature drops below this level The device is designed to operate in this manner because of regulations that tissue is not to be heated above 41 C The probe heats the tissue a
4. BPM NEUROMONITORING GUIDE BOWMAN PERFUSION SYSTEM BOWMAN PERFUSION MONITOR BPM QELOW 500 PROBE QFLOW 500 UMBILICAL CORD J HEMEDEX fA Copyright 2006 2011 Hemedex Inc All Rights Reserved H E M D EX a ooo pad HEMEDEX TABLE OF CONTENTS INTRODUCTION BOWMAN PERFUSION MONITOR SECTION 1 BOWMAN PERFUSION SYSTEM GENERAL OVERVIEW SECTION 2 MONITOR SET UP SECTION 3 MONITOR DISPLAY SCREEN DESCRIPTION OF FEATURES SECTION 4 MEASUREMENT CYCLE SECTION 5 USER INTERFACE MENU PROBE PLACEMENT IN THE INTENSIVE CARE UNIT SECTION 1 BEDSIDE ICU PROBE INSERTION INDICATIONS AND PROBER INSERTION SITE SELECTION SECTION 2 PROBE INSERTION AND FIXATION PROTOCOL WITH BOLT SECTION 3 PROBE INSERTION AND FIXATION PROTOCOL WITH TUNNELING SECTION 4 CONFIRM READING SECTION 5 POTENTIAL SOURCES OF INTERFERENCE PROBE PLACEMENT IN THE OPERATING ROOM SECTION 1 INTRA OPERATIVE PROBE INSERTION AND PROBE INSERTION SITE SELECTION SECTION 2 INSERTION THROUGH A BURR HOLE ADJACENT TO THE CRANIOTOMY SECTION 3 INSERTION THROUGH THE CRANIOTOMY SECTION 4 CONFIRM PROBE PLACEMENT ASSISTANT PPA AND K VALUES SECTION 5 POTENTIAL SOURCE OF INTERFERENCE PROBE INSERTION CASES SECTION 1 CORRECT PROBE INSERTION INTO THE ACA VASCULAR TERRITORY SECTION 2 MISPLACEMENT OF THE PROBE SUB EPIDURAL SECTION 3 MISPLACEMENT OF THE PROBE INTO THE LATERAL VENTRICLE SECTION 4 MISPLACEMENT OF THE PROBE TOO DEEP
5. CEREBRAL BLOOD FLOW MEASUREMENT CASES NORMAL FLOW IN WHITE MATTER PROBE REPOSITIONING FROM GRAY TO WHITE VASOSPASM EARLY DETECTION MATTER TREATMENT EFFICACY PAPAVERINE CARDIAC INDUCED BRAIN VESSEL PULSATIONS TREATMENT EFFICACY NIMODIPINE FEVER AND PERFUSION MONITORING EC IC BYPASS SURGERY PROBE IN INFARCTED TISSUE ANEURYSM REPAIR SURGERY TAO IMPAIRED AUTOREGULATION CBF RESPONSE TO CO2 REACTIVITY CHALLENGE BRAIN COOLING PERFUSION ARTIFACT CHANGE IN LOCAL PERFUSION WAVEFORM STATUS EPILEPTICUS THERMAL GRADIENT INDUCED HYPEREMIA PERFUSION ARTIFACT PROBE TISSUE PERFUSION WAVEFORMS PERIODIC CORTICAL MOVEMENT SPREADING DEPRESSION CSD FREQUENTLY ASKED QUESTIONS FAQ TROUBLESHOOTING GUIDE REFERENCE INTRODUCTION PURPOSE The purpose of this guide is to aid in the placement and fixation of the QFlow 500 Perfusion Probes in neurosurgery cases and to help interpret the data recorded by the Bowman Perfusion Monitor This BPM Neuromonitoring Guide provides a general technical overview and is not intended to replace the User Manual or IFUs for individual products For detailed information please refer to the User Manual of the Bowman Perfusion Monitor and IFU for the QFlow 500 Perfusion Probe The successful use of the Bowman Perfusion Monitor requires that The probe is inserted at the appropriate site and to the appropriate depth for the given indication The probe is kept fixed at this location
6. available on the Hemedex website for instructions on uploading collected data that you would like to preserve and then deleting that data from the BPM c Check the time in the lower right hand corner of the BPM display screen to insure that it is synchronized with your main time source 59 Know the flow TROUBLESHOOTING GUIDE Measurement Cycle CBF Measurement Measurement Cycle Temperature Stabilization Know the flow Message Error CBF gt 50ml min 100g CBF lt 10ml min 100g CBF varies 10ml min 100g with respiration rate and or heart rate CBF varies 10 ml min 100g over minute s CBF artifact Message Error Temperature not yet stable monitor is retrying x XXxx Temp gradient too high for perfusion measurement x xxx Paitent temp too high for perfusion measurement x XXXXX X XXX Possible Causes Probe may be in gray or mixed gray white matter Patient may be hyperemic Patient may be in vasospasm Probe may be in infarcted tissue Probe may be too deep Probe may be in the ventricle Probe may be epidural Slow variations may be due to impaired autoregulation Changes in temperature gradient between tissue calibrations Possible Causes Tissue temperature changing at rate greater than stability criteria Probe not deep enough Damp umbilical to probe connection Probe not deep enough Probe is epidural Damp umbilical to probe connection Fe
7. back to the temperature stabilization measurement phase CYCLE REPETITION All BPM measurement phase transitions are made automatically Under normal conditions the length of time the monitor operates in each phase will be dependent on the settings the user has selected perfusion measurements may be set for 2 minutes to 2 hours However the BPM automatically monitors the measurement conditions and may restart the measurement cycle to insure robust data For example if probe motion is detected the monitor will truncate a perfusion measurement phase and return to temperature stabilization Similarly if tissue parameters calculated during the calibration stage are outside of the acceptable range the BPM will return to the temperature stabilization phase and try the measurement again Perfusion is measured using thermal dilution so stable temperatures are critical If the tissue temperature is not sufficiently stable or is elevated such that perfusion measurements cannot be made without exceeding the regulatory limits set for heating tissue the monitor will remain in the temperature stabilization phase indefinitely As soon as thermal conditions allow the BPM will automatically transition to the calibration phase to continue perfusion measurements To manually set the Re Calibration time interval begin at the START MENU then use arrow keys to adjust time parameters and press OK to allow the monitor to close out the dialogue box This means
8. Based on neurosurgeon preference the intra operative placement of the probe through a burr hole may not be desirable In this case the probe may still be placed through an open craniotomy However extra care must be taken to position the probe at the edge of the craniotomy away from the main surgery site to minimize artifact from retraction irrigation and mechanical interference In the event that post operative monitoring is desired it is best to forward tunnel the probe Also make sure to insert the probe through the site of one of the burr holes that was used to create the craniotomy In this way when the bone flap is put back in place there will be an opening for the probe shaft to exit The procedural steps for the probe placement through a craniotomy with tunneling are as follows 1 Create Tunnel Use a 14 gauge Tuohy needle to tunnel the probe under the scalp by inserting the needle from the edge of the craniotomy under the scalp to exit at the The needle cannot slide over the desired location approximately 6 cm away Remove any trocar that may be in the needle lumen Pass the probe tip through the lumen in the distal end of the Tuohy needle and advance the probe tip toward the craniotomy While holding the probe in place slide the Tuohy needle out from under the scalp and discard 2 Insert Probe Using the blue centimeter markings on the probe shaft as a guide insert the probe to a depth of 25 mm below the level
9. Change Verifier and what does it do Are there times it should not be used The Perfusion Change Verifier is a user selectable feature designed to provide greater data integrity This feature will automatically recalibrate if the perfusion value increases by 7 5 ml 100g min or decreases by 5 ml 100g min within one perfusion measurement cycle This recalibration is to verify that the perfusion change is either real or induced by a change in tissue thermal conditions primarily the tissue temperature gradient between the two sensors When the PCV feature is enabled recalibration is automatic I am interested in performing Perfusion Challenges Is there anything I should be aware of before I do them a Check the time remaining in the perfusion measurement period This is indicated in the status bar at the top of the screen Make sure there is a sufficient amount of time remaining to complete the challenge before the next recalibration period If you don t have enough time you can extend the perfusion period mid cycle It is good practice to manually calibrate at the end of one challenge before starting the next one b Perfusion Change Verifier PCV should be turned off for challenges When you have completed the challenge turn PCV on again for unattended monitoring What routine checks should make at the start of patient monitoring a Before you connect a new probe check the available data storage space in days b See the user manual
10. ES C yt 10 Know the flow PROBE PLACEMENT ASSISTANT PPA The Probe Placement Assistant PPA is a feature to aid in optimal placement of the perfusion probe The Probe Placement Assistant PPA gives a measure of the quality of the placement of the probe and therefore the perfusion measurement PPA is expressed as a number ranging from O to 10 and indicates the relative level of pulsatile signal present in the calibration data A value of 0 0 indicates ideal measurement conditions A value greater than 5 indicates that the level of artifact in the measurement may be unacceptable The BPM will not provide perfusion values when the PPA is 5 0 or above If such is the case the status bar at the top of the monitor display will instruct the user to reposition the probe Meanwhile the monitor will continue to check for an acceptable PPA To better assist the user the PPA displays via color and numeric indicators Green less than 2 indicates good placement Aa TO 4 9 TREND MODE In Trend Mode the monitor is configured to provide short snapshots of perfusion 2 minutes in length approximately every 15 minutes Trend Mode forces frequent in situ calibration and thus minimizes the effects of changes in the thermal gradient and in hydration levels during the measurement It presents the user with maximum frequency of independent perfusion measurements The factory default setting for Trend Mode is off
11. Note that the recalibration and the subsequent CBF values displayed after 03 20 show that CBF was most likely steady the entire time from 03 00 to 03 20 25 PROBE MOVEMENT Probe motion causes an artifact in the measurement with an apparent and characteristic spike upward in perfusion measurement This is caused by the fact that the distal sensor must rapidly re establish the thermal field in the tissue at the site where the sensor has been translated to If the perfusion measurement does not return to the pre motion level the monitor will automatically recalibrate These spikes are examples of micromovements that are sometimes the result of patient seizures They can also be caused by small tugs on an unsecured umbilical cord A number of these micro movements can cumulatively result in the probe moving from white or gray matter or even being moved to the extent that the proximal sensor is not deep enough in the tissue to get reliable readings It is good practice to record the initial position of the probe using the cm reference markers to know if it was inadvertently moved For small motion the CBF value returns to its level prior to the motion In the event that the CBF does not return to its pre motion level the BPM will automatically recalibrate Menu Scroll Data Continuous Mode Alarms A Temp C 4 ni l l Temp C 3 Clips are provided with the K PPA umbilical cord to secure it so the NoLabel bp 14 51 30 1
12. Set Label menu 2 The date of the first use of the probe in the patient The probe is approved for single patient use 3 The time of the first use of the probe in the patient 14 Know the flow VIEW 1 DATA Press Set Time Range and us up and down arrow buttons to select the time range of horizontal axis He default value is 15 minutes Use left and right arrow buttons to scroll the data Press OK to allow the time range dialog box to close and the plots on the display screen adjust to reflect the time range of the user s choice 2 Press Scroll Time and use arrow buttons to select which portion of the data you want to display 3 Press Set Perfusion Range and use arrow buttons to adjust the upper extend of the perfusion plot shown on the display screen Press Autoscale to turn ON or OFF autoscale When autoscale is on the monitor will automatically adjust the displayed plot to allow for the highest range of perfusion detected 4 Press Select Plots amp List K to view various temperature plots and list of K values PERF Measure perfusion manually advances to the temperature stabilization phase to expedite perfusion measurement phase The function of this button toggles between Measure Perfusion and CAL Calibration manually terminates the current Calibrate depending on the phase perfusion measurement phase and initiates a new measurement cycle of temperature Stabilization calibration and perfusion measurement rf
13. blood flow In addition total power on the EEG is well synchronized with the rhythmicity index and the existence of high frequency waves in the spectrogram suggesting a seizure rhythm The authors conclude that brain multimodality monitoring is a feasible method for evaluating secondary brain injury associated with seizure activity after cardiac arrest 53 Know the flow CBF CASE PERIODIC CORTICAL SPREADING DEPRESSION CSD Depolarisations are hypothesised but have not yet been conclusively proven to be an independent predictor of poor clinical outcome CSD manifests itself as periodic waves of depressed electrical activity that spread in the cerebral cortex along with associated changes in temperature perfusion and other important tissue parameters Because of the unusual character of the slowly moving temperature waves typically a few mm min the magnitudes of the thermally derived perfusion changes may not be accurate but a pattern of recurrent stereotyped complex changes in apparent perfusion MAY indicate the presence of CSDs which is important information on the status of the patient Perfusion measurement Recalibration i Continuous Mode Eo Alarms Stop Temp C 37 759 x K 5 435 PPA No Label Calibrate view Data Options Courtesy of Dr A Strong King s 9 00 10 00 10 30 i College London UK 1737 Ad Figure 43 The data illustrate the time course of the Hemedex perfusion output in a recent patient with m
14. disconnected to prevent fluid from splashing onto the contacts of either connector If moisture does get in the connections can be dried out and monitoring resumed 7 Does the focal measurement reflect the regional blood flow The regional perfusion measurement is indicative of the flow in the vascular territory 56 Know the flow 10 11 12 13 14 15 16 What is the maximum time a QFlow 500 Probe can be left in situ The probe is indicated for 10 days implantation Are the QFlow 500 Probes reusable No the QFlow 500 Probe is a disposable single patient use item Is the QFlow 500 Probe MRI or CT compatible a The QFlow 500 Probe is CT compatible and radio opaque b The QFlow 500 Probe is not MRI compatible Besides perfusion what else does the BPM tell me a Tissue temperature i in the process of measuring perfusion the BPM measures baseline tissue temperature near the tip of the probe the proximal sensor b Tissue thermal conductivity K i the K Value when PPA is zero is a function of tissue water content and may be an indication of edema Can the BPM accommodate more than one probe The BPM is a single channel device If you want to simultaneously monitor more than one patient each with their own probe you will need additional BPMs Alternatively multiple probes could be used at alternating intervals with a single BPM Data is automatically stored to the correct file based on the prob
15. ischemia in humans Letter to the Editor Stroke 31 1195 1197 2000 P Vajkoczy H Roth P Horn T Luecke C Thom U Huebner G T Martin C Zappletal E Klar L Schilling and P Schmiedek Continuous monitoring of regional cerebral blood flow Experimental and clinical validation of a novel thermal diffusion microprobe Journal of Neurosurgery 93 265 274 2000 See the Hemedex website for an updated list 63 Know the flow wee HEMEDEX ADDRESS TELEPHONE FAX SUPPORT SALES WEBSITE Rev H44000015 Revision C 222 THIRD STREET SUITE 0123 CAMBRIDGE MA 02142 617 577 1759 866 HEMEDEX TOLL FREE 617 577 9328 617 577 1759 EXTENSION 50 617 577 1759 EXTENSION 51 WWW HEMEDEX COM
16. minimum of 1 C leaving a safety factor TH 1507 Monier 29361 3 0 5 Probe tA2A1D Start 2009 08 13 n tit 130 t r e Eam RT 4 3 44 E i 4 amp one Es aa oe eS ee CF aA WES 2200 00 00 0700 04 00 J t y i i gt s 4 amp 40 4 y z 31 i 5 20 paN i inns prta 4 5 40 J 0 A m n J 2200 00 00 O7 60 0400 4 j 7 T 7 E Y F 4 4 ani as 2 y a E i V 4 iy 4 4 7s A ad Fell 00 00 07 00 04 00 start 2009 08 15 Figure 36 The waveforms illustrate the operation of the BPM when tissue temperature exceeds 39 5 C 48 Know the flow CBF CASE PROBE IN TISSUE INFARCT The probe tip can become situated in infarcted tissue by being inserted into a pre existing infarction or being enveloped by a growing infarction Menu View Data Continuous Mode Alarms A Temp C 3 083 Temp C 36 122 K 5 644 PPA No Label Select Plots amp ListK 13 15 13 16 13 17 Return 0 13 12 13 13 anns 13 16 99 Mon Nov 14 2005 12 56 50 Mon Nov 14 2005 15 39 40 Figure 37 The BPM shows the corresponding CBF measured by this probe while it is situated in infarcted white matter tissue Note the low CBF below 10 ml min 100g though the K value is normal 5 644 Figure 38 The CT scan shows the CBF probe tip placed in infarcted tissue 49 Know the flow CBF DURING IMPAIRED AUTOREGULATION CBF i
17. of the dura into the white matter Loop 4 5 cm of probe slack in a circle around the site where the probe exits from under the scalp and secure the probe shaft with three sutures spaced evenly apart Confirm adequate placement of the probe by checking the PPA and K values Figure 14 The placement of the QFlow 500 Perfusion Probe via a craniotomy and tunneled 29 Know the flow SECTION 4 CONFIRM PROBE PLACEMENT ASSISTANT PPA AND K VALUES Confirm adequate placement of the probe by checking the PPA and K Values Connect the probe to the umbilical cord and Monitor and the measurement will automatically begin After about 3 minutes the Monitor will go into calibration and display PPA and K Values If the probe is in a location where it is affected by pulsatile motion you will receive an error message High PPA value Suggest reposition perfusion probe If you have a high PPA Value gt 5 0 move the probe 1 mm by either pulling it back or advancing it if conditions allow If you have a PPA value between 2 and 5 with a yellow background we suggest you try lt J 12a iJ VDT OQ AIN A MAS t FA vdaluc QOWT DEIOW Z SECTION 5 POTENTIAL SOURCES OF LIMITATIONS AND INTERFERENCE During intra operative procedures the measurement of perfusion may be affected by the following Thermal instability from tissue cooling via the open craniotomy Thermal instability from fluid irrigation Probe ti
18. perfusion measurement from bipolar 13 39 Tuesday Nov 1 2006 19 44 Tuesday Nov 1 2005 PROBE MOVEMENT Probe movement may be caused by retraction or by external interference with the probe shaft Linear movement of the probe along the insertion track causes a characteristic artifactual spike in the perfusion measurement This is recognized by the Monitor which then produces an error message If the motion is significant enough the monitor will automatically recalibrate Small patient seizures can sometime cause tiny probe movements that cumulatively can cause the probe to be withdrawn Noting the initial position of the probe relative to the printed cm markings can aid in noticing these subtle probe movements over time Also 31 Know the flow PROBE INSERTION CASES SECTION 1 CORRECT PROBE INSERATION INTO THE ACA VASCULAR TERRITORY The CT scan left shows that the CBF Probe is placed at the proper depth 25 mm below the dura In this case the probe is inserted into the ACA vascular territory in an SAH patient on day 1 post hemorrhage Scroll time of displayed data Perfusion p mi 100g min Figure 16 The BPM shows the white matter cerebral blood flow CBF is steady at approximately 25 ml min 100 g and the 0 K value is 5 423 normal range 4 89 to 14 00 14 05 14 10 14 15 5 98 13 44 Friday Apr 29 2005 19 47 Sunday May 1 2005 SECTION 2 MISPLACEMENT OF THE PROBE SUB EPIDURAL Th
19. where the probe was initially placed in gray matter CBF 55 to 70 ml 100g min higher K values with PPA values of 3 4 not shown At 15 00 the CBF probe was subsequently moved to white matter CBF of 20 to 35 ml 100g min lower K values with PPA values of zero not shown The higher vascular volume associated with the higher CBF in gray matter contributes to the greater thermal conductivity K as tissue thermal conductivity is a function of tissue water content The K values for both gray and white matter are within the 4 8 to 5 9 range The values of perfusion and K both before and after probe reposition are typical of probe movement from gray to white matter 45 Know the flow CBF CASE CARDIAC INDUCED BRAIN VESSEL PULSATIONS HIGH PULSATILITY HIGH PPA AND RESULT OF PURPOSEFUL REPOSITIONING Perfusion ml 100g min 5 SE a ee ee ee Tp T i 1 ie T Sense Tamp C 46 Know the flow CBF CASE CARDIAC INDUCED BRAIN VESSEL PULSATIONS HIGH PULSATILITY HIGH PPA AND RESULT OF PURPOSEFUL REPOSITIONING CONTINUED Figure 35 Top is a plot of the thermal conductivity k values calculated at the beginning of each 15 min perfusion measurement run The early runs all have PPA s of 10 The perfusion probe was repositioned on 2 13 at approximately 20 00 to a site without measureable pulsatility and thus no pulsatile induced artifact in K see the reduced value of K and the high level of reproducibility
20. 10 2367 72 2005 Clausen T Scharf A Menzel M Soukup J Holz C Rieger A Hanisch F Brath E Nemeth N Miko I Vajkoczy P Radke J Henze D Influence of moderate and profound hyperventilation on cerebral blood flow oxygenation and metabolism Brain Research Sep 3 1019 1 2 113 23 2004 P Vajkoczy P Horn C Thom E Munch and P Schmiedek Regional cerebral blood flow monitoring in the diagnosis of delayed ischemia following aneurismal subarachnoid hemorrhage Journal of Neurosurgery 98 1227 1234 2003 62 Know the flow C Thom P Vajkoczy P Horn C Bauhuf U Hubner and P Schmiedek Continuous monitoring of regional cerebral blood flow during temporary arterial occlusion in aneurysm surgery Journal of Neurosurgery 95 3 402 411 2001 P Horn P Vajkoczy C Thom E Muench L Schilling P Schmiedek Xenon induced flow activation in patients with cerebral insult who undergo xenon enhanced ct blood flow studies AJNR Am J Neuroradiol 2001 Sep 22 8 1543 9 P Horn P Vajkoczy C Thome M Quintel H Roth L Schilling P Schmiedek Effects of 30 stable xenon on regional cerebral blood flow in patients with intracranial pathology Keio Journal of Medicine 49 1 A161 163 2000 P Vajkoczy U Hubner P Horn C Bauhuf C Thome L Schilling and P Schmiedek Intrathecal sodium nitroprusside improves cerebral blood flow and oxygenation in refractory cerebral vasospasm and
21. 4 52 00 14 52 30 14 53 00 Return 13 58 01 Mon Oct 24 2005 15 45 00 Mon Oct 24 2005 18 04 08 Figure 12 The probe can migrate if it is not adequately fixed If a probe migrates it must develop a new thermal field on which to report perfusion If this new position is less than optimal e g adjacent to a pulsating vessel then the ae qe k f J i i Ar D A f P A r I N 4 A AA gt fr gt CIA fi Or OUIO DE 1 IC Orager TO CO ale p TUSION q 26 Know the flow PROBE PLACEMENT IN THE OPERATING ROOM SECTION 1 INTRA OPERATIVE PROBE INSERTION AND PROBE INSERTION SITE SELECTION Proper probe insertion requires consideration of the following The probe measures focal perfusion in a volume of approximately 0 27ml 0 3cc This focal measurement in absolute units ml 100mg min represents the cerebral blood flow delivered by the supplying vasculature to that territory Placement should be made into the tissue or vascular territory of interest The probe uses a thermal technique for the quantification of perfusion The measurement may be affected by rapid changes in tissue temperature irrigation rapid infusion of fluids etc Relative probe tissue motion will cause artifact and possibly recalibration if severe enough The probe should be properly fixed to the bolt or sutured to the scalp It is good practice to mark or record the initial position of the probe using the cm refere
22. CASE PERFUSION ARTIFACT CHANGE IN THERMAL GRADIENT The probe does contain a reference temperature sensor that permits the monitor to compensate the signal for changes in patient temperature However when the tissue temperature changes direction this may induce artifact in the temperature difference or gradient between the two sensors and correspondingly in the perfusion measurement Any artifact in perfusion measurement is corrected at the next recalibration Plug in probe and press Start to start mez ATemp Start elit Automatic K Cycle Run i MoLabel Stored Data nt 02 50 03 00 03 20 03 30 03 40 Pri iis E 22 00 Saturday Nov 5 10 50 Saturday Now 12 2005 E E T a ee ee Figure 32 CBF measurement artifact during 03 00 to 03 10 as a result of an abrupt cerebral tissue temperature decrease of 0 2 C in 5 minutes temperature data not shown Note that the recalibration and the subsequent CBF values displayed after 03 20 show that CBF was most likely steady he entire time from 03 00 to 03 20 Note that the recalibration and the subsequent values displayed after 03 20 show that CBF was most likely steady the entire time from 03 00 to 03 20 43 Know the flow CBF CASE PERFUSION ARTIFACT PROBE TISSUE MOVEMENT Probe motion causes an artifact in the measurement with an apparent and characteristic spike upward in perfusion measurement This is caused by the fact that the distal sensor must rapidly reestablish the
23. IONS AND INTERFERENCE FEVER The Bowman Perfusion Monitor automatically suspends measuring perfusion when the tissue temperature reaches 39 5 C or above Perfusion measurement is automatically resumed when the tissue temperature drops below this level The device is designed to operate in this way because the FDA mandates that tissue must not be heated above 41 C The probe will heat the tissue up by 1 C above the baseline of 39 5 C This leaves a safety factor of 0 5 C RAPIDLY CHANGING TEMPERATURE GRADIENT The probe does contain a reference temperature sensor that permits the monitor to compensate the signal for changes in patient temperature However when the tissue temperature changes rapidly this may induce drift in the temperature difference or gradient between the two sensors and correspondingly in the perfusion measurement Any drift in perfusion measurement is corrected at the next recalibration If the temperature gradient between the sensors does not change the monitor provides accurate measurements through large changes in tissue temperature Plug in probe and press Start to start meas Alarms St art Automatic Cycle Run NoLabel Stored Dat 0 02 50 03 00 03 10 03 20 03 30 03 40 10 50 Saturday Nov 12 2005 Pt Know the flow Figure 11 CBF measurement artifact during 03 00 to 03 10 as a result of an abrupt cerebral tissue temperature decrease of 0 2 C in 5 minutes temperature data not shown
24. adequate placement of the probe by checking the PPA and K Values 20 4 Secure the bolt locking mechanism as described by bolt manufacturer 5 Be sure to position the umbilical cord using the attached clips in such a fashion to prevent accidents minimize movement and keep the probe connector away from fluids Figure 9 Insertion of the QFlow 500 Perfusion Probe fixed with bolt Know the flow 21 SECTION 3 PROBE INSERTION AND FIXATION PROTOCAL WITH TUNNELING 1 Create burr hole Shave and prep the determined site and exit area for tunneling using aseptic technique Drape the shaved prepped area Mark the incision site with a marking pen and ruler Consider injecting the area with a local anesthetic Use the 15 blade scalpel to make a linear incision 2 3 cm long and carried to the bone Use the self retaining retractor to expose bone Prepare drill according to manufacturer s instruction Using a 2 7 mm twist drill drill through the outer and inner tables of the skull taking care to prevent any damage to the dura or underlying structures If necessary use sterile saline to flush the site for better visibility Make an incision in the dura using a 11 blade scalpel or bipolar securing hemostasis as necessary Visually confirm that there are no obstructions to probe insertion 2 Create tunnel Use a 14 gauge Tuohy needle to tunnel the probe under the scalp by inserting the
25. ajor problem in patients recovering after surgical treatment of cerebral aneurysms or traumatic brain injury The BPM allows real time detection of vasospasm It demonstrates in real time the effect of pharmaceutical and adjunctive therapy on the restoration of flow allows the clinician to determine the effectiveness of the therapy reduces the decision burden on the clinician helps the clinician determine the appropriate times at which expensive global imaging technologies should be applied Papaverine Infusion 60 Figure 23 Papaverine is a potent T 50 vasodilator that has been proposed to counteract vasospasm in patients bo 40 with subarachnoid hemorrhage In 2001 Vajkoczy using continuous gt 30 BPM CBF measurements generated a detailed dose response curve to IAP T 20 that show the benefits of IAP in e treating vasospasm are transient 0 0 10 20 30 40 30 60 70 a0 90 Time minutes Vajkocy et al Stroke 2001 50 m Moderate vasospasm 40 Severe vasospasm oN 30 Figure 24 Follow up measurements demonstrated that 12 hour CBF is not f significantly different from the pre IAP SS 20 baseline The BPM can be used to validate LL alternative therapeutic strategies to improve E cerebral blood flow in patients with cerebral 10 vasospasm 0 1 01 3 6 12 Time after Papaverine hours y Know the flow CBF CASE TREATMENT EFFICACY NIMODIPINE Nimodipine is indicated for
26. ange x x Possible Causes Probe pulled out of tissue e 4 8 gt K gt 2 probe likely pulled into bolt e K lt 1 5 probe in air Pulsatility present in probe interrogation volume Probe may be too deep Probe may be in the ventricle Probe may be sub epidural Probe may be near a vessel Probe motion Damp umbilical to probe connection Probe may be too deep Probe may be in the ventricle Probe may be sub epidural Probe may be near a vessel Damp umbilical to probe connection Damp umbilical to probe connection Possible Causes Probe insufficiently secured Patient may be having seizures Relative probe tissue motion Moving the patient Electrocautery Interference Temperature change of greater than 1 degree during perfusion period Perfusion Change Verifier PCV is on Possible Solutions Verify probe is at an appropriate depth 2 5 cm subdural BPM will automatically recalibrate tissue parameters if problem persists then e Verify probe is at an appropriate depth 2 5 cm subdural e Move the probe about 1 mm along the insertion track e Confirm probe location with CT Separate connection and dry electrical contacts on umbilcial and probe using Bair Hugger or air source e Verify probe is at an appropriate depth 2 5 cm subdural e Move the probe about 1 mm along the insertion track e Confirm probe location with CT Separate connection and dry electrical contacts on umbilc
27. e CT scan right shows the CBF probe misplaced subdurally View Data Perfusion ml 100g min Figure 17 The BPM shows the artifactual CBF measurement as a result of the probe tip placed subdurally Note the significant variability and a subnormal level of flow The K value is high approximately 6 5 14 04 Friday Nov 18 2005 14 57 Sunday Nov 20 2005 32 Know the flow SECTION 3 MISPLACEMENT OF THE PROBE INTO THE LATERAL VENTRICLE CT scan left shows that the CBF probe is misplaced into the ventricle Plug in probe and press Start to start measurement Perfusion ml 100g min Figure 18 The BPM shows the artifactual CBF data for this probe while it was in the ventricle Note the significant and artifactual variation in CBF over the 5 minute measurement window These artifactual variations in CBF measurement are caused by respiration and heart rate induced CSF fluid motion around the probe 09 58 Sunday Nov 16 2003 07 53 Friday Nov 21 2003 tip in the ventricle Also in this case the K value is slightly higher than normal 5 932 SECTION 4 MISPLACEMENT OF THE PROBE TOO DEEP The CT scans show that the probe is inserted too deep 41 mm below the dura Normally the probe should be 2 2 5 cm below the dura At such a depth cardiac and respiration induced brain motion cause the CBF measurement to artifactually fluctuate due to small amounts of probe tissue relative motion Thi
28. e ID Can the BPM interface with other patient monitors The BPM provides both analog and digital outputs which interface with a number of patient monitors and data acquisition systems How much data can be stored retrieved When the monitor collects data at a rate of once per second 1 Hz there is enough memory to store the data for 15 days Does the Probe need to be calibrated or zeroed out No the probe does not need to be zeroed out or calibrated like some other catheters TThe probe is permanently calibrated at Hemedex and does not require any sort of technical recalibration The user therefore does not need to do anything to zero out the probe At the time of insertion how long do have to wait for the BPM System to give PPA K values and an initial perfusion reading It takes 2 7 minutes to acheive temperature stability and for the probe heating to calculate the K and PPA values It takes approximately 4 minutes following probe heating for the temperature field to develop sufficiently for perfusion measurements 57 Know the flow 17 18 19 20 21 22 23 What are the short periodic gaps in the perfusion data The BPM recalibrates on a set period which accounts for the gaps in the data Ina recalibration cycle the BPM shuts off power to the probe allowing the tissue to return to its baseline temperature After this cool down period the monitor will start a new cycle of perf
29. ely 2 C above that of the baseline The power required to maintain the initial 2 C temperature elevation varies directly with to the cerebral blood flow CBF in the interrogation volume the spherical interrogation volume has a diameter of approximately 8 mm The greater the blood flow the higher the thermal dissipation from the active thermistor and the greater the power required to maintain the 2 C temperature elevation Proximal thermister measures the baseline temperature Figure 4 Know the flow INSERTION QFlow 500 probes are inserted similarly to other cerebral probes i e intraparenchymal ICP probes via a burr hole The probes can also be tunneled under the scalp IMPLANTATION The probe tip should be placed approximately 25 mm below the dura completely surrounded by tissue and preferably in white matter The probe should be placed in the vascular territory of interest including areas at risk for ischemia areas downstream of a vasospasm or in any area in which you are interested in measuring CBF The probe should be placed in a position without cardiac or respiratory pulsatile effects If too shallow the proximal temperature sensor can be near or outside the dura and introduce temperature artifact The risks associated with implanting the QFlow 500 probe are the same as those associated with implanting other minimally invasive intraparenchymal probes Contraindications are the same as catheter insert
30. for the analog output and a 9 pin female connector DB 9 for serial communications RS 232 to an outboard computer The rear panel also contains the power cord connector and an indicator showing the power input compatible to the monitor This is the fuse and line voltage selector The switch must be set accordingly for the country of use Air Filter Equipotential Terminal Cord Cable Storage Hooks Serial Number Ratings Label Pole Clamp Serial I O RS 232 Fuse and Line Voltage Selector Power Connector Analog Output Figure 2 PRINTER AND LOAD PAPER The printer records the real time perfusion measurements on paper for review and record keeping When Print option is requested the data shown on the display screen will be printed with the probe label and the unique probe ID number with option to Print Perfusion Print Perfusion amp Temperature Print PPA and K Values or Print Settings Load paper in the Bowman Perfusion Monitor before operating The printer uses standard 50mm thermographic print rolls To load paper in the printer 1 Open printer access panel by flipping door down 2 Push black trigger on lower right side to access paper compartment 3 Insert paper roll into opening with paper coming off the bottom 4 Close paper door and printer access door Figure 3 Know the flow MULTI MODAL MONITORING The Bowman Perfusion Monitor provides both digital and analog outputs whic
31. g f L OTTN ISION measi f T PRINT Press Print to request printing of data All printed strips of data include label information and the unique probe ID Select one of the four options to print data Know the flow 1 Print Perfusion Print the perfusion trace plot that currently appears on the display screen 2 Print Perfusion amp Temperature Print plots of perfusion and proximal temperature tissue baseline temperature 3 PrintK and PPA Values Print all the values recorded for thermal conductivity PPA and the time and date they were recorded 4 Print Settings Print all the current settings 15 OPTIONS MENU OPTIONS MENU 1 RESTORE DEFAULTS To restore manufacturer s defaults stop all measurements press Restore Defaults and then Confirm Restore SET LABEL Use arrow keys to select Delete old label if appropriate or to enter patient name by pressing OK for each selected character Choose Label Complete when finished Be sure to press Return to get back to the main screen OPTIONS MENU 2 SET ALARM Audio The Bowman Perfusion Monitor includes audio and visual Press Audio to turn audio alarm ON perfusion alarms When perfusion drops below the alarm or OFF The speaker symbol on the lower bound for a specified period of time the monitor display screen brightens or dims triggers the alarm Similarly when perfusion rises above the alarm upper bound for a specified period of time the monitor triggers the alar
32. h interface with a number of patient monitors and data acquisition systems The digital output connects directly to any standard RS 232 serial port Digital data is streamed through a serial port and can be sent to multimodal monitoring data collection systems or uploaded to a laptop BPM users have interfaced with a number of digital output systems including the following ICU Pilot by CMA Microdialysis AB Component Neuromonitoring System by CNS Technologies LLC Bedmaster by Excel Medical ICM by University of Cambridge UK BPM users have interfaced with a number of analog output systems including the following Philips Monitors using VueLink by Philips PowerLab by AD Instruments BCI2000 For further questions regarding multi modal monitoring please contact Hemedex QFLOW 500 PROBE The QFlow 500 Probe is placed in the soft tissue of the brain and is able to quantify perfusion through the use of thermal diffusion To determine a perfusion measurement the probe must be appropriately placed in the target tissue connected to the umbilical cord and the umbilical cord must be connected to the monitor Distal thermister measures flow via heat transfer to the capillaries Each QFlow 500 Probe has 2 thermistors one at its tip and one 8 mm proximal to the tip The passive thermistor measures the baseline temperature of the tissue while the active thermistor is heated so that its surface temperature is approximat
33. i nce in using Options Menu 4 Advanced Settings lt Blank gt lt Blank gt lt Blank gt Figure 7 17 PROBE PLACEMENT IN THE INTENSIVE CARE UNIT SECTION 1 BEDSIDE ICU PROBE INSERTION INDICATIONS AND PROBE INSERTION SITE SELECTION Proper probe insertion requires consideration of the following The probe measures focal perfusion in a volume of approximately 0 27ml 0 3cc This focal measurement in absolute units ml 100mg min represents the cerebral blood flow delivered by the supplying vasculature to that territory Placement should be made into the tissue or vascular territory of interest The probe uses a thermal technique for the quantification of perfusion The measurement may be affected by rapid changes in tissue temperature irrigation rapid infusion of fluids etc Relative probe tissue motion will cause artifact and possibly recalibration if severe enough The probe should be properly fixed to the bolt or sutured to the scalp It is good practice to mark or record the initial position of the probe using the cm reference markers to know if it is subsequently inadvertently moved TRAUMATIC BRAIN INJURY TBI In order to maximize the diagnostic information the probe should be placed in a frontal lobe in tissue that is most at risk for secondary ischemic injury Care should be taken to insure that the probe is not placed in a contusion infarct or a hematoma It is suggested that the
34. ial and probe using Bair Hugger or air source Separate connection and dry electrical contacts on umbilcial and probe using Bair Huggar or air source Possible Solutions Verify probe is at an appropriate depth 2 5 cm subdural Assure appropriate probe strain relief secure umbilical cord in a position that does not pull on probe Monitor automatically recalibrates tissue parameters Deactivate PCV for perfusion challenges 61 REFERENCES S Wolf H Martin J F Landscheidt S O Rodiek L Schurer and C B Lumenta Continuous Selective Intraarterial Infusion of Nimodipine for Therapy of Refractory Cerebral Vasospasm Neurocritical Care December 2009 Strong AJ Spreading depolarisations tsunamis in the injured brain review 2009 Advances in Clinical Neuroscience and Rehabilitation 1 32 34 Jens Soukup Isa Bramsiepe Matthias Brucke Lhaghava Sanchin and Matthias Menzel Evaluation of a Bedside Monitor of Regional CBF as a Measure of CO2 Reactivity in Neurosurgical Intensive Care Patients Journal of Neurosurgical Anesthesiology 20 4 249 255 October 2008 O W Sakowitz K L Krajewksi D Haux B Orakcioglu A W Unterberg and K L Kiening Quantification of Transient Ischemic and Metabolic Events in Patients after Subarachnoid Haemorrage Acta Neurochirurgica Supplement 104 395 397 2008 Jaeger M Soehle M Schuhmann MU Winkler D Meixensberger J Correlation of continuously mo
35. ic Cycle Run ROEEID Stored Data Release of Cross Clamp 0 14 05 14 10 14 15 14 25 14 30 Release of Bypass tanp Hyperemia New CBF Figure 27 The annotated view of the BPM shows 30 minutes of intra operative CBF measurements made in the MCA vascular territory during an EC IC bypass using the saphenous vein to connect the common carotid artery CCA to the MCA Note the hyperemia after the release of the bypass clamp and the subsequent establishment of a new and higher CBF level Know the flow 39 CBF CASE ANEURYSM REPAIR SURGERY TAO CLIPPING Temporary arterial occlusion TAO during aneurysm surgery carries the risk of ischemic sequelae Because monitoring of regional cerebral blood flow rCBF may limit neurological damage Thome et al evaluated the BPM for use in the continuous and quantitative assessment of rCBF during TAO Occlusion induced ischemia is reliably detected within the 1st minute after clip application This capability may enable the surgeon to alter the surgical strategy early after TAO to prevent ischemic brain injury 35 Hyperemia 30 Baseline flow 23 Collateral flow 20 15 CBF ml min 100 g TAO Clip On TAO Clip Off 10 19 46 19 49 19 52 19 55 19 58 20 00 20 03 20 06 Figure 28 The waveform above illustrates typical CBF during a TAO clipping procedure The perfusion baseline is first established before placing the temporary clip at approximately 19 51 when an im
36. ic drop in CBF associated with the drop in CPP CPP and CBF track each other as they both eventually bottom out and recover An hour later at 21 52 there is another recalibration and a seamless pickup of the perfusion data 50 Know the flow CBF DURING BRAIN COOLING Recent studies indicating that the ischemic brain is sensitive to minor variations in temperature and has created new interest in hypothermia and brain temperature Km mW cm C T 1949 E oo ae O ao E a Cc 2 n q E ci i a ga f27 pagi Hare g grg oa ST Gr pr FF ara Grp oO ok E aD aD N Cc a 4 4 Li E f iT E LIFE TF PLE ET Orne OT re org ELT Orie Date Courtesy of Dr Stephan Mayer and Dr Sang Bae Ko Columbia University Presbyterian Hospital Figure 40 A 6 5 day record of thermal conductivity K perfusion and temperature during brain tissue cooling for ICP control Notice hyperemia on re warming The increase in k during 7 1 to 7 2 low stable CBF is due to edema The further increase in k from 7 3 on reflect higher tissue water from increased vascular volume 51 Know the flow CBF CASE STATUS EPILEPTICUS SEIZURES INDUCED HYPEREMIA FOLLOWING CARDIAC ARREST Real time continuous measurement of brain physiological parameters is increasingly available through multimodality monitoring MMM Continuous recording of cerebral physiology include intracortical electroencephalography ICE brain
37. ion into tissue Histological stides reveal only minimal tissue destruction and no bleeding around insertion track There have ne no signs of inflammation edema or thermal damage to tissue In compliance with regulatory requirements the tissue is never heated above 41 C 105 8 F CAPABILITIES The QFlow 500 probe is CT compatible and radio opaque The QFlow 500 probe is not MRI compatible If the patient needs an The probe does not need to be zeroed out or calibrated like some other catheters The probe is permanently calibrated at Hemedex and does not require any sort of technical recalibration The user does not need to do anything to zero out the probe Know the flow FOCAL AND REGIONAL PERFUSION Vajkoczy et al found that in the 16 patients tested XeCT and BPM perfusion values correlated very well Ideally a correlation fit line would have a unity slope and zero intercept The actual slope found was very close to unity 1 01 and the intercept was very close to zero 1 56 ml 100 g min For this correlation measurements with both techniques were registered in time and space The XeCT images were taken from a 5 ml region of white matter surrounding the BPM probe This study concludes that the focal perfusion probe measured in a 0 3 ml approximately volume correlates with regional perfusion measured in a 5 ml volume rrusion measurement Is Indicative QFLOW 500 UMBILICAL CORD The Umbilical Cord i
38. lity to automatically calibrate within a pre set time interval ranging every 2 minutes to 2 hours The default setting in the monitor for re calibration is every 60 minutes Re calibration may last 3 5 minutes During this time no perfusion measurement is taken To manually set the Re Calibration time interval begin at the START MENU use arrow keys to adjust time parameters and press OK to allow the monitor to close out the dialogue box This means the monitor will automatically recalibrate at the time interval set for the perfusion period PERFUSION Perfusion measurement begins after the calibration is complete but no reading appears until 2 minutes later BPM is capable of detecting cerebral blood perfusion ranging from O to 200 ml 100g min Perfusion measurements are displayed both numerically and graphically on the screen These values are updated once per second The length of the perfusion measurement phase depends on the settings the user has selected By default this measurement phase will last up to 60 minutes At the completion of the perfusion measurement phase the monitor will return to the temperature stabilization phase New perfusion measurements will be unavailable until the BPM completes temperature stabilization and calibration again The user may terminate the perfusion measurement phase by pressing the Stop button which discontinues all measurements or by pressing the Calibration button which forces the monitor
39. m To set Upper Bound or Lower Bound for perfusion alarm the user can set the value of the bound trigger time and suspend time Trigger Time specifies how long measured perfusion must lie outside the bound before the monitor triggers the alarm Suspend Time specifies how long a triggered alarm remains suspended temporarily disable after you acknowledge it Enable the bound to ensure the activation of the alarm Return three times to get back to the main screen SET DATE TIME Use this option to set the date and time for the monitor SET PERF PERIOD Use arrow keys to adjust time parameters Once the time parameters are set the monitor will automatically re calibrate at the interval user set for the perfusion period Re Calibration generally takes 3 5 minutes at which time no perfusion measurement will be taken On the display screen the breaks in the perfusion vs time graph represent these re calibrations 16 Know the flow OPTIONS MENU 3 SET BAUD RATE Use arrow keys to adjust baud rate parameters RESEARCH SETTINGS OPTIONS MENU 4 ADVANCED SETTINGS Start Menu Options Menu 1 Restore Defaults set Label Overview Menu P More Options Know the flow Options Menu 2 Set Alarms Set Date Time Set Perf Period More Options Contact Hemedex for assista DECCCAD CH CLETTI N ER anA PAL y Options Menu 3 Set Baud Rate Research Settings More Options IC Di C
40. mediate reduction of CBF is seen Illustrated is the rather high collateral flow and for this patient a subsequent recruitment of capillaries At approximately 19 59 the temporary clip is removed the BPM then shows reactive hyperemia followed by return to baseline perfusion 40 Know the flow CBF CASE ANEURYSM REPAIR SURGERY TAO CLIPPING CONTINUED 60 E 50 Figure 29 Claudius Thom Study l 20 patient population D 40 CBF measurements recorded S Patient with relatively before TAO clip p high collateral CBF during TAO clip en or 30 Mai and after TAO clip Wok A 20 10 Potient with virtually ma i collateral CBF 0 Baseline TAO Hyperemia Post TAOQ HHHH Patients who did Figure 30 Using the data collected Thom k 5 expenence infarct calculated a Hypoperfusion Index HPI for 3 hypoperfusion index gmin Znal each patient HPI Time Flow z Of the 20 patients followed the 17 patients with a HPI below the indicated threshold did not experience infarct Using this data Thom concluded that the maximum time in which the TAO clip should be in place could be calculated using the following equation Patients who did not experience infarct Ii HPI Flow Time For Surgery no CT changes hy portent y wn pasi ap CT 41 Know the flow CBF CASE CBF RESPONSE TO CO2 REACTIVITY CHALLENGE Reduction in CBF is one of the major causes of secondary cerebral ische
41. mia in the damaged or edematous brain The cerebral vascular is exquisitely sensitive to CO2 changing 3 4 mm Hg in PaCO2 the loss of CO2 reactivity is generally associated with a poor prognosis Menu View Data i Continuous Mode Aen Set A Temp C 4 ee Time Range Temp C K PPA 1NoLabel Scroll BELE Set Perf Scale Select Plots amp ListK 13 55 14 00 14 05 14 10 14 15 14 20 Return 13 10 01 Wed Mar 23 2011 q4 24 ao Wed War 23 2011 eee ee EY 17 11 39 Courtesy of Professor Susan Margulies and Professor Stuart Friess University of Pennsylvania Figure 31 This waveform illustrates the responsivity of the BPM System and CBF to a CO2 challenge Here a 7 0 kg piglet intubated and ventilated with 50 oxygen to avoid hypoxemia during hypoventilation anesthetized with 0 5 isoflurane and fentanyl infusion 50 mcg kg hr mean arterial pressure ranging between 53 and 56 mm Hg was presented with the following ventilator changes at the indicated times 13 55 ventilator rate set at 18 Baseline perfusion is 40 ml 100 gm min 13 59 ventilator rate changed from 18 to 5 Near immediate response in CBF no further ventilator changes until 14 10 A few spontaneous breaths were observed at 14 02 14 03 which may have affected the CO2 and the CBF 14 10 ventilator rate changed to 30 14 16 ventilator rate changed to 25 14 20 ventilator rate changed to 18 14 24 ventilator rate changed to 22 42 Know the flow CBF
42. n overall 35 Know the flow CBF CASE VASOSPASM EARLY DETECTION The Bowman Perfusion Monitor alerts clinicians in real time to the onset of vasospasm allowing early intervention before permanent damage Any cause of SAH including TBI can trigger vasospasm About 30 000 persons are diagnosed with a ruptured brain aneurysm every year in the U S Cerebral vasospasm leads to death or serious disability in about 20 of ruptured brain areurysms The prevalence of TBI is much greater Perfusion measurement Recalibration in 0 Continuous Mode A Temp C 2 234 Temp C 38 412 K 5 61 MoLabel 0 6 00 12 00 15 00 2 48 31 Sat Oct 15 2005 15 02 29 Sat Oct 15 2005 amp Figure 21 The Bowman Perfusion Monitor above shows 12 hours of CBF measurements taken in an SAH patient during the onset of vasospasm The data is approximately 4 days after aneurysm rupture Vasospasm with CBF below 15 ml min 100 g is seen at approximately 10 30 AM with CBF going below 15 ml min 100 g The diagnosis of vasospasm was independently confirmed with a perfusion CT scan figure 22 taken on October 15 at 14 30 and a neurological exam CBF deficit Figure 22 The diagnosis of vasospasm was independently confirmed with a perfusion CT scan taken on Oct 15 at 14 30 and a neurological exam Courtesy of Dr Stephan B Lewis University of Florida 36 Know the flow CBF CASES TREATMENT EFFICACY PAPAVERINE Cerebral vasospasm remains a m
43. nce markers to know if it is subsequently inadvertently moved ANEURYSM REPAIR SURGERY According to the published article Continuous Monitoring of Regional Cerebral Blood Flow during Temporary Arterial Occlusion in Aneurysm Surgery by Thom Vajkoczy Horn et al J Neurosurg Volume 95 September 2001 the implantation site of the bolt was chosen according to the vascular territory of interest parasagitally either 2 cm lateral to the midline for aneurysms of ACD or 6 cm lateral to the midline for aneurysms of the MCA or ICA EC IC BYPASS SURGERY The probe should be inserted in the vascular territory determined by the neurosurgical clinician to be most affected by the bypass to assess the adequacy of flow 27 Know the flow SECTION 2 INSERTION THROUGH A BURR HOLE ADJACENT TO THE CRANIOTOMY Figure 13 shows a rendition of the placement of the probe though a burr hole adjacent to the craniotomy In the event that post operative monitoring is desired it is best to forward tunnel the probe The procedural steps for the probe placement with tunneling are as follows 1 Create Burr Hole At the site for probe insertion use a scalpel with a 15 blade to make a linear incision 2 3 cm long and carry it to the bone Use a self retaining retractor to provide bone exposure Using a 2 7 mm drill bit drill through the outer and inner tables of the skull taking care to minimize any potential for damage to the dura or the unde
44. needle into incision site and moving under the scalp to exit 6 cm from scalp incision Remove and discard any trocar Pass the Probe tip into distal end of needle exit site and out proximal end incision site slide the needle from the Probe and discard The needle cannot slide over the blue connector at the end of the probe Therefore it is necessary to feed the needle from 3 Insert probe Using the centime markings on the Probe as a guide insert the probe to a depth of 25 mm subdurally into the target white matter tissue Before breaking the sterile field confirm adequate placement of the probe by checking PPA and K Value After confirming placement with good PPA and K Value allow measurement to continue and suture dura and scalp as necessary 4 Clean and dry the Probe site 22 Know the flow 5 Attach Hemedex Fixation Disk f desired attach the probe shaft to the scalp using the Hemedex Fixation Disk Catalog Number 3600 Position the disk onto the Probe via the slit as described in the Disk instructions for use Slide the Disk onto the scalp and secure Disk in place with sutures Close the clamp completely ensuring that the Probe is still adequately positioned 25 mm deep subdurally f necessary apply adhesive dressing 6 Loop 4 5 cm of probe slack in a circle around the probe exit site and secure Shaft to scalp with three 3 sutures spaced evenly apart 7 Apply app
45. nitored regional cerebral blood flow and brain tissue oxygen Acta Neurochir Wien Jan 147 1 51 6 2005 Elke Muench Peter Horn Christian Bauhuf Harry Roth Mark Philipps Peter Hermann Michael Quintel Peter Schmiedek and Peter Vajkoczy Effects of Hypervolemia and Hypertension on Regional Cerebral Blood Flow Intracranial Pressure and Brain Tissue Oxygenation after Subarachnoid Hemorrhage Critical Care Medicine 35 8 1844 1851 August 2007 M Barth H H Capelle E Munich C Thome F Fielder P Schmiedek P Vajkoczy Effects of the selective endothelin A ETa receptor antagonist Clazosentan on cerebral perfusion and cerebral oxygenation following severe subarachnoid hemorrhage preliminary results from a randomized clinical series Acta Neurochirurgica Aug 2007 J C Hemphill M M Knudson N Derugin D Morabito and G T Manley Carbon dioxide reactivity and pressure autoregulation of brain tissue oxygen Neurosurgery 48 2 377 384 2001 Dirk Henze Matthias Menzel Jens Soukup Alexander Scharf Carsten Holz Norbert Nemeth Frank Hanisch and Tobias Clausen Endothelin 1 and Cerebral Blood Flow in a Porcine Model Journal of Clinical Neuroscience 14 7 650 657 July 2007 Muench E Bauhuf C Roth H Horn P Phillips M Marquetant N Quintel M Vajkoczy P Effects of positive end expiratory pressure on regional cerebral blood flow intracranial pressure and brain tissue oxygenation Critical Care Medicine 33
46. phic display shows perfusion measurement in real time Know the flow SECTION 3 MONITOR DISPLAY SCREEN DESCRIPTION OF FEATURES The Bowman Perfusion Monitor is shipped configured to Factory default settings We strongly suggest that users monitor with these factory defaults left in place Further we suggest that any change to the monitor settings is not optimal and we recommend talking to Hemedex prior to changing these settings Mode Temp K Status Bar continuous or AT on o baseline thermal trend temp conductivity Continuous Mode PCV CBF A Temp C 2588 ae i Temp C 37 027 J 2M PPA units 4 982 PPA Probe Placement Assistant CBF plotted every second oei gen Current Time 15 22 00 15 22 30 13 76257 Thu S 2010 Perfusion Cycle Figure 6 plot at first data point and last data point PERFUSION CHANGE VERIFIER PCV The Perfusion Change Verifier PCV is a feature which forces recalibration to verify in situ calibration parameters if perfusion increases from the baseline by 7 5 ml 100g min or Us rs that perform Perfusion decreases from the baseline by 5 ml 100gm min within one Challenges s lake sure t perfusion measurement cycle The factory default setting is PCV on The user may disable this function by pressing the Options and then the Overview Menu keys At this point pressing the Perf Change Verifier key toggles the feature on and off I a T A i AE EEN ERA EE ERAEN EEE TAE I
47. printed a Yes the BPM displays and prints averaged perfusion values when in Trend Mode In Trend Mode the monitor is configured to provide snapshots of averaged perfusion 2 minutes in length approximately every 15 minutes b In Continuous Mode the BPM displays perfusion values in real time only and does not have the capability to display a mean or average CBF value What is the correlation between CBF and ICP CPP MAP etc a If pressure autoregulation is intact then you should expect to see CBF stay constant regardless of MAP changes within a certain range However in a traumatized brain or following certain vasodilator agents CBF may become blood pressure dependent This means the autoregulation mechanism has been compromised and as a result CBF will increase as arterial pressure rises causing an increase in cerebral volume b The increase in cerebral volume will cause an increase in ICP Conversely without autoregulation if MAP decreases so does CBF causing a decrease in blood volume and eventually a decrease in ICP 58 Know the flow 24 25 26 27 Can determine if the probe is responsive to a change in perfusion either on insertion or on a daily basis Yes any procedure or challenge which is known to induce a perfusion change can be used to demonstrate the responsiveness of the probe These challenges can be pharmaceutical CO2 change in respiration rate et cetera What is the Perfusion
48. probe be placed ipsilateral to the primary injury in viable tissue A CT scan should be taken to insure the probe is properly placed Based on neurosurgeon preference however the probe may be placed contralateral to the primary contusion to monitor the less affected hemisphere 18 Know the flow SUBARACHNOID HEMORRHAGE SAH For patients with subarachnoid hemorrhage SAH Fisher Grade III IV or V a probe should be placed in the vascular territory most at risk for vasospasm ICA MCA ACA Ipsilateral to aneurysm 10 mm anterior to the coronal suture 60 mm lateral to midline MCA MCA Ipsilateral to aneurysm 10 mm anterior to the coronal suture 60 mm lateral to midline ACA ACA ipsilateral Ipsilateral or contralateral to aneurysm ACA contralateral 10 mm anterior to the coronal suture 20 mm lateral to midline AcomA ACA ipsilateral Ipsilateral or contralateral to aneurysm ACA contralateral 10 mm anterior to the coronal suture 20 mm lateral to midline Standard localisation ACA AP 11 cm lateral 3 3 5 cm Standard localisation MCA AP 11 cm lateral 4 5 5 5 cm Alternative MCA if also EVD AP 12 23 cm lateral 4 5 5 5 cm if EVD is also required regular 4 cm lateral Figure 8 19 Know the flow SECTION 2 PROBE INSERTION AND FIXATION PROTOCAL WITH BOLT CRANIAL BOLT Know the flow Create burr hole Shave prep and drape the insertion site using aseptic technique Mark the inse
49. rlying structures If necessary use a Sterile flush to enhance visibility Make an incision in the dura using a 11 blade or bipolar securing hemostasis as necessary 2 Create Tunnel Use a 14 gauge Tuohy needle to tunnel the probe under the scalp by inserting tne needle from the site of the burr hole under the scalp to exit at the desired location approximately 6 cm from the burr hole Remove any trocar that may be in the needle lumen Pass the probe tip through the lumen in the distal end of the Tuohy needle and advance the probe tip toward the burr hole While holding the probe in place slide the Tuohy needle out from under the scalp and discard 3 Insert Probe Figure 13 Drawing of the QFlow 500 Probe placed via a burr hole and tunneled adjacent to a craniotomy Note in the insert the centimeter cm spaced markings with a double mark at 5 Using the blue centimeter markings on the probe shaft as a guide insert the probe through the burr hole to a depth of 25 mm below the level of the dura into the white matter Suture scalp over burr hole as necessary Loop 4 5 cm of probe slack in a circle around the site where the probe exits from under the scalp and secure the probe shaft with three sutures spaced evenly apart cm from the tip There are also larger solid marks at 10 cm and an additional mark at 2 5 cm that are not visible here 28 Know the flow SECTION 3 INSERTION THROUGH THE CRANIOTOMY
50. ropriate dressing to burr hole and probe exit site 8 If appropriate tape the blue probe connector to the patient s neck or shoulder to minimize movement 9 Be sure to position the umbilical cord using the attached clips in such a fashion to prevent accidents minimize movement and keep the probe umbilical cord connection away from fluids Fluid can travel down the surface of the probe and collect at this connection Figure 10 Insertion of the QFlow 500 Perfusion Probe via burr hole and tunneled 23 Know the flow SECTION 4 CONFIRM READING Before breaking the sterile field confirm adequate placement of the probe by checking the K and PPA Values Connect the probe to the umbilical cord and Monitor and the measurement will automatically start After a few minutes the Monitor will go into calibration and display PPA K Value and initial AT If the probe is not in a good location you will receive an error message High PPA value Suggest repositioning perfusion probe If you have a high PPA Value gt 5 0 move the probe 1 mm by either pulling it back or advancing it if conditions allow Another way to ensure proper depth placement is with a CT scan The probe is Y NAQGIICPC A n O0 aAITNOUSN aenotn markings 10 ni OT ANNeEALr ON atest scan Tn WA Uw LU Ay CAT LU YJ US Yi fv amp J Se u A NI WG UMM M YU d j S es UA ip te 24 Know the flow SECTION 5 POTENTIAL SOURCES OF LIMITAT
51. rtion site with a marking pen and ruler Consider injecting the area with a local anesthetic Use the 15 blade scalpel to make a linear incision 2 3 cm long and carried to the bone Use the self retaining retractor to provide bone exposure Prepare drill according to manufacturer s instruction Drill through the outer and inner tables of the skull taking care to minimize any potential for damage to the dura or underlying structures f necessary use sterile saline to flush the site for better visibility Make a cruciate incision in the dura using a 11 blade scalpel or bipolar securing hemostatis as necessary If the opening in the dura is not sufficient the probe will not properly track into the cerebral tissue Visually confirm that there are no obstructions to probe insertion on the tissue surface Insert the cranial bolt Follow manufacturer s instructions Be sure to attach the compression cap for the QFlow 500 Probe Insert probe Remove QFlow 500 Probe from package Be sure to mark the probe for adequate depth insertion Feed the probe through the corresponding port of the bolt being careful not to bend the rigid tip of the probe Using the centimeter markings on the probe glide the probe to a depth of 25 mm subdurally into the target white matter tissue Make sure to account for any space left between the end of the bolt and the dura Before breaking the sterile field confirm
52. s also causes the K Mes value to be artifactually high 6 194 aarrebe tip Perfusion measurement Recalibration in 00 29 46 Perfusion mi 100g min 18 43 31 Tue Nov 2 2004 19 19 39 Tue Nov 2 2004 Figure 19 The BPM shows the corresponding artifactual CBF measurements 33 Know the flow CEBERABL BLOOD ELOW MEASUREMENT CAS NORMAL FLOW IN WHITE MATTER VASOSPASM EARLY DETECTION TREATMENT EFFICACY PAPAVERINE TREATMENT EFFICACY NIMODIPINE EC IC BYPASS SURGERY ANEURYSM REPAIR SURGERY TAO CBF RESPONSE TO CO2 REACTIVITY CHALLENGE PERFUSION ARTIFACT CHANGE IN LOCAL THERMAL GRADIENT PERFUSION ARTIFACT PROBE TISSUE MOVEMENT PROBE REPOSITIONING FROM GRAY TO WHITE MATTER CARDIAC INDUCED BRAIN VESSEL PULSATIONS FEVER AND PERFUSION MONITORING PROBE IN INFARCTED TISSUE IMPAIRED AUTOREGULATION BRAIN COOLING STATUS EPILEPTICUS INDUCED HYPEREMIA FOLLOWING CARDIAC ARREST PERIODIC CORTICAL SPREADING DEPRESSION CSD CBF CASE NORMAL FLOW IN WHITE MATTER Perfusion measurement Recalil RU Try a Continuous Mode PCV A Temp c 2 582 Temp C 37 027 K 4 982 No Label dd 15 22 00 15 22 30 15 23 00 15 23 30 Return 15 16 31 Thu Jule 2010 15 42 38 Thu Jul 8 2010 Figure 20 Normal white flow matter is between 20 and 35 ml 100g min The PPA value is green and the K value is between 4 8 and 5 9 CBF waveform shows stable trend and averages about 28 ml 100g mi
53. s normally maintained at a relatively constant level by cerebrovascular autoregulation of CVR over a wide range of CPP values Auto regulation of CVR can become dysfuntional impaired autoregulation in certain pathologic states such as stroke and trauma when the brain becomes exquisitely sensitive to even minor changes in CPP Impaired autoregulation is associated with poor outcomes 140 120 100 50 60 40 20 0 18 43 19 12 19 40 20 09 20 38 21 07 21 36 2204 22 33 m CPP PbtO2 m rCBF m CO2 EX Courtesy of Dr Stephan Mayer and Dr Sang Bae Ko Columbia University Presbyterian Hospital Figure 39 This CBF waveform shows approximately 4 hours of rCBF BPM and CPP data from a patient in a state of impaired cerebral autoregulation The rCBF clearly tracks with CPP throughout the entire data set Each one hour CBF run is followed by a recalibration in which certain tissue parameters which change with time are reestablished namely tissue thermal conductivity a function of tissue water content and the tissue temperature gradient The periodic requantification of these time varying tissue parameters is important in assuring quality CBF data Note that the second CBF run ends at approximately 20 43 hours minutes at a value of 41 ml 100 gm min and at approximately 20 47 the CCP falls dramatically from 120 to about 94 mmHg The third CBF run which starts at approximately 20 49 at a value of 20 ml 100 gm min picks up the dramat
54. s used to connect the QFlow 500 Probe to the Bowman Perfusion Monitor It is 12 feet in length The umbilical cord must be cleaned and disinfected prior to each use The umbilical cord will only work with the Bowman Perfusion System No other cable will connect to either the QFlow 500 Probe or BPM Re A EE LL eae Loe ci VY f Figure 5 Know the flow SECTION 2 MONITOR SET UP 1 Place monitor on shelf or securely mount on IV pole Plug power cord into back of monitor and opposite end into Please note that the wall power outlet When the monitor is not plugged into monitor does not have the wall or is turned off it will not lose previously recorded data The monitor will retain a total 15 days of data Connect umbilical cord into connector on front left panel of the monitor The umbilical cord is 12 feet long Connect the umbilical cord to the appropriately placed QFlow 500 probe Press ON OFF switch on front right panel of monitor The display screen of the monitor should turn on The message line is on the top of the display screen Measurement of tissue temperature PPA K value and initial AT during the Temperature Stabilization Phase will begin automatically If the probe has been placed appropriately in white matter perfusion measurement will begin 4 minutes after the automatic calibration process is completed Perfusion measurement is displayed in absolute units of ml 100g min The gra
55. seizure periods sudden surges in CBF and drops in PbtO2 were repeated Microdialysis data showed high lactate pyruvate ratio suggesting metabolic disturbance As lorazepam and levetiracetam was administered arrow the seizure activity disappeared Grey bar indicated the more detailed time frame shown in Figure 42 Know the flow 52 CBF CASE STATUS EPILEPTICUS SEIZURES INDUCED HYPEREMIA FOLLOWING CARDIAC ARREST CONTINUED Repetitive electrographic seizure activity detected at the start of monitoring was associated with dramatic reductions in brain tissue oxygen tension and striking surges in cerebral blood flow and brain temperature Intravenous lorazepam and levetiracetam resulted in immediate cessation of the seizures and these associated derangements Lactate pyruvate ratio was initially elevated and trended down after administration of anticonvulsants MAP 150 re 100 CPP 40 50 Brain temperature BWW zorgd HUU y th BWW 443 BWW 43 WIL BOO LW 445 z ny amod 533 a2 T ho a l amea dwaj wei a EEG Power Rhythmicity index Spectrogram 12 00 12 30 13 00 13 30 14 00 14 30 15 00 15 30 16 00 time Figure 42 This waveform shows the relationship of physiological variables with quantitative EEG parameter during seizure events During the repetitive seizure events PbtO2 consistently decreased followed by a surge in intracrainial pressure brain temperature and cerebral
56. ssue relative motion from tissue retraction Reduced perfusion from tissue compression via retraction Probe motion from external interference or patient seizures Electrocautery interference especially unipolar i e Bovie Based on these considerations it is recommended that the probe be inserted though a burr hole just adjacent to the craniotomy to reduce thermal and mechanical interference to the probe IRRIGATION Tissue irrigation close to the entry location of the probe may cause thermal instability in the reading and prevent an accurate measurement of blood flow and or induce a longer stabilization time 30 Know the flow RETRACTION Retraction can affect the measurement by 1 Inducing the cerebral tissue to move relative to the probe thus causing a motion artifact 2 By decreasing the blood flow by compression of the tissue behind the retractor Therefore it is suggested that the probe be placed away from the site of retraction ELECTORCAUTERY Options part 1 Electrocautery both unipolar Bovie and bipolar us we Start can cause electrical interference with the Monitor Automatic so o ml 100g mir Cycle Run This interference can introduce noise into the 3 NoLabe Stored Data perfusion data and possibly cause the monitor to automatically recalibrate The operation of the device should return to normal as soon as the electrocautery ceases Figure 15 Interference in the 0 14 53 14 54 14 56 14 57
57. t the probe tip The BMP has a graphical user interface and a thermal printer A maximum of fifteen days of data can be stored on the hard drive of the monitor Data can be downloaded to a computer for storage and analysis Know the flow BOWMAN PERFUSION MONITOR Please refer to the User Manual for complete and detailed instructions SECTION 1 BOWMAN PERFUSION SYSTEM GENERAL OVERVIEW BOWMAN PERFUSION MONITOR The Bowman Perfusion Monitor is designed as a stand alone unit for patient bedside use Perfusion is measured with QFlow 500 probes which must be inserted properly into the target tissue and attached to the monitor FRONT PANEL The front panel of the Bowman Perfusion Monitor holds the power switch Printer display screen menu buttons and umbilical cord connector for the QFlow 500 probe To take measurement a QFlow 500 probe must be appropriately placed in the target tissue connected to the umbilical cord and the umbilical cord must be connected to the monitor The monitor checks for a probe to start the measurement and continues checking to ensure the probe is not disconnected during the measurement Menu Labels Message Line Menu Buttons Perfusion vs Time Graph __ Printer Paper Slot On Off Switch Umbilical Cord Connector Umbilical P Cord QFlow 500 py Figure 1 Probe Know the flow REAR PANEL The rear panel of the Bowman Perfusion Monitor contains a BNC connector
58. tabilization 2 7 min Perfusion Measurement 34 min Figure 7 TEMPERATURE STABILIZATION At the start of each new measurement the monitor will automatically begin with temperature stabilization phase During this phase the monitor is confirming the stability of the tissue baseline temperature which usually takes several minutes and no perfusion measurement is taken at this time If the patient s temperature is not sufficiently stable or is undergoing dramatic changes a warning message will display as Temp not yet stable Check Settings Monitor is trying the monitor will continue to check for temperature stability and no perfusion measurement will be taken Once the tissue temperature meets the stabilization criteria the BPM system will continue to the calibration phase CALIBRATION The BPM system calibrates periodically to update the measurement of those tissue parameters which vary with time and have an impact on determination of perfusion During each calibration the then current tissue parameters of PPA pulsatility in the interrogation volume K thermal conductivity reflecting changes in tissue hydration edema and initial A T tissue thermal gradient are quantified 12 Know the flow The monitor automatically calibrates during the period immediately after temperature stabilization and before perfusion measurement while the probe is implanted in the target tissue The monitor has the capabi
59. the improvement of neurological outcome by reducing the incidence and severity of ischemic deficits in patients with subarachnoid hemorrhage Scroll time of displayed data Alarms OE 1i Automatic Cycle Run 11111NoLabel 0 An 14 10 4 14 30 14 40 14 50 13 94 saturday Sep 6 2 SS SS SS Eee Figure 25 While nimodipine is known to slightly decrease mean arterial pressure MAP it was thought to not adversely affect CBF Figure 25 top shows a screen shot taken from the monitor of CBF during the administration of nimodipine Note the sharp and sudden decrease in CBF along with the corresponding decrease in mean arterial pressure MAP and cerebral perfusion pressure CPP in Figure 26 below CBF and CPP return to baseline values after 30 minutes This effect was repeatable with each dose of the drug 130 Figure 26 Wolf et al 2009 studied the use of 120 continuous intraarterial infusion of nimodipine in saa patients with refractory cerebral vasospasm They found that the Hemedex rCBF measurement was the 100 most effective technique for monitoring the impact aa of nimodipine The authors conclude that Pressure mm Hg continuous infusion of nimodipine may be beneficial 80 for specific patients and that CBF monitoring should oa be employed with the infusion of nimodipine 14 00 14 30 15 00 38 Know the flow CBF CASE EC IC BYPASS SURGERY Alarms Sta rt Automat
60. the monitor will automatically recalibrate at the time interval set for the perfusion period 13 Know the flow SECTION 5 USER INTERFACE MENU Use the menu on the right hand side of the main screen to control the Bowman Perfusion Monitor to set measurement and device parameters and to manage the viewing of data A menu shows up to five selections at a time The menus are arranged in a hierarchical tree so selection of one option often opens a new set of menu items at the next level in the tree Start Menu Stop Menu Start Stop Stored Data Perf Cal View Data iew Data Options Options Print Print Perf Cal could read either Measure Perfusion or Calibration Figure 8 On initial connection of the START gt Starts a perfusion measurement STOP Stops a perfusion measurement This action overrides the measurement control cycle The monitor takes a few moments to shut down the measurement process STORED Stored Data option allows the user to review delete or upload data The DATA Bowman Perfusion Monitor saves data automatically with a maximum limit of 15 days The monitor creates a new perfusion file for each probe If more than 15 days of data are collected on a single file the additional data will overwrite beginning at day one Data can be uploaded to a computer The stored data is identified with three different tags 1 The user designated label which is entered in the
61. thermal field in the tissue at the site where the sensor has been translated to If the perfusion measurement does not return to the pre motion level the monitor will automatically recalibrate for new tissue conditions Menu Scroll Data zz Continuous Mode rans A Temp C oe Temp C f lai PPA NoLabel dd 14 51 30 14 52 00 14 52 30 14 53 00 Return 13 58 01 Mon Oct 24 2005 15 45 00 Mon Oct 24 2005 Figure 33 Motion Artifacts at 14 52 10 and 14 52 38 which temporarily cause the CBF measurement to artifactually increase For small motion the CBF value returns to its level prior to motion In the event the CBF does not return to its pre motion level the monitor will automatically recalibrate 4h Know the flow CBF CASE PROBE REPOSITIONING FROM GRAY TO WHITE MATTER The probe may be purposely or inadvertantly repositioned in the tissue Purposefully in instances when one seeks to avoid the presence of cardiac induced brain tissue pulsations in the thermal interrogation volume of the thermal CBF probe these pulsations can cause artifact in the calculation of thermal conductivity K Inadvertant probe repositioning via migration can result if the probe is not securely fixed in position and there is patient movement external tugs on the catheter seizures etc ail E Kmimvwiem C in in Po I 14 00 16 00 18 00 20 00 Perfusion ml 100g min Figure 34 This 8 hour record illustrates a case
62. tissue oxygen tension PbtO2 and regional CBF and microdialysis provides hourly measurements of extracellular metabolites such as glucose lactate and pyruvate While MMM has been used mostly in comatose patients with severe traumatic brain injury subarachnoid hemorrhage and intracerebral hemorrhage its use is currently expanding to include patients with cardiac arrest and status epilepticus SE The MMM graphs show strong correlation between seizure and hemodyamic parameters MAP 100 50 CPP ie 5 ICP ade AAA f Ny i i y i mA i poe hi Ne Salt utd oa A UN ap ee o IL MaN ae i aii O Glar S o oO a hy ONC A AANA JAN F FF S Sef EPS Ej Temperature AS NAA LAS A 3 z a 9 Z gt lt i lt z at oP 3 sf gla spy Pbt02 yo ise a oaa ee i on lt lt 4 N N YW AW ja 5 Sins 20 CBF 3 th AL WU oti tt 8 ik a h l fh i z My W ja Pa a E N AR p i WP N A N y 3 YNI y baw A 10 Total power EEG LPR Q r o EI j ee S on 5 Lactate os iil a 0 _ o E irae o __ Pyruvate ___ 4 _ oo a a ee a a 4 Glucose Pe ___ 04 00 06 00 08 00 10 00 12 00 14 00 16 00 18 00 Time Ff OW aje 9e7 Hawd aye anid owu asoanjg Figure 41 Shows the real time relationship of patient physiological parameters As EEG monitoring was initiated high power electrical activity was observed suggesting seizure For the entire duration of the
63. uld be completely surrounded by tissue preferably white matter 3 What risks are there in implanting the QFlow 500 Probe a Risks are the same as those associated with implanting other minimally invasive intraparenchymal probes b Contraindications are the same as catheter insertion into tissue c Histological studies reveal only minimal tissue destruction and no bleeding around insertion track d There have been no signs of inflammation edema or thermal damage to tissue In compliance with regulatory requirements the tissue is never heated above 41 C 105 8 F 4 At what depth should the QFlow 500 Probe tip be placed The probe tip should be placed approximately 25 mm below the dura This generally insures that the probe tip is in white matter Markings on the probe aid in placement and can be used to assess if the probe has moved after the initial placement 5 How do I know I have the QFlow 500 Probe in a good location When you have a good PPA less than 2 followed by good K value 4 8 5 9 and a good delta T 6 What happens if the probe umbilical cord connection gets wet How do you keep it from getting wet How do I determine if the probe cable connection is wet How do I fix it The connection between the probe and umbilical cord is water resistant but not water proof If the connection sits in a pool of liquid the liquid may eventually wick into the electrical connections Care should be taken when the probe is
64. ultiple periodic cortical spreading depression depolarisation CSD episodes EcoG not shown in which each perfusion event was time locked to a depolarisation 54 Know the flow CBF CASE PERIODIC CORTICAL SPREADING DEPRESSION CSD CONTINUED w p _ a ml 100g min 30 min Courtesy of Dr Jed Hartings University of Cincinnati Figure 44 Periodic perfusion changes associated with multiple CSDs in a second patient The onsets of slow potential changes of CSD ECoG not shown are indicated by black arrows which are followed in a fixed time interval by perfusion decreases onset indicated by dashed lines Depolarisations CSD sometimes occur without any change in heat clearance signal and when present perfusion changes may vary considerably as illustrated Thus ECoG monitoring with a subdural electrode strip remains the gold standard for CSD detection 55 Know the flow FREQUENTLY ASKED QUESTIONS FAQ 1 How do you insert the QFlow 500 Probe a Similar to other cerebral probes i e intraparenchymal ICP probes which are inserted via a burr hole b The probes can also be tunneled under the scalp 2 Where do you implant the QFlow 500 Probe a The probe should be placed in the vascular territory of interest i In areas which are at risk for ischemia ii In areas downstream of a vasospasm iii In any area in which you are interested in measuring Cerebral Blood Flow CBF b The probe tip sho
65. usion monitoring which includes determining the then current tissue parameters Why does the BPM system recalibrate How long does recalibration take The BPM system recalibrates to periodically update those tissue parameters which vary with time and have an impact on determination of perfusion The recalibration phase lasts between 2 and 7 minutes The length of this recalibration period varies depending on the level of CBF The lower the CBF the more slowly heat dissipates and the longer it will take to complete the recalibration Conversely the higher the CBF the faster the heat dissipates the shorter the recalibration period Does the BPM have alarms Yes BPM alarms can be set to sound if perfusion reaches above or below a certain threshold for a user defined time period i e a quick spike above or below the alarm thresholds will not set off the alarm The alarms are not enabled by default they must be enabled and limits must be set by the user What can you print You have the option to print the following a Print perfusion b Print perfusion and temperature on the same strip c Print a list of the K and PPA Values d Print the current BPM settings Can the data be smoothed No the BPM does not smooth data The time range can be adjusted so that the data can be compressed or expanded over time which allows for more detailed viewing at specific points in time Can average or mean perfusion values be displayed or
66. ver above 39 5 C Possible Solutions Verify probe is at an appropriate depth 2 5 cm subdural Confirm probe location with CT Verify probe is at an appropriate depth 2 5 cm subdural Confirm probe location with CT Compare CBF variations with ICP CPP and MAP variations Activate PCV or manually recalibrate Possible Solutions Wait BPM will automatically check stability every 30 seconds Verify probe is at an appropriate depth 2 5 cm subdural Separate connection and dry electrical contacts on umbilcial and probe using Bair Hugger or air source Verify probe is at an appropriate depth 2 5 cm subdural Confirm probe location with CT Separate connection and dry electrical contacts on umbilcial and probe using Bair Hugger or air source When patient temperature goes below 39 5 C CBF measurement will automatically restart 60 Measurement Cycle Calibration Measurement Cycle Unscheduled Recalibrations during Perfusion Measurement Know the flow Message Error Low K value make sure probe is in tissue High PPA suggest prepositiong probe x x xxx High K value suggest repositioning probe Temp discontinuity check probe and umbilical cord x x xxx Temperature change during calibration x xxx Message Error Probe may have moved recalibration xx x x xxx Baseline temperature drifted recalibratin x xxx Recalibrating to verify perfusion ch

1 Know the flow… © Copyright 2006-2011. Hemedex, Inc. All Rights

Contents

Download Pdf Manuals

Related Search

Related Contents

1 Know the flow&hellip; &copy; Copyright 2006-2011. Hemedex, Inc. All Rights

Contents

Download Pdf Manuals

Related Search

Related Contents

1 Know the flow… © Copyright 2006-2011. Hemedex, Inc. All Rights