VivoSense ® Complex Respiratory Analysis
Contents
1. VivoSense automatically applies a default calibration upon import of a data file This calibration weights the AB and RC bands with equal unit weighting and scales the average volume over the entire duration of the session to 400ml 4 1 AB RC Weightings The Calibration of a single band system implies the conversion of computer units to physical units The simplest case is a linear approximation which requires the scaling of the waveform by a constant gain factor The purpose of any calibration procedure is the numerical determination of this factor This scenario of a linear approximation can be immediately generalized to the case of a dual band system Here the tidal Volume Vt can be expressed simply as sum of the filtered and calibrated thoraco abdominal waveforms Vt ABR RC After identification of an appropriate region the actual QDC algorithm will be run to determine relative weightings for both AB and RC bands These may be represented as follows AB AB gain ABu RC RC gain RCu Here RCu and ABu are the uncalibrated waveforms and AB gain RC gain are the calibration parameters Alternatively Vt can be parameterized as Vt Gain RCu Kratio ABu ee AB gain Kratio where RC gain is the constant relative calibration parameters introduced in favor of AB gain and Gain is equivalent to RC gain These calibration parameters need to be approximated before any breath detection can be applie2. Minimum Tidal Volume The minimum difference between the maximum and the minimum of Vt during a breath Figure 5 Breath Detector Settings User Documentation Complex Respiration Analysis Module Page 12 of 25 VivoSense Complex Respiration Analysis Module If it is certain that a correct breath identification has occurred and a failure to calibrate still results it may be necessary to adjust the QDC duration or location to enable this to perform correctly If neither of these results in a suitable calibration then this suggests a problem with the actual recording and it is recommended that a new session be recorded 4 3 Fixed Volume Calibration FVC A successful QDC calibration will rescale Vt such that the average breath volume over the QDC region will be equal to the default breath volume specified in the preferences see section 4 6 Note the primary purpose of QDC is the determination of the K ratio while the overall gain factor RC gain is based on the assumption that the average breath volume is known The accuracy may be improved by performing a FVC on a selected set of breaths Note while any FVC only changes the value of RC gain and keeps K ratio constant QDC modifies both K ratio and RC gain If simultaneous additional volume measurements were made with an external device such as a fixed volume bag or spirometer it may be possible to further calibrate the respiration volumes for greater accuracy To do
3. Complex Respiration Analysis Module 8 CRA Layouts The VivoSense software contains a collection of Layouts specific to the Complex Respiratory Analysis module The following layouts are provided with this module Basic The Basic Layout contains phase plots of Konno Mead AB vs RC and Flow Volume Loops Vt vs dVt as well as the basic respiratory volume charts containing AB and RC as well as Vt Flow Volume This Layout contains the Flow Volume Loop phase plots The Flow Volume 1 chart has a Trigger Count of 3 and a Trigger Offset of 0 while the Flow Volume 2 chart has a Trigger Count of 3 and a Trigger Offset of 3 seconds The layout also contains waveform plots of Vt and dVt Flow Volume Loops may be used to illustrate obstructive or restrictive lung disease in individual subjects Konno Mead This Layout contains the Konno Mead phase plots The Konno Mead 1 chart has a Trigger Count of 3 anda Trigger Offset of 0 while the Konno Mead 2 chart has a Trigger Count of 3 and a Trigger Offset of 3 seconds The layout also contains waveform plots of AB RC and Vt The monitoring of thoraco abdominal asynchrony as displayed in the Konno Mead plots is a useful non invasive indicator of respiratory muscle load or respiratory muscle dysfunction and can be used to determine response to therapy in individual subjects Phase Angle The Phase Angle Layout contains Phase Angle plots Phase Angle and Phase Angle Area as well as the percent Rib Cage
4. dual band IP technology requires additional signal processing and analysis to wholly exploit the value of these measuremenis It is important to appropriately calibrate these measurements and assign relative weightings for the contribution of each respiratory compartment Once calibrated there are many additional measures that may be derived from two band respiration and these will be discussed in the ensuing chapters tan A A AT UU LEU t Rib Cage Signal RC Pe a a ae ee y ae ii VU UU Abdominal Signal AB Figure 2 Dual Band Respiratory Inducutance Plethysmography User Documentation Complex Respiration Analysis Module Page 9 of 25 VivoSense Complex Respiration Analysis Module 4 Calibration There are several possible methods for calibrating dual band respiratory measurements VivoSense software allows for the following types of calibration 1 Qualitative Diagnostic Calibration QDC This is used to weight the relative gains of each respiratory compartment and should be applied prior to any other calibrations QDC calibrations may be applied automatically or manually 2 Fixed Volume Calibration FVC This calibration sets the overall gain of the volume signal so that the average breath volume over the calibration period is equal to an externally measured breath volume This may be from a fixed volume bag or a spirometer flowmeter It is recommended to apply a FVC calibration following a QDC calibration
5. exchange ventilation nearly matches pulmonary arterial blood flow perfusion If mismatched impairment of oxygen and carbon dioxide transfer results The concentration of oxygen PO2 in any lung unit is measured by the ration of ventilation to blood flow VENTILATION PERFUSION or V Q This relationship also applies to carbon dioxide nitrogen and any other gas present The Ventilation Perfusion relationship can be measured by calculating the alveolar a Arterial A PO2 difference PAO2 can be calculated using the equation FlO2 Patm PH2O PaCO2 R The three basic elements of the respiratory control system are SENSORS CENTRAL CONTROLLERS and EFFECTORS SENSORS The sensors that contribute to the control of breathing include lung stretch receptors in the smooth muscle of the airway irritant receptors located between airway epithelial cells joint and muscle receptors that stimulate breathing in response to limb movement and juxtacapillary or J receptors located in alveolar walls which sense engorgement of the pulmonary capillaries and cause rapid shallow breathing The most important sensors are central chemoreceptors in the medulla as well as peripheral chemoreceptors in the carotid and aortic bodies The central chemoreceptors in the medulla respond to changes in the pH of the CSF Decreases in CSF pH produce increases in breathing hyperventilation whereas increases in pH result in hypoventilation The peripheral chem
6. of Breaths E Respiration Average Breath Volume in ml Relative Deadspace Minimum Flow in ml sec Calibration Period Default duration of the time period used to perform a QDC calibration Figure 7 Respiration Preferences for Calibration User Documentation Complex Respiration Analysis Module Page 15 of 25 VivoSense Complex Respiration Analysis Module 5 Respiration Processing Data Channels The core VivoSense software module supports a basic single channel of respiratory plethysmography This single channel may result from a single measurement band or the un weighted sum of two measurement bands The plethysmograph sensors supported by the core may originate from a variety of sensor types including but not limited to piezoelectric strain gauges hall effect magnetometers and inductance bands The VivoSense CRA module supports respiratory measurements arising from two breathing compartments This allows the derivation of several additional measures that assess the degree of co ordination between these two compartments In addition to these measures this module also allows access to a number of patented metrics to assess the magnitude of neural drive to the respiratory center This manual describes only those respiratory channels that are not included in the core module However all core channels are still available Respiration Waveforms AB Abdominal Respiration AB is the filtered and scaled respiratory abdominal wa
7. released Elastance depends on the elastic tissue of the lung and chest wall SURFACE TENSION is the collapsing pressure exerted upon the alveoli It results from the attractive forces between molecules of liquid lining the alveoli and follows LaPlace s Law P 2T r where P is the collapsing pressure T is the surface tension and r is the radius of the alveolus SURFACTANT lines the alveoli and reduces surface tension by disrupting intermolecular forces between molecules of liquid This reduction in surface tension prevents alveoli from collapsing and increases compliance RESISTANCE of the airway opposes the flow of gases Air flow is characterized as Laminar when it is stream lined low velocity and follows Poiseuille s Law It is usually confined to the small peripheral airways Air flow is characterized as turbulent when the movement of molecules of gas is disorganized it occurs when User Documentation Complex Respiration Analysis Module Page 5 of 25 VivoSense Complex Respiration Analysis Module velocity of flow exceeds a limiting value or when irregularities in the configuration of the airway preclude laminar flow It follows POISEUILLE s LAW an equation which describes laminar flow in a straight tube i e laminar flow V Pr 8nl where V flow P driving pressure r radius of tube n fluid viscosity I length of tube Since length and viscosity of the airway are usually constant the radius or diameter of the airway is t
8. sin waves the area closed loop covering one cycle can be expressed in terms of the phase angle as Area sin Ph Angle AB Max AB Min RC Max RC Min The sign of the phase angle indicates whether AB is ahead of RC in our convention this means Ph Angle gt 0 or behind Ph Angle lt 0 Ph Angle Area Absolute value of Ph Angle Area Same as Ph Angle but computed using the entire enclosed area User Documentation Complex Respiration Analysis Module Page 17 of 25 VivoSense Complex Respiration Analysis Module Respiratory Drive Measures Vt Ti Mean Inspiratory Flow The mean inspiratory flow is a measure of respiratory center drive The higher its value the greater the drive and vice versa In situations in which thoracoabdominal discoordination is present Vt Ti may underestimate drive since it does not take into account the drive needed to move the paradoxically moving compartment In obstructive apneas where respiratory efforts take place the value of Vt Ti approaches zero and therefore falsely indicates that no drive is present In this situation respiratory drive is better measured from drive measures of the RC or AB compartments Respiration Trends Trends exist for all the above respiration measures contained in mirrored trend folders User Documentation Complex Respiration Analysis Module Page 18 of 25 VivoSense Complex Respiration Analysis Module 6 Respiration Phase Space Plots Phase C
9. ACITY IC Volume of maximal inspiration IRV TV FUNCTIONAL RESIDUAL CAPACITY FRC Volume of gas remaining in lung after normal expiration cannot be measured by spirometry because it includes residual volume ERV RV VITAL CAPACITY VC Volume of maximal inspiration and expiration IRV TV ERV IC ERV TOTAL LUNG CAPACITY TLC The volume of the lung after maximal inspiration The sum of all four lung volumes cannot be measured by spirometry because it includes residual volume IRV TV ERV RV IC FRC DEAD SPACE Volume of the respiratory apparatus that does not participate in gas exchange approximately 300 ml in normal lungs ANATOMIC DEAD SPACE Volume of the conducting airways approximately 150 ml PHYSIOLOGIC DEAD SPACE The volume of the lung that does not participate in gas exchange In normal lungs is equal to the anatomic dead space 150 ml May be greater in lung disease User Documentation Complex Respiration Analysis Module Page 7 of 25 VivoSense Complex Respiration Analysis Module FORCED EXPIRATORY VOLUME in 1 SECOND FEV1 The volume of air that can be expired in 1 second after a maximal inspiration It is normally 80 of the forced vital capacity expressed as FEV1 FVC In restrictive lung disease both FEV1 and FVC decrease thus the ratio remains greater than or equal to 0 8 In obstructive lung disease FEV1 is reduced more than the FVC thus the FEV1 FVC ratio is less than 0 8 User Docu
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11. SO it is necessary to identify the location of the external measurement in the VivoSense session Depending on the recording device used there may be annotations associated with this region to help locate it Once the region is located it is necessary to plot the Insp Vol channel on the SCP This channel is located in the Respiration gt Measures gt Volumes folder in the Data Explorer It is also available on the Breath Detection amp Calibration layout for convenience The user may then select the region containing the breaths used in the external measurement with the mouse and upon releasing the mouse button a context menu will appear containing the item Calibration Respiration Fixed Volume Calibration Selecting this will result in a dialog in which you may enter the actual volume obtained with the external device see Figure 6 VivoSense will then scale the average value of the selected breaths to be equal to this volume User Documentation Complex Respiration Analysis Module Page 13 of 25 VivoSense Complex Respiration Analysis Module Fixed Volume Calibration Use the median of the tidal volume of the selected breaths for a Fixed Volume Calibration Start Time 08 34 48 Duration 00 03 16 Volume Volume Median tidal volume of all selected breaths in ml Figure 6 Fixed Volume Calibration 4 4 Manually Editing Calibration Parameters The calibration parameters are available as properties in the Vt channel for ma
12. VIVON ETICS VivoSense User Manual Complex Respiratory Analysis CRA VivoSense Complex Respiratory Analysis Version 2 0 Vivonoetics San Diego Office 3231 Huerfano Court San Diego CA 92117 3630 Tel 858 876 8486 Fax 248 692 0980 Email info vivonoetics com Web www vivonoetics com VivoSense Complex Respiration Analysis Module Cautions and disclaimer The VivoSense software is not a medical diagnostic tool and is for research and investigational purposes only and is not intended to be or to replace medical advice or review by a physician Copyright Notice Copyright 2011 Vivonoetics All rights reserved User Documentation Complex Respiration Analysis Module Page 2 of 25 VivoSense Complex Respiration Analysis Module Table of Contents e 11 18 6 03 6 genre ener enema tyes rte net MORO pent ee Er Rene ree ree en ee 4 1 1 Complex Respiratory Analysis CRA for VIVOSENSE cccceeecceceeceeeeeeeeeeeeeeeeeeeeaeeeeeeeeeeeessaaaaeees 4 We OVEM TREGUIFCIMIGINS sade sencochene sacred ak setete a a A 4 2 MESPIFANON BACKOFOUNG cerci on oenn nr ere E ON 5 2al IEXOSPIPALOLRY PNYSIOIOGY cra ni atbtc alah lt salah at bbe ata enol ln baa eat idaho de avert ahwiiaa 5 3 Thoraco abdominal MEaSUreMen ccccccccsseccseeecseeeceeeecsueecseeecseeessueessaeessaeenes 9 Ain CAIU pacer tees crete a eae anlar aaa eee aia aa meee 10 Als AB RO Wening aninga a Melee miMrotimimlemamren 10 AP QD
13. and points To turn points or lines on off use their Style property and set the Point Style to None or Line Style to None To turn directional arrows off set the Arrow Count to 0 Lines can be visualized using the Staircase mode where the value of the plot is maintained between points instead of using linearly interpolating the values This results in a staircase appearance of the plot To use this feature set the Line Staircase property to true See Figure 11 User Documentation Complex Respiration Analysis Module Page 22 of 25 VivoSense Complex Respiration Analysis Module 7 CRA Exports To assist with the export of Complex Respiratory Analysis data pre configured exports are available in the VivoSense CRA module Exporting data using the standard core export functionality will allow the generation of CRA exports that are meaningful For example selecting a Known range and exporting data in that range will provide a table of CRA indices and the corresponding exported values The preconfigured CRA exports under Complex Respiratory Analysis are All Respiratory Measures all Respiration measures channels All Respiratory Trends All Respiration trend channels All Respiratory Waveforms All Respiration waveform channels Phase Relation Measures all Phase Angle channels Phase Relation Trends all Phase Angle trend like channels Ole E User Documentation Complex Respiration Analysis Module Page 23 of 25 VivoSense
14. contribution to inspiration and expiration This layout may be used to determine the relative contribution and synchrony to breathing of the Rib Cage and Abdominal compartments User Documentation Complex Respiration Analysis Module Page 24 of 25 VivoSense Complex Respiration Analysis Module 9 Bibliography 1 Vivonoetics Vivosense Core Manual 2010 2 Calibration of respiratory inductive plethysmograph during natural breathing Sackner MA Watson H Belsito AS Feinerman D Suarez M Gonzalez G Bizousky F Krieger B 1989 Jan 66 1 J Appl Physiol pp 410 20 3 Validation of the phase angle technique as an objective measure of upper airway obstruction Hammer J Newth CJL and Deakers TW s l Pediatr Pulmonol 1995 Vols 19 167 173 User Documentation Complex Respiration Analysis Module Page 25 of 25
15. d A good staring value for Kratio is 1 while an approximate value for RC gain can be derived from the raw waveforms by the same method used for single band respiration systems described in ref 1 4 2 QDC Calibration The QDC calibration is based on the principles of the iso volume maneuver calibration see ref 1 and it is thus necessary to identify a suitable period of quiet natural breathing to perform this calibration over The User Documentation Complex Respiration Analysis Module Page 10 of 25 VivoSense Complex Respiration Analysis Module default recommended duration for a QDC calibration is a 5 minute period however it is possible to override this duration should it be necessary to calibrate over shorter or longer periods Automatic QDC VivoSense software is able to search an entire session for the most appropriate 5 minute period of natural or quiet breathing to ensure optimal QDC results To enable this search select from the Session Menu Session gt Calibration gt QDC Automatic Following this VivoSense will determine the most suitable calibration period and perform a QDC calibration If the calibration procedure is successful the user will be prompted with the dialog similar to Figure 3 QDC Summary QDC Calibration was successful RC gain 136 5555 AB gain 112 863 K ratio 0 8264991 Number of breaths observed 90 Number of breaths used 74 Accept these values Figure 3 QDC Calibrati
16. ehavior is correlated to the cardiovascular behavior to control the gaseous exchange between cells and blood Both behaviors are intensified by physical activity Just as blood moves through the cardiovascular system because of the pumping action of the heart gas flows into and out of the lungs because of pressure gradients created by the diaphragm and thoracic cage Although the abdominal and internal intercostal muscles are used for expiration during exercise or states of increased airway resistance exhalation is usually a passive process secondary to the elasticity of the lung chest wall The flow of air is proportional to change in pressure over resistance Thus change in pressure drives ventilation and resistance opposes it Inspiration occurs when the intrapulmonary pressure decreases to below atmospheric pressure this can be secondary to an increase in intrapulmonary volume that occurs when the chest wall expands and the diaphragm descends towards the abdomen Expiration occurs when the intrapulmonary pressure increases to exceed atmospheric pressure or when intrapulmonary volume decreases The following describes a series of relevant respiratory physiology terminology COMPLIANCE is the ability of the lung to stretch its distensibility It represents the change in volume that occurs for a given change in pressure It is inversely related to ELASTASTICITY the ability of the lung to recoil to its resting volume after the stretching force is
17. harts A Phase Chart contains a single Phase Plot of multiple data channels in the session the Y Channel X Channel and optionally a Trigger Channel The Y Channel is plotted on the y axis against the X Channel on the x axis The units of the axes are specific to each data channel Arrows along the plot reference the direction forward in time Figure 8 shows a Synchronized Chart Panel with two Time Series Charts Compartments and Combined and two Phase Charts Konno Mead and Flow Volume New Phase Charts can be added by right clicking on the SCP area and choosing Chart gt New gt Phase The user will be prompted to select the Y Channel X Channel and optional Trigger Channel when the Phase Chart is added Phase Plots are discussed in the following section BR Sample Session bcr vsn Session Layout Start Time 13 29 52 841 Duration 00 01 32 822 Session Start Time 13 16 53 Duration 00 27 07 as dit mlis Flow Volime Konno Mead 1000 Vt ml 0 y L Gl M i I i i 200 i Compartments iy PUY EY Uo 600 500 1400 5 i 1400 13 29 52 841 13 31 25 663 4 Time 13 30 49 461 Cursor 1384 711 Value Vt 1272 322 Figure 8 Synchronized Chart Panel With Phase Charts Trigger Channel The Trigger Channel is optional but also must be set when the Phase Chart is created It is the channel that triggers the range of data shown on the Phase Plot When no Trigger Channel is set then Phase Chart
18. he most powerful determinant of airway resistance resistance and radius are inversely related The smaller the airway radius the greater the resistance to flow Nearly 90 of airway resistance can be attributed to the trachea and bronchi both characterized by rigid structures and together accounting for the smallest total cross sectional area of the airway VENTILATION which can be spontaneous as in breathing or artificial as in mechanical ventilation is the movement of AIR Air is a mixture of gases According to Dalton s Law the total pressure of a mixture of gases is the sum of the pressures of the individual gases In dry air at an atmospheric pressure of 760 mm HG 78 of the total pressure is due to nitrogen molecules and 21 is due to oxygen between the environment and the alveoli It is measured as the frequency of breathing multiplied by the volume of each breath Ventilation maintains normal concentrations of oxygen and carbon dioxide in the alveolar gas and through the process of diffusion also maintains normal partial pressures of oxygen and carbon dioxide in the blood flowing from the capillaries MINUTE VENTILATION or the volume of gas ventilated in one minute is expressed as TIDAL VOLUME x BREATHS MIN ALVEOLAR VENTILATION or the volume of gas available to the alveolar surface per minute is expressed as TIDAL VOLUME DEAD SPACE X BREATHS MIN Ventilation and perfusion are normally matched in the lungs so that gas
19. hysical disorders ventilation is also profoundly affected by mental and psychophysiological states and disorders and detailed monitoring of respiratory function inside and outside the laboratory can greatly enhance our understanding of these phenomena This manual describes a set of tools in the VivoSense software that may be used to further visualize and analyze non invasive respiratory measurements The types of measurements that may be used with this tool specifically result from the use of dual band inductance plethysmography IP sensors IP is the gold standard for unobtrusive respiratory monitoring and has been used widely in clinical and research settings The VivoSense Complex Respiratory Analysis software module includes analysis tools that enable a user to maximize the utility of respiratory measurements These tools include the capability to appropriately calibrate respiratory data visualize complex two dimensional phase space plots and derive a set of metrics and end points that reveal detailed information about a subject s respiratory state as a function of time 1 2 System Requirements This module is an add on analysis module to VivoSense In addition to the VivoSense requirements the CRA module has the following system requirements e Dual band respiratory inductance plethysmography RIP sensor system o The VivoSense CRA module is agnostic to the specific hardware system used to acquire the RIP data User Documentation Comp
20. ith the dialog shown in Figure 3 see Automatic QDC for more details User Documentation Complex Respiration Analysis Module Page 11 of 25 VivoSense Complex Respiration Analysis Module Unsuccessful QDC It may occur that insufficient breaths were available for a QDC calibration in which case the routine will report a failure to calibrate see Figure 4 VivoSense lt QDC calibration failed the number of breaths used is 10 required mininum is 16 Figure 4 Unsuccessful QDC Calibration If this occurs one should examine the breath detection properties and ensure that accurate breath detection is being performed To do so open any channel in the respiration measures folder and expand the Parameters Properties to reveal the Breath Detector Settings seen in Figure 5 This allows over ride of a single parameter called Minimum Tidal Volume This parameter assumes a default average volume of 400ml but may operate off a calibrated volume This represents the minimum volume that must be exceeded for a breath to be considered a true breath Decreasing this will result in more peak trough excursions being considered as a breath and increasing this will result in fewer considerations It is recommended that one of the Breath Detection amp Calibration Layout for your Import Module be used when adjusting this setting Properties Channe espiratior mequiar E Parameters Breath Detector Settings Minimum Tidal Volume 48
21. lation during Inspiration This measure of phase relation expresses the percentage agreement between direction of RC and AB movements during the inspiratory phase of respiration Ph Rel Exp Phase Relation during Expiration The measure of phase relation expresses the percentage agreement between direction of RC and AB movements during expiration It is computed in the same way as Ph Rel Insp except that the expiratory limb of respiration is sampled Ph Rel Total Phase Relation of Entire Breath This measure of phase relation expresses the percentage agreement between direction of RC and AB movements during the entire breath It is computed in the same way as Ph Rel Insp except that both inspiratory and expiratory limbs of respiration are sampled Ph Angle Absolute value of AB RC Phase Angle The phase angle is computed from Lissajous loops between RC and AB excursions also Known as Konno Mead loops 2 A phase angle of 0 indicates perfect in ohase movement while a value of 180 indicates completely out of phase movement between the two compartments Phase angle determinations do not require calibration of RIP since they depend solely upon timing relationships between RC and AB movements Phase angle computations assume that respiratory excursions are sinusoidal when in fact they are not and therefore values may differ from computations of similar timed electrically generated sine waves Ph Angle Area AB RC Phase Angle For perfect
22. lex Respiration Analysis Module Page 4 of 25 VivoSense Complex Respiration Analysis Module 2 Respiration Background 2 1 Respiratory Physiology In respiratory physiology respiration is defined as the transport of oxygen from the outside air to the cells within tissues and the transport of carbon dioxide in the opposite direction The respiratory system works in concert with a circulatory system to carry gases to and from the tissues Respiration of oxygen includes four stages e Pulmonary ventilation moving of the ambient air into and out of the alveoli of the lungs e Pulmonary gas exchange exchange of gases between the alveoli and the pulmonary capillaries e Gas transport movement of gases within the pulmonary capillaries through the circulation to the peripheral capillaries in the organs and then a movement of gases back to the lungs along the same circulatory route e Peripheral gas exchange exchange of gases between the tissue capillaries and the tissues or organs impacting the cells composing these and mitochondria within the cells Ventilation and gas transport require energy to power the heart and the muscles of respiration mainly the diaphragm In heavy breathing energy is also required to power additional respiratory muscles such as the intercostal muscles The energy requirement for ventilation and gas transport is in contrast to the passive diffusion taking place in the gas exchange steps Respiratory b
23. mentation Complex Respiration Analysis Module Page 8 of 25 VivoSense Complex Respiration Analysis Module 3 Thoraco abdominal Measurement The Complex Respiratory Analysis module is intended for use with dual band inductance plethysmography IP sensors IP is the gold standard for unobtrusive respiratory monitoring and has been used widely in clinical and research settings Several thousand published scientific studies have used this technology and established it as the standard for non invasive assessment of the pattern of breathing An IP sensor consists of a sinusoidal arrangement of electrical wires embedded in elastic cotton bands A high frequency low voltage oscillating current is passed through the wires to generate a magnetic field needed to measure the self inductance of the coils which is proportional to the cross sectional area surrounded by the band No electrical currents are passed through the body Use of this measurement methodology approximates the amount of air moved by the respiratory system by measuring the expansion and contraction of both the rib cage RC and abdominal AB compartments The RC motion reflects activity mostly of the intercostal muscles and to a lesser extent the accessory muscles while AB motion mostly reflects activity of the diaphragm Thus this requires two bands with one placed at the level of the thorax and the other at the level of the abdomen See Figure 2 Measurement of respiration using
24. nual editing This can be used to reuse calibration parameters computed in another session from the same subject 4 5 Restoring Default Calibrations In general a calibration procedure requires a certain number of identified breaths However occasionally it can happen that the respiratory waveforms are poor and a suitable region with enough good breaths cannot be found In this case it may be necessary to reset the calibration parameters to their default values This can be done by selecting Session gt Calibration gt Reset QDC or Session gt Calibration gt Reset FVC Both procedures will reset the gain factor The difference is that each procedure will only remove the annotation related to the specified calibration and leave the others unchanged In addition resetting the QDC calibration will also set the K ratio to 1 while resetting FVC will retain the K ratio User Documentation Complex Respiration Analysis Module Page 14 of 25 VivoSense Complex Respiration Analysis Module 4 6 Preferences User preferences for respiratory parameters can be accessed by going to Tools gt Preferences and clicking on the Respiration tab See Figure 7 The configurable parameters are Calibration Period This is the default duration for a QDC calibration Minimum Number of Breaths This is the minimum number of breaths required for a QDC calibration Folders Respiration E QDC Calibration Calibration Period Minimum Number
25. on Summary If the user accepts these values they will be used to rescale the respiratory waveforms All dependent channels will also be recomputed In addition an annotation named QDC Calibration will be created to indicate the period used by the calibration The color of the annotation will be Aquamarine to signify that this was an automatically identified region Manual QDC Should the user not wish to use the automated region identification feature in VivoSense it is possible to do this manually To do so it is necessary to have Insp Vol Exp Vol or at least one channel contained in the Respiration Waveform Volumes folder plotted on a chart Subsequently the user can select the menu item labeled Calibration QDC Calibration This menu item can be accessed by right clicking on the chart at start of the calibration period In this case the default QDC period as specified in Preferences see section 4 6 will be used Alternatively the user can specify start time and period duration by selecting a rectangular region of data on the corresponding chart using the left mouse button The duration of the QDC period is unconstrained as long as the period encompasses a sufficient number of good breaths The minimum number of breaths needed for a successful QDC calibration and the average breath volume are also specified in Preferences see section 4 6 If the calibration procedure was successful the user will be prompted w
26. oreceptors in the carotid and aortic bodies cause an increase in ventilation in response to decreases in arterial PO2 increases in arterial PCO2 and increases in arterial hydrogen concentrations decrease in pH CENTRAL CONTROLLERS Central control of breathing is achieved at the brainstem specifically the pons and midbrain responsible for involuntary breathing and the cerebral cortex responsible for voluntary breathing EFFECTORS The effectors are the muscles of respiration including the diaphragm intercostal muscles abdominal muscles and accessory muscles such as the sternocleidomastoid User Documentation Complex Respiration Analysis Module Page 6 of 25 VivoSense Complex Respiration Analysis Module Lung volumes and capacities capacities are the summation of volumes are summarized in the following See Figure 1 Figure 1 Common pulmonary volumes and capacities TIDAL VOLUME Vt Waveform of volume of inspired or expired with each normal breath Actual volumes are peak to trough differences INSPIRATORY RESERVE VOLUME IRV Maximum volume that can be inspired over the inspiration of a tidal volume normal breath Used during exercise exertion EXPIRATRY RESERVE VOLUME ERV Maximal volume that can be expired after the expiration of a tidal volume normal breath RESIDUAL VOLUME RV Volume that remains in the lungs after a maximal expiration This volume cannot be measured by spirometry INSPIRATORY CAP
27. the entire data set and have equal range This is useful if the shape of the curve circular vs elliptical is important Set Auto Scale to XYAxis to have each axis scale independently See Figure 10 User Documentation Complex Respiration Analysis Module Page 20 of 25 VivoSense Complex Respiration Analysis Module Properties Phase Chart j Volume Loop B Appearance Auto Scale XYAxis_Symmetric Background Color _ White Caption Aow Volume Loop Foreground Color E ControlText Caption The caption for the control Figure 10 Phase Chart Properties Phase Plot Properties The Phase Plot properties provides control over the line and point color style width size while also providing access to alternate ways of visualizing the plot such as Line Staircase mode and Spike visualization User Documentation Complex Respiration Analysis Module Page 21 of 25 VivoSense Complex Respiration Analysis Module Properties Phase Plot E Annows Arrow Color D Bown Arow Count 12 Arow Size 12 Data Trigger Channel Breath Trigger Count 3 Trigger Enabled True Trigger Offset 0 Channel Vi Y Channel Lines Line Style H Solid Line Width 1 Points Point Color BE DarkBlue Foint Size 5 5 Point Style None Line Color The color of the line connecting the data points of the plot Figure 11 Phase Plot Properties Other Phase Plot Properties include settings for color style and size width for lines
28. ve form RC Rib Cage Thoracic Respiration RC is the filtered and scaled respiratory abdominal wave form ARC Derivative of RC Excursions Flow from the RC band only dAB Derivative of AB Excursions Flow from the AB band only d2RC 2 Derivative of RC Excursions Acceleration from the RC band only d2AB 2 Derivative of AB Excursions Acceleration from the AB band only Respiration Measures All respiration measures are computed on a breath by breath basis referenced to the time of the beginning of inhalation on the Vt waveform Timing Measures Tpet Te Time to reach peak expiratory tidal flow over expiration time This is the time to reach peak expiratory tidal flow as a percentage of expiratory time User Documentation Complex Respiration Analysis Module Page 16 of 25 VivoSense Complex Respiration Analysis Module Phase Measures RCi Percent Rib Cage Inspiratory Contribution to Tidal Volume Ratio The RCi contribution to Tidal Volume ratio is obtained by dividing the inspired volume in the RC band by the inspired volume in the algebraic sum of RC AB at the point of the peak of inspiratory tidal volume RCe Percent Rib Cage Expiratory Contribution to Tidal Volume Ratio The RCe contribution to Tidal Volume ratio is obtained by dividing the expired volume in the RC band by the expired volume in the algebraic sum of RC AB at the point of the peak of expiratory tidal volume Ph Rel Insp Phase Re
29. will User Documentation Complex Respiration Analysis Module Page 19 of 25 VivoSense Complex Respiration Analysis Module plot the data within the time range displayed in the SCP When a Trigger Channel is specified then the range of data plotted is specified by the crosshair cursor position on the SCP Trigger Channel Trigger Count and Trigger Offset For example to plot Vt vs dVt Flow Volume for three breaths from the crosshair cursor set the Trigger Channel to Resp Rate Trigger Count to 3 and Trigger Offset to 0 To plot the three breaths following those set Trigger Count to 3 and Trigger Offset to 3 See Figure 9 Select Trigger Channel Channel Resp Rate Figure 9 Selecting the Trigger Channel and Settings The Trigger Count and Trigger offset may be modified in the phase plot properties See Figure 11 Phase Plots A Phase Plot is a visualization of one Data Channel versus another Data Channel within a given Phase Chart For each Phase Plot added to a chart there is a legend symbol To modify the Phase Plot properties make sure the Properties window Is visible and click on the Legend Symbol Phase Chart Properties To modify the Phase Chart properties make sure the Properties window is visible and click on the Phase Plot The Phase Chart Properties provides control over the colors and name of the chart as well as how the data is scaled in the Auto Scale property Set Auto Scale to XYAxis_ Symmetric to show
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