volumetric capnography - philips - united states | philips · on accreditation of healthcare...

W H I T E P A P E R

ABSTRACT

Current trends in monitoring and patient safety are leading to the adoption of capnography as a standard of care in many clinical environments and the recognition of the importance of volumetric capnography. This paper contrasts volumetric capnography with time-based capnography.

INTRODUCTION

Standards – Within the last two decades, the clinical utility of time-based capnography, end-tidal CO2 monitoring, and volumetric capnography have found widespread recognition. Medical societies representing anesthesiology [12], cardiology [13,14], critical care [15], pediatrics [16], respiratory therapy [17], emergency medicine [18] and other organizations have either mandated or strongly recommended the use of capnography for patient monitoring during general anesthesia, conscious sedation, resuscitation, intubation, weaning, transport [19] and a variety of other procedures. Some societies including the American Society of Anesthesiologists have recognized the importance of monitoring carbon dioxide and volume, and while not yet mandating the monitoring of expired volume, have “strongly encouraged” it:

Every patient receiving general anesthesia shall have the adequacy of ventilation continually evaluated. Continual monitoring for the presence of expired carbon dioxide shall be performed unless invalidated by the nature of the patient, procedure or equipment. Quantitative monitoring of the volume of expired gas is strongly encouraged. (3.2.1 in [12])

Such requirements in conjunction with Joint Commission on Accreditation of Healthcare Organizations (JCAHO) require-ments, indicating the standard of care for sedated patients must beuniform throughout the institution [20], suggest that capnography be performed during sedation on patients throughout the hospital. Combined monitoring of carbon dioxide and expired volume serves as an important monitoring and diagnostic tool in a number of areas including ventilator management (e.g. PEEP titration), intraoperative assessment, patient transport, cardiopulmonary resusciation and pulmonary embolism manage-

Volumetric Capnography – The Next Advance in CO2 Monitoring

ment [21-23]. For example, to increase the confidence in safety during conscious sedation it has been recommended that ventila-tion be monitored in addition to the vital signs and pulse oximetry. While pulse oximetry may detect the onset of hypoxia in sedated patients, it infers the partial pressure of oxygen through a surrogate of SaO2 (i.e., SpO2). Capnography, on the other hand, provides for earlier detection of ventilatory depression and respiratory failure and as such has become much more widespread in its usage. However, in spite of its broad clinical utility and advantages such as being non-invasive, easy to use, easy to maintain and relatively inexpensive, capnography still remains underutilized [24]. This has been attributed to the lack of education and understanding of the wide range of applications of the technology. While easy to use, capnography’s use and interpretation must be performed in a careful and informed manner to avoid clinical errors. Manufacturer specific algorithms must be considered as well as sampling site, sample rate, interfering gases and design specifics. On the other hand, since the transport of volume is central to the function of the lung, volumetric capnography provides a clearer and more comprehensive picture of the patient than a single point measure of the patient such as the end-tidal value.

History – The history of volumetric capnography spans the last century (Figure 1)[1]. One of the earliest infrared measurements of CO2 in the expired human breath was reported by John Tyndall in 1865 in his famous Rede Lecture “On Radiation” at Cambridge University. However, it took another century before these measurements reached the bedside. Similarly, some of the earliest measurements of vital capacity reported in 1846 by John Hutchinson preceded the development of devices which permitted convenient measurement of flow (and hence volume) by over 75 years. The importance of measuring volume with carbon dioxide has long been recognized by physiologists and clinicians. Early methods such as the Haldane method and its various derivatives used chemical absorbents (i.e. sodium or potassium hydroxide for CO2) and measured the diminution of volume, while the gas was kept at a constant temperature and pressure. This served as the reference method for a volumetric measure of CO2 for many years.

VOLUMETRIC CAPNOGRAPHYRESPIRONICS, INC. PAGE 2

Since the early 1900s, gas exchange was often clinically measured by either the “gold standard” Douglas bag method or with the Tissot spirometer. The Douglas bag required the collection of exhaled air in large, impermeable canvas bags (50 l), and subsequent sampling and analysis of the collected gas to measure the mixed gas fractions and the total expired volume by manually “squeezing” the entire contents of the bag through a spirometer. This method provided neither the flow waveform nor capnogram. One of the earliest descriptions of the volumetric capnogram and a method to determine “airway” dead-space is that of Aitken and Clark-Kennedy (1928) [2]. Fowler (1948)[3] in describing the single breath test for nitrogen (SBT-N2) curve sought to use uniform terminology to clarify the “meaning of dead-space”, and, thus, divided this curve into four phases: I, II, III, and IV. Different methods to sample “alveolar” CO2 gas were developed, including single and multiple breath methods. Elam (1955) working on the problem of CO2 elimination from closed circuit anesthesia systems under U.S. Army support published early pioneering work in the field. Using newly developed CO2 gas monitors, they were the first to publish capnographic profiles of human respiration in the anesthesiology literature [4]. Their work on CO2 homeostasis, published in a series of four papers, included both normal and abnormal characteristics of the capnographic profile and measurements of dead-space and alveolar ventilation. While single breath curves for CO2 appeared as early as 1961 in the literature, it was not until Fletcher (1980) [5] presented the concepts of dead-space and CO2 elimination in a unified framework known as the single breath CO2 curve that this approach began to gain clinical recognition. In 1976, the Model 930 CO2 analyzer (for use with the 900 Servoventilators) offered the first commercial volumetric capnograph, featuring mainstream CO2

and ventilator derived flow. In the early 1990’s, the first efforts to integrate CO2 and flow from the airway manifested with the introduction of the on-airway D-lite sensor (Instrumentarium, Helsinki, Finland) combining, in a single adapter piece, a flow-restrictor element for flow and a port to allow sidestream gas sampling. The sidestream approach requires sophisticated computer algorithms to align and compensate the flow and CO2 signals [6]. The mid-1990’s saw the introduction of the first “all-mainstream” devices for on-airway volumetric capnography (Novametrix, Wallingford,CT)[7]. These devices evolved from separate flow and CO2 sensors connected to separate devices (e.g., Ventrak 1550/Capnogard) and became integrated CO2/flow-airway adapters interfaced to the same host system (e.g. CO2SMO+, NICO). The Ventrak Model 1550 system allowed a capnometer (e.g. CO2SMO or Capnogard) to be interfaced via a

serial port to the 1550 module so that volumetric capnographic variables such as VCO2 and dead space could be computed. The CO2SMO Plus! monitor was the first monitor to integrate on-airway flow measurements with capnography (and pulse oximetry) in a single small package to enable continuous bedside monitoring of mechanically ventilated patients. The NICO2

monitor introduced to the market in 1998, was the first widely available clinical device to non-invasively measure pulmonary capillary blood flow (and cardiac output) using the indirect Fick partial rebreathing technique. With the use of a NICO sensor (i.e. combined CO2/flow sensor with valve and adjustable loop of tubing) and the use of a rebreathing maneuver controlled by an in-line valve, cardiac output and pulmonary capillary blood flow (PCBF) could be estimated every 3 minutes. The development of these products and a new family of flow/CO2 adapters (neonatal, pediatric and adult) required a number of key technological developments such as a novel thick-film IR source, a robust, fixed-orifice flow sensor, and extremely sensitive low-cost differential pressure sensors[8]. The combination adult sensor design included the sample cell and fixed-orifice portion side-by-side, with the sample cell proximal to the patient, whereas the combination neonatal sensor used a split orifice design that merged the sample cell and fixed-orifice portions tightly together. These designs allow for relative immunity to unpredictable flow velocity profiles, without the need to add excessive length to the flow sensor adapter (i.e. minimizing dead space). (For more details on the development of these products please refer to the whitepaper “From Novametrix to Philips – A History of Innovation, 1978-2010” OEM1106A).

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TIME-BASED CAPNOGRAPHY OVERVIEW

The concentration of carbon dioxide is expressed either as a gas fraction (FCO2) or partial pressure (PCO2). It can be displayed graphically in both time and volume-based formats. Capnography when used without qualification refers to time-based capnography. In addition to capnometry,1 capnography includes a plot of the instantaneous CO2 concentration over the course of a respiratory cycle [25]. From this plot the cyclic changes from inspiration and expiration can be visualized. The “textbook” capnogram (Figure 2) comprises two segments, an expiratory and inspiratory segment, which while suggestive in name is actually somewhat misleading [26]. The expiratory segments consist of a varying upslope that will level to a constant or slight upslope whereas the inspiratory segment consists of a sharp downslope that settles to a plateau of negligible inspired CO2. Waveform patterns distinctly different from the typical pattern can often be used to qualitatively assess adequacy of ventilation and/or anesthesia, and faults in the breathing circuit. Various journal articles and even textbooks [22,23,27,28] have been written outlining these patterns. However, other than the end-tidal partial pressure of CO2, only breathing frequency and a measure of inspiratory CO2 levels are clinically reported. This is the case because, while the transition between the expiratory and inspiratory segments appear to be delineated in the capnogram, only in the absence of rebreathing does this transition correspond to the time of the actual beginning of inspiration, as can be reliably identified by the flow waveform. The transition between inspiration and expiration cannot be reliably discerned from the capnogram because of the presence of anatomic dead space that fills with inspiratory gas at end-expiration. This uncertainty further complicates the clinical decision making process. For example, is the alveolar ventilation adequate? While time-based capnographic measurements of height, frequency, rhythm, baseline, and shape have been used in the research literature, the terminology used to characterize features of time-based capnography has exhibited little uniformity and provided conflicting usage of the same terminology [26]. A terminology that has been adopted and is analogous in some respects to volumetric capnography allows comparisons to be drawn more easily between time-based and volumetric approaches (Tables 1,2). Both approaches designate phases I, II and III and the mechanisms underlying each phase for both approaches are similar. However, to allow these phases of the time-based capnogram to

be better defined, they are delineated using the start and end of inspiration (i.e., zero crossing points) from simultaneously recorded flow. As such, with the addition of the flow waveform to the CO2 waveform, time-based capnography would no longer be just the capnogram, although volumetric capnography can present the data in a more useful form. Regardless, this “creepage” of time-based capnography strengthens the actual and perceived value of volumetric capnography, and over time should lead to a greater adoption of volumetric capnography for a wider range of clinical uses.


Figure 2 - Time-based Capnogram. Inspiratory segment (Phase 0) and expiratory segment (divided into Phases I, II, III) a angle = angle between Phase II and Phase III, b angle = angle between Phase III and descending limb of Phase 0 (inspiration) (Adapted from Kodali BS, Philips J. Anesth Analg. 2000; 91(4): 973-7.)

VOLUME CAPNOGRAPHY OVERVIEW

The integration of flow or volume signals with the CO2 signal and the measurement of indices characterizing this curve is widely referred to as volumetric capnography. It has also been referred to as the single breath test for CO2 [29] and CO2 spirography [30]. It provides information based in physiology using an established and uniform terminology. This terminology was originally used by Fowler to describe the SBT-N2 (single breath test for nitrogen) curve where instantaneous nitrogen concentration is plotted against expired volume [31]. This curve was used to study uneven ventilation in lungs and is divided into four phases labeled phases I through IV. If instantaneous CO2 fractional concentration is plotted against the expired volume, the resulting curve resembles the SBT-N2 curve in shape and has been referred to as an SBT-CO2 curve [29] or volumetric capnogram [32]. The graphical presen-tation shown in Figure 4 provides a unified framework for such physiological measures as CO2 elimination, alveolar deadspace and rates of emptying. This plot of CO2 vs. volume has been divided into three phases I through III [29]. (Table 2) (Figure 3).

1 Capnometry - the measurement of carbon dioxide in a volume of gas; Capnography - the measurement of inhaled and exhaled carbon dioxide concentrations, as recorded on a capnogram. (From Dorland’s Medical Dictionary, 2007)

Figure 3 - The three phases of a volumetric capnogram. Phase I is the CO2-free ineffective tidal volume. Phase II represents the transition between airway and alveolar gas. Phases II and III together are the CO2 containing part of the breath, the effective tidal volume, Vteff. Phase I comprises the CO2 free volume while phase II comprises the transitional region characterized by a rapidly increasing CO2 concentration resulting from progressive emptying of the alveoli. Phase III, the alveolar plateau, typically, has a positive slope indicating a rising PCO2. Using these three recognizable components of the volumetric capnogram, physiologically relevant measures such as the volumes of each phase, the slopes of phase II and III, carbon dioxide elimination as well as deadspace tidal volume and ratios of anatomic and physiologic deadspace can be determined.

Carbon dioxide elimination (VCO2), the net volume of CO2 eliminated can be viewed as the area between the expiratory and inspiratory curves (Figure 5). With no rebreathing, the volume of CO2 eliminated during expiration is the area under the volumetric capnogram. However, the presence of inspiratory CO2 must be accounted for when reporting and interpreting VCO2 [33]. During steady-state conditions the lung will excrete CO2 at the same rate as the total body production rate, and there will be no net change in body CO2 stores. In this case VCO2 is representative of total body production. However, changes in VCO2 can provide an instantaneous indication of the change in alveolar ventilation [34].


Figure 4 - Top- components of volumetric capnogram (CO2 / Volume Plot). Bottom – Deadspaces shown graphically. Airway dead space as illustrated by a Triangles p and q are of equal area. Area X is the volume of CO2 in the expired breath, while areas Z and Y are from airway and alveolar deadspace (Vdaw and Vdalv) Because it does not contribute to CO2 elimination this is wasted ventilation. (Adapted from Arnold, JH et al., Crit Care Med. 1996; 24(1): 96-102).

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The respiratory dead space also known as “wasted” ventilation is considered to be that volume of each breath that is inhaled but does not participate in gas exchange. Airway deadspace, a functional surrogate of anatomic deadspace, is calculated from the CO2-volume curve by Fowler’s method [31], which requires that the slope of phase III be estimated. Physiologic dead space, the sum of the airway dead space and alveolar dead space, can also be calculated but requires an estimate of the alveolar PCO2. Arterial PCO2 often serves as an estimate of alveolar PCO2 given the normally close relationship [35]. The portion of the physiologic dead space that does not take part in gas exchange but is within the alveolar space is considered the alveolar dead space. It is considered to be that volume of each breath that is inhaled but does not reach functional terminal respiratory units. The term functional has important implication, because alveolar ventilationdepends upon the output of CO2. A respiratory unit that is ventilated but not eliminating CO2 (i. e., deprived of its blood flow) is included in the alveolar dead space volume. An increase in the alveolar dead space also occurs when regions of the lung are ventilated, but under-perfused. Alveolar dead space is affected by any condition that results in a V/Q mismatch. This includes (a) hypovolemia, (b) pulmonary hypotension, (c) pulmonary embolus, (d) ventilation of non-vascular air space, (e) obstruction of pre-capillary pulmonary vessels, (f) obstruction of the pulmonary circulation by external forces, and (g) over extension of the alveoli [36].

Additionally, other potentially useful parameters have been calculated from the combination of CO2 and volume including new surrogates and better estimates of alveolar CO2, estimates of ventilatory efficiency, measures of the non-synchronous emptying of the alveoli with unequal ventilation/perfusion ratios [37] and additional normalized measures of CO2 elimination using a concept known as the mean distribution time [39]. Efficiency, as defined, requires an arterial blood gas and provides a single value that summarizes the emptying of the lung relative to an ideal lung (Table 2). Alveolar ejection volume has been suggested by Romero [37] to serve as a measure of the non-synchronous emptying of the alveoli with unequal ventilation/perfusion ratios [37] but characterized as a misnomer by Fletcher [38]. This measure of emptying can be contrasted with physiologic deadspace, which can be viewed as reflecting the emptying characteristics of different alveoli [37]. The better understanding of respiratory physiology and related disease processes that volumetric capnography can help provide is only now beginning to be realized.

VOLUMETRIC AND TIME-BASED CAPNOGRAPHY CONTRASTED

Time-based capnography can only delineate the transition between the expiratory and inspiratory segments and as such only permit the calculation of the frequency of breathing. It cannot delineate the transition between inspiration and expiration. This fundamental limitation makes the analysis of time-based capnograms duringinspiration difficult and results in an unreliable assessment of rebreathing, usually underestimating it. For example, the inability to expeditiously detect rebreathing caused by an incompetent inspiratory valve in the standard anesthesia circle circuit has been reported by different investigators [30, 40]. It has been suggested [26] that the incorporation of flow direction information into mainstream capnography would allow a more physiologically meaningful interpretation of time-based capnograms. Side stream systems on the other hand do not allow meaningful comparisons between the flow and CO2 waveforms because of the several second time delay associated with the six to eight foot sampling tube. To properly calculate the various measurements associated with volumetric capnography, the basic measurements of proximal CO2, flow and airway pressure are required (Table 1). Devices that utilize differential pressure sensors to calculate flow typically measure airway pressure from the proximal side of the sensor. Together, the measurements derived from flow and CO2 and flow and airway pressure (respiratory mechanics) allow a comprehen-sive clinical and physiological assessment of the patients cardiorespiratory status. For a discussion of the volumetric capnog-raphy and measurement sites, refer to the Respironics white paper,

Figure 5 - Plot of PCO2 vs. volume illustrating both the expiratory and inspiratory portions. While often the inspiratory portion is negligible, the net CO2 volume per breath is the difference between the area under the expired and inspired portions of the curve or similarly the area within the loop.


Volumetric Gas Measurements - Measurement Site Considerations (OEM 1109A). The ventilation-perfusion relationships of the lung are accurately reflected in the slope of phase III by a volumetric capnogram rather than in that of a time-based capnogram in which the gradient of the phase III slope is usually less obvious and can be misleading. This may be because a smaller volume of expired gases (approximately the final 15%) often occupies half the time availablefor expiration, so that a similar change in the CO2 concentrationis distributed over a greater length of time in the time-based capnogram than in the volumetric capnogram. This phenomenon is illustrated in Figure 6. Figure 6a illustrates a neonatal subject with a long expiratory pause period during which very minor inspiratory efforts are made resulting in a capnogram that is difficult to interpret. In Figure 6b the plot of the expired volume vs. the partial pressure of CO2 during expiration clearly shows the plateau from which an end-tidal value may be determined as well as all of the parameters associated with volumetric capnography, including the physiologic dead space and carbon dioxide elimination, which cannot be determined from a time-based capnogram. However, VCO2 may only accurately reflect the underlying physiology when there are no leaks in the collecting system and where conditions permit the measurement of all the gas that is considered part of the alveolar ventilation (i.e., absence of pneumothorax with leak or endotracheal tube cuff leaking on exhalation).

Table 1 - Time-Based and Volumetric Capnography Measurements

Basic Measurements Units Measurements

TIME-BASED CAPNOGRAPHY

CO2 Partial pressure End-tidal CO2 (torr) and respiratory rate

VOLUMETRIC CAPNOGRAPHY

CO2 Gas fraction Time-based mHg/%/kPa) measurements plus VCO2, dead space(s) and other measurements

Flow (volume) L/min (ml)

Airway pressure* cm H2O

*flow and airway pressure provides respiratory mechanics

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Figure 6 - Time-based and volumetric capnogram for a neonatal subject with a long expiratory pause. Note: CO2 units for time capnogram are in mmHg whereas units for the volumetric capnogram are often shown in %.

(a) Time-based

(b) Volumetric

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Volumetric Capnography Time-based Capnography

End-tidal CO2 Time based average Time based average

Inspired CO2 Various measures may be computed Minimum value during inspiratory segment including inspired CO2 volume often calculated

Breathing frequency May be computed using flow waveform Inverse of time between the transition from expiratory to and/or capnogram. inspiratory segments of successive breaths

Inspiratory/Expiratory Time Timing from start of inspiration and expiration Approximate values may be calculated if deadspace and determined from flow waveform. rebreathing not significant

Mixed Expired CO2 Volume weighted average of CO2. Not available(PeCO2or FeCO2)

CO2 Elimination (VCO2) Net volume of CO2 measured at the mouth Not available or airway, and calculated as the difference between expired and inspired CO2

PHASES

Phase I CO2 free gas from the airways

Duration Time from start of expiration to increase in PCO2 Not available

Volume Volume from start of expiration to increase in PCO2 Not available

Phase II Rapid S-shaped upswing on the tracing caused by the mixing of dead space gas with alveolar gas

Duration Time from end of phase I to intersection of Approximate measure available predictive slopes of phase II and III

Volume Volume during phase II Not available

Slope Curve fit of central portion of phase II volume Curve fit of central portion of time based phase II

Phase III Alveolar plateau representing CO2 rich gas from the alveoli

Duration Time from end of phase II to end of expiration Approximate measure available

Volume Volume during phase III Not available

Slope Curve fit of central portion of phase III volume Curve fit of central portion of time-based phase III

Alpha Angle Angle between phase II and III Angle between phase II & III (usually ranges between 100 & 110 degrees)

DEAD SPACE(S)

Airway (“anatomic”) Volume of the conducting airways at the ‘midpoint’ of Not available(Fowler) the transition from dead space to alveolar gas

Physiologic*** Total dead space and as calculated includes Not available alveolar, airway and apparatus deadspaces

Alveolar*** Dead space that is not airway dead space volume Not available and is calculated by subtracting the airway dead space volume from the ‘physiologic’ dead space

DEAD SPACE RATIOS

Airway Functional anatomic deadspace calculated via Not available Fowler’s method divided by expired tidal volume

Physiologic Total deadspace calculated graphically, with Enghoff Not available -modified Bohr equation or alternate methods

Alveolar Alveolar volume divided by expired tidal volume Not available

OTHER

Efficiency Ratio of volume of CO2 contained in the breath and Not available the volume of CO2 that would have been eliminated by an ideal lung at the same effective volume and end-tidal fractional CO2

fdlate Late dead-space fraction (arterial-end-tidal PCO2 Not available difference at 15% predicted total lung capacity/ arterial PCO2)

**Definitions derived from Fletcher [5], Arnold [29], Eriksson [80] and other sources; Figures 3-5 illustrates a number of these definitions. ***Requires PaCO2

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Table 2 - Comparison of Common Measures Available in Volumetric and Time-based Capnography**


CLINICAL UTILITY OF TIME-BASED AND

VOLUMETRIC CAPNOGRAPHY

The measured concentration of carbon dioxide is the result of ventilation, perfusion and metabolism, and their interactions, and is affected by changes of any of these components (Table 3). Knowledge of the absolute values of and changes in the time-based and volumetric capnograms can assist in the diagnosis of a variety of physiological and pathological phenomena and serve as a valuable tool during a wide variety of clinical situations (Table 4). The clinical utility of time-based and volumetric capnography for many of the indications listed in Table 4 are contrasted in Table 5. Selected references for time and volumetric capnography are provided supporting the respective indication. Note some applications are more established and this has been noted.

Table 3 - Factors that determine PCO2 Levels (adapted from Foley [41])

Increased PCO2 Decreased PCO2

Fever Pulmonary embolism

Sepsis Cardiac arrest

Malignant hyperthermia Hypothermia

Hypoventilation Hyperventlation

Bicarbonate bolus Hypometabolic states

Venous carbon dioxide embolism Hypotension

Increased cardiac output Decreased cardiac output

Restoration of pulse with Esophageal intubationcardiopulmonary resusciation

Chronic obstructive lung disease Disconnection from ventilator

Extubation

Table 4 - Current and potential indications for capnography (adapted from Genuit [42])

Indication

Acute clinical situations Cardiopulmonary resusciation (cardiac and respiratory arrest)

Endotracheal Intubation

Feeding tube placement

Acute Airway obstruction/ assessment of broncho-spasm

Pulmonary embolism

Routine Monitoring Preoperative respiratory assessment

Intraoperative monitoring (including intubation)

Postoperative ventilator weaning

Transport of ventilated patients

Monitoring of mechanical ventilation

Assessment of pulmonary perfusion

Ventilator weaning

Titration of PEEP with VCO2 and Vdphys

Assist pulmonary artery and central venous pressure during insertion

Monitoring during conscious sedation

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In some of these clinical situations, accurate knowledge of the end-tidal value may be clinically sufficient while in other situations the time-based capnogram is required for proper clinical interpretation. In many clinical scenarios, the time-based capnogram is inadequate as a reliable diagnostic tool or indicator. However, volumetric capnography can serve as a more reliable clinical tool and indicator for a number of clinical situations including intubation and pulmonary embolism screening, although the added clinical value of these monitoring modalites often remain unrecognized. The recognition of the value of a physiologic-based approach such as volumetric capnography continues to grow and new clinical applications continue to be uncovered. While not all research to date on this subject has proved fruitful, the clinical value of volumetric capnography is rapidly expanding allowing insight into complex physiological phenomena.

CONCLUSION

Only recently has time-based capnography become widely adopted as a standard of care for a number of applications and is considered an essential tool for the clinician. Its use during general anesthesia is nearly universal in the developed world, and it has been recommended that the use of continuous capnography in other clinical environments (e.g. ICU) be universally adopted as well [43]. Additionally, clinicians are just now beginning to appreciate the application and importance of volumetric capnography. The wealth of relevant physiological information afforded by volumetric capnography is beginning to be tapped, allowing for a better understanding of cardiopulmonary physiology. Volumetric capnography has significant applications for patients with lung disease such as acute respiratory distress syndrome, chronic obstructive pulmonary disease, and asthma as well as adult and pediatric patients with cardiovascular disease. The use of this important technique will allow for an even better understanding of cardiorespiratory interactions. The costs, medical and legal, associated with adverse outcomes related to respiratory events have been significant [44]. Clinical tools made possible through the use of volumetric capnography which offer so much more than capnography alone have potential for improved patient monitoring and management and the associated reduction the cost of patient care.


Table 5 - Clinical Utility of Time-based and Volumetric Capnography Contrasted

Clinical Use Time-based Capnography Selected Refs/Status Volumetric Capnography Selected Refs/Status

ACUTE CLINICAL SITUATIONS

Avoiding Fast detection of exhaled [45-51] Presence of CO2 and flow [52] esophageal CO2 verifies placement, Accepted strongly indicative [22 P. 49-50] intubation during Can give false positives of tracheal intubation SpeculativeETT placement

Avoiding tracheal Fast detection of exhaled [53] Lack of CO2 and flow strongly —intubation during CO2 to verify incorrect Developing indicative of not in trachea Speculative NG tube placement placement.

Avoiding Variable, Not-sensitive, [54-56] Combination of CO2, flow, airway [22 P 41]endobronchial Significant changes in end-tidal levels Developing pressure and derived measures can [57]intubation during may be observed assist detection SpeculativeETT placement

Prognosis and PETCO2 can guide efforts and [58-63] In addition – provides a direct [64]adequacy of indicate patients response; Accepted assessment of ventilation Speculativecardiopulmonary predictive of survivalresuscitation

Assessment of Variable [65-70] Slope of phase III [71-72], airway obstruction Accepted [73-74]** Speculative

Screening for suspect Poor, Useful only in extreme cases [75-76] Alveolar deadspace or fdlate [77-87]pulmonary embolism Developing combined with D-dimer Developing

ROUTINE MONITORING

Preoperative Potential quick screening tool, [88] See airway obstruction - above —assessment of as part of OSA screening Developing Speculative disease

Detection of circuit Good but may miss some [90] Allows for quantitative [89,91]leaks and/or leaks, rebreathing assessment Accepted assessment of leaks Developingrebreathing only qualitative and rebreathing

Detection of Monitoring of PETCO2 [92-93] Monitoring of the capnogram [22-23, 89] disconnection and waveform in intubated [22 pp 49-50] and flow can alert clinician to Developing patients helps identify tube Accepted even partial disconnects displacement

Weaning, Limited Use by itself [94-96] Allows for wide range of [89,97-100] Outcome predictor Developing relevant measures used in Developing protocols to be computed (i.e., VCO2, RSBI)

PEEP Titration Arterial end-tidal difference [101] VCO2, Slope of Phase III [102-103] Developing Developing

PETCO2 as a Normal and constant [104-108] PETCO2 predictive of PaCO2 if [109-110]Surrogate of PaCO2 ET-a gradients�improved PaCO2 Developing physiological deadspace not Developing estimate and less blood gas samples too large

Pulmonary Capillary PETCO2 variable [111-112] VCO2 surrogate with stable VE; [113-116]Blood Flow/Cardiac Developing partial rebreathing Fick method DevelopingOutput Estimation for PCBF

Monitoring Identifies tube displacement, verifies [117-120] Proximal CO2, flow and airway [23 Ch 8 Ch 9]during continuous ventilation helps to [23 Ch 8, Ch9] pressure (and derived variables) Speculativetransport optimize ventilation Accepted allows for continuous assessment of cardiorespiratory status

Intraoperative Good as front line monitor [12],[23 Ch 6] Proximal CO2, flow and airway [12], [23 Ch 6]Assessment (see breathing circuit leaks Accepted pressure (and derived variables) Developing and detection of disconnection) allows for continuous assessment of cardiorespiratory status

Assessment/ Improved patient safety [121-130] CO2 with flow allows for better [23]safety of sedation/ [23 ch 12] identification of hypoventilation Speculativeparalytic therapy Accepted Key: Accepted - Widely accepted as standard practice, Developing - Developing application, OSA - Obstructive sleep apnea, fdlate - see Table 4, RSBI - Rapid shallow breathing index, ** COPD references

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REFERENCE1. Jaffe, MB,Volumetric Capnography – A Brief History, Abstracts of the 2011 Annual Meeting of the American Society of Anesthesiologists, Chicago, Illinois.

2. Aitken RS, Clark-Kennedy AE. On the fluctuation in the composition of the alveolar air during the respiratory cycle in muscular exercise. J Physiol. 1928 Aug 14; 65(4): 389-411.

3. Fowler WS. Lung function studies; the respiratory dead space. Am J Physiol. 1948 Sep 1; 154(3): 405-16.

4. Elam JA, Brown EL, Ten Pas RH. Carbon dioxide homeostasis during anesthesia. Instrumentation. Anesthesiology. 1955; 16: 876 -885.

5. Fletcher, R. The single breath test for carbon dioxide (Thesis). Lund, Sweden, 1980.

6. Meriläinen P, Hänninen H, Tuomaala L. A novel sensor for routine continuous spirometry of intubated patients.J Clin Monit. 1993 Nov; 9(5): 374-80.

7. Jaffe MB. Infrared measurement of carbon dioxide in the human breath: “breathe-through” devices from Tyndall to the present day. Anesth Analg. 2008 Sep; 107(3): 890-904.

8. Jaffe MB, Orr JA. Continuous monitoring of respiratory flow and CO(2): challenges of on-airway measurements. IEEE Eng Med Biol Mag. 2010 Mar-Apr ; 29(2): 44-52.

9. Haldane, J.S. (1912). Methods of Air Analysis. London: Griffin.

10. Tyndall J. Heat - A mode of motion. 6th ed. New York. D. Appleton and Company, 1890.

11. Tyndall, J. On Radiation. The “Rede” Lecture, delivered May 16, 1865.

12. American Society of Anesthesiologists (ASA). Basic Standards for Anesthetic Monitoring; Committee of Origin: Standards and Practice Parameters (Approved by the ASA House of Delegates on October 21, 1986, and last amended on October 20, 2010 with an effective date of July 1, 2011).

13. Wenzel V, Voelckel WG, Krismer AC, Mayr VD, Strohmenger HU, Baubin MA, Wagner-Berger H, Stallinger A, Lindner KH. The new international guidelines for cardipulmonary resuscitation: an analysis and comments on the most important changes. Anaesthesist. 2001; 50(5): 342-57.

14. Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010 Nov 2; 122 (18 Suppl 3): S729-67.

15. Society of Critical Care Medicine: Task force on guidelines. Recommendations for services and personnel for delivery of care in a critical care setting. Crit Care Med. 1988; 16(8): 809-11.

16. American Academy of Pediatrics, Committee on Drugs: Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures. Pediatrics. 1992; 89(6 Pt 1): 1110-5 Addendum- Pediatrics. 2002 Oct; 110(4): 836-8. Update- Pediatrics. 2006 Dec; 118(6): 2587-602.

17. Walsh BK, Crotwell DN, Restrepo RD Capnography/ Capnometry during mechanical ventilation: 2011. Respir Care. 2011; 56(4): 503-9.

18. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Part 7.1: Adjuncts for Airway Control and Ventilation. Circulation 2005; 112: IV-51 – IV-57.

19. Association of Anaesthetists of Great Britain & Ireland. SafetyGuideline: Interhospital Transfer. http://www.aagbi.org/sites/default/files/interhospital09.pdf (accessed 8/03/2011).

20. Joint Commission on Accreditation of Healthcare Organizations (JCAHO): Comprehensive Accrediation Manual for Hospitals, Chicago, IL, JCAHO, 1996, pp. TX73-79.

21. Weingarten M. Respiratory monitoring of carbon dioxide and oxygen: a ten-year perspective J Clin Monit .1990; 6(3): 217-25.

22. J. S.Gravenstein, M. B. Jaffe, and D. A. Paulus, Eds., Capnography: Clinical Aspects. Cambridge, U.K.: Cambridge Univ. Press, 2004, p. 441.

23. J. S.Gravenstein, M. B. Jaffe, N. Gravenstein and D. A. Paulus, Eds., Capnography (2nd edition). Cambridge, U.K.: Cambridge Univ. Press, 2011, p. 488.

24. Ahrens T, Wijeweera H, Ray S. Capnography. A key underutilized technology. Crit Care Nurs Clin North Am. 1999; 11(1): 49-62.

25. Kodali BS, Philips J. Defining segments and phases of a time capnogram. Anesth Analg. 2000; 91(4): 973-7.

26. Kodali BS, Kumar AY, Moseley HSL, Hallsworth RA. Terminology and the current limitations of time capnography: A Brief Review. J Clin Monit. 1995; 11(3): 175-82.

27. Gravenstein JS, Paulus DA, Hayes TJ. Gas Monitoring in clinical practice 2nd ed. Butterworth-Heinemann, New York, 1995.

28. Smalhout B, Kalenda Z. An Atlas of Capnography. Kerckebosche Zeist. The Netherlands. 2nd ed. 1981: 163.

29. Arnold JH, Thompson JE, Arnold LW.. Single breath CO2 analysis: description and validation of a method. Crit Care Med. 1996; 24(1): 96-102.

30. Breen PH, Bradley PJ. Carbon dioxide spirogram (but not capnogram) detects leaking inspiratory valve in a circle circuit. Anesth Analg. 1997; 85(6): 1372-6.

31. Fowler WS. Lung function studies. II. The respiratory dead space. Am J Physiol 1948; 154: 405-416.

32. Ream RS, Schreiner MS, Neff JD, McRae KM, Jawad AF, Scherer PW, Neufeld GR. Volumetric capnography in children. Influence of growth on the alveolar plateau slope. Anesthesiology. 1995; 82(1): 64-73.

33. Breen PH, Serina ER, Barker SJ. Measurement of pulmonary CO2 elimination must exclude inspired CO2 measured at the capnometer sampling site. J Clin Monit. 1996; 12(3): 231-6.

34. Taskar V, John J, Larsson A, Wetterberg T, Jonson B. Dynamics of carbon dioxide elimination following ventilator resetting. Chest. 1995; 108(1): 196-202.



35. Enghoff H. Volumen inefficax. Bemerkungen zur Frage des schädlichen Raumes. Uppsala LäkFör Förh. 44: 191-218, 1938.

36. Nunn, JF, (1969). Applied respiratory physiology, 2nd edn. London, Butterworths & Co Ltd.

37. Romero PV, Lucangelo U, Lopez Aguilar J, Fernandez R, Blanch L. Physiologically based indices of volumetric capnography in patients receiving mechanical ventilation. Eur Respir J. 1997; 10(6): 1309-15.

38. Fletcher R, Drummond GB. Alveolar ejection volume: a misnomer? Eur Respir J. 2000; 15(1): 232-3.

39. Uttman L, Jonson B. A new determinant of CO2 elimination reflecting flow wave pattern, inspiratory time and post-inspiratory pause. Am J Respir Crit Care Med. 2001; 163(5): A129.

40. Kumar AY, Kodali BS, Moseley HS, Delph Y. Inspiratory valve malfunction in a circle system: pitfalls in capnography. Can J Anaesth. 1992; 39(9): 997-9.

41. Foley MP, Truwit. Capnography – Its design and application. J Resp Care Pract. 1998; 11(1): 55-62.

42. Genuit T, Napolitano LM. Capnography in the critically ill. Int J Intensive Care. 2000 Summer, 7: 1-7.

43. Whitaker DK. Time for capnography - everywhere. Anaesthesia. 2011; 66(7): 544-9.

44. Caplan RA, Posner KL, Ward RJ, Cheney FW. Adverse respiratory events in anesthesia: a closed claims analysis. Anesthesiology.1990; 72(5): 828-33.

Additional References for Table 5

Intubation45. Falk JL, Sayre MR. Confirmation of Airway Placement. Prehospital Emergency Care. 1999; 3(4): 273-278.

46. Repetto JE, Donohue PA-C PK, Baker SF, Kelly L, Nogee LM. Use of capnography in the delivery room for assessment of endotracheal tube placement. J Perinatol. 2001; 21(5): 284-7.

47. Roberts WA, Maniscalco WM, Cohen AR, Litman RS, Chhibber A.The use of capnography for recognition of esophageal intubation in the neonatal intensive care unit. Pediatr Pulmonol. 1995 May; 19(5): 262-8.

48. Grmec S. Comparison of three different methods to confirm tracheal tube placement in emergency intubation. Intensive Care Med. 2002; 28(6): 701-4.

49. Katz SH, Falk JL. Misplaced endotracheal tubes by paramedics in an urban emergency medical services system. Ann Emerg Med. 2001; 37(1): 32-7.

50. Knapp S, Kofler J, Stoiser B, Thalhammer F, Burgmann H, Posch M, Hofbauer R, Stanzel M, Frass M. The assessment of four different methods to verify tracheal tube placement in the critical care setting. Anesth Analg. 1999; 88(4): 766-70.

51. Rudraraju P, Eisen LA. Confirmation of endotracheal tube position: a narrative review. J Intensive Care Med. 2009 Sep-Oct; 24(5): 283-92.

52. Cheifetz IM, Myers TR. Respiratory therapies in the critical care setting. Should every mechanically ventilated patient be monitored with capnography from intubation to extubation? Respir Care. 2007 Apr ; 52(4): 423-38

53. Chau JP, Lo SH, Thompson DR, Fernandez R, Griffiths R. Use of end-tidal carbon dioxide detection to determine correct place-ment of nasogastric tube: a meta-analysis. Int J Nurs Stud. 2011; 48(4): 513-21.

54. McCoy EP, Russell WJ, Webb RK. Accidental bronchial intubation: an analysis of AIMS incident reports from 1988 to1994 inclusive. Anaesthesia 1997; 52: 24-31.

55. Gandhi SK, Mushi CA, Kampine JP. Early warning sign of accidental endobronchial intubation: A sudden drop or sudden rise in PACO2. Anesthesiology 1986; 65: 114-5.

56. Gandhi SK, Munshi CA, Coon R, Bardeen-Henschel A. Capnography for detection of endobronchial migration of an endotracheal tube. J Clin Monit. 1991; 7(1): 35-8.

57. Mahajan A, Wald SH, Schroeder R, Turner J, Detection of Endobronchial Intubation in Infants and Children Using Spirometry, Anesthesiology 2002; 97(3): A1268.

CPR58. Kalenda Z. The capnogram as a guide to the efficacy of cardiac massage. Resuscitation 1978; 6(4): 259-63.

59. Falk JL, Rackow EC, Weil MH. End-tidal carbon dioxide concentration during cardiopulmonary resuscitation. N Engl J Med. 1988; 318(10): 607-11.

60. White RD, Asplin BR. Out-of-hospital quantitative monitoring of end-tidal carbon dioxide pressure during CPR. Ann Emerg Med. 1994; 23(4): 25-30.

61. Asplin BR, White RD. Prognostic value of end-tidal carbondioxide pressures during out-of-hospital cardiac arrest. Ann Emerg Med. 1995; 25(6): 756-61.

62. Levine RL, Wayne MA, Miller CC. End-tidal carbon dioxide and outcome of out-of-hospital cardiac Aarrest. New Eng J Med. 1997; 337(5): 301-6.

63. White RD, Goodman BW, Svoboda MA. Neurologic recovery following prolonged out-of-hospital cardiac arrest with resuscita-tion guided by continuous capnography. Mayo Clin Proc. 2011; 86(6): 544-8

64. Terndrup TE, Rhee J. Available ventilation monitoring methods during pre-hospital cardiopulmonary resuscitation. Resuscitation. 2006; 71(1): 10-8.

Airway obstruction65. You B, Peslin R, Duvivier C, Vu VD, Grilliat JP. Expiratory capnography in asthma: evaluation of various shape indices. Eur Respir J. 1994; 7(2): 318-23.

66. Yaron M, Padyk P, Hutsinpiller M, Cairns CB. Utility of the expiratory capnogram in the assessment of bronchospasm. Ann Emerg Med. 1996; 28(4): 403-7.

67. You, B; Mayeux, D; Rkiek, B; Autran, N.; Vu, VD.; Grilliat, JP. Expiratory capnography in asthma perspectives of use in children and as a monitoring of asthma. Rev Mal Respir. 1992: 9(5): 547-52.

68. Moores LK, Rayburn DB, Phillips YY, Fitzpatrick TM. Utilization of Capnography as a Non-Volitional Means of Estimating Airway Obstruction. Am J Respir Crit Care Med. 1997; 155(4) A595.

69. Brown LH, Gough JE, Seim RH. Can quantitative capnometry differentiate between cardiac and obstructive causes of respiratory distress? Chest. 1998; 113(2): 323-6.

70. Nik Hisamuddin NA, Rashidi A, Chew KS, Kamaruddin J, Idzwan Z, Teo AH. Correlations between capnographic waveforms and peak flow meter measurement in emergency department management of asthma. Int J Emerg Med. 2009 Feb 24; 2(2): 83-9.

71. Almeida CC, Almeida-Júnior AA, Ribeiro MA, Nolasco-Silva MT, Ribeiro JD. Volumetric capnography to detect ventilation inhomogeneity in children and adolescents with controlled persistent asthma. J Pediatr (Rio J). 2011 Mar-Apr ; 87(2): 163-8.

72. Liu JM, Hu HC, Shi MH, Yang WL, Zheng W, Wang YM. [The significance of volumetric capnography in assessment of asthmatic acute exacerbation staging]. Zhonghua Jie He He Hu Xi Za Zhi. 2008 Mar ; 31(3): 186-90.

73. Romero PV, Rodriguez B, de Oliveira D, Blanch L, Manresa F. Volumetric capnography and chronic obstructive pulmonary disease staging. Int J Chron Obstruct Pulmon Dis. 2007; 2(3): 381-91.

74. Veronez L, Moreira MM, Soares ST, Pereira MC, Ribeiro MA, Ribeiro JD, Terzi RG, Martins LC, Paschoal IA. Volumetric capnography for the evaluation of pulmonary disease in adult patients with cystic fibrosis and noncystic fibrosis bronchiectasis. Lung. 2010 Jun; 188(3): 263-8. Epub 2010 Jan 5.

PEP75. Thys F, Elamly A, Marion E, Roeseler J, Janssens P, El Gariani A, Meert P, Verschuren F, Reynaert M. PaCO2/ETCO2 gradient: early indicator of thrombolysis efficacy in a massive pulmonary embolism.Resuscitation. 2001; 49(1): 105-8.

76. Courtney DM, Watts JA, Kline JA. Use of Capnometry to Distinguish Cardiac Arrest Secondary to Massive Pulmonary Embolism from Primary Cardiac Arrest. Acad Emerg Med. 2001; 8(5): 433.

77. Kline JA, Kubin AK, Patel MM, Easton EJ, Seupal RA. Alveolar dead space as a predictor of severity of pulmonary embolism. Acad Emerg Med. 2000; 7(6): 611-7.

78. Olsson K, Jonson B, Olsson CG, Wollmer P. Diagnosis of pulmonary embolism by measurement of alveolar dead space. J Intern Med. 1998; 244(3): 199-207.

79. Eriksson L, Wollmer P, Jonson B, Fletcher R, Albrechtsson U, Larusdottir H, Olsson CG. SBT-CO2: a new method for the diagnosis of pulmonary embolism? Clin Physiol. 1985; 5 (Suppl 3): 111-5.

80. Eriksson L, Wollmer P, Olsson CG, Albrechtsson U, Larusdottir H, Nilsson R, Sjogren A, Jonson B. Diagnosis of pulmonary embolism based upon alveolar dead space analysis. Chest. 1989; 96(2): 357-62.

81. Anderson JT, Owings JT, Goodnight JE. Bedside noninvasive detection of acute pulmonary embolism in critically ill surgical patients. Arch Surg. 1999; 134(8): 869-75.

82. Burki NK. The dead space to tidal volume ratio in the diagnosis of pulmonary embolism. Am Rev Respir Dis. 1986; 133(4): 679-85.

83. Patel MM, Rayburn DB, Browning JA, Kline JA. Neural network analysis of the volumetric capnogram to detect pulmonary embolism. Chest. 1999; 116(5): 1325-32.

84. Johanning JM, Veverka TJ, Bays RA, Tong GK, Schmiege SK. Evaluation of suspected pulmonary embolism utilizing end-tidal CO2 and D-dimer. Am J Surg. 1999; 178(2): 98-102.

85. Kline JA, Israel EG, Michelson EA, O’Neil BJ, Plewa MC, Portelli DC. Diagnostic accuracy of a bedside D-dimer assay and alveolar dead-space measurement for rapid exclusion of pulmonary embolism: a multicenter study. JAMA. 2001; 285(6): 761-8.

86. Moreira MM, Terzi RG, Cortellazzi L, Falcão AL, Moreno H Jr, Martins LC, Coelho OR. Volumetric capnography: in the diagnos-tic work-up of chronic thromboembolic disease. Vasc Health Risk Manag. 2010; 25; 6: 317-9.

87. Verschuren F, Heinonen E, Clause D, Roeseler J, Thys F, Meert P, Marion E, El Gariani A, Col J, Reynaert M, Liistro G Volumetric capnography as a bedside monitoring of thrombolysis in major pulmonary embolism. Intensive Care Med. 2004; 30(11): 2129-32.

Pre-operative screening88. Block FE Jr, Reynolds KM, Kajaste T, Nourijelyani K. Pre-operative oximetry and capnometry: potential respiratory screening tools. Int J Clin Monit Comput. 1996; 13(3): 153-6.

Mechanical Ventilation89. Blanch L, Romero PV, Lucangelo U. Volumetric capnography in the mechanically ventilated patient. Minerva Anestesiol. 2006 Jun; 72(6): 577-85.

Leaks, rebreathing90. Healzer JM, Spiegelman WG, Jaffe RA. Internal gas analyzer leak resulting in an abnormal capnogram and incorrect calibration. Anesth Analg. 1995; 81(1): 202-3

91. Breen PH, Bradley PJ. Carbon dioxide spirogram (but not capnogram) detects leaking inspiratory valve in a circle circuit. Anesth Analg. 1997; 85(6): 1372-6.


Disconnection92. Kennedy RR, French RA. A breathing circuit disconnection detected by anesthetic agent monitoring. Can J Anesth. 2001; 48(9): 847-9.

93. Tripathi M, Tripathi M. A partial disconnection at the main stream CO2 transducer mimics “curare-cleft” capnograph. Anesthesiology. 1998; 88(4): 1117-9.

Weaning94. Morley TF, Giaimo J, Maroszan E, Bermingham J, Gordon R, Griesback R, Zappasodi SJ, Giudice JC. Use of capnography for assessment of the adequacy of alveolar ventilation during weaning from mechanical ventilation. Am Rev Respir Dis. 1993; 148(2): 339-44.

95. Saura P, Blanch L, Lucangelo U, Fernandez R, Mestre J, Artigas A. Use of capnography to detect hypercapnic episodes during weaning from mechanical ventilation. Intensive Care Med. 1996; 22(5): 374-81.

96. Hamade M, Mangalaboyi J, Chambrin MC, Jourdain M, Fourrier F, Chopin C. Use Of capnography to detect hypercapnia episodes during weaning from mechanical ventilation. Am J Respir Crit Care Med.1998; 157(3) A309.

97. Taskar V, John J, Larsson A, Wetterberg T, Jonson B. Dynamics of carbon dioxide elimination following ventilator resetting. Chest. 1995 Jul; 108(1): 196-202.

98. Boynton JH, O’Keefe G. The use of VCO2 in predicting libera-tion from mechanical ventilation. Resp Care. 1999: 44(10): 1243.

99. Hubble CL, Gentile MA, Tripp DS, Craig D Meliones JN, Cheifetz IM Deadspace to tidal volume ratio predicts successful extubation in infants and children. Crit Care Med. 2000; 28(6): 2034-40.

100. Nuckton TJ, Alonso JA, Kallet RH, Daniel BM, Pittet JF, Eisner MD, Matthay MA. Pulmonary dead-space fraction as a risk factor for death in the acute respiratory distress syndrome. N Engl J Med. 2002 25; 346(17): 1281-6.

PEEP Titration101. Murray IP, Modell JH, Gallagher TJ, Banner MJ. Titration of PEEP by the arterial minus end-tidal carbon dioxide gradient. Chest. 1984 Jan; 85(1): 100-4.

102. Böhm SH, Maisch S, von Sandersleben A, Thamm O, Passoni I, Martinez Arca J, Tusman G. The effects of lung recruitment on the Phase III slope of volumetric capnography in morbidly obese patients.Anesth Analg. 2009 Jul; 109(1): 151-9.

103. Tusman G, Bohm SH, Suarez-Sipmann F, Scandurra A, Hedenstierna G Lung recruitment and positive end-expiratory pressure have different effects on CO2 elimination in healthy and sick lungs. Anesth Analg. 2010 Oct; 111(4): 968-77.

PetCO2 as PaCO2 surrogate104. Chan KL, Chan MT, Gin T. Mainstream vs. sidestream capnometry for prediction of arterial carbon dioxide tension during supine craniotomy. Anaesthesia. 2003; 58(2): 149-55.

105. Lahn M, Gallagher E, Bijur P, Abrams S. End Tidal CO2 Determination to Predict PaCO2 in Emergency Department Asthmatics. Acad Emerg Med 2003; 10(5): 566.

106. King JC, Boitano LC, Benditt JO. End-Tidal Carbon Dioxide (ETCO2) Accurately Predicts Arterial Carbon Dioxide (PaCO2) in Patients with Neuromuscular Disease. Am J Respir Crit Care Med. 2003; 167(7): A424.

107. Barton CW, Wang ES. Correlation of end-tidal CO2 measurements to arterial PaCO2 in nonintubated patients. Ann Emerg Med. 1994; 23(3): 560-3.

108. McDonald MJ, Montgomery VL, Cerrito PB, Parrish CJ, Boland KA, Sullivan JE. Comparison of end-tidal CO2 and Paco2 in children receiving mechanical ventilation. Pediatr Crit Care Med. 2002; 3(3): 244-249.

109. Banner MJ. Partial pressure of end-tidal CO2 in the ICU: Reevaluating old beliefs. Anesthesiology. 2000; SCCA: B8.

110. McSwain SD, Hamel DS, Smith PB, Gentile MA, Srinivasan S, Meliones JN, Cheifetz IM. End-tidal and arterial carbon dioxide measurements correlate across all levels of physiologic dead space. Respir Care. 2010; 55(3): 288-93.

Cardiac Output111. Ornato JP, Garnett AR, Glauser FL. Relationship between cardiac output and the end-tidal carbon dioxide tension. Ann Emerg Med. 1990 Oct;19(10): 1104-6.

112. Saleh HZ, Pullan DM. Monitoring cardiac output trends with end-tidal carbon dioxide pressures in off-pump coronary bypass. Ann Thorac Surg. 2011 May; 91(5): e81-2.

113. Gedeon A, Forslund L, Hedenstierna G, Romano E. A new method for noninvasive bedside determination of pulmonary blood flow. Med Biol Eng Comput. 1980; 18(4): 411-8.

114. Capek JM, Roy RJ. Noninvasive measurement of cardiac output using partial CO2 rebreathing. IEEE Trans Biomed Eng. 1988; 35(9): 653-61

115. Jaffe, MB. Partial CO2 Rebreathing Cardiac Output – Operating Principles of the NICO System. J Clin Monit. 1999; 15(6) 387-401.

116. Young BP, Low LL. Noninvasive monitoring cardiac output using partial CO2 rebreathing. Crit Care Clin. 2010 Apr ; 26(2): 383-92,

Transport117. Ruckoldt H, Marx G, Leuwer M, Panning B, Piepenbrock S. Pulse oximetry and capnography in intensive care transportation: combined use reduces transportation risks. Anasthesiol Intensivmed Notfallmed Schmerzther. 1998; 33(1): 32-6.



118. Bacon CL, Corriere C, Lavery RF, Livingston DH. The use of capnography in the air medical environment. Air Med J. 2001; 20(5): 27-9.

119. Tobias JD, Lynch A, Garrett J: Alterations of end-tidal carbon dioxide during the intrahospital transport of children. Pediatr Emerg Care 1996; 12: 249–251.

120. Langhan ML, Ching K, Northrup V, Alletag M, Kadia P, Santucci K, Chen L. A Randomized Controlled Trial of Capnography in the Correction of Simulated Endotracheal Tube Dislodgement. Acad Emerg Med. 2011; 18(6): 590-596.

Sedation121. Wright SW. Conscious sedation in the emergency department: the value of capnography and pulse oximetry. Ann Emerg Med .1992; 21(5): 551-5.

122. Dang K, Breen PH. Ambulatory Capnography.. J Resp Care Pract. 1998; 11: June/July.

123. Miner JR, Tibbles C, Rhead C, Heegaard W, Plummer D. End-tidal Carbon Dioxide Monitoring of Procedural Sedation. Acad Emerg Med. 2001; 8(5): 423-4.

124. McQuillen KK, Steele DW. Capnography during sedation/analgesia in the pediatric emergency department. Pediatr Emerg Care. 2000; 16(6): 401-4.

125. Hart LS, Berns SD, Houck CS, Boenning DA. The value of end-tidal CO2 monitoring when comparing three methods of conscious sedation for children undergoing painful procedures in the emergency department. Pediatr Emerg Care 1997; 13(3): 189-93.

126. Tobias JD. End-tidal carbon dioxide monitoring during sedation with a combination of midazolam and ketamine for children undergoing painful, invasive procedures. Pediatr Emerg Care. 1999; 15(3): 173-5.

127. Burton JH , Harrah JD , Germann CA , Dillon DC . Does end-tidal carbon dioxide monitoring detect respiratory events prior to current sedation monitoring practices? Acad Emerg Med 2006; 13: 500 –4.

128. McCarter T, Shaik Z, Scarfo K, Thompson LJ. Capnography Monitoring Enhances Safety of Postoperative Patient-Controlled Analgesia AMERICAN HEALTH & DRUG BENEFITS June 2008 28-35.

129. Deitch K, Miner J, Chudnofsky CR, Dominici P, Latta D. Does end tidal CO2 monitoring during emergency department procedural sedation and analgesia with propofol decrease the incidence of hypoxic events? A randomized, controlled trial. Ann Emerg Med. 2010; 55(3): 258-264.

130. Langhan ML, Chen L, Marshall C, Santucci KA. Detection of hypoventilation by capnography and its association with hypoxia in children undergoing sedation with ketamine. Pediatr Emerg Care. 2011 27(5): 394-7.

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