#CAPNOGRAPHY RANGE SERIES#

The normal physiologic dead space to tidal volume ratio (Vd/Vt) is 0.20-0.35. In a patient with lung disease, the addition of alveolar dead space further dilutes ETCO 2 relative to PaCO 2. 20, 21, 22 Although typical alveolar CO 2 concentrations are slightly greater than that of arterial blood, ETCO 2 is normally 2-5 mm Hg lower than PaCO 2 23 due to mixing of CO 2-containing alveolar gas with exhaled gas devoid of carbon dioxide from the anatomical dead space. The gradient between ETCO 2 and PaCO 2 is directly proportional to the degree of physiologic dead space. Physiologic dead space ventilation is the sum of anatomical dead space from the conducting airways and alveolar dead space from disease processes and/or therapies employed. The analyses utilized in these studies are highly variable and fail to consider physiologic dead space and/or its effect on the relationship between PaCO 2 and ETCO 2 as dead space increases. 13, 14, 15, 16, 17, 18, 19 However, many of these clinical situations involve patients with significant elevations in physiologic dead space. Critics of capnography reference multiple studies that conclude that ETCO 2 and PaCO 2 do not reliably correlate in some clinical situations. Advocates of capnography feel that end-tidal carbon dioxide (ETCO 2) may be used as a surrogate of arterial carbon dioxide (PaCO 2), which would provide a quick and noninvasive assessment of the adequacy of ventilation. There is less agreement about the utility of continuous capnography for ventilated intensive care unit patients 12. Capnography is also useful for monitoring the integrity of the ventilator circuit for early detection of mishaps such as inadvertent extubation 9, 10, 11. xliii, 2128 pages p.Capnography is a useful monitoring tool during mechanical ventilation and is the standard of care for confirmation of endotracheal tube placement 1, 2, 3, 4, 5 and for monitoring in the operating room setting 6, 7, 8. Tintinalli’s emergency medicine : a comprehensive study guide. Tintinalli JE, Stapczynski JS, Ma OJ, Cline D, Meckler GD, Yealy DM. Comparison of end-tidal carbon dioxide and arterial blood bicarbonate levels in patients with metabolic acidosis referred to emergency medicine.

Taghizadieh A, Pouraghaei M, Moharamzadeh P, Ala A, Rahmani F, Basiri Sofiani K. Philadelphia, PA: Elsevier/Saunders 2014. Rosen’s emergency medicine : concepts and clinical practice.

Capnography in the Emergency Department: A Review of Uses, Waveforms, and Limitations. End-tidal carbon dioxide and outcome of out-of-hospital cardiac arrest. Capnography during cardiopulmonary resuscitation: Current evidence and future directions. Comparison of three different methods to confirm tracheal tube placement in emergency intubation. Does end tidal CO2 monitoring during emergency department procedural sedation and analgesia with propofol decrease the incidence of hypoxic events? A randomized, controlled trial.

An early indicator of reperfusion from ROSC is sudden rise in EtCO 2 and thereby may help to decrease deleterious pauses in chest compressions for pulse checksĭeitch K, Miner J, Chudnofsky CR, Dominici P, Latta D.

Prognostic factor of ROSC if <10 mmHg at 20 min of CPR ( Levin 1997).

Can provide a quantitative measure of chest compression effectiveness.The gold standard for confirmation of tracheal placement ( Grmec 2002).Pattern also seen in leaks in breathing system (endotracheal tube leaks).Upsloping of alveolar plateau due to alveolar leak of CO 2.Metabolic acidosis → decreased HCO 3 → compensatory hyperventilation → increased minute ventilation and decreased ETCO 2.May also detect other adverse effects, such as bronchospasm, laryngospasm, or upper airway obstruction.Median time to difference in detection = 60 seconds.Earlier recognition of respiratory depression when compared to pulse-oximetry ( Deitch 2010).Unlike pulse-oximetry, not prone to motion artifact.Sedated patients (Opioid Abuse, EtOH intoxication, procedural sedation, etc.).Purple ( 50 mmHg or increase greater than 10 mmHg from baselineĬlinical Applications in the Emergency Department.Colorimetric – qualitative measure (color change) of expired CO 2 covering a wide range of values, therefore use is limited primarily to verify correct ETT placement.

Can be placed in parallel and can be used in non-intubated patients (e.g.

Side Stream detector – takes sample of expired gas.

#CAPNOGRAPHY RANGE SERIES#

In series with endotracheal intubation tube.Mainstream – must be attached to the ventilator circuit.Definition: Noninvasive measurement of the concentration (partial pressure) of expired carbon dioxide over time.

Capnography range