Clinical
Reviews in Emergency Medicine

The Journal of Emergency Medicine, Vol. 53, No. 6, pp. 829–842, 2017

This clinical review highlights the value of capnography in Emergency Medicine. The following is the abstract and readers are encouraged to read the full text of the article from the Journal site.

The authors conducted a literature search of Medline, EBSCO, and Google Scholar for search terms pertaining to capnography and related terms (capnography, capnogram, interpretation, cardiac arrest,
procedural sedation, end-tidal, return of spontaneous circulation, trauma, injury, metabolic acidosis/acidemia, critical illness, pulmonary embolism, seizure, sepsis, and obstructive airway disease. This was not a systematic review or meta-analysis but a comprehensive review of capnography for Emergency Medicine Physicians.

Abstract:

Abstract—Background: Capnography has many uses in
the emergency department (ED) and critical care setting,
most commonly cardiac arrest and procedural sedation.
Objective of the Review: This review evaluates several indications
concerning capnography beyond cardiac arrest and
procedural sedation in the ED, as well as limitations and
specific waveforms. Discussion: Capnography includes the
noninvasive measurement of CO2, providing information
on ventilation, perfusion, and metabolism in intubated and
spontaneously breathing patients. Since the 1990s, capnography
has been utilized extensively for cardiac arrest and
procedural sedation. Qualitative capnography includes a
colorimetric device, changing color on the amount of CO2
present. Quantitative capnography provides a numeric
value (end-tidal CO2), and capnography most commonly
includes a waveform as a function of time. Conditions in
which capnography is informative include cardiac arrest,
procedural sedation, mechanically ventilated patients, and
patients with metabolic acidemia. Patients with seizure,
trauma, and respiratory conditions, such as pulmonary
embolism and obstructive airway disease, can benefit from
capnography, but further study is needed. Limitations
include use of capnography in conditions with mixed pathophysiology,
patients with low tidal volumes, and equipment
malfunction. Capnography should be used in conjunction
with clinical assessment. Conclusions: Capnography demonstrates
benefit in cardiac arrest, procedural sedation, mechanically
ventilated patients, and patients with metabolic
acidemia. Further study is required in patients with seizure,
trauma, and respiratory conditions. It should only be used in
conjunction with other patient factors and clinical assessment.