Normal capnogram. Phase I: At the start of exhalation, carbon dioxide concentration in the exhaled gas is essentially zero, representing gas from the
anatomic dead space that does not participate in gas exchange. Phase II: As the anatomic dead space is exhaled, carbon dioxide concentration rises as
alveolar gas exits the airway. Phase III: For most of exhalation, carbon dioxide concentration is constant and reflects the concentration of carbon dioxide in
alveolar gas. Phase IV: During inhalation, carbon dioxide concentration decreases to zero as atmospheric air enters the airway. [Reproduced with
permission from Krauss B, Hess DR: Capnography for procedural sedation and analgesia in the emergency department. Ann Emerg Med 50: 172, 2007
(Table 1, p. 176). Copyright Elsevier.]
Source: Procedural Sedation in Adults, Tintinalli's Emergency Medicine: A Comprehensive Study Guide
Citation: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. Tintinalli's Emergency Medicine: A Comprehensive Study
Guide; 2011 Available at: http://mhmedical.com/ Accessed: July 31, 2017
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