End-tidal to arterial PCO₂ ratio: a bedside meter of the overall gas exchanger performance.

ABSTRACT:

Background

The physiological dead space is a strong indicator of severity and outcome of acute respiratory distress syndrome (ARDS). The "ideal" alveolar PCO₂, in equilibrium with pulmonary capillary PCO₂, is a central concept in the physiological dead space measurement. As it cannot be measured, it is surrogated by arterial PCO₂ which, unfortunately, may be far higher than ideal alveolar PCO₂, when the right-to-left venous admixture is present. The "ideal" alveolar PCO₂ equals the end-tidal PCO₂ (P_ETCO₂) only in absence of alveolar dead space. Therefore, in the perfect gas exchanger (alveolar dead space = 0, venous admixture = 0), the P_ETCO₂/PaCO₂ is 1, as P

SUBMITTER: Bonifazi M 

PROVIDER: S-EPMC8054233 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature