Definition
Any obstruction to outflow can potentially lead to increased airway pressure, reduced minute ventilation, lung hyperinflation, and subsequent cardiopulmonary effects (ex. hypotension due to decreased venous return, lung injury due to volutrauma/barotrauma). The capnograph may show a prolonged expiratory upstroke (similar to in COPD)
An expiratory valve stuck in the open position may be detected by failure of capnogram to return to zero.
Expiratory Valve Dysfunction
- Stuck Closed: rise in airway pressures, reduced MV
- Stuck Open: failure of capnogram to return to zero
Subspecialty
Related Media
Keyword history
See Also:
Sources
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Dorsch JA and Dorsch SE. Understanding Anesthesia Equipment, 5th edition, LWW: p 414-5, 715. 2008
PubMed
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S T Pyles, L S Berman, J H Modell Expiratory valve dysfunction in a semiclosed circle anesthesia circuit–verification by analysis of carbon dioxide waveform. Anesth. Analg.: 1984, 63(5);536-7 [PubMed:6424510]
