Ventilation monitoring during monitored anesthesia care: a review.

The use of capnography during general anesthesia has become not only state of the art but also a recommended standard of care. In intubated patients, measurements of partial pressure of carbon dioxide in exhaled pulmonary gases approximate partial pressure of carbon dioxide in arterial blood under stable conditions. End-tidal carbon dioxide measurement has allowed anesthetists to continuously follow carbon dioxide concentration in exhaled gases; indirectly, it has enabled them to continuously monitor carbon dioxide concentration in arterial blood. This information has proven indispensable in the care of patients receiving general anesthesia, with its accompanying respiratory depressant effects. Recently, attention has focused on the utilization of capnography in sedated, nonintubated patients to follow carbon dioxide concentrations and access respiratory system function. This review of the current body of literature outlines development in capnography monitoring for sedated, nonintubated patients. Emphasis is placed on current techniques of measurement, the degree of correlation, and ramifications for clinical practice.