Cardiopulmonary monitoring in the respiratory intensive care unit.

Respiratory monitoring using airway measurements of flow, pressure, and oxygen and carbon dioxide concentrations is practical and useful for intensive care patients on respirator support. End-tidal PCO2 minute and tidal volumes, and compliance are the most useful simple measurements. On-line plots of pressure against volume and flow against volume are helpful in early detection of difficulty. More sophisticated pulmonary function tests such as maximum flows and volumes, functional residual capacity, and measurement of fast space and slow space can be easily automated under computer control. Respiratory monitoring provides painless, nonpenetrating measurements which are immediately available, and which reduce the incidence of undetected life-threatening respiratory accidents.