Oxygen wash-in method for monitoring functional residual capacity
Atelectasis, pulmonary edema, fibrosis, pneumothorax, and mucous plug airway obstruction all result in reduced lung volume. The oxygen (O2) wash-in method provides a way to monitor routinely the functional residual capacity (FRC) in the ICU without disconnecting the patient from the ventilator and w...
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Published in | Critical care medicine Vol. 10; no. 8; p. 529 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.08.1982
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Subjects | |
Online Access | Get more information |
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Summary: | Atelectasis, pulmonary edema, fibrosis, pneumothorax, and mucous plug airway obstruction all result in reduced lung volume. The oxygen (O2) wash-in method provides a way to monitor routinely the functional residual capacity (FRC) in the ICU without disconnecting the patient from the ventilator and without additional personnel or instrumentation. This method is a modification of an open-circuit nitrogen (N2) wash-out procedure and requires a computer-based respiratory monitoring system with a fast response O2 analyzer and respiratory flowmeter. FRC is computed after a 20% or greater change in the ventilator FIO2 setting. The accuracy and reproducibility of the method were evaluated using artificial lungs, normal subjects, and postcardiac surgery patients. FRC estimates by O2 wash-in and helium dilution were highly correlated, with r = 0.97 and a regression slope and zero intercept of 1.06 and -0.13, respectively. The FRC difference between 23 repeated trials in 18 postcardiac surgery patients was 70 +/- 160 ml (mean +/- SD). |
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ISSN: | 0090-3493 |
DOI: | 10.1097/00003246-198208000-00010 |