Determination of functional residual capacity by oxygen washin-washout: a validation study.

Objective: To validate a new system for functional residual capacity (FRC) measurements using oxygen washin/washout in spontaneously breathing humans. The system (LUFU, Drägerwerk AG, Lübeck, Germany) consists of an unmodified EVITA 4 ventilator, a side-stream paramagnetic oxygen sensor and a dedicated software.

Design: Laboratory study and measurements in spontaneously breathing volunteers.