Validation of an oxygen-wash in/wash out technique for determination of FRC

DOI: 10.36210/BerMedJ/epub662019

Abstract

The routine determination of the functional residual capacity (FRC) was to assess the progress and to monitor therapeutic procedures to ventilated patients benefit. It was measured by means LUFU FRC (LUFU FRC) in 20 healthy volunteers when sitting or lying, and in 15 lung disease patients in a sitting position with the determined by helium dilution FRC (He-FRC) and with the determined by body plethysmography intrathoracic gas volume (ITGV ) compared. In each case four LUFU FRC values (FiO2 change of 0.21 to 0.5 and back to 0.21 and from 0.21 to 1.0 and back to 0.21) and two He-FRC and two were ITGV values bestimmt.Bei the volunteers had mean LUFU FRC sitting at 3.26 L, the He-FRC sitting at 3.11 L and 3.08 L ITGV in while the values lying on 2.29 L in LUFU FRC and 2.00 L reduced in the He-FRC. The correlation between LUFU FRC and FRC He gave a sitting R2 of 0.84 and lying a R2 of 0.80. Average arose for sitting and lying measurements a correlation of R2 = 0.87. Between LUFU FRC and ITGV was the correlation R2 = 0.81 and was between He-FRC and ITGV the R2 = 0.82. The comparison of the FiO 2 of 0.29 and 0.79 in the LUFU FRC showed together for lying and sitting position a correlation of R2 = 0.96. From the comparison of the determined by Sauerstoffeinatmung and Sauerstoffauswaschung average FRC an R2 = 0.95 resulted. The comparison of the first and second measurement revealed in all methods of determination from 0.74 to 0.96.