Dependency of Tidal Volume on Mean Airway Pressure in High-Frequency Oscillatory Ventilation

Abstract

Recent studies have shown that there exists a dependence of tidal volume on a mean airway pressure in high-frequency oscillatory ventilation. Objective of the present study was to examine if the dependence is caused by changing the mean airway pressure value itself or if it is caused by a change of the mechanical properties of the respiratory system according to a change of the mean airway pressure. Ventilator 3100B and rigid respiratory system models of volumes 25 L, 35 L, 50 L and 120 L with constant mechanical properties were used in the experimental circuit. Volume flow and tidal volume was measured with custom-made orifice and 2100 Respiration Monitor. Mean airway pressure was increased from baseline value by 4 cmH₂O every 1.5 min. It was shown that there is a statistically significant relationship between tidal volume and the mean airway pressure in constant mechanical properties of the respiratory system.