Effects of pressure-support ventilation on recovery from acute diaphragmatic fatigue in rabbits.

Abstract

To examine the effects of pressure-support ventilation on recovery from acute diaphragmatic fatigue. Prospective laboratory trial. Experimental laboratory. Twenty-one healthy, adult New Zealand white rabbits. Diaphragmatic fatigue was induced with 50-Hz phrenic nerve stimulation for 30 mins. Recovery was compared between pressure-support ventilation 0 cm H2O (SB), 10 cm H2O (P10), and 20 cm H2O (P20) for 90 mins immediately after the end of the fatigue inducing procedure. After the fatigue-inducing procedure, pressure-support ventilation reduced transdiaphragmatic pressure and integrated diaphragmatic electromyogram both at P20 and P10, but not in SB. Recovery was assessed by airway occlusion pressure (Poccl) generated by high- (100 Hz) and low- (20 Hz) frequency phrenic nerve stimulation. Poccl at 100 Hz was lower in P10 and P20 than in SB (74.6 +/- 6.2 [SEM] %, 66.9 +/- 3.3%, and 94.8 +/- 3.6% of the baseline at 90 mins for P10, P20, and SB, respectively), while those at 20 Hz showed no differences between the three groups. Recovery from acute diaphragmatic fatigue might be disturbed with pressure-support ventilation.