A prospective randomized study on noninvasive pressure support versus proportional assist ventilation in chronic respiratory failure

Objective To compare the effects and compliance of noninvasive proportional assist ventilation(PAV) and pressure support ventilation(PSV) in the treatment of chronic respiratory failure(CRF).Methods PAV and PSV were randomly applied in 20 patients in clinically stable condition with CRF due to COPD.The average tidal volume(V_T),minute ventilation(V_E),peak inspiratory pressure(PIP) and nocturnal ventilation time were recorded during ventilation.The sleep quality,ventilation comfort and side effects were evaluated by visual analog scale(VAS).Results There were no significant differences in V_E and V_T between PAV and PSV(P0.05).The PIP was slightly lower during PAV [(12.2±2.4)cm H_2O vs(15.6±3.8)cm H_2O,t=2.391,P0.05].Nocturnal ventilation time significantly prolonged in PAV [(3.3±0.7)h vs(2.6±0.5)h,(P)0.05].The VAS score showed that the degree of nasal and pharynx dryness [(3.6±0.7) vs((4.5±0.9)),P0.05] as well as oral air leak [(3.3±0.6) vs(4.4±0.8),P0.01] were milder in PAV as compared to PSV.Conclusion Noninvasive PAV shows better patient compliance in CRF.