Comparison Between Different Ventilator Hyperinflation Maneuvers

controlled volume ventilation mode under constant flow of 20 Lpm. The inspired volume was progressively increased until the Pmax reached 40cmH2O.

volume controlled ventilation mode under constant flow of 40 Lpm. The inspired volume was progressively increased until the Pmax reached 40cmH2O.

controlled ventilation mode, 1 second inspiratory time. The inspiratory pressure was increased every 5 cmH2O, until reaching the maximum pressure of 40 cmH2O.

controlled ventilation and inspiratory pressure was increased every 5 cmH2O until the maximum pressure was 40 cmH2O. The inspiratory time was gradually increased until the inspiratory flow reached the baseline. Concomitantly, the respiratory rate was decreased to allow the expiratory flow also to reach the baseline, to avoid self-PEEP.

ventilatory mode with pressure support, with progressive increases of 5 cmH2O at inspiratory pressure, until reaching Pmax of 40 cmH2O. The expiratory sensitivity was adjusted by 25% for all patients.