A new method to obtain positive end-expiratory pressure

The currently used method for obtaining PEEP (Positive End Expiratory Pressure) in mechanical lung ventilation employs a constant pressure valve at the end of the expiratory tube. In some circumstances, this procedure leads to an auto-PEEP, resulting from lung dynamic hyperinflation. The proposed method uses a controlled on-off valve based on parameters obtained from the respiratory system (RS). It is capable of reducing the minimum expiratory time maintaining the desired PEEP and thus reduces the possibility of auto-PEEP. In simulations with homogeneous viscoelastic models of the RS, representing normal and ARDS patients, this method controlled the PEEP, with errors bellow 0.5 cm H ₂O in the majority of the tests. The method seems robust and secure with good performance also when RS nonlinearities are introduced and with noisy pressure and flow signals