Accuracy of the dynamic signal analysis approach in respiratory mechanics during noninvasive pressure support ventilation: a bench study.

Objective: To evaluate the accuracy of respiratory mechanics using dynamic signal analysis during noninvasive pressure support ventilation (PSV).

Methods: A Respironics V60 ventilator was connected to an active lung simulator to model normal, restrictive, obstructive, and mixed obstructive and restrictive profiles. The PSV was adjusted to maintain tidal volumes (V) that achieved 5.0, 7.0, and 10.0 mL/kg body weight, and the positive end-expiration pressure (PEEP) was set to 5 cmHO. Ventilator performance was evaluated by measuring the flow, airway pressure, and volume. The system compliance (C) and airway resistance (inspiratory and expiratory resistance, R and R, respectively) were calculated.

Results: Under active breathing conditions, the C was overestimated in the normal and restrictive models, and it decreased with an increasing pressure support (PS) level. The R calculated error was approximately 10% at 10.0 mL/kg of V, and similar results were obtained for the calculated R at 7.0 mL/kg of V.

Conclusion: Using dynamic signal analysis, appropriate tidal volume was beneficial for R, especially for estimating R during assisted ventilation. The C measurement was also relatively accurate in obstructive conditions.