A novel method to determine respiratory system mechanics during assisted ventilation
نویسندگان
چکیده
Methods We included 20 mechanically ventilated patients. Respiratory system compliance was calculated by dividing the volume change induced by small changes in pressure-support level by the corresponding change in mean inspiratory airway pressure with subsequent adjustment for the pressure-support termination criterion (25% of peak inspiratory flow). To determine the respiratory time constant (τ), every expiratory flow-volume curve was divided into ten slices of equal volume. τ was calculated as the mean value of the curve ́s slopes in every slice of one breath only in the breaths with linear flow-volume relationship. Respiratory system resistance was derived by dividing compliance by τ. As a reference, we determined respiratory system mechanics measured during volumecontrolled ventilation with constant inspiratory flow.
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