Severely Reduced Compliance in Pressure Control

Why low airway pressures in pressure control can hide severely reduced compliance — focus on the delivered tidal volume.

PCMechanicsM3M4

Fig 1.This waveform shows a patient on Pressure Control. Even though airway pressures are low, this should not be interpreted as a sign of normal respiratory system mechanics. Since pressure is set by the operator and controlled by the ventilator in PC, it’s important to focus on the delivered tidal volume, which in this case is only 35 mL, indicating very poor mechanics. Static or lung/chest wall compliance in this case is 35ml/4.8cmH2O, which equals about 7ml/cmH2O and is severely reduced (normal >50ml/cmH2O).

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Comprehensive · M3 — Airway resistance vs. compliance

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