Dispelling ICU myths: “Pressure control ventilation is safer than volume control ventilation.”

This is a common misconception that Pressure Control Ventilation (PCV) is somehow “safer” than Volume Control Ventilation (VCV), presumably because the pressure is controlled. Similarly, some believe that VCV can ventilate better than PCV because the volume is set.

Neither notion is based on understanding physics and physiology. Lung compliance (lungs’ ability to stretch) determines the relationship between the volume of a breath and the pressure difference needed to deliver that volume.

Compliance = delta V / delta P

Please note that the ventilation mode is NOT a part of this equation. Consequently, the relationship stands for both pressure-controlled and volume-controlled breath.

If lung compliance changes with time due to improving or worsening underlying conditions, both modes have safeguards to warn the clinicians about the change. In PCV, low/high tidal volume/minute ventilation alarms will be activated. In VCV, high/low peak inspiratory pressure will alarm.

The ONLY benefit of pressure control ventilation I can think of is related to the ability of PCV to provide variable flows during inspiration, therefore providing better synchrony in patients with high inspiratory demand.

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