Detecting Excessive Inspiratory Effort on Volume Control Waveforms

These ventilator scalars are from a patient on volume control ventilation. The airway pressure trace shows a brief dip below baseline during inspiration, suggesting strong inspiratory efforts. The flow-time scalar displays a rounded inspiratory contour instead of the typical straight line seen in volume control mode with constant flow. This occurs due to a ventilator feature called flow adaptation, in which the ventilator senses strong inspiratory effort and automatically adjusts to deliver pressure support breath instead of a mandatory volume-controlled one. In effect, mandatory breaths are converted into a spontaneous pressure-supported breaths, allowing the ventilator to better match the patient's demand.