Is pressure-regulated volume control mode appropriate for severely obstructed patients?

Abstract

Purpose: Management of mechanical ventilation in severely obstructed patients remains controversial. Pressure-regulated volume control ventilation (PRVCV) has been suggested to be the best option, as it should ensure a prefixed tidal volume at the lowest peak inspiratory pressure. We sought to determine the accuracy of the delivered volume, compared with the programmed volume, when using PRVCV.

Materials and methods: Experimental work performing ventilation simulations using volume control ventilation (VCV), PRVCV, and pressure control ventilation (PCV). Each mode was tested at tidal volumes (TVs) of 200 and 500 mL at both low and high airway resistance. Evita XL and Servo-i ventilators were used.

Results: At 200 ml TV with high resistance, volume delivered with Evita XL was 165 mL (95% confidence interval, 158-169) in VCV, 117 mL (95% confidence interval, 117-120) in PCV, and 120 (95% confidence interval, 115-121) in PRVCV (P<.001). Volume delivered with Servo-i was 133 mL (95% confidence interval, 130-136) in VCV, 108 mL (95% confidence interval, 104-111) in PCV, and 104 (95% confidence interval, 101-108) in PRVCV (P<.001).

Conclusions: In high-resistance simulations, the delivered volume was lower when using PCV or PRVCV modes than VCV mode. Pressure control ventilation or PRVCV may fail to provide programmed TV, ultimately leading to hypoventilation of the patient.

Keywords: Airway resistance; Asthma; Bronchiolitis; Hypoventilation; Mechanical ventilation; Tidal volume.