Mechanical Power Differs Between Pressure-Controlled Ventilation and Different Volume-Controlled Ventilation Modes.

OBJECTIVES

Mechanical power (MP) is a way of estimating the energy delivered by the ventilator to the patient. For both volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) methods have been described to calculate the MP. The pressure-volume (PV) loop, from which the MP is calculated, is different for VCV compared with PCV. We aimed to compare the MP of VCV with zero pause time (VCV-0), VCV with 10% pause time (VCV-10), and PCV within patients in different patient categories based on severity of lung injury.

DESIGN

In a proof-of-concept study, we enrolled 46 mechanically ventilated patients without spontaneous breathing efforts. Baseline measurements were done in pressure-controlled mode. Subsequently, measurements were done in VCV-0 and VCV-10. Tidal volume and all other settings were kept the same.

SETTING

ICU, single university medical center.

PATIENTS

Fifty-eight cases in 46 patients on controlled ventilation modes.

INTERVENTIONS

Comparison between the MP of PCV, VCV-0, and VCV-10.

MEASUREMENT AND MAIN RESULTS

The mean MP of VCV-0, VCV-10, and PCV was 19.30, 21.80, and 20.87 J/min, respectively ( < 0.05 for all comparisons). The transpulmonary MP of VCV-0, VCV-10, and PCV was 6.75, 8.60, and 7.99 J/min, respectively ( < 0.05 for all comparisons).

CONCLUSIONS

In patients ventilated in a controlled mode, VCV without pause time had the lowest MP followed by PCV. VCV with 10% pause time had the highest MP.