Beyond pressure and volume: mechanical power levels in a cohort of intensive care unit patients.

Abstract

Background: Several ventilator parameters can be used to evaluate gas exchange and mechanical properties of the respiratory system in acute respiratory failure patients. The calculation of mechanical power (MP), a critical parameter that summarizes the energy transferred from the ventilator to the patient's lungs, is not routinely made in these patients.

Methods: This study analyzed the distribution of MP in a cohort of 70 patients requiring mechanical ventilation and investigated its association with clinical outcomes.

Results: This study included 39 men and 31 women with a mean age of 57.7 ± 15.1 years. The mean MP index decreased significantly from 10.4 J/min ± 5.65 on day 2 of mechanical ventilation to 8.3 J/min ± 4.1 on day 4 (p = 0.045). The mean length of mechanical ventilation was 5.2 ±6.5days. Mechanical power measured on day 2 (r = 0.317, p = 0.052) and day 4 (r = 0.352, p = 0.030) positively correlated with the duration of mechanical ventilation. There were no differences in MP between survivors and non-survivors on both day 2 (p = 0.458) and day 4 (p = 0.373).

Conclusions: This study analyzed the distribution of MP levels in mechanically ventilated patients in an ICU. Mechanical power measured on days 2 and 4 of mechanical ventilation had a positive correlation with the duration of ventilation, but it was not a significant predictor of ICU mortality.