The power of mechanical ventilation may predict mortality in critically ill patients

Mechanical power (MP) is the amount of energy transferred from the ventilator to the patient within a unit of time. It has been emphasized in ventilation-induced lung injury (VILI) and mortality. However, its measurement and use in clinical practice are challenging. "Electronic recording systems (ERS)" using mechanical ventilation parameters provided by the ventilator can be helpful to measure and record the MP. The MP (J/minutes) formula is 0.098 x tidal volume x respiratory rate x (Ppeak - ½ ∆P), in which ∆P is the driving pressure and Ppeak is the peak pressure. We aimed to define the association between MP values and ICU mortality, mechanical ventilation days, and intensive care unit length of stay (ICU-LOS). The secondary outcome was to determine the most potent or essential component of power in the equation that has a role in mortality.

This retrospective study was performed in two centers (VKV American Hospital and Bakırköy Sadi Konuk Hospital ICUs) that used ERS (Metavision IMDsoft) between 2014 and 2018. We uploaded the power formula (MP (J/minutes)=0.098×VT×RR×(Ppeak - ½ ∆P) to ERS (METAvision, iMDsoft, and Consult Orion Health) and calculated the MP value by using MV parameters automatically sent from the ventilator. (∆P; driving pressure, VT; tidal volume, RR; respiratory rate and Ppeak; peak pressure).

A total of 3042 patients were included in the study. The median value of MP was 11.3 J/min. Mortality in MP<11.3 J/min was 35.4%, and 49.1% in MP>11.3J/min.; P<0.001. Mechanical ventilation days and ICU-LOS were also statistically longer in the MVP>11.3 J/min group.

The first 24 h MP maybe a predictive value for the ICU patients' prognosis. This implies that MP may be used as a decision-making system to define the clinical approach and as a scoring system to predict patient prognosis.