Mechanical Power Normalized to Predicted Body Weight is Associated with Mortality in Critically Ill Patients: A Cohort Study

Background: Mechanical power (MP), defined as the amount of energy produced by mechanical ventilation and released into the respiratory system, has long been considered a critical factor in the pathogenesis of ventilator-induced lung injury. However, our knowledge suggests that the effects of MP may be proportional to their involvement in total lung function size. Therefore, MP normalized to predicted body weight (norMP) should be greater than absolute MP value. The objective of this research is to determine the connection between norMP and mortality in critically ill patients who have been on invasive ventilation for at least 48 hours. Methods: : This is a study of data stored in the databases of the MIMIC–III, which contains data of critically ill patients for over 50,000. The study involved critically ill patients who had been on invasive ventilation for at least 48 hours. norMP was the relevant exposure. The major endpoint was ICU mortality, the secondary endpoints were 30-day, 90-day mortality; ICU length of stay, the number of ventilator-free days at day 28. Result: The study involved a total of 1301 critically ill patients. This study revealed that norMP was correlated with ICU mortality [OR per quartile increase 1.20 (95% CI 1.07–1.35), p = 0.009]. Similarly, norMP was correlated with ventilator-free days at day 28, ICU length of stay. In the subgroup analysis, high norMP was associated with ICU mortality whether low or high Vt (OR 1.22, 95% CI 1.01–1.47, p = 0.040; OR 1.28, 95% CI 1.06–1.54, p = 0.011, respectively). But high norMP was associated with ICU mortality only in low PIP (OR 1.18, 95% CI 1.01–1.37, p = 0.034) Conclusion: Our findings indicate that higher norMP is independently linked with elevated ICU mortality and various other clinical findings in critically ill patients with a minimum of 48 hours of invasive ventilation.