Association between mechanical power normalized to compliance and prognosis of critically ill patients: A retrospective cohort study

Abstract

Abstract Background: The mechanical power (MP) of a ventilator, which is the accumulated energy load of multiple respiratory cycles per unit time, can vary based on the physiological state of the ventilated lungs, leading to different effects on the respiratory system. Accordingly, it is most reasonable to normalize the mechanical power to accurately reflect the actual volume of air reaching the lungs. At present, the relationship between MP normalized to compliance (MPCRS) and prognosis in critically ill patients under ventilation is not clear. Methods: This retrospective cohort study included a total of 3551 patients in the Medical Information Mart for Intensive Care (MIMIC) IV, with ICU mortality and in-hospital mortality as study outcomes. Multivariate regression analysis and subgroup analysis were used to explore the associations between MPCRS and prognosis in ventilator-supported critically ill patients. The results were illustrated using smoothing curves and forest plots. Results: Participants' mean age was 61.3 ± 17.0 years and the median [IQR]baseline MPCRS was 0.4(0.2,0.6) J/min/mL/cmH2O. After adjusting for covariates, the ORs [95% confidence intervals (CIs)] for ICU mortality were 1.22 (95% CI: 0.94-1.59), 1.68 (95% CI: 1.29-2.19), and 2.93 (95% CI: 2.20-3.90), respectively, with quartile 1as reference. Similar results were found for hospital mortality. After correcting for all covariables, the smoothing curves revealed a consistent linear relationship between ICU and hospital mortality. Conclusion: These results demonstrate that a higher MPCRS is associated with poor clinical outcomes in critically ill patients. Higher MPCRS can lead to a higher mortality among ICU and in-hospital patients.