Association between mechanical power and intensive care unit mortality according to the use of neuromuscular blockade in patients under pressure-controlled ventilation

초록

Background and Aims Mechanical power (MP), which integrates ventilator variables affecting ventilator-induced lung injury, is reported to be associated with clinical outcomes. Because original MP equation is derived from paralyzed patient under volume-controlled ventilation, its application to practice could be limited. Recently, simplified equation for patients under pressure-controlled ventilation(PCV) is developed. We investigated association between MP and intensive care unit (ICU) mortality, and cut-off value according to the use of neuromuscular blockade(NMB) in patients under PCV. Methods We conducted a post-hoc analysis of Korean data from the fourth International Study on Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using following equation: MPPCV = 0.098 * RR * VT *(△Pinsp + PEEP). Multivariate logistic regression and receiver operating characteristic curve were used for analysis. Results Of 160 patients under PCV on day 1, MPPCV can be obtained from 125 patients. Nineteen patients were treated with NMB, and 9 died in ICU. MPPCV was 16.0 J/min in survivor and 22.2 J/min in non-survivors (p=0.013). Cut-off value for mortality was 20.4 J/min. Of 106 patients without NMB, 29 died in ICU. MPPCV was 17.6 J/min in survivors and 26.3 J/min in non-survivors (p< 0.001). MPPCV was independently associated with ICU mortality (oddsratio, 1.108; 95% confidence interval, 1.048-1.171;p< 0.001). Cut-off value was 23.5 J/min. Conclusion MPPCV was associated with ICU mortality inpatients under PCV, and the cut-off value was similar in both NMB users and non-users. Acknowledgment We appreciate all members of the Korean Study Group on Respiratory Failure (KOSREF).