Mechanical power in patients receiving mechanical ventilation in the surgical intensive care unit and its association with increased mortality: a retrospective cohort study

Abstract

INTRODUCTION: A potential correlation between mechanical power (MP) and clinical outcomes in mechanically ventilated patients has been reported. Limited data exist regarding MP among patients admitted to surgical intensive care units (SICUs) who require mechanical ventilation (MV) support. The primary objective of this study was to determine MP in mechanically ventilated patients admitted to the SICU, and the secondary objective was to explore whether MP was associated with clinical outcomes. METHODS: This retrospective cohort study conducted at the SICU of the tertiary university-based hospital included 283 postoperative patients admitted to the SICU who required MV support for ≥12 hours. Ventilator parameters were recorded at MV initiation and 24 hours, and MP was subsequently computed. Cox regression analysis was employed to assess the association between MP and 90-day mortality. RESULTS: MP at MV initiation and 24 hours were median 11.9 (IQR 8.6-17.1) J/min and 11.9 (8.9-16.8) J/min, respectively. MP was significantly higher in non-survivors both at MV initiation and 24 hours (15.4 (12.5-21.2) J/min vs 11 (8.3-15.6) J/min, p<0.001 and 15.9 (10.6-20.2) J/min vs 10.9 (8.5-15.4) J/min, p=0.001, respectively). MP ≥12 J/min at MV initiation was associated with increased 90-day mortality (HR 2.21, 95% CI 1.09 to 4.48), particularly among patients with high acuity, those at a high risk of acute lung injury and those who did not receive lung protective ventilation. In patients with MP ≥12 J/min at MV initiation, a subsequent rise in MP of ≥5 J/min at 24 hours was correlated with accentuated 90-day mortality. CONCLUSION: Among mechanically ventilated patients in the SICU, MP at the initiation and at 24 hours of MV support was approximately 12 J/min. An elevated MP was an independent predictor of elevated 90-day mortality, especially in cases with high illness acuity. Alterations in MP during MV support could impact the 90-day mortality in these individuals.