Intraoperative mechanical power and postoperative pulmonary complications: association and threshold analysis in adult intra-abdominal surgery.

BACKGROUND

Postoperative pulmonary complications (PPCs) contribute to perioperative morbidity and mortality. Mechanical powers (MPs) determined using different deviations from originally described MP have been shown to be associated with PPCs. We aimed to evaluate the association between a standardized derivation of MP and PPCs and to explore a threshold associated with increased risk in multicentre cohort of adults undergoing intra-abdominal surgery.

METHODS

Data on adult patients who underwent intra-abdominal surgery under general anaesthesia were obtained from the Multicentre Perioperative Outcomes Group registry. The primary outcome was a composite of PPCs comprising an expanded subset of diagnoses consistent with European Perioperative Clinical Outcome definitions. The association between intraoperative MP and PPCs was evaluated using multivariable logistic regression, adjusting for patient, surgical, and institutional factors.

RESULTS

Among 79,149 patients from 56 institutions, 4,812 (6.1%) developed PPCs. Each 1 J/ min increase in MP was associated with 5% higher odds of PPCs (OR = 1.05, 95% CI [1.05-1.06]; p < 0.0001). Receiver operating characteristic analysis identified a threshold of 12 J/ min (sensitivity = 0.54, specificity = 0.51), above which patients had 54% higher adjusted odds of PPCs (ORadj = 1.54, 95% CI [1.42-1.66]; p < 0.0001).

CONCLUSIONS

Higher MP was associated with increased risk of PPCs in patients undergoing intra-abdominal surgery. Although MP values above 12 J min⁻1 were associated with significantly increased odds of PPCs, this threshold demonstrated notably low standalone discriminatory performance. Further research is required to evaluate whether MP-directed lung-protective ventilation strategy could prospectively improve clinical outcomes. RESEARCH REGISTRATION NUMBER: https://doi.org/10.17605/OSF.IO/WRQ6B .