Mechanical power during one-lung ventilation is associated with postoperative pulmonary complications in patients undergoing lobectomy: a single-center prospective cohort study

Citation:

Zhang Y, Wang X, Zhang Z, Zhang Y, Deng Z, Lei X, et al. Mechanical power during one-lung ventilation is associated with postoperative pulmonary complications in patients undergoing lobectomy: a single-center prospective cohort study. BMC Anesthesiology. 2026; Epub ahead of print.

This single-center prospective cohort of thoracoscopic lobectomy patients found that higher mechanical power during one-lung ventilation was statistically associated with more postoperative pulmonary complications, mainly pneumonia. However, residual confounding, a single time-point exposure measure, and wide confidence intervals mean the evidence is very uncertain for a causal effect, so proposed mechanical power thresholds should be viewed as hypothesis-generating rather than practice-changing.

Study at a glance

- Design and setting: Prospective single-center observational cohort at a university-affiliated hospital in China, enrolling adults with low American Society of Anesthesiologists physical status undergoing elective thoracoscopic lobectomy with one-lung ventilation between August two thousand twenty two and July two thousand twenty four (one hundred eighteen patients).

- Exposure and comparator: Mechanical power delivered by the ventilator during one-lung ventilation, measured at one hour after the start of one-lung ventilation and derived from tidal volume, pressures, respiratory rate, elastance, resistance, and inspiratory to expiratory ratio; analyses considered mechanical power as a continuous predictor, its elastic and resistive components, and a threshold around three point seven joules per minute, comparing higher versus lower mechanical power under routine anaesthetic care.

- Primary outcome: Postoperative pulmonary complications during the in-hospital period, defined as a composite of pneumonia, atelectasis, acute respiratory distress syndrome, or clinically evident aspiration using standardized perioperative endpoint criteria; forty of one hundred eighteen patients developed at least one complication (about one third), predominantly pneumonia, with no cases of acute respiratory distress syndrome or aspiration observed.

- Key findings: After adjustment for body mass index, hypertension, side of surgery, propofol dose, and inspired oxygen fraction at one hour, higher mechanical power at that time point was associated with increased odds of postoperative pulmonary complications (for example, mechanical power per unit increase odds ratio about one point six seven, ninety five percent confidence interval roughly one point zero one to two point seven six). Driving pressure alone at the same time point showed little to no association, while elastic and resistive components of mechanical power and mechanical power scaled to ventilated lung volume showed similar harmful patterns.

- Threshold analysis and oxygenation: A data-derived threshold around three point seven joules per minute suggested that patients at or above this level had higher odds of complications (adjusted odds ratio about two point nine one, ninety five percent confidence interval approximately one point zero eight to seven point eight six), but estimates were imprecise. Impaired postoperative oxygenation within twenty four hours and higher inflammatory cytokine levels, particularly interleukin six, interleukin eight, and interleukin ten on postoperative day two, were more frequent among patients with complications, consistent with an inflammatory lung injury phenotype.

- Certainty and risk of bias: Overall certainty that higher mechanical power causally increases postoperative pulmonary complications is rated very low, due to serious risk of bias from residual and unmeasured confounding (limited adjustment set, no advanced causal modelling), potential exposure misclassification from relying on a single one-hour measurement, possible outcome misclassification, and imprecision with only forty events and wide confidence intervals around the odds ratios.

- Practice implications: Findings support paying attention to mechanical power as an integrative marker of ventilator stress during one-lung ventilation and considering reductions in unnecessary ventilatory energy where feasible, in the context of established lung-protective strategies. However, the data are hypothesis-generating only; clinicians should not adopt a rigid mechanical power threshold from this study, and high-quality interventional trials are needed to test whether actively targeting lower mechanical power improves clinical outcomes.