Innate Biological Vulnerability: Male Sex as an Independent Risk Factor for Postoperative Pulmonary Complications in Infants Undergoing One-lung Ventilation.

OBJECTIVE

To determine whether male sex independently increases the risk of postoperative pulmonary complications (PPCs) in infants undergoing video-assisted thoracic surgery with one-lung ventilation.

DESIGN

Retrospective cohort study (2018-2023).

SETTING

Single high-volume tertiary pediatric thoracic surgery center.

PARTICIPANTS

We included 547 infants (median age, 6 months; interquartile range, 3-9 months) who underwent elective video-assisted thoracic surgery lung resection. Exclusion criteria were preoperative mechanical ventilation, congenital heart disease, or incomplete records.

INTERVENTIONS: None (observational study). All patients received standardized intraoperative management including one-lung ventilation via bronchial blocker and postoperative fast track extubation.

MEASUREMENTS AND MAIN

RESULTS

PPCs (respiratory failure, pneumonia, prolonged air leak, and therapeutic bronchoscopy for atelectasis) were adjudicated by two independent clinicians blinded to sex. Overall PPC incidence was 17.4% (95% confidence interval [CI], 14.3-20.8). Boys had a higher crude rate than girls (24% vs 11%; absolute risk difference 13%; 95% CI, 7-19). Six multivariable logistic regression models were constructed to address anthropometric and respiratory-mechanics multicollinearity: each of three anthropometric variables (age, height, weight) was paired with two alternative ventilation-parameter sets-either the individual components (PEEP, peak airway pressure, respiratory rate, tidal volume; Models 1-3) or mechanical power as their composite (Models 4-6)-while keeping ASA class, estimated blood loss, operation type, lesion side, OLV duration, and surgeon experience constant. Male sex was an independent predictor of PPCs in all six models (adjusted OR range, 2.28-2.49; all p ≤ 0.002); the age-adjusted OR was 2.31 (95% CI, 1.36-3.93; p = 0.002).After 1:1 propensity-score matching (n = 190), the association remained unchanged (adjusted OR, 2.34; 95% CI, 1.31-4.17; p = 0.004). Interaction analyses showed no effect modification by ventilation duration (Pinteraction = 0.755), surgeon experience (Pinteraction = 0.554), or procedure type (Pinteraction = 0.612).

CONCLUSIONS

Male sex is associated with a 2.5-fold increase in PPC risk that persisted after adjusting for surgical complexity and perioperative course. These data support the concept of an innate male biological vulnerability and highlight the potential value of considering sex-specific perioperative surveillance strategies in infant thoracic surgery.