Impaired oxygenation after lung resection: Incidence and perioperative risk factors

Study objective: To estimate the incidence of postoperative oxygenation impairment after lung resection in the era of lung-protective management, and to identify perioperative factors associated with that impairment. Design: Registry-based retrospective cohort study. Setting: Two large academic hospitals in the United States. Patients: 3081 ASA I-IV patients undergoing lung resection. Measurements: 79 pre- and intraoperative variables, selected for inclusion based on a causal inference framework. The primary outcome of impaired oxygenation, an early marker of lung injury, was defined as at least one of the following within seven postoperative days: (1) SpO₂ < 92%; (2) imputed PaO₂/FiO₂ < 300 mmHg [(1) or (2) occurring at least twice within 24 h]; (3) intensive oxygen therapy (mechanical ventilation or > 50% oxygen or high-flow oxygen). Main results: Oxygenation was impaired within seven postoperative days in 70.8% of patients (26.6% with PaO₂/FiO₂ < 200 mmHg or intensive oxygen therapy). In multivariable analysis, each additional cmH₂O of intraoperative median driving pressure was associated with a 7% higher risk of impaired oxygenation (OR 1.07; 95%CI 1.04 to 1.10). Higher median intraoperative FiO₂ (OR 1.23; 95%CI 1.14 to 1.31 per 0.1) and PEEP (OR 1.12; 95%CI 1.04 to 1.21 per 1 cm H₂O) were also associated with increased risk. History of COPD (OR 2.55; 95%CI 1.95 to 3.35) and intraoperative albuterol administration (OR 2.07; 95%CI 1.17 to 3.67) also showed reliable effects. Conclusions: Impaired postoperative oxygenation is common after lung resection and is associated with potentially modifiable pre- and intraoperative respiratory factors.