Incidence, Morbidity, and Mortality of Pulmonary Complications in Free Flap Reconstruction: Limitations of Predictive Models.

[OBJECTIVE] Herein, we evaluate the incidence, risk factors, and prognostic implications of postoperative pulmonary complications (PPCs) in head and neck microvascular free flap (MVFF) reconstruction. Current prediction models were assessed, and a head and neck MVFF-specific model is proposed.

[STUDY DESIGN] Retrospective review of 638 head and neck MVFF cases from August 2019 to May 2024.

[SETTING] Tertiary academic center.

[METHODS] Data were collected via chart review focusing on preoperative, intraoperative, and postoperative risk factors for PPCs within 30 days of surgery.

[RESULTS] Grades 2 to 5 PPCs occurred in 27% of patients. Predictors of PPCs in univariate analysis include prolonged surgery (mean: 10.06 ± 2.67 hours, P = .006), estimated blood loss ≥ 200 mL (n = 111, P = .006), advanced tumor stage (III/IV: n = 123, P = .013), hematoma (n = 25, P < .001), and postoperative transfusion (n = 20, P = .037). Tumor stage (odds ratio [OR] 1.29, 95% CI 1.06-1.57, P = .012), surgery duration (OR 1.08, 95% CI 1.01-1.17, P = .031), and hematoma (OR 2.98, 95% CI 1.50-5.94, P = .002) remained significant predictors of grades 2 to 5 PPCs on multivariable analysis. In-hospital mortality was 1.4% (n = 9), and all experienced grade 5 PPCs. The 1-year mortality rate was 13.48 per 100 patients, with significantly lower survival in patients with grades 2 to 5 PPCs (75.6% vs 89.4%). PPC was independently associated with mortality (hazard ratio [HR] 3.94, 95% CI 1.69-9.22, P = .002). Our model (area under the curve [AUC] 0.65) outperformed the ARISCAT (AUC = 0.51) and Gupta scores (AUC = 0.45) in predicting PPCs.

[CONCLUSION] PPCs are common after MVFF, contributing to significant morbidity and mortality. Current models are inadequate, highlighting the need for a tailored model specific to oncologic head and neck surgery.