Lung-protective ventilation strategies (LPVS) are widely used to reduce postoperative pulmonary complications (PPCs) in patients undergoing one-lung ventilation. The relationship between the partial pressure of carbon dioxide in end-expiratory gas (PetCO₂) and postoperative outcomes remains unclear. This study investigated the association of PetCO₂ with PPCs in patients undergoing thoracoscopic lobectomy with LPVS. This retrospective, observational, single-centre study included patients who underwent thoracoscopic lung lobectomy with LPVS between 31 December 2020 and 31 December 2024. The primary outcome was the incidence of PPCs during hospitalisation; the secondary outcome was postoperative length of stay. General and intraoperative characteristics were compared between patients who developed and those who did not develop PPCs. Multivariable logistic regression was performed to determine independent risk factor of PPCs. Subsequently, a predictive nomogram for PPC events was developed in R. The performance of nomogram model was comprehensively evaluated through ROC curve, calibration plot, and the Hosmer–Lemeshow goodness-of-fit test. Among the 383 patients included, 74 (19.3%) developed PPCs. The PPCs group had significantly lower PetCO₂ levels (t = 3.007, p = 0.003) and longer (t = 2.102, p = 0.036). Receiver operating characteristic analysis identified 40.9 mmHg as the optimal PetCO₂ threshold (sensitivity: 80.0%, specificity: 43.4%). Multivariable regression showed that PetCO₂ ≥ 40.9 mmHg (p = 0.040; odds ratio OR = 0.516), age (p < 0.001; OR = 1.032), American Society of Anaesthesiologists Physical Status Classification grade III (p = 0.029; OR = 1.876), forced expiratory volume in 1 s/forced vital capacity (p = 0.015; OR = 0.979), and estimated blood loss (p = 0.030; OR = 1.723 per 100mL) were independent risk factor of PPCs. The predictive nomogram model demonstrated an area under the ROC curve of 0.790 (95% CI:0.711–0.827). Calibration assessment revealed a slope approximating unity, and the Hosmer–Lemeshow goodness-of-fit test indicated an adequate model fit (χ² = 5.668, P = 0.196). The incidence of PPCs in patients undergoing thoracoscopic lung lobectomy with LPVS was 19.3%. PetCO₂ ≥ 40.9 mmHg was independently associated with a lower risk of PPCs. The constructed nomogram exhibited favorable predictive accuracy for PPCs in patients undergoing thoracoscopic lung lobectomy with LPVS.
Zhu et al. (Mon,) studied this question.