This retrospective cohort study aims to evaluate whether spontaneous breathing laryngeal mask anesthesia (LMA-SBA) reduces the incidence of postoperative pneumonia compared to single-lung isolation mechanical ventilation in patients undergoing thoracoscopic wedge resection. Using propensity score overlap weighting, we will adjust for multiple confounders, including age, COPD, surgical duration, and preoperative laboratory values. Secondary outcomes include postoperative recovery time, fever severity, white blood cell count, neutrophil percentage, length of hospital stay, and ICU admission rate. The study has been approved by the Ethics Committee of the First Affiliated Hospital of Shandong First Medical University (Approval No. YXLL-KY-2025(037)).

Background: Postoperative pneumonia is a significant complication following thoracoscopic wedge resection, potentially linked to the type of anesthesia used. Spontaneous breathing laryngeal mask anesthesia (LMA-SBA) may offer advantages over traditional single-lung isolation mechanical ventilation by preserving natural respiratory function and reducing mechanical ventilation-related lung injury.

Objective: The primary objective is to compare the incidence of postoperative pneumonia between LMA-SBA and single-lung isolation mechanical ventilation groups. Secondary objectives include assessing differences in postoperative recovery time, fever severity, white blood cell count, neutrophil percentage, length of hospital stay, and ICU admission rate.

Methods: This retrospective cohort study will include patients aged ≥18 years who underwent thoracoscopic wedge resection under general anesthesia (LMA-SBA or single-lung isolation mechanical ventilation) at the First Affiliated Hospital of Shandong First Medical University between March 1, 2024, and November 31, 2024. Exclusion criteria include prior thoracic surgery, pleural adhesions, conversion to single-lung isolation during surgery, severe cardiopulmonary dysfunction, and inability to cooperate with postoperative assessments. Data will be collected from electronic medical records, and propensity score overlap weighting will be used to adjust for confounders.

Outcome Measures: Postoperative pneumonia will be diagnosed based on fever (>38°C), cough, new infiltrates on imaging, and abnormal white blood cell count (>10,000/μL or <4,000/μL). Secondary outcomes will be analyzed using weighted regression models.

Ethics: The study protocol has been approved by the Ethics Committee of the First Affiliated Hospital of Shandong First Medical University (Approval No. YXLL-KY-2025(037)).

Inclusion Criteria:

1. Age ≥ 18 years ;
2. Patients undergoing thoracoscopic pulmonary wedge resection ;
3. General anesthesia administered intraoperatively (LMA-SBA or endotracheal intubation);
4. Complete preoperative and postoperative clinical data.

Exclusion Criteria:

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1)History of prior thoracic surgery; 2）Pleural adhesion or pleural effusion caused by tuberculosis or other diseases; 3)Intraoperative conversion from tubeless anesthesia to single-lung isolation-controlled ventilation; 4)Severe cardiopulmonary dysfunction (e.g., history of acute exacerbation of COPD within 1 month preoperatively, patients requiring emergency treatment, or cardiac insufficiency with limited mobility) ; 5)Preoperative neurological dysfunction or sensory abnormalities affecting pain assessment 6)Inability to cooperate with postoperative pain assessment and follow-up 7)Pregnant or breastfeeding women; 8)Patients transferred from other departments with complex comorbidities, prior treatment history, or unstable conditions .

adult patients undergoing thoracoscopic wedge resection of the lung under general anesthesia