Association between SII and postoperative pulmonary infection in elderly patients undergoing laparoscopic abdominal surgery

Abstract

Objectives: This study aimed to identify the contributing factors, including systemic immune-inflammation index (SII), for pulmonary infections in elderly patients undergoing laparoscopic abdominal surgery with tracheal intubation under general anesthesia. Methods: A total of 356 eligible elderly patients were monitored post-surgery for pneumonia. Pathogens were identified from sputum samples, and factors like age, smoking, chronic obstructive pulmonary disease (COPD), intubation, anesthesia duration, and SII were analyzed for their influence on infection risk. Results: The pathogens were predominantly Gram-negative bacteria, with Klebsiella pneumoniae being the most common (26%). Significant risk factors for developing pneumonia included advanced age, smoking, COPD, prolonged intubation, and extended anesthesia. A higher preoperative SII was associated with an increased risk of pneumonia and correlated with infection severity and elevated levels of inflammatory markers. Multivariate analysis identified age over 70 (OR = 1.273, p = 0.021), age over 80 (OR = 2.085, p < 0.001), COPD (OR = 1.528, p = 0.009), prolonged intubation >2 h (OR = 2.187, p < 0.001), general anesthesia >4 h (OR = 1.846, p = 0.006), operative time > 2 h (OR = 1.415, p = 0.016), and preoperative SII >489.3 (OR = 1.403, p = 0.012) as independent risk factors for postoperative pulmonary infection. Conclusion: Our study highlighted critical risk factors for postoperative pulmonary infections in elderly patients undergoing laparoscopic abdominal surgery. Preoperative SII could be a novel predictor, offering potential for improved pre-surgical risk assessment.