Lung ultrasound aeration score for prediction of postoperative pulmonary complications after major abdominal surgery: Secondary analysis of a randomized controlled trial

Postoperative pulmonary complications (PPC) after major abdominal surgery are common and incidence may reach up to 30%. PPCs contributes to increased morbidity, cost of care and length of hospital stay. In this secondary analysis of a randomized controlled trial, we identified whether a postoperative lung ultrasound aeration score can predict PPCs after elective major abdominal surgery. Patients and methods This is study is a secondary analysis of a previously published randomized controlled trial [1] where n = 82 adult patients of American Society of Anesthesiologists physical status I or II, undergoing elective major open abdominal surgery under general anaesthesia were recruited. In group T patients, PEEP was titrated incrementally till lowest driving pressure is achieved and the same procedure was repeated in every 2 h. In group F patients, a PEEP of 5 cm H2O was used throughout the surgery. Lung USG aeration score was evaluated before and after induction of general anaesthesia and at the end of surgery (before and after extubation). Patients were followed till postoperative day 3 for PPC and oxygen requirement. Results Postoperative lung USG score (before extubation) was able to predict PPC [AUROC (95% CI) 0.65 (0.51–0.79)] and postoperative oxygen requirement [AUROC (95% CI) 0.70 (0.59–0.83)]. Postoperative lung USG score (after extubation) was able to predict PPC [AUROC (95% CI) 0.63 (0.49–0.78)] and postoperative oxygen requirement [AUROC (95% CI) 0.70 (0.58–0.83)]. After adjustment of age (p = 0.06), body mass index (p = 0.01), serum albumin (p = 0.02), duration of anaesthesia (p = 0.29), smoking status and type of surgery; lung USG score after extubation was an independent predictor of postoperative oxygen requirement [adjusted OR (95% CI) 1.28 (1.05–1.55)]. Conclusion Lung USG aeration score at the end of surgery (before and after extubation) was able to predict postoperative oxygen requirement with some degree of accuracy. References 1. Mini G, Ray BR, Anand RK, Muthiah T, Baidya DK, Rewari V, Sahni P, Maitra S. Effect of driving pressure-guided positive end-expiratory pressure (PEEP) titration on postoperative lung atelectasis in adult patients undergoing elective major abdominal surgery: A randomized controlled trial. Surgery. 2021 Jul;170(1):277–283.