Pulmonary complications following urological, gastrointestinal and gynaecological abdominal Surgery––A post-hoc analysis of an observational study in 29 countries

Background: The incidence of postoperative pulmonary complications (PPCs33Postoperative Pulmonary Complications.) following abdominal surgery varies across surgical specialties. It remains unclear to what extent the incidence of PPCs is attributable to known patient–related factors and anaesthesia duration, rather than to differences inherent to the surgical specialty itself. Methods: Post-hoc analysis of an observational study describing postoperative outcomes in patients undergoing urological, gastrointestinal, and gynaecological abdominal surgery. The primary endpoint was a composite measure of PPCs. Secondary endpoints included the individual incidence of each PPC. Propensity score weighting was used to create a cohort with similar patient characteristics and anaesthesia duration. Results: The cohort consisted of 3306 patients across 146 centres in 29 countries–367 underwent urological surgery, 2100 underwent gastrointestinal surgery, and 839 underwent gynaecological surgery. Risk scores for PPCs were highest in urological surgical patients, followed by gastrointestinal and gynaecological surgical patients. PPCs also occurred most often after urological surgery (17.7%), followed by gastrointestinal (14.9%) and gynaecological surgery (9.8%) (p < 0.001). After weighting, these differences in incidence disappeared, with comparable rates across the three groups (urological surgery 15.7%, gastrointestinal 14.5%, gynaecological 12.2%; p = 0.340). Apart from unplanned supplementary oxygen, all PPCs were most frequent after gastrointestinal surgery and least common following gynaecological surgery. Conclusions: In this worldwide cohort of patients undergoing abdominal surgery, the incidence of PPCs varied across urological, gastrointestinal, and gynaecological surgery; the differences in incidence may be more strongly influenced by patient–related factors and anaesthesia duration than by the characteristics of the surgical specialty itself. Gastrointestinal surgeries showed the highest rates of severe PPCs.