Timing of surgical site infection and pulmonary complications after laparotomy

Background: Surgical site infection (SSI) and other postoperative complications are associated with high costs, morbidity, secondary surgery, and mortality. Many studies have identified factors that may prevent SSI and pulmonary complications, but it is important to know when they in fact occur. The aim of this study was to investigate the diagnostic timing of surgical site infections and pulmonary complications after laparotomy. Material and methods: This is a secondary analysis of the PROXI trial which was a randomized clinical trial conducted in 1400 patients undergoing elective or emergent laparotomy. Patients were randomly allocated to either 80% or 30% perioperative inspiratory oxygen fraction. Results: SSI or pulmonary complications were diagnosed in 24.2% (95% CI: 22.0%-26.5%) of the patients at a median of 9 days [IQR: 5-15] after surgery. Most common was surgical site infection (19.6%); median time 10 days after surgery [IQR: 7-18]. The corresponding figures for anastomotic leakage was 5.7%, 8 days [IQR: 6-10]; pneumonia 3.5%, 5 days [IQR: 3-9]; and respiratory failure 2.3%, 3 days [IQR: 1-8]. The oxygen allocation was not significantly related to time of diagnosis for postoperative surgical site infections or pulmonary complications. Conclusion: A high percentage of patients undergoing laparotomy develop a postoperative complication. This study adds new knowledge by identifying time intervals within which medical professionals should be aware of surgical site infections and pulmonary complications in order to initiate appropriate treatment of the patients.