Predicting patient outcomes after major abdominal surgery: the role of shock index and heart rate

Abstract

Background The aim of this work was to evaluate the ability of postoperative vital signs and risk scores in identification of postoperative complications and mortality after major abdominal surgery. Methods This prospective observational study included adults (aged ≥ 18 years) after elective major abdominal surgery. Heart rate and shock index were recorded at day-zero and day-one postoperatively. Patients were followed up for any postoperative medical and/or surgical complications until discharge from hospital. Postoperative complications were graded according to Clavien-Dindo grading system and a score > II was classified as severe complications. Outcomes were the ability of shock index (primary outcome) and heart rate, at day-one postoperatively, in predicting severe postoperative complication and in-hospital mortality using the area under receiver operating characteristic curve (AUC). Results The final analysis included 133 patients. The number of patients who developed severe postoperative complications was 27/133 (20%) and in-hospital mortality was 16/133 (12%). Shock index and heart rate, at day-one postoperatively showed good predictive ability for severe complications (AUC [95% confidence interval]: 0.85[0.77–0.90] and 0.82[0.76–0.89], respectively) and in-hospital mortality (AUC [95% confidence interval]: 0.85[0.78–0.91] and 0.83[0.75–0.89], respectively). a cutoff value of 0.75 for shock index had negative predictive values of 97 and 98% for severe postoperative complications and in-hospital mortality, respectively. Cutoff values for heart rate of 102 and 104 had negative predictive values of 95 and 99% for severe postoperative complications and in-hospital mortality, respectively. Conclusion Shock index and heart rate at day-one postoperatively accurately predicted severe complications and in-hospital mortality after major abdominal surgery. Shock index ≤ 0.75 and heart rate < 104 bpm can rule out in-hospital mortality with 98–99% accuracy.