Role of serial lactate measurement to predict 28-day mortality in patients undergoing emergency laparotomy for perforation peritonitis: prospective observational study

BACKGROUND: Serial lactate measurement is found to predict mortality in septic shock. Majority of patients with perforation peritonitis for emergency laparotomy are in sepsis and mortality rate is substantial. However, lactate dynamics has not been studied in this patient population. METHODS: After institutional ethics clearance and informed written consent, 113 patients with suspected or proven perforation peritonitis presenting for emergency laparotomy were recruited in this prospective observational trial. Baseline Mannheim peritonitis index (MPI), SOFA and APACHE II score were calculated. Lactate values were obtained at baseline, immediate and 24-h postoperative period. Primary outcome was 28-day mortality. RESULTS: Mortality was 15.04% at 28 days. Age, SOFA, qSOFA, APACHE, preoperative lactate, MPI and site of perforation were significantly different between survivors and non-survivors. Arterial lactate values at preoperative (cut off 2.75 mmol/L), immediate postoperative (cut off 2.8 mmol/L) and 24 h-postoperative period (cut off 2.45 mmol/L) independently predicted mortality at day 28. Combination of MPI and 24-h lactate value was best predictor of mortality with AUC 0.99. CONCLUSION: Preoperative, immediate postoperative and 24-h postoperative lactate value independently predict 28-day mortality in perforation peritonitis patients undergoing emergency laparotomy. Combination of MPI and 24-h lactate value is the most accurate predictor of mortality. TRIAL REGISTRATION: Clinical Trial Registry of India - CTRI/2018/01/011103.