External Validation of a Decision Tool To Guide Post-Operative Management of Patients with Secondary Peritonitis

Timely identification of patients in need of an intervention for abdominal sepsis after initial surgical management of secondary peritonitis is vital but complex. The aim of this study was to validate a decision tool for this purpose and to evaluate its potential to guide post-operative management.

A prospective cohort study was conducted on consecutive adult patients undergoing surgery for secondary peritonitis in a single hospital. Assessments using the decision tool, based on one intra-operative and five post-operative variables, were performed on the second and third post-operative days and when the patients' clinical status deteriorated. Scores were compared with the clinical reference standard of persistent sepsis based on the clinical course or findings at imaging or surgery. Additionally, the potential of the decision tool to guide management in terms of diagnostic imaging in three previously defined score categories (low, intermediate, and high) was evaluated.

A total of 161 assessments were performed in 69 patients. The majority of cases of secondary peritonitis (68%) were caused by perforation of the gastrointestinal tract. Post-operative persistent sepsis occurred in 28 patients. The discriminative capacity of the decision tool score was fair (area under the curve of the receiver operating characteristic = 0.79). The incidence rate differed significantly between the three score categories (p < 0.001). The negative predictive value of a decision tool score categorized as low probability was 89% (95% confidence interval [CI] 82-94) and 65% (95% CI 47-79) for an intermediate score. Diagnostic imaging was performed more frequently when there was an intermediate score than when the score was categorized as low (46% vs. 24%; p < 0.001).

In patients operated on for secondary peritonitis, the decision tool score predicts with fair accuracy whether persistent sepsis is present.