Identification of patients at risk for development of tertiary peritonitis on a surgical intensive care unit.

Background: Tertiary peritonitis (TP) is defined as a severe recurrent or persistent intra-abdominal infection after adequate surgical source control of secondary peritonitis (SP). The aim of this study was to analyze the characteristics of patients with SP who will further develop TP in order to define early diagnostic markers for TP.

Study Design: Over a 1-year period, all patients on the surgical intensive care unit (ICU) with SP were prospectively assessed for the development of TP applying the definition of the ICU consensus conference. The Mannheim Peritonitis Index (MPI), C-reactive protein (CRP) and Simplified Acute Physiology Score II (SAPS II) were assessed at the initial operation (IO) that was diagnostic for SP and in the postoperative period.

Results: Among 69 patients with SP, 15 patients further developed TP, whereas 54 patients did not develop TP. Compared to SP, patients with transition to TP had significantly higher MPI at IO (28.6 vs. 19.8; p < 0.001), relaparotomy rate (2.00 vs. 0.11; p < 0.001), mortality (60% vs. 9%; p < 0.001), duration of ICU stay (14 vs. 4 days; p < 0.005), as well as SAPS II (45.1 vs. 28.4; p < 0.005) and CRP (265 mg/dL vs. 217 mg/dL; p < 0.05) on the second postoperative day after IO.

Conclusions: The MPI at IO as well as CRP and SAPS II at the second postoperative day helps to identify patients at risk for tertiary peritonitis.