Derivation of a PIRO Score for Prediction of Mortality in Surgical Patients With Intra-Abdominal Sepsis

Mortality in patients with intra-abdominal sepsis remains high. Recognition and classification of patients with sepsis are challenging; about 70% of critical care specialists find the existing definitions confusing and not clinically useful.

To assess the usefulness of the predisposition, infection/injury, response, organ dysfunction (PIRO) concept in surgical intensive care patients with severe sepsis or septic shock due to an intra-abdominal source.

Data from 2005 through 2010 of a prospective observational cohort were reviewed retrospectively.

Among 905 patients, overall mortality was 21.3%, but patients with septic shock had a mortality of 40.6%. The variables in each PIRO subset with P ≤ .10 were entered into a stepwise backward elimination logistic regression. A PIRO score was developed that included the following variables: age greater than 65 years; comorbid conditions; leukopenia; hypothermia; and cardiovascular, renal, respiratory, and central nervous system failure. One point was given for each feature detected. The mean score was significantly higher (P < .001) in non-survivors (3.9) than in survivors (2.3). When the data were distributed according to PIRO scores, mortality rate increased (P < .001). The area under the receiver operating characteristic curve indicated consistent mortality discrimination by PIRO scores (0.80; 95% CI, 0.79-0.83), outperforming the Acute Physiology and Chronic Health Evaluation II (0.72; 95% CI, 0.68-0.75) and the Sequential Organ Failure Assessment (0.72; 95% CI, 0.68-0.76) (P < .001).

The PIRO score is useful for predicting mortality in patients with surgically related intra-abdominal sepsis.