PIRO concept: staging of sepsis

Sepsis is common presenting illness to the emergency services and one of the leading causes of hospital mortality. Researchers and clinicians have realized that the systemic inflammatory response syndrome concept for defining sepsis is less useful and lacks specificity. The predisposition, infection (or insult), response and organ dysfunction (PIRO) staging of sepsis similar to malignant diseases (TNM staging) might give better information.

A prospective observational study was conducted in emergency medical services attached to medicine department of a tertiary care hospital in Northern India. Patients with age 18 years or more with proven sepsis were included in the first 24 hours of the diagnosis. Two hundred patients were recruited. Multivariate logistic regression analysis was done to assess the factors that predicted in-hospital mortality.

Two hundred patients with proven sepsis, admitted to the emergency medical services were analysed. Male preponderance was noted (M: F ratio = 1.6:1). Mean age of study cohort was 50.50 ± 16.30 years. Out of 200 patients, 116 (58%) had in-hospital mortality. In multivariate logistic regression analysis, the factors independently associated with in-hospital mortality for predisposition component of PIRO staging were age >70 years, chronic obstructive pulmonary disease, chronic liver disease, cancer and presence of foley's catheter; for infection/ insult were pneumonia, urinary tract infection and meningitis/encephalitis; for response variable were tachypnea (respiratory rate >20/minute) and bandemia (band >5%). Organ dysfunction variables associated with hospital mortality were systolic blood pressure <90mm Hg, prolonged activated partial thromboplastin time, raised serum creatinine, partial pressure of oxygen in arterial blood/ fraction of inspired oxygen (PaO 2 /FiO 2 ) ratio <300, decreased urine output in first two hours of emergency presentation and Glasgow coma scale ≤9. Each of the components of PIRO had good predictive capability for in-hospital mortality but the total score was more accurate than the individual score and increasing PIRO score was associated with higher in-hospital mortality. The area under receiver operating characteristic curve for cumulative PIRO staging system as a predictor of in-hospital mortality was 0.94.

This study finds PIRO staging as an important tool to stratify and prognosticate hospitalised patients with sepsis at a tertiary care center. The simplicity of score makes it more practical to be used in busy emergencies as it is based on four easily assessable components.