Objective: To develop a scoring system for stratifying patients in intensive care units (ICUs) by risk of developing nosocomial pneumonia (NP), based on variables generally available in an ICU, and to determine the probability of a patient developing NO in the ICU.
Design and setting: a 2-year prospective cohort study conducted in a medical and surgical ICU.
Patients: 756 patients admitted to the ICU for 48 h or more were followed up until the development of NP or death or discharge from the ICU.
Measurements and results: 129 (17.1%) patients developed NP, 106 (14%) in the first 2 weeks. The following independent risk factors were identified by multivariate analysis: no infection on admission [relative risk (RR) = 3.1, 95% confidence intervals (CI) = 2.0 to 4.81; thorax drainage (RR = 2.1, 95% CI = 1.2 to 3.5); administration of antacids (RR = 2.1, 95% CI = 1.4 to 3.1); partial pressure of oxygen (PO2) > 110 mmHg (RR = 1.6, 95% CI = 1.0 to 2.6); administration of coagulation factors (RR = 1.8 95% CI = 1.0 to 3.2); male gender (RR = 2.7, 95% CI = 1.2 to 6.3); urgent surgery (RR = 2.4, 95% CI = 0.9 to 6.4); and neurological diseases (RR = 4.2, 95% CI = 1.9 to 9.4). To obtain a predictive risk index for NP, a scoring system was developed using a multivariate model. The probability of developing NP varied between 11.0% in the lowest risk group and 42.3% in the highest risk group. The patients' risk of acquiring NP was seven times higher in the highest score category (i.v.) than in the lowest one (I).
Conclusions: ICU patients can be stratified into high- and low-risk groups for NP. No infection on admission, thorax drainage, administration of antacids, and PO2 > 110 mmHg were associated with a higher risk of NP during the entire 2-week period.