Validity of medical staff assessment at admission of patient's risk of nosocomial infection: a prospective study in a surgical intensive care unit.

Objective: To evaluate the ability of a surgical intensive care unit (SICU) medical staff to assess at admission the individual risk of nosocomial infection (NI) during SICU stay in patients admitted for at least 48 h.
Design: Prospective observational study.
Setting: A tertiary-care university hospital.
Patients and Participants: 201 admissions to the SICU from November 19, 2003, until April 16, 2004.
Measurements and Results: Assessment by medical staff at admission of each patient's estimated risk of NI (pneumonia, venous central catheter-related infection, symptomatic urinary tract infection, and bacteremia) during SICU hospitalization, in order to classify patients into four groups: NI risk very low or absent (group 1), low (group 2), high (group 3), very high or certain (group 4). NI was diagnosed via routine surveillance according to Centers for Disease Control case definitions.
Results: 154 patients were assessed; the percentage of patients with NI increased with estimated risk at admission, from 0% in group 1 to 14.3% in group 4. Positive predictive value of medical assessment varied from 8.4% to 14.5%, according to the cutoff value. Negative predictive value varied from 92.1% to 100%.
Conclusion: Our study suggests that ICU physicians encounter a major difficulty when informing patients or patients' families about the risk of NI occurrence, as they cannot predict this risk accurately. This limitation should be explained to patients and their families.