Risk assessment and standardized nosocomial infection rate in critically ill children

Objectives: To develop and validate a pediatric nosocomial infection risk ( PNIR) assessment model, and to compare the daily trends in risk factors bet ween patients with nosocomial infection (cases) and without nosocomial infe ction (controls) in the pediatric intensive care unit (ICU). Design: Prospective cohort. Setting: A 16-bed pediatric ICU in an urban, university-affiliated, multidi sciplinary, regional referral center. Patients: Patients available for study included consecutive admissions to t he unit between May 1, 1992, and April 30, 1993, and between May 9, 1995, a nd December 11, 1995. Patients from both data collection periods were poole d and randomly divided into training (70%) and validation (30%) samples. Measurements and Main Results: In the logistic regression analysis using ad mission day data, three factors were shown to remain as independent risk fa ctors. Invasive device use, parenteral nutrition, and the interaction betwe en severity of illness-modified Pediatric Risk of Mortality III-24 score an d postoperative care were associated with 2, 6, and 1.5 times the risk of d eveloping nosocomial infection, respectively. This PNIR model performed wel l in both the training and validation samples as indicated by the goodness- of-fit test, which evaluated standardized nosocomial infection rates (obser ved vs. predicted nosocomial infection rates). The internal validity of the PNIR model was good. in trend analysis, severity of illness and invasive d evice use appear to have similar trend patterns, during the first week of p ediatric ICU stay. There was no difference in any of these risk factors bet ween cases and controls after 7 days of pediatric ICU stay. Conclusions: The PNIR assessment model incorporates intrinsic factors, such as patient severity of illness, and extrinsic factors contributing to the development of nosocomial infection in this high-risk population. The metho dology using intrinsic and extrinsic factors to adjust for nosocomial infec tions should be taken into consideration when evaluating interhospital comp arison of nosocomial infection rates, quality assessment, intervention stra tegies, and use of treatment modalities.