Objective: To validate Pediatric Risk of Mortality (PRISM) scoring in infants and children admitted for intensive care.
Design: Validation cohort.
Setting: A five-bed pediatric ICU and three cots providing intensive care for surgical neonates, within a 159-bed tertiary care children's hospital.
Patients: All patients admitted for intensive care during an 18-month period, January 1990 to July 1991.
Methods: Admission (first 24 hrs) PRISM scoring was introduced as a routine procedure. Discretion was allowed in requesting arterial blood gas measurements and clotting studies. All other parameters were intended to be measured on all patients.
Measurements and main results: PRISM scores were obtained on 380 (88%) of 433 patients. Median age was 15 months. A complete PRISM score was obtained in 24% of cases and a score as intended (i.e., allowing discretionary omissions) was obtained in 56% of patients. Comparison of observed and predicted mortality rates using chi square goodness-of-fit tests showed a significantly better observed outcome for all patients (chi 2(5) = 12.04, p < .05). In-depth analysis indicates that the model works well for children (chi 2(5) = 1.80, p > .75), but that observed outcome is significantly better than predicted for infants (chi 2(5) = 17.46, p < .01). Underscoring of children is not the cause of this finding.
Conclusions: In our center, PRISM scoring overestimates severity of illness in infants. PRISM scoring is not institutionally independent and therefore, at present, a comparison between units may not be justified. A reappraisal of the parameter ranges for infants is suggested.