PIM2 (Pediatric Index of Mortality 2) is a validated scoring system developed by Slater et al. (2003) to predict the probability of death in pediatric ICU patients using 10 variables measured at or shortly after admission.

When should PIM2 data be collected?

All variables should be recorded at the time of first face-to-face contact with the PICU physician, or within the first hour of admission. Use the worst value if the variable changes rapidly.

What does the probability of death mean?

A probability of 10% means that in a group of 100 similar patients, approximately 10 would be expected to die. It is a statistical estimate, not a prediction for an individual patient.

Is this calculator a substitute for clinical judgment?

No. PIM2 is a population-level benchmarking and research tool. Individual patient management decisions must always be based on full clinical assessment by qualified healthcare professionals.

What is the FiO2/PaO2 ratio?

Enter FiO2 as a decimal (e.g., 0.21 for room air, 1.0 for 100% oxygen). Enter PaO2 in mmHg from an arterial blood gas. The ratio FiO2/PaO2 is used directly in the formula.

Which diagnoses count as "high-risk" for PIM2?

High-risk diagnoses include cardiac arrest before PICU admission, severe combined immune deficiency (SCID), leukemia/lymphoma after first induction, bone marrow transplant, hepatic failure, and neurodegenerative disease.

PIM2 Pediatric Mortality Index Calculator

Summary

Enter 10 admission variables to calculate the PIM2 score and estimated PICU mortality probability.

How it works

Enter the 10 clinical variables collected at or within the first hour of PICU admission.
The calculator applies the validated PIM2 logistic regression formula.
A raw score (logit) is computed from the weighted sum of variables.
The logit is converted to a probability of death using the standard logistic function.
Results are categorized into Low, Moderate, High, or Very High risk ranges.

Use cases

Estimate mortality risk for newly admitted PICU patients.
Benchmark PICU outcomes against predicted mortality (SMR calculation).
Stratify patients by severity for clinical research studies.
Support quality improvement initiatives in pediatric critical care.
Communicate prognosis to clinical teams during rounds.
Track severity-adjusted mortality trends over time.