Healthcare & Clinical Calculators
PIM-3 (Pediatric Index of Mortality 3) PICU Admission Risk Formula
Calculate first-hour PICU standardized mortality probability from Straney et al.’s (2013) PIM-3 logistic model incorporating pupillary reaction, mechanical ventilation, base excess, and diagnosis risk tier.
First-hour PICU risk-adjusted benchmarking across 53,112 pediatric intensive-care admissions!
To audit Pediatric Intensive Care Unit (PICU) standardized mortality ratios without treatment-induced lead-time bias, Lahn Straney et al. (Pediatric Critical Care Medicine, 2013) calibrated PIM-3 strictly on physiologic variables recorded within 1 hour of PICU contact: z = -5.3501 + 3.8233*(Pupils_Fixed > 3 mm) + 0.9763*(Mech_Vent_1st_Hr) + 0.0671*|Base_Excess_mmol_L| + β_SBP_FiO2_Dx, converting log-odds into predicted PICU mortality P(%) = 100 / (1 + EXP(-z))!
Evaluate an intubated child (Mech_Vent = 1, reactive pupils = 0) with arterial base excess -8.5 mmol/L and combined SBP/oxygenation/diagnosis log-odds adjustment +0.85: linear predictor z = -2.9535 predicts 4.96% PICU mortality—whereas bilateral fixed dilated pupils (> 3 mm, Pupils_Fixed = 1) spikes predicted mortality to 70.47%!
| First-Hour PICU Presentation | PIM-3 Logit z | Predicted PICU Mortality (%) | Quality Audit Tier |
|---|---|---|---|
| Ventilated, Reactive Pupils, BE -8.5, Adj +0.85 | -2.9535 | 4.96% | Moderate Acuity PICU Admission |
| Same Child + Fixed Dilated Pupils > 3 mm (B2 = 1) | +0.8698 | 70.47% | Critical Neurologic Catastrophe |
| Invalid Binary Flag (< 0 or > 1) | Undefined | "Binary Flags Must Be 0 or 1" | Input Validation Guard |
PIM-3 Predicted PICU Mortality Probability (%)
Evaluates 100 / (1 + EXP(-(-5.3501 + 3.8233*B2 + 0.9763*B3 + 0.0671*ABS(B4) + B5))) from fixed-pupil flag B2 (0/1), first-hour mechanical ventilation B3 (0/1), base excess B4 (mmol/L), and combined SBP/FiO2/diagnosis log-odds term B5.
=IF(OR(B2 < 0, B2 > 1, B3 < 0, B3 > 1), "Binary Flags Must Be 0 or 1", ROUND(100 / (1 + EXP(-(-5.3501 + 3.8233 * B2 + 0.9763 * B3 + 0.0671 * ABS(B4) + B5))), 2))PIM-3 Linear Log-Odds Score z
Outputs the underlying PIM-3 logit score used for PICU Standardized Mortality Ratio (SMR = Observed / Σ Expected) funnel plots.
=IF(OR(B2 < 0, B2 > 1, B3 < 0, B3 > 1), "Binary Flags Must Be 0 or 1", ROUND(-5.3501 + 3.8233 * B2 + 0.9763 * B3 + 0.0671 * ABS(B4) + B5, 4))Try the example
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