PIM3 Calculator

Physiology at first ICU contact / within first hour

Systolic BP (mmHg) Leave blank if unknown. Strict PIM3 default = 120 mmHg. If cardiac arrest, record 0. If shocked and immeasurable, record 30.

Base excess (mmol/L) Enter the value exactly as shown on the ABG report, with its + or − sign. Example: −8.5 or +3.0. Arterial or capillary only. Leave blank if unknown. Strict PIM3 default contribution = 0.

FiO₂ (fraction) Enter as a fraction, not percent. Example: room air = 0.21, 50% oxygen = 0.50.

PaO₂ (mmHg) Arterial PaO₂ only. FiO₂ and PaO₂ should refer to the same time point.

100 × FiO₂ / PaO₂ Auto-calculated from FiO₂ and PaO₂. If either is missing, strict PIM3 default = 0.23.

PIM3 uses the first available value, not the worst value. Missing data are treated as normal, except the oxygenation ratio defaults to 0.23.

Binary admission factors

Pupils fixed to bright light Code yes only if both pupils are > 3 mm and both are fixed, and the finding is not due to drugs, toxins, or direct eye injury. β = +3.8233 Elective ICU admission Admission after an elective procedure, elective monitoring, elective PICU procedure, or review of home ventilation. Unexpected ICU admission after elective surgery is not elective. β = −0.5378 protective Mechanical ventilation within first hour Includes invasive ventilation, CPAP, BiPAP, and other non-invasive ventilation. Excludes HFNC. β = +0.9763

Recovery category choose one

No recovery-from-procedure category Use this when recovery from surgery/procedure is not the main reason for PICU admission. β = 0 Recovery from bypass cardiac procedure Use only when recovery is the main reason for PICU admission and the procedure was a bypass cardiac procedure. β = −1.2246 protective Recovery from non-bypass cardiac procedure Use only when recovery is the main reason for PICU admission and the procedure was cardiac but non-bypass. β = −0.8762 protective Recovery from non-cardiac procedure Use only when recovery is the main reason for PICU admission and the procedure was non-cardiac. β = −1.5164 protective

Diagnosis risk category highest tier overrides

No low / high / very-high-risk diagnosis selected Use when none of the listed strict PIM3 diagnostic categories apply, or if in doubt. β = 0 Low-risk diagnosis Asthma, bronchiolitis, croup, obstructive sleep apnoea, diabetic ketoacidosis, or seizures — only if this is the main reason for PICU admission. β = −2.1766 protective High-risk diagnosis Spontaneous cerebral haemorrhage, cardiomyopathy/myocarditis, hypoplastic left heart syndrome, neurodegenerative disorder, or necrotising enterocolitis. β = +1.0725 Very-high-risk diagnosis Cardiac arrest preceding ICU admission, SCID, leukaemia/lymphoma after first induction, bone marrow transplant recipient, or liver failure. β = +1.6225

Oncology ICU option

Show oncology ICU caution panel Advisory only. This does not change strict PIM3 mathematics. It adds a warning that general PIM3 may underestimate mortality in hemato-oncological subgroups and should be interpreted cautiously for individual patients.

Predicted hospital mortality probability

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Enter admission data above

0%25%50%75%100%

PIM3 score (logit)

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Constant

−1.7928

SBP quadratic term

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100×FiO₂/PaO₂ term

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Worked example check (ANZPICR booklet, Jan 2019)
Six-year-old child with relapsed leukaemia after first induction, non-elective admission, ventilated, reactive pupils, SBP 70 mmHg, base excess −12, 100×FiO₂/PaO₂ = 100×0.7/65 = 1.0769, no recovery category, very-high-risk diagnosis.
Expected PIM3 score ≈ −0.1111 → mortality ≈ 47.22%.

Primary coding source ANZPICR PIM2 & PIM3 Information Booklet, Jan 2019.

Validation references
Jung JH, Sol IS, Kim MJ, et al. Validation of pediatric index of mortality 3 for predicting mortality among patients admitted to a pediatric intensive care unit. Acute Crit Care 2018;33:170–177.
Straney L, Clements A, Parslow RC, et al. Paediatric index of mortality 3: An updated model for predicting mortality in pediatric intensive care. Pediatr Crit Care Med 2013;14:673–681.
Wolfler A, Osello R, Gualino J, et al. Validation of the pediatric index of mortality 3 score. Pediatr Crit Care Med 2016;17:251–256.
Arias López MDP, Boada N, Fernández A, et al. Performance of the pediatric index of mortality 3 score in PICUs in Argentina: A prospective multicenter study. Pediatr Crit Care Med 2018;19:e653–e661.

Strict PIM3 logic implemented: SBP unknown=120, base excess unknown=0, oxygenation ratio unknown=0.23, and only the highest diagnosis tier is used. Mechanical ventilation includes CPAP/BiPAP but excludes HFNC.

For clinical audit, educational and research use only. PIM3 is intended for groups of patients and benchmarking; it should not be used to make management decisions for individual patients.

PIM3 — Paediatric Index of Mortality