APACHE II
Severity of illness in intensive care: 12 physiological variables, age and chronic health. Maximum 71 points.
Updated · Methodology
Use the WORST values from the first 24 hours after admission to intensive care.
About this calculator
The total combines three parts: acute physiology, age and chronic health. Acute physiology covers twelve variables scored 0-4, among them temperature, mean arterial pressure, heart rate, respiratory rate, oxygenation, pH, sodium, potassium, creatinine, haematocrit, white cell count, and the Glasgow Coma Scale, which enters as 15 minus the patient's score. Age adds up to 6 points and chronic health up to 5. Three parts are not scored directly. Oxygenation: at FiO2 of 0.5 or above the alveolar-arterial gradient is used, below 0.5 it is PaO2, and the inspired mixture decides which branch applies, not whichever is easier to measure. Creatinine: its points double in acute renal failure. Chronic health: the same history weighs 5 points for a medical or emergency surgical admission and only 2 after elective surgery. Use the worst values from the first 24 hours in the unit. About the mortality figures: they come from a 1985 cohort, before protective ventilation, early goal-directed sepsis care and modern renal replacement therapy, so today they run high. The score remains a tool for comparing groups and describing unit case mix rather than a prognosis for one patient.
Source
Formula version: knaus-1985-v1
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