APACHE II Calculator
Assess critically ill patient severity using APACHE II score (Acute Physiology and Chronic Health Evaluation).
Important Medical Disclaimer
This calculator is an educational and clinical decision support tool. Results DO NOT replace professional medical evaluation, laboratory tests, or clinical judgment. Always consult a qualified healthcare professional for diagnosis, treatment, and clinical decisions. Calculations are based on scientifically validated formulas but may not be applicable to all patients.
Calculate APACHE II
What is APACHE II?
APACHE II (Acute Physiology and Chronic Health Evaluation) is a severity score for critical patients, developed in 1985. Evaluates 12 physiological variables in first 24h of ICU, age, and previous chronic health. Score 0-71 points. Used for risk stratification, ICU quality comparison, and hospital mortality prediction.
When to use APACHE II?
Use in first 24h of ICU admission for risk stratification and benchmarking between ICUs. Don't use for individual support decisions (a patient with APACHE 30 can survive). Useful in clinical research to adjust for severity. APACHE III and IV are newer but proprietary versions.
Limitations and Considerations
Developed in 1985, may underestimate current mortality (improved care). Not validated in cardiac surgery postop, burns, coronary, or pediatrics. Uses worst 24h value, which may penalize aggressive interventions. Doesn't consider modern comorbidities (HIV, immunosuppression). Use as population guide, not individual.
Frequently Asked Questions about APACHE II
Does high APACHE II mean don't invest?
No. APACHE predicts population mortality, not individual. An APACHE 35 has 85% mortality, but 15% survive. Use to inform family prognosis, not to limit therapy. End-of-life decisions should consider patient wishes, prior quality of life, and response to initial therapy.
What's the difference between APACHE, SAPS, and SOFA?
APACHE II: global severity in 24h, predicts hospital mortality. SAPS II: similar to APACHE, more used in Europe. SOFA: serial organ dysfunction, used to monitor daily evolution and define sepsis. APACHE for admission, SOFA for follow-up.
How to improve ICU APACHE II?
APACHE reflects case-mix (patient severity). ICU with high average APACHE isn't bad if mortality is lower than predicted (good quality). Focus: reduce observed/expected mortality ratio (SMR <1). Improve protocols, reduce infections, optimize support.
Does APACHE II apply to COVID-19?
Applicable but underestimates mortality. Severe COVID has particularities (cytokine storm, microthrombi) not captured by APACHE. Studies showed COVID with same APACHE had 1.5-2x higher mortality. Use with caution, consider specific scores if available.