Apache Ii Score Calculator
Calculate the APACHE II severity of disease score for ICU patients. Enter values for instant results with step-by-step formulas.
Formula
APACHE II = Acute Physiology Score (0-60) + Age Points (0-6) + Chronic Health Points (0-5)
12 physiologic variables are scored based on deviation from normal (worst values in first 24 hours of ICU admission). Age adds 0-6 points. Chronic health adds 0-5 points. Total ranges from 0 to 71, though scores above 40 are rare. Higher scores indicate greater disease severity and predicted mortality.
Worked Examples
Example 1: Low Severity ICU Admission
Problem: 55-year-old post-elective surgery, mild tachycardia, all labs normal, alert.
Solution: Heart Rate: 2 (110-139)\nAge: 3 (55-64)\nChronic: 0\nAll others: 0\nTotal APACHE II = 5\nPredicted mortality: ~8%
Result: APACHE II 5 — Low-Moderate severity
Example 2: High Severity Septic Shock
Problem: 72-year-old with septic shock, temp 40.5°C, MAP 45, HR 155, acute renal failure, GCS 8.
Solution: Temperature: 3\nMAP: 4\nHR: 3\nCreatinine: 4 (acute)\nGCS points: 9\nAge: 5\nChronic: 5\nTotal APACHE II = 33\nPredicted mortality: ~73%
Result: APACHE II 33 — Critical severity, very high predicted mortality
Frequently Asked Questions
What is the APACHE II score?
APACHE II (Acute Physiology and Chronic Health Evaluation II) is a severity-of-disease classification system used in ICUs worldwide. Introduced in 1985 by Knaus et al., it uses 12 physiologic variables, age, and chronic health status to generate a score from 0-71. Higher scores indicate more severe disease and higher predicted mortality. It is calculated within 24 hours of ICU admission using the worst values.
How is APACHE II mortality predicted?
APACHE II provides an estimated in-hospital mortality based on the total score. Approximate mortality by score range: 0-4: ~4%, 5-9: ~8%, 10-14: ~15%, 15-19: ~25%, 20-24: ~40%, 25-29: ~55%, 30-34: ~73%, ≥35: ~85%. The actual mortality equation also incorporates the primary diagnosis category, but the score alone provides a reasonable estimate.
What are the limitations of APACHE II?
Limitations include: 1) Developed in the 1980s, may not reflect modern ICU practices. 2) Uses worst values in 24 hours, which may be affected by treatment. 3) Does not account for lead-time bias. 4) Chronic health assessment is subjective. 5) Newer versions (APACHE III, IV) exist but are proprietary. 6) Should not be used for individual patient prognosis or withdrawal of care decisions.
When should APACHE II values be collected?
APACHE II should be calculated using the worst (most abnormal) values from the first 24 hours after ICU admission. If a variable is not measured, it is assumed to be normal (score 0). The GCS component should use the pre-sedation or pre-intubation value when possible. Serial calculations are not standard but may be used to track disease progression.
How accurate are the results from Apache Ii Score Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.