Simplified APACHE II Score Calculator Formula

Understand the math behind the simplified apache ii score calculator. Each variable explained with a worked example.

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Formulas Used

Simplified APACHE Score

simplified_score = age_points + temp_points + hr_points + gcs_points

Age Points

age_component = age_points

Physiology Points

physiology_component = temp_points + hr_points + gcs_points

Variables

VariableDescriptionDefault
ageAge(years)60
temperature_fTemperature(F)101
heart_rateHeart Rate(bpm)100
gcsGCS Score(/15)14
age_pointsDerived value= age >= 75 ? 6 : (age >= 65 ? 5 : (age >= 55 ? 3 : (age >= 45 ? 2 : 0)))calculated
temp_cDerived value= (temperature_f - 32) * 5 / 9calculated
temp_pointsDerived value= abs(temp_c - 37) >= 4 ? 4 : (abs(temp_c - 37) >= 3 ? 3 : (abs(temp_c - 37) >= 2 ? 2 : (abs(temp_c - 37) >= 1 ? 1 : 0)))calculated
hr_pointsDerived value= abs(heart_rate - 80) >= 70 ? 4 : (abs(heart_rate - 80) >= 45 ? 3 : (abs(heart_rate - 80) >= 30 ? 2 : 0))calculated
gcs_pointsDerived value= 15 - gcscalculated

How It Works

Simplified APACHE II Score

The full APACHE II uses 12 physiologic variables, age, and chronic health status. This simplified version uses the most accessible variables.

Age Points

AgePoints <450 45-542 55-643 65-745 75+6

Score Interpretation

Higher scores indicate greater severity. The full APACHE II (0-71) correlates with ICU mortality risk. This simplified version provides a directional estimate.

Worked Example

A 60-year-old ICU patient: temp 101F, HR 100, GCS 14.

age = 60temperature_f = 101heart_rate = 100gcs = 14
  1. 01Age points = 3 (55-64)
  2. 02Temp = 38.3C, deviation = 1.3, points = 1
  3. 03HR deviation from 80 = 20, points = 0
  4. 04GCS points = 15 - 14 = 1
  5. 05Total = 3 + 1 + 0 + 1 = 5

Frequently Asked Questions

What is the APACHE II score?

APACHE II (Acute Physiology and Chronic Health Evaluation) is a severity scoring system for ICU patients. It predicts hospital mortality based on physiologic derangements.

What is a high APACHE II score?

In the full APACHE II, scores above 25 indicate very high mortality risk (>50%). Scores below 10 generally indicate low risk. This simplified version is proportionally lower.

Is this the complete APACHE II?

No. The full APACHE II includes 12 physiologic variables, age, and chronic health points. This simplified version uses 4 accessible variables for educational purposes.

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