Skip to main content
Calcimator

APACHE II Score Calculator

Calculate the APACHE II (Acute Physiology and Chronic Health Evaluation) score for ICU mortality prediction.

Progress0%

Step 1 of 5

°C

Normal: 36–38.4°C; APACHE II: 0 pts normal; 4 pts for ≥41°C or <30°C

mmHg

Normal MAP: 70–100 mmHg; critical: <50 mmHg (shock) or >160 mmHg (hypertensive crisis)

bpm

Normal HR: 60–100 bpm; APACHE II: 4 pts for HR ≥180 or <40 bpm

How to Use This Calculator
  1. Enter all acute physiology variables: temperature, MAP, heart rate, respiratory rate, and arterial pH.
  2. Add oxygenation, sodium, potassium, creatinine, hematocrit, WBC, and GCS score.
  3. Set age and chronic health points.
  4. Review APACHE II Score and estimated ICU mortality risk.

How the result changes with Glasgow Coma Scale

Glasgow Coma ScaleAPACHE II ScoreApprox. Mortality
4.213.8pts15%
7.210.8pts15%
117pts8%
144pts4%

What each input means

Temperature
Core body temperature in degrees Celsius (rectal preferred). APACHE II awards 0 points for 36–38.4°C (normal), up to 4 points for extreme values (≥41°C or <30°C).
Mean Arterial Pressure
Mean Arterial Pressure. MAP = (SBP + 2×DBP) / 3. APACHE II: 0 pts for MAP 70–109 mmHg (normal); 4 pts for MAP ≥160 or <50 mmHg.
Heart Rate
Ventricular rate (beats per minute). APACHE II: 0 pts for HR 70–109 bpm (normal); 4 pts for HR ≥180 or <40 bpm.
Respiratory Rate
Respiratory rate (ventilated or non-ventilated) in breaths per minute. APACHE II: 0 pts for RR 12–24; 4 pts for RR ≥50 or <6 breaths/min.
Arterial pH
Arterial blood gas pH value. Normal range 7.35–7.45. APACHE II: 0 pts for pH 7.33–7.49; 4 pts for pH ≥7.7 or <7.15 (life-threatening acidosis/alkalosis).
Sodium
Serum sodium concentration in mEq/L. APACHE II: 0 pts for Na 130–149; 4 pts for Na ≥180 or <111 mEq/L. Normal range 136–145 mEq/L.
Potassium
Serum potassium concentration in mEq/L. APACHE II: 0 pts for K 3.5–5.4; 4 pts for K ≥7 or <2.5 mEq/L. Normal range 3.5–5.0 mEq/L.
Creatinine
Serum creatinine in mg/dL reflecting renal function. APACHE II: 0 pts for Cr 0.6–1.4; 4 pts for Cr ≥3.5 (doubled if acute renal failure present). Normal: 0.7–1.3 mg/dL.
Acute Renal Failure
Double creatinine points if present.
Hematocrit
Hematocrit percentage. APACHE II: 0 pts for Hct 30–45.9%; 4 pts for Hct ≥60% or <20%. Normal range 37–52% (male), 36–48% (female).
WBC Count
White blood cell count in thousands per microliter (×10³/µL). APACHE II: 0 pts for WBC 3–14.9; 4 pts for WBC ≥40 or <1 ×10³/µL. Normal range 4.5–11.0 ×10³/µL.
Glasgow Coma Scale
GCS total score (3-15). Points = 15 - GCS.
Age
Patient age. ≥75: 6pts, 65-74: 5pts, 55-64: 3pts, 45-54: 2pts, <45: 0pts.
Chronic Health Points
0 = no chronic disease, 2 = elective postop with chronic disease, 5 = non-operative or emergency postop with chronic organ insufficiency.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Temperature = 37, Mean Arterial Pressure = 80, Heart Rate = 80, Respiratory Rate = 16 = 14 input(s) provided
  2. Calculate APACHE II Score
    APACHE II Score
    3 = 3
  3. Calculate Approx. Mortality
    Approx. Mortality
    4 = 4%
  4. Calculate Acute Physiology Score
    Acute Physiology Score
    0 = 0
  5. Calculate GCS Points
    GCS Points
    0 = 0

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Clinical Medicine

MELD Score Calculator

Calculate the Model for End-Stage Liver Disease (MELD) score to assess severity of chronic liver disease and transplant priority.

Clinical Medicine

Glasgow Coma Scale Calculator

Calculate the Glasgow Coma Scale (GCS) score from eye, verbal, and motor responses for assessing consciousness level.

Clinical Medicine

IV Drip Rate Calculator

Calculate drops per minute and mL per hour for IV fluid administration based on volume, time, and drop factor.

More in Medical & Clinical.