Table: Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II Scoring System*

Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II Scoring System*

	Physiologic Variable†	Point Score
		+4	+3	+2	+1	0	+1	+2	+3	+4
1	Temperature, core (°C)	≥41°	39–40.9°	—	38.5–38.9°	36–38.4°	34–35.9°	32–33.9°	30–31.9°	≤29.9°
2	Mean arterial pressure (mm Hg)	≥ 160	130–159	110–129	—	70–109	—	50–69	—	≤ 49
3	Heart rate	≥ 180	140–179	110–139	—	70–109	—	55–69	40–54	≤ 39
4	Respiratory rate (nonventilated or ventilated)	≥ 50	35–49	—	25–34	12–24	10–11	6–9	—	≤ 5
5	Oxygenation: a) FIO2 ≥ 0.5: use A-aDO2	≥ 500	350–499	200–349	—	< 200	—	—	—	—
5	b) FIO2 < 0.5: use PAO2 (mm Hg)	—	—	—	—	> 70	61–70	—	55–60	< 55
6	Arterial pH	≥ 7.7	7.6–7.69	—	7.5–7.59	7.33–7.49	—	7.25–7.32	7.15–7.24	< 7.15
7	Serum sodium (mmol/L or mEq/L)	≥ 180	160–179	155–159	150–154	130–149	—	120–129	111–119	≤ 110
8	Serum potassium (mmol/L or mEq/L)	≥ 7	6–6.9	—	5.5–5.9	3.5–5.4	3–3.4	2.5–2.9	—	< 2.5
9	Serum creatinine (micromol/L or mg/dL); double point score for patients with acute renal failure	≥ 3.5	2–3.4	1.5–1.9	—	0.6–1.4	—	< 0.6	—	—
10	Hematocrit (%)	≥ 60	—	50–59.9	46–49.9	30–45.9	—	20–29.9	—	< 20
11	White blood cells (in 1000s)	≥ 40	—	20–39.9	15–19.9	3–14.9	—	1–2.9	—	< 1
12	Glasgow coma score (GCS)		Score = 15 minus actual GCS (see table Glasgow Coma Scale Glasgow Coma Scale )
Acute physiology score is the sum of the 12 individual variable points.
Add 0 points for age < 44 years; 2 points, 45–54 years; 3 points, 55–64 years; 5 points, 65–74 years; 6 points ≥ 75 years.
Add chronic health status points: 2 points for elective postoperative patient with immunocompromise or history of severe organ insufficiency; 5 points for nonoperative patient or emergency postoperative patient with immunocompromise or severe organ insufficiency.‡
(13)§	Serum bicarbonate (venous–mmol/L or mEq/L)	≥ 52	41–51.9	—	32–40.9	23–31.9	—	18–21.9	15–17.9	< 15
* APACHE II score = acute physiology score + age points + chronic health points. Minimum score = 0; maximum score = 71. Increasing score is associated with increasing risk of hospital death.
† Choose worst value in the past 24 hours.
‡ Chronic health status: Organ insufficiency (eg, hepatic, cardiovascular, renal, pulmonary) or immunocompromised state must have preceded current admission.
§ This variable is optional; use only if no arterial blood gases are available.
A-a DO2 = alveolar–arterial oxygen gradient; FIO2 = fractional inspired oxygen.
Adapted from Knaus WA, Draper EA, Wagner DP, Zimmerman JE: APACHE II: A severity of disease classification system. Critical Care Medicine 13:818–829, 1985.