APACHE Score

Description

The APACHE (Acute Physiology And Chronic Health Evaluation) is a system for classifying patients in the intensive care unit. Patients are evaluated by physiologic scores and evaluation of chronic health status. Physiologic scores correlate with severity of illness. Results of the evaluation can be used to estimate the mortality rate for patients in the ICU and during the hospitalization.

Physiologic classes of variables (total 8 classes with 34 variables):

(1) cardiovascular: 7 variables

(2) respiratory: 3 variables

(3) renal: 3 variables

(4) gastrointestinal: 6 variables

(5) hematologic: 4 variables

(6) septic: 4 variables

(7) metabolic: 6 variables

(8) neurologic: 1 variable

Scoring:

(1) The physiologic data is evaluated during the first 32 hours after admission to the ICU.

(2) Each variable is assigned a value of 0 to 4, based on significance of deviation from normal, with more severe deviations given higher values.

Cardiovascular

Parameter	Finding	Points
heart rate ventricular response	>= 180	+4
	141 – 179	+3
	111- 140	+2
	70 – 110	0
	56 – 69	+2
	41 – 55	+3
	<= 40	+4
mean arterial pressure in mm Hg	>= 160	+4
	131 – 159	+3
	111 – 130	+2
	70 – 110	0
	51 – 69	+2
	<= 50	+4
right atrial pressure or central venous pressure in mm HG	>= 26	+2
	16 - 25	+1
	1 - 15	0
	< 1	+1
evidence of acute MI	Yes	+4
	No	0
ECG arrhythmias	atrial arrhythmias and hemodynamic instability	+3
	atrial arrhythmias alone	+2
	> 6 PVCs per minute	+3
	ventricular tachycardia or fibrillation	+4
serum lactate in mg/dL	> 72	+4
	30.7 – 72	+3
	0 – 36.6	0
arterial pH	>= 7.70	+4
	7.60 – 7.69	+3
	7.51 – 7.59	+1
	7.33 – 7.50	0
	7.25 – 7.32	+2
	7.15 – 7.24	+3
	< 7.15	+4

where:

• mean arterial blood pressure = (((systolic blood pressure) + (2 * (diastolic blood pressure))) / 3)

• Evidence of an acute MI may include ECG, serum marker changes, or other.

• serum lactate expressed in mEq/L, which is no longer used routinely. This was assumed to be equivalent to mmol/L, which is converted to mg/dL by multiplying by 9

Respiratory

Parameter	Finding	Points
respiratory rate nonventilated	>= 50	+4
	35 – 49	+3
	26 – 34	+1
	12 – 25	0
	10 – 11	+1
	7 – 9	+2
	<= 6	+4
P(A-a)O2 with FIO2 = 1.0	>= 500	+4
	351 – 499	+3
	200 – 350	+1
	< 200	0
PaCO2	>= 70	+4
	61 - 69	+3
	50 - 60	+2
	30 - 49	0
	25 - 29	+2
	20 - 24	+3
	< 20	+4

where:

• The P(A-a)O2 for FIO2 is given as ((FIO2 as fraction from 0.21 to 1.00) * 713) - PaCO2 - PaO2); however, the decision points for lower FIO2s are not given. These are unlikely to be comparable to those of an FIO2 of 1.00.

Renal

Parameter	Finding	Points
urine output in L per day	>= 5	+2
	> 3.5 to < 5.0	+1
	0.7 to 3.5	0
	0.48 to < 0.70	+2
	0.12 – 0.47	+3
	< 0.12	+4
serum BUN in mg/dL	> 150	+4
	101 – 150	+3
	81 – 100	+2
	21- 80	+1
	10 – 20	0
	< 10	+2
serum creatinine in mg/dL	> 7.0	+4
	3.6 – 7.0	+3
	2.1 – 3.5	+2
	1.6 – 2.0	+1
	0.6 – 1.5	0
	< 0.6	+1

Gastrointestinal

Parameter	Finding	Points
serum amylase in IU/L	> 2,000	+4
	501 – 1,999	+3
	<= 500	0
serum albumin in g/dL	> 8	+4
	3.5 – 8.0	0
	2.5 – 3.4	+1
	< 2.5	+2
total bilirubin in mg/dL	>= 15	+3
	5.1 – 14.9	+1
	0 - 5	0
alkaline phosphatase in IU/L	> 160	+1
	0 - 160	0
SGOT in IU/L	>= 1,500	+2
	101 – 1,499	+1
	0 - 101	0
anergy by skin testing	total	+4
	relative	+2
	none	0

where:

• total anergy = no response to all provocative skin tests including mumps and fungal

• relative anergy = reduced response to skin tests indicative of compromised cellular immunity

Hematological

Parameter	Finding	Points
hematocrit in percent	> 60	+4
	51 – 60	+2
	47 – 50	+1
	30 – 46	0
	20 – 29	+2
	< 20	+4
WBC in thousands per µL	> 40	+4
	> 20 to 40	+2
	> 15 to 20	+1
	> 3 to 15	0
	1 – 3	+2
	< 1	+4
platelet count in thousands per µL	> 1000	+2
	> 600 to 1000	+1
	80 to 600	0
	20 to < 80	+2
	< 20	+4
prothrombin time in seconds greater than control	> 12.0	+4
	5.1 – 12.0	+3
	3.1 – 5.0	+2
	0 – 3.0	0

where:

• Prothrombin time is that of the patient when not anticoagulated.

Septic

Parameter	Finding	Points
CSF positive culture	Yes	+4
	No	0
blood culture positive	Yes	+4
	No	0
fungal culture positive	blood and/or CSF positive for fungi	+4
	2 sites other than blood or CSF positive for fungi	+3
	1 site other than blood or CSF positive for fungi	+1
	No	0
rectal temperature in °C	> 41°C	+4
	39.1 – 41.0	+3
	38.6 – 39.0	+1
	36.0 – 38.5	0
	34.0 – 35.9	+1
	32.0 – 33.9	+2
	30.0 – 31.9	+3
	<= 29.9	+4

Metabolic

Parameter	Finding	Points
serum calcium in mg/dL	>= 16	+4
	14.0 – 15.9	+2
	11.1 – 13.9	+1
	8.0 – 11.0	0
	5.0 – 7.9	+2
	< 5.0	+4
serum glucose in mg/dL	> 800	+4
	500 - 800	+3
	251 – 499	+1
	70 – 250	0
	50 – 69	+2
	30 – 49	+3
	< 30	+4
serum sodium in mEq/L	> 180	+4
	161 – 180	+3
	156 – 160	+2
	151 – 155	+1
	130 – 150	0
	120 – 129	+2
	110 – 119	+3
	< 110	+4
serum potassium in mEq/L	> 7.0	+4
	6.1 – 7.0	+3
	5.6 – 6.0	+1
	3.5 – 5.5	0
	3.0 – 3.4	+1
	2.5 – 2.9	+2
	< 2.5	+4
serum bicarbonate in mEq/L	> 40	+3
	31 – 40	+1
	20 – 30	0
	10 – 19	+1
	5 – 9	+3
	< 5	+4
serum osmolarity	> 350	+4
	321 – 350	+3
	301 – 320	+1
	260 – 300	0
	240 – 259	+2
	220 – 239	+3
	< 220	+4

Neurological

Parameter	Finding	Points
Glasgow coma score	3	+4
	4 – 6	+3
	7 – 9	+2
	10 – 12	+1
	13 - 15	0

APACHE score =

= (points for cardiovascular status) + (points for respiratory status) + (points for renal status) + (points for gastrointestinal status) + (points for hematological status) + (points for septic status) + (points for metabolic status) + (points for neurological status)

Preadmission Health Status

Qualifying Questions, based on health status 3-6 months before admission	Group	Description
Did the patient have weekly visits to a physician? Was the patient unable to work because of illness? Was the patient bedridden or institutionalized because of illness? Had the patient suffered a relapse after systemic treatment for carcinoma?	D	Severe restriction of activity due to disease; includes patients bedridden or institutionalized due to illness
Was the patient's usual daily activity limited? Did symptoms occur with mild exercise? Had the patient received treatment for neoplasm with remission? Had the patient received uncomplicated hemodialysis?	C	chronic disease producing serious but not incapacitating restriction of activity
Did the patient see a physician monthly? Did the patient take medication chronically? Was the patient mildly limited in activity level due to illness? Did the patient have diabetes mellitus, chronic renal failure, a bleeding disorder, or chronic anemia?	B	mild to moderate limitation in activity because of chronic health problem
negative responses to all of the above questions	A	prior good health with no functional limitations

Interpretation:

• minimum score: 0

• maximum score: 129 (cardiovascular 27; respiratory 12; renal 12; gastrointestinal 18; hematological 16; septic 16; metabolic 24; neurological 4)

Probability of Death in Hospital based on APACHE score

Score	Mortality Rate
0 - 5	2.3%
6 - 10	4.3%
11 - 15	8.6%
16 - 20	16.4%
21 - 25	28.6%
26 - 30	56.4%
31+	70%

data extrapolated from Figure 1, page 595

Relationship between chronic health status and patient outcome

Overall

Preadmission Health Status	Probability of Dying in the ICU	Probability of Dying in the Hospital
A	7.3%	12%
B	5.9%	12%
C	10.5%	16.5%
D	11.7%	25%

Nonoperative

Preadmission Health Status	Probability of Dying in the ICU	Probability of Dying in the Hospital
A	14%	20.9%
B	10.1%	20.2%
C	12.8%	21.7%
D	22.2%	50%

Operative

Preadmission Health Status	Probability of Dying in the ICU	Probability of Dying in the Hospital
A	3%	6.2%
B	2.2%	7.2%
C	8.6%	12.3%
D	3%	6%

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