Assessing patient severity and predicting patient outcome

W. A. Knauss et al. (1981) developed and implemented the APACHE (Acute Physiology and Chronic Health Evaluation) classification system, applicable to adults and older children, which provides for the use of routine parameters in the intensive care unit and is designed to assess all major physiological systems. A distinctive feature of this scale was that assessments that use specific parameters of organ system dysfunction are limited to diseases of these systems, while assessment of systems that could provide more extensive information about the patient's condition requires extensive invasive monitoring.

Initially, the APACHE scale contained 34 parameters, and the results obtained in the first 24 hours were used to determine the physiological status in the acute period. The parameters were assessed from 0 to 4 points, the health status was determined from A (full health) to D (acute multiple organ failure). The probable outcome was not determined. In 1985, after revision (APACHE II), the scale remained 12 main parameters determining the main processes of vital activity (Knaus WA et al., 1985). In addition, it turned out that a number of indicators, such as glucose and albumin concentrations in plasma, central venous pressure or diuresis, are of little significance in assessing the severity of the scale and reflect the treatment process more. The Glasgow scale indicator was assessed from 0 to 12, and creatinine, which replaced urea, from 0 to 8 points.

Direct determination of oxygen in arterial blood began to be performed only at Fi02 less than 0.5. The other nine parameters did not change their assessment. The general state of health is assessed separately. Moreover, patients without surgery or with surgery for emergency indications were significantly less likely to survive compared to planned patients. The total assessment of age and general health cannot exceed 71 points; in individuals with an assessment of up to 30-34 points, the probability of a fatal outcome is significantly higher than in patients with a higher assessment.

In general, the risk of developing a fatal outcome varied in different diseases. Thus, mortality in people with low output syndrome is higher than in patients with sepsis, with the same assessment on the scale. It turned out to be possible to introduce coefficients that take into account these changes. In the case of a relatively favorable outcome, the coefficient has a large negative value, and in the case of an unfavorable prognosis, this coefficient is positive. In the case of pathology of an individual organ, a certain coefficient also takes place.

One of the major limitations of the APACHE I score is that the mortality risk prediction is based on ICU patient outcomes from 1979 to 1982. In addition, the score was not originally designed to predict death for an individual patient and had an error rate of approximately 15% in predicting in-hospital mortality. However, some investigators have used the APACHE II score to determine the prognosis for an individual patient.

The APACHE II scale consists of three blocks:

1. assessment of acute physiological changes (acute physiology score-APS);
2. age assessment;
3. assessment of chronic diseases.

Data for the "Acute Physiological Changes Assessment" block are collected during the first 24 hours of the patient's admission to the ICU. The worst assessment option obtained during this time period is entered into the table.

[ 1 ], [ 2 ], [ 3 ]

Acute Physiological Disorders and Chronic Disorders Assessment Scale

Acute Physiology and Chronic Health Evaluation II (APACHE II) (Knaus WA, Draper EA et al., 1985)

Acute Physiology Score (APS)

Sign	Meaning	Points
Rectal temperature, C	>41	+4
	39-40.9	+3
	38.5-38.9	+1
	36-38.4	0
	34-35.9	+1
	32-33.9	+2
	30-31.9	+3
	>29.9	+4
Mean arterial pressure, mmHg	>160	+4
	130-159	+3
	110-129	+2
	70-109	0
	50-69	+2
	>49	+4
Heart rate, min	>180	+4
	140-179	+3
	110-139	+2
	70-109	0
	55-69	+2
	40-54	+3
	>39	+4
RR, min	>50	+4
	35-49	+3
	25-34	+1
	12-24	0
	10-11	+1
	6-9	+2
	>5	+4

Sign	Meaning	Points
Oxygenation (A-a002 or Pa02)	А-аD02 > 500 and РFiO2 > 0.5	+4
	А-аD0, 350-499 and Fi02 > 0.5	+3
	A-aD02 200-349 and Fi02 > 0.5	+2
	A-aD02 > 200 and Fi02 > 0.5	0
	Ra02 > 70 and Fi02 > 0.5	0
	Ra02 61-70 and Fi02 > 0.5	+!
	Ra02 55-60 and Fi02 > 0.5	+3
	Ra02 > 55 and Fi02 > 0.5	+4
Arterial blood pH	>7.7	+4
	7.6-7.69	+ 3
	7.5-7.59	+ 1
	7.33-7.49	0
	7.25-7.32	+2
	7.15-7.24	+3
	>7.15	+4
Serum sodium, mmol/l	>180	+4
	160-179	+3
	155-159	+2
	150-154	+ 1
	130-149	0
	120-129	+2
	111-119	+3
	>110	+4
Serum potassium, mmol/l	>7.0	+4
	6.0-6.9	+3
	5.5-5.9	+ 1
	3.5-5.4	0
	3.0-3.4	+1
	2.5-2.9	+2
	>2.5	+4

Sign	Meaning	Points
	>3.5 without OPN	+4
	2.0-3.4 without OPN	+3
	1.5-1.9 without OPN	+2
	0.6-1.4 without OPN	0
Creatinine, mg/100 ml	> 0.6 without OPN	+2
	>3.5 s OPN	+8
	2.0-3.4 with OPN	+6
	1.5-1.9 s OPN	+4
	0.6-1.4 with OPN	0
	>0.6 s OPN	+4
	>60	+4
	50-59.9	+2
Hematocrit, %	46-49.9	+ 1
	30-45.9	0
	20-29.9	+2
	>20	+4
	>40	+4
	20-39.9	+2
Leukocytes	15-19.9	+1
(mm3 x 1000 cells)	3-14.9	0
	1-2.9	+2
	>1	+4
Glasgow Rating	3-15 points in Glasgow

Note: The estimate for serum creatinine is duplicated if the patient has acute kidney injury (AKI). Mean arterial pressure = ((syst. BP) + (2 (diast. BP))/3.

If no blood gas data are available, serum bicarbonate may be used (the authors recommend using this parameter instead of arterial pH).

Sign	Meaning	Points
Bicarbonate (mmol/L)	>52.0	+4
	41.0-51.9	+3
	32.0-40.9	+ 1
	22.0-31.9	0
	18.0-21.9	+2
	15.0-17.9	+3
	>15.0	+4

Patient age assessment

Age	Points
>44	0
45-54	2
55-64	3
65-74	5
>75	6

Assessment of concomitant chronic diseases

Surgical intervention	Associated pathology	Points
Non-operated patients	History of severe organ failure OR immunodeficiency	5
	There is no history of severe organ failure or immunodeficiency.	0
Patients after emergency operations	History of severe organ failure OR immunodeficiency	5
	There is no history of severe organ failure or immunodeficiency.	0
Patients after planned operations	History of severe organ failure OR immunodeficiency	2
	There is no history of severe organ failure or immunodeficiency.	0

Note:

• Organ (or system) failure or immunodeficiency preceded the current hospitalization.
• An immunodeficiency state is defined if: (1) the patient has received therapy that reduces the immune system (immunosuppressive
• therapy, chemotherapy, radiation therapy, long-term steroid use, or short-term high-dose steroid use), or (2) has diseases that suppress immune function, such as malignant lymphoma, leukemia, or AIDS.
• Liver failure if: there is liver cirrhosis confirmed by biopsy, portal hypertension, episodes of bleeding from the upper gastrointestinal tract against the background of portal hypertension, previous episodes of liver failure, coma or encephalopathy.
• Cardiovascular failure - class IV according to the New York classification.
• Respiratory failure: if there is respiratory limitation due to chronic restrictive, obstructive or vascular diseases, documented chronic hypoxia, hypercapnia, secondary polycythemia, severe pulmonary hypertension, ventilator dependence.
• Renal failure: if the patient is on chronic dialysis.
• APACH EII score = (Acute Physiological Changes Scale score) + (Age score) + (Chronic Disease score).
• High APACHE II scores are associated with a high risk of mortality in the ICU.
• The scale is not recommended for use in patients with burns and after coronary artery bypass grafting.

Disadvantages of the APACHE II scale:

1. Not for use by persons under 18 years of age.
2. General health status should only be assessed in seriously ill patients, otherwise adding this indicator leads to overestimation.
3. No assessment available prior to admission to the intensive care unit (introduced in the APACHE III score).
4. In case of death within the first 8 hours after admission, data assessment is meaningless.
5. In sedated, intubated patients, the Glasgow score should be 15 (normal); in the case of a history of neurological pathology, this score may be reduced.
6. With frequent repeated use, the scale gives a slightly higher rating.
7. A number of diagnostic categories are missed (preeclampsia, burns and other conditions), the damaged organ coefficient does not always give an accurate picture of the condition.
8. With a lower diagnostic coefficient, the scale assessment is more significant.

[ 4 ], [ 5 ], [ 6 ]

The scale was later transformed into the APACHE III scale.

APACHE III was developed in 1991 to expand and improve the prognostic assessments of APACHE II. The database for creating the scale was collected for the period from 1988 to 1990 and included data on 17,440 patients in intensive care units. The study included 42 units in 40 different hospitals. Urea, diuresis, glucose, albumin, and bilirubin were added to the scale to improve the assessment of prognosis. Parameters for the interaction between different variables (serum creatinine and diuresis, pH, and pCO2) were added. The APACHE III scale pays more attention to the state of immunity (Knaus WA et al., 1991).

The development of APACHE III had the following objectives:

1. Re-evaluate the sample and the significance of the deviations using objective statistical models.
2. Update and increase the size and representativeness of the data under consideration.
3. To evaluate the relationship between scores on the scale and the patient's length of stay in the intensive care unit.
4. Distinguish the use of prognostic assessments for groups of patients from the prediction of mortality in each individual case.

The APACHE III system has three major advantages. First, it can be used to assess disease severity and risk patients within a single diagnostic category (group) or an independently selected group of patients. This is because increasing scores on the scale correlate with increasing risk of in-hospital mortality. Second, the APACHE III scale is used to compare outcomes in intensive care unit patients, although the diagnostic and selection criteria are similar to those used to develop the APACHE III system. Third, APACHE III can be used to predict treatment outcomes.

APACHE III predicts in-hospital mortality for groups of intensive care unit (ICU) patients by matching patient characteristics on the first day of ICU admission to 17,440 patients originally included in the database (between 1988 and 1990) and 37,000 patients admitted to intensive care units in the United States who were included in an updated database (1993 and 1996).

Acute Physiological Disorders and Chronic Disorders Assessment Scale III

Acute Physiology and Chronic Health Evaluation III (APACHE III) (Knaus WA et al., 1991)

The APACHE III score is composed of several components - age, chronic diseases, physiological, acid-base and neurological status. In addition, scores reflecting the patient's condition at the time of admission to the ICU and the category of the underlying disease are also taken into account.

Based on the severity assessment, the risk of death in hospital is calculated.

Assessment of the patient's condition before admission to the ICU

Assessment of the condition before admission to the intensive care unit for patients with a medical profile

Primary hospitalization prior to admission to the ICU	Grade
Emergency Department
Other hospital department	0.2744
Transferred from another hospital
Other ICU
Re-admission to the ICU
Operating room or postoperative ward

Assessment of admission to the intensive care unit for surgical patients

Type of surgical intervention before admission to the intensive care unit	Grade
Emergency surgery	0.0752
Elective surgery

[ 7 ], [ 8 ], [ 9 ], [ 10 ]

Category of the underlying disease for patients in the therapeutic profile

Organ system	Pathological condition	Grade
Cardiovascular system	Cardiogenic shock	1.20
	Heart failure	1.24
	Aortic aneurysm	1D1
	Congestive heart failure	1.30

Organ system	Pathological condition	Grade
	Peripheral vascular diseases	1.56
	Rhythm disturbances	1.33
	Acute myocardial infarction	1.38
	Hypertension	1.31
	Other cardiovascular diseases	1.30
Respiratory system	Parasitic pneumonia	1.10
	Aspiration pneumonia	1.18
	Tumors of the respiratory system, including the larynx and trachea	1,12
	Respiratory arrest	1.17
	Non-cardiogenic pulmonary edema	1.21
	Bacterial or viral pneumonia	1.21
	Chronic obstructive pulmonary diseases	1.28
	TELA	1.24
	Mechanical airway obstruction	1.30
	Bronchial asthma	1.40
	Other diseases of the respiratory system	1.22
Gastrointestinal tract	Liver failure	1,12
	Perforation or obstruction of the "bowel"	1.34
	Bleeding from varicose veins of the gastrointestinal tract	1.21
	Inflammatory diseases of the gastrointestinal tract (ulcerative colitis, Crohn's disease, pancreatitis)	1.25
	Bleeding, perforation of gastric ulcer	1.28
	Gastrointestinal bleeding due to diverticulum	1.44
	Other gastrointestinal diseases	1.27

Organ system	Pathological condition	Grade
Diseases of the nervous system	Intracranial hemorrhage	1.37
	Subarachnoid hemorrhage	1.39
	Stroke	1.25
	Infectious diseases of the nervous system	1.14
	Tumors of the nervous system	1.30
	Neuromuscular diseases	1.32
	Cramps	1.32
	Other nervous diseases	1.32
Sepsis	Non-urinary related	1.18
	Urinary sepsis	1.15
Injury	TBI with or without concomitant injury	1.30
	Combined injury without TBI	1.44
Metabolism	Metabolic coma	1.31
	Diabetic ketoacidosis	1.23
	Drug overdose	1.42
	Other metabolic diseases	1.34
Blood diseases	Coagulopathy, neutropenia, or thrombocytopenia	1.37
	Other blood diseases	1.19
Kidney diseases		1.18
Other internal diseases		1.46

Category of the underlying disease for surgical patients

System	Type of operation	Grade
Cardiovascular system	Surgeries on the aorta	1.20
	Peripheral vascular surgery without prosthetics	1.28
	Heart valve surgeries	1.31
	Abdominal Aortic Aneurysm Surgery	1.27
	Peripheral artery surgery with prosthetics	1.51

System	Type of operation	Grade
	Carotid endarterectomy	1.78
	Other cardiovascular diseases	1.24
Respiratory system	Respiratory tract infection	1.64
	Lung tumors	1.40
	Tumors of the upper respiratory tract (oral cavity, sinuses, larynx, trachea)	1.32
	Other respiratory diseases	1.47
Gastrointestinal tract	Gastrointestinal perforation or rupture	1.31
	Inflammatory diseases of the gastrointestinal tract	1.28
	Gastrointestinal obstruction	1.26
	Gastrointestinal bleeding	1.32
	Liver transplantation	1.32
	Tumors of the gastrointestinal tract	1.30
	Cholecystitis or cholangitis	1.23
	Other gastrointestinal diseases	1.64
Nervous diseases	Intracranial hemorrhage	M7
	Subdural or epidural hematoma	1.35
	Subarachnoid hemorrhage	1.34
	Laminectomy or other spinal cord surgery	1.56,
	Craniotomy for a tumor	1.36
	Other diseases of the nervous system	1.52
Injury	TBI with or without concomitant injury	1.26
	Combined injury without TBI	1.39
Kidney diseases	Kidney tumors	1.34
	Other kidney diseases	1.45
Gynecology	Hysterectomy	1.28
Orthopedics	Fractures of the hip and limbs	1.19

[ 11 ], [ 12 ], [ 13 ], [ 14 ], [ 15 ], [ 16 ], [ 17 ]

Physiological scale APACHE III

The physiological scale is based on a variety of physiological and biochemical parameters, with scores given according to the severity of the pathological condition at the moment.

The calculation is based on the worst values during 24 hours of observation.

If the indicator has not been studied, then its value is taken as normal.

Pulse, bpm	Grade
>39	8
40-49	5
50-99	0
100-109	1
110-119	5
120-139	7
140-154	13
>155	17

Mean BP	Grade
>39	23
40-59	15
60-69	7
70-79	6
80-99	0
100-119	4
120-129	7
130-139	9
>140	10

Temperature, °C	Grade
>32.9	20
33-33.4	16
33.5-33.9	13
34-34.9	8
35-35.9	2
36-39.9	0
>40	4

Respiratory rate	Grade
£5	17
6-11	8 if there is no mechanical ventilation; 0 if mechanical ventilation is performed
12-13	7 (0 if RR = 12 and mechanical ventilation is performed)
14-24	0
25-34	6
35-39	9
40-49	11
>50	18

Ra02,mm He	Grade
>49	15
50-69	5
70-79	2
>80	0

A-a BO,	Grade
>100	0
100-249	7
250-349	9
350-499	11
£500	14

Hematocrit, %	Grade
>40.9	3
41-49	0
>50	3

Leukocytes, µl	Grade
>1000	19
1000-2900	5
3000-19 900	0
20,000-24,999	1
>25,000	5

Creatinine, mg/dl, without acute renal failure	Grade
>0.4	3
0.5-1.4	0
1.5-1.94	4
>1.95	7

Diuresis, ml/day	Grade
>399	15
400-599	8
600-899	7
900-1499	5
1500-1999	4
2000-3999	0
>4000	1

Residual urea nitrogen, mg/dL	Grade
>16.9	0
17-19	2
20-39	7
40-79	11
>80	12

Sodium, mEq	Grade
>119	3
120-134	2
135-154	0
>155	4

Albumin, g/dl	Grade
>1.9	11
2.0-2.4	6
2.5-4.4	0
>4.5	4

Bilirubin, mg/dl	Grade
>1.9	0
2.0-2.9	5
3.0-4.9	6
5.0-7.9	8
>8.0	16

Glucose, mg/dl	Grade
>39	8
40-59	9
60-199	0
200-349	3
>350	5

Note.

1. Mean BP = Systolic BP + (2 x Diastolic BP)/3.
2. The Pa02 assessment is not used in intubated patients Fi02>0.5.
3. A-a D02, used only in intubated patients with Fi02 > 0.5.
4. The diagnosis of ARF is made when the creatinine concentration is > 1.5 mg/dL, the urine output rate is > 410 ml/day and there is no chronic dialysis.

Assessment on a physiological scale = (Pulse assessment) + (CAP assessment) + (Temperature assessment) + (RR assessment) + (Ra02 or A-a D02 assessment) + (Hematocrit assessment) + (Leukocyte assessment) + (Creagin level assessment +/- ARF) + (Diuresis assessment) + (Residual nitrogen assessment) + (Nagar assessment) + (Albumin assessment) + (Bilirubin assessment) + (Glucose assessment).

Interpretation:

• Minimum rating: 0.
• Maximum score: 192 (due to limitations of Pa02, A-aD02 and creatinine). 2.5.

Acid-base balance assessment

The assessment of pathological conditions of the acid-base balance is based on the study of the pCO2 content and pH of the patient's arterial blood.

The calculation is based on the worst values within 24 hours. If a value is not available, it is considered normal.

[ 18 ], [ 19 ], [ 20 ], [ 21 ], [ 22 ], [ 23 ], [ 24 ]

Assessment of neurological status

The neurological status is assessed based on the patient's ability to open his eyes, verbal communication, and motor response. The score is based on the worst values over 24 hours. If the value is not available, it is considered normal.

The APACHE III score for assessing the severity of illness in ICU patients can be used throughout hospitalization to predict the likelihood of in-hospital mortality.

Each day of the patient's stay in the ICU, the APACHE III score is recorded. Based on the developed multivariate equations, the probability of the patient's death on the current day can be predicted using the daily APACHE III scores.

Daily risk = (Acute Physiology Score on day 1 of patient's ICU stay) + (Acute Physiology Score during the current day) + (Change in Acute Physiology Score from the previous day).

The multivariate equations for estimating daily mortality risk are copyrighted. They are not published in the literature but are available to subscribers of the commercial system.

Once the parameters included in the APACHE III score are tabulated, severity scores and the likelihood of in-hospital death can be calculated.

Data requirements:

• The assessment is performed to determine the indications for hospitalization in the intensive care unit.
• If the patient has medical pathology, select the appropriate assessment before admission to the ICU.
• If the patient has undergone surgery, select the type of surgery (emergency, planned).
• The assessment is made for the main category of the disease.
• If the patient is a medical patient, select the main pathological condition requiring hospitalization in the intensive care unit.
• If the patient has undergone surgery, select the main pathological condition among surgical diseases requiring hospitalization in the intensive care unit.

[ 25 ], [ 26 ]

Overall APACHE III score

Total APACHE III score = (Age score) + (Chronic disease score) + (Physiological status score) + (Acid-base balance score) + (Neurological status score)

Minimum total APACHE III score = O

Maximum total APACHE III score = 299 (24 + 23+ 192 + 12 + 48)

APACHE III Severity Score = (Pre-ICU Score) + (Major Disease Category Score) + + (0.0537(0total APACHE III Score)).

Probability of death in hospital = (exp(APACHE III severity score)) / ((exp(APACHE III risk equation)) + 1)

Again, it should be emphasized that prognosis scores are not intended to predict death for an individual patient with 100% accuracy. High scores on the scale do not mean complete hopelessness, just as low scores do not guarantee against unexpected complications or accidental death. Although prediction of death using APACHE III scores obtained on the first day of ICU admission is reliable, it is still rare to be able to determine an accurate prognosis for an individual patient after the first day of intensive care. The ability to predict an individual patient's probability of survival depends, in part, on how he or she responds to therapy over time.

Clinicians using predictive models must be mindful of the capabilities of modern therapy and recognize that confidence intervals for each value are widening every day, increasing the number of positive results that are more important than absolute values, and that some factors and indicators of response to therapy are not determined by acute physiological abnormalities.

In 1984, the SAPS scale (UFSHO) was proposed, the main goal of which was to simplify the traditional method of assessing seriously ill patients (APACHE). This version uses 14 easily determined biological and clinical indicators that to a sufficiently high degree reflect the risk of death in patients in intensive care units (Le Gall JR et al., 1984). The indicators are assessed in the first 24 hours after admission. This scale correctly classified patients into groups with increased probability of death regardless of diagnosis and turned out to be comparable with the physiological scale of acute conditions and other assessment systems used in intensive care units. UFSHO turned out to be the simplest and took significantly less time for its assessment. Moreover, as it turned out, it is possible to conduct a retrospective assessment of the condition, since all the parameters used in this scale are routinely recorded in most intensive care units.

Original simplified scale for the assessment of physiological disorders

Original Simplified Acute Physiology Score (SAPS) (Le Gall JR, 1984)

The Simplified Acute Physiology Score (SAPS) is a simplified version of the APACHE Acute Physiology Score (APS). It allows for easy scoring using available clinical information; the scores correspond to the patient's risk of mortality in the ICU.

Data:

• received during the first 24 hours of stay after admission to the intensive care unit;
• 14 information values versus 34 values according to APACHE APS.

Parameter	Meaning	Points
Age, years	>45	0
	46-55	1
	55-65	2
	66-75	3
	>75	4
Heart rate, bpm	>180	4
	140-179	3
	110-139	2
	70-109	0
	55-69	2
	40-54	3
	>40	4
Systolic blood pressure, mmHg	>190	4
	150-189	2
	80-149	0
	55-79	2
	>55	4
Body temperature, “C	>41	4
	39-40.9	3
	38.5-38.9	I
	36-38.4	0
	34-35.9	1
	32-33.9	2
	30-31.9	3
	>30	4
Spontaneous breathing, RR, min	>50	4
	35-49	3
	25-34	1
	12-24	0
	10-11	1
	6-9	2
	>6	4
	On artificial ventilation or CPAP	3

Parameter	Meaning	Points
	55700	2
	3.5-4.99	1
Diuresis in 24 hours, l	0.70-3.49	0
	0.50-0.69	2
	0.20-0.49	3
	>0.20	4
	£154	4
	101-153	3
Urea, mg/dl	81-100	2
	21-80	1
	10-20	0
	>10	1
	>60	4
	50-59.9	2
Hematocrit, %	46-49.9	1
	30-45.9	0
	20.0-29.9	2
	>20.0	4
	>40	4
	20-39.9	2
	15-19.9	1
	3.0-14.9	0
	1.0-2.9	2
	>1.0	4
Leukocytes, 1000/l	>800	4
	500-799	3
	250-499	1
	70-249	0
	50-69	2
	29-49	3
	>29	4

Parameter	Meaning	Points
Potassium, mEq/L	>7.0	4
	6.0-6.9	3
	5.5-5.9	1
	3.5-5.4	0
	3.0-3.4	1
	2.5-2.9	2
	>2.5	4
Sodium, mEq/L	>180	4
	161-179	3
	156-160	2
	151-155	1
	130-150	0
	120-129	2
	119-110	3
	>110	4
НС03 meq/l	>40	3
	30-39.9	1
	20-29.9	0
	10-19.9	1
	5.0-9.9	3
Glasgow Coma Scale, points	>5.0	4
	13-15	0
	10-12	1
	7-9	2
	4-6	3
	3	4

Notes:

1. Glucose converted to mg/dL from mol/L (mol/L multiply by 18.018).
2. Urea converted to mg/dL from mol/L (mol/L x 2.801). Total SAPS score = Sum of all SAPS scores. Minimum score is 0 and maximum is 56. The probability of death is shown below.

SAPS	Mortality risk
4
5-6	10.7 ±4.1
7-8	13.3 ±3.9
9-10	19.4 ±7.8
11-12	24.5 ±4.1
13-14	30.0 ± 5.5
15-16	32.1 ±5.1
17-18	44.2 ±7.6
19-20	50.0 ± 9.4
>21	81.1 ±5.4

The scale was subsequently modified by the authors and became known as SAPS II (Le Gall JR et al., 1993).

New simplified scale of assessment of physiological disorders II

New Simplified Acute Physiology Score (SAPS II) (Le Gall JR. et al., 1993; Lemeshow S. et al., 1994)

The new Simplified Acute Physiology Score (SAPS II) is a modified simplified acute physiology score. It is used to assess ICU patients and can predict mortality risk based on 15 key variables.

Compared to SAPS:

• Excluded: glucose, hematocrit.
• Added: bilirubin, chronic diseases, reason for admission.
• Changed: Pa02/Fi02 (zero points if not on mechanical ventilation or on CPAP).

The SAPS II score ranges from 0 to 26 versus 0 to 4 for the SAPS.

Variable indicator	Evaluation Guidelines
Age	In years from last birthday
Heart rate	The highest or lowest value in the last 24 hours that will give the highest score
Systolic blood pressure	The highest or lowest value in the last 24 hours that will give the highest score
Body temperature	The greatest value
Coefficient >p>Pa02/Fi02	Only if on ventilator or CPAP, use the lowest value
Diuresis	If the period is less than 24 hours, then bring it to the value for 24 hours
Serum Urea or BUN	The greatest value
Leukocytes	The highest or lowest value in the last 24 hours that will give the highest score
Potassium	The highest or lowest value in the last 24 hours that will give the highest score
Sodium	The highest or lowest value in the last 24 hours that will give the highest score
Bicarbonate	The smallest value
Bilirubin	The smallest value
Glasgow Coma Scale	Lowest value; if patient is loaded (sedated), then use pre-load data
Type of admission	Elective surgery if scheduled at least 24 hours prior to surgery; unplanned surgery with less than 24 hours notice; for health reasons if no surgery has been performed in the last week prior to ICU admission
AIDS	HIV-positive with AIDS-associated opportunistic infection or tumor
Blood cancer	Malignant lymphoma; Hodgkin's disease; leukemia or generalized myeloma
Metastasis of cancer	Metastases detected during surgery by radiography or other available method

Parameter	Meaning	Points
Age, years	>40	0
	40-59	7
	60-69	12
	70-74	15
	75-79	16
	80	18
Heart rate, bpm	>40	11
	40-69	2
	70-119	0
	120-159	4
	>160	7
Systolic blood pressure, mmHg	>70	13
	70-99	5
	100-199	0
	>200	2
Body temperature, °C	>39	0
	>39	3
Pa02/Fi02 (if on mechanical ventilation or CPAP)	>100	11
	100-199	9
	>200	6
Diuresis, l per 24 h	>0,500	11
	0.500-0.999	4
	>1,000	0
Urea, mg/dl	>28	0
	28-83	6
	>84	10
Leukocytes, 1000/l	>1.0	12
	1.0-19.9	0
	>20	3
Potassium, mEq/L	>3.0	3
	3.0-4.9	0
	>5.0	3

Parameter	Meaning	Points
Sodium, mEq/L	>125	5
	125-144	0
	>145	1
HCO3, mEq/L	>15	6
	15-19	3
	>20	0
Bilirubin, mg/dl	>4.0	0
	4.0-5.9	4
	>6.0	9
Glasgow Coma Scale, points	>6	26
	6-8	13
	9-10	7
	11-13	5
	14-15	0
Chronic diseases	Metastatic carcinoma	9
	Blood cancer	10
	AIDS	17
Type of admission	Planned surgery	0
	For health reasons	6
	Unscheduled surgery	8

>SAPS II = (Age score) + (HR score) + (Systolic BP score) + (Body temperature score) + (Ventilation score) + (Diuresis score) + (Blood urea nitrogen score) + (White blood cell count score) + (Potassium score) + (Sodium score) + (Bicarbonate score) + + (Bilirubin score) + (Glasgow Score) + (Chronic disease score) + (Admission type score).

Interpretation:

• Minimum value: O
• Maximum value: 160
• logit = (-7.7631) + (0.0737 (SAPSII)) + ((0.9971(LN((SAPSII) + 1))),
• Probability of dying in hospital = exp (logit)/( 1 + (exp (logit))).

[ 27 ], [ 28 ], [ 29 ], [ 30 ], [ 31 ]

Lung Injury Score (Murray JF, 1988)

Estimated parameter	Indicator	Meaning	Grade
Chest X-ray	Alveolar consolidation	No alveolar consolidation	0
		Alveolar consolidation in one quadrant of the lungs	1
		Alveolar consolidation in two quadrants of the lungs	2
		Alveolar consolidation in three quadrants of the lungs	3
		Alveolar consolidation in the four quadrants of the lungs	4
Hypoxemia	Ra02/Ri02	>300	0
		225-299	1
		175-224	2
		100-174	3
		>100	4
Respiratory system compliance, ml/cm H20 (with mechanical ventilation)	Compliance	>80	0
		60-79	1
		40-59	2
		20-39	3
		>19	4
Positive end-expiratory pressure, cm H20 (with artificial ventilation)	PDKV	>5	0
		6-8	1
		9-11	2
		12-14	3
		>15	4
Total points	Presence of lung damage	No lung damage	0
		Acute lung injury	0.1-2.5
		Severe lung injury (ARDS)	>2.5

RIFLE scale

(National Kidney Foundation: K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification and Stratification, 2002)

To unify approaches to defining and stratifying the severity of acute renal failure, a group of experts from the Acute Dialysis Quality Initiative (ADQI) created the RIFLE scale (rifle), which includes the following stages of renal failure:

• Risk - risk.
• Injury - damage.
• Failure - insufficiency.
• Loss - loss of function.
• ESKD (end stage renal disease) - final stage kidney disease = terminal renal failure.

Class	Serum creatinine	Diuresis rate	Specificity/ sensitivity
I (risk)	Increase in serum creatine concentration by 1.5 times Decreased glomerular filtration rate (GFR) by more than 25%	More than 0.5 ml/kg/h for 6 hours	High sensitivity
I (damage)	Increase in serum creatinine concentration by 2 times or. Decreased SCF by more than 50%	More than 0.5 ml/kg/h for 12 h
F(insufficiency)	Increase in serum creatinine concentration by 3 times Decreased SCF by more than 75% Increase in serum creatinine concentration to 4 mg/dL (>354 μmol/L) or more with a rapid increase to >0.5 mg/dL (>44 μmol/L)	More than 0.3 ml/kg/h for 24 h or anuria for 12 h	High specificity
L (loss of kidney function)	Persistent ARF (complete loss of kidney function) for 4 weeks or more
E (terminal renal failure)	Terminal renal failure for more than 3 months

This classification system includes criteria for assessing creatinine clearance and diuresis rate. When examining a patient, only those assessments are used that indicate that the patient has the most severe class of kidney damage.

It should be borne in mind that with an initially elevated serum creatinine (Scr) concentration, renal failure (F) is diagnosed even in cases where the Scr increase does not reach a threefold excess over the initial level. This situation is characterized by a rapid increase in Scr by more than 44 μmol/l to a serum creatinine concentration above 354 μmol/l.

The designation RIFLE-FC is used when a patient with chronic renal failure has an acute deterioration in renal function "acute renal failure to chronic renal failure" and an increase in serum creatinine concentration compared to the baseline level. If renal failure is diagnosed based on a decrease in the rate of hourly urine output (oliguria), the designation RIFLE-FO is used.

The “high sensitivity” of the scale means that most patients with the above-mentioned features are diagnosed with moderate renal dysfunction even in the absence of true renal failure (low specificity).

With “high specificity,” there is virtually no doubt about the presence of severe kidney damage, although in some patients it may not be diagnosed.

One of the limitations of the scale is that it requires knowledge of the baseline renal function to stratify the severity of ARF, but this is usually unknown in patients admitted to the ICU. This was the basis for conducting another study, Modification of Diet in Renal Disease (MDRD), based on the results of which ADQI experts calculated estimates of “baseline” values for serum creatinine concentrations at a given glomerular filtration rate of 75 ml/min/1.73 m2.

Estimation of "basal" serum creatinine values (μmol/L) corresponding to glomerular filtration rate values of 75 mg/min/1.73 mg for Caucasians

Age, years	Men	Women
20-24	115	88
25-29	106	88
30-39	106	80
40-54	97	80
55-65	97	71
>65	88	71

Based on the results obtained, experts from the Acute Kidney Injury Network (AKIN) subsequently proposed a system for stratifying the severity of AKI, which is a modification of the RIFLE system.

Kidney damage according to AKIN

Stage	Patient's serum creatinine concentration	Diuresis rate
1	Serum creatinine concentration (Beg) > 26.4 μmol/l or its increase by more than 150-200% from the initial level (by 1.5-2.0 times)	More than 0.5 ml/kg/h for six or more hours
2	An increase in the concentration of Beg by more than 200% but less than 300% (more than 2 but less than 3 times) from the initial level	More than 0.5 ml/kg/h for 12 hours or more
3	Increase in the concentration of Beg by more than 300% (more than 3 times) from the initial value or concentration of Beg >354 μmol/l with a rapid increase of more than 44 μmol/l	More than 0.3 ml/kg/h for 24 h or anuria for 12 h

The proposed system, based on changes in serum creatinine concentration and/or hourly urine output rate, is similar in many ways to the RIFLE system, but still has a number of differences.

In particular, RIFLE classes L and E are not used in this classification and are considered as outcomes of acute kidney injury. At the same time, category R in the RIFLE system is equivalent to the first stage of AKI in the AKIN system, and RIFLE classes I and F correspond to the second and third stages according to the AKIN classification.