ICU Scoring Systems

Iman Galal, MD
Pulmonary Medicine Department
E-mail: dr.imangalal@gmail.com
ICU Scoring Systems
telemed.shams.edu.eg/moodle

Introduction
► Severity of illness scoring systems are developed to
evaluate delivery of care & provide prediction of
outcome of groups of critically ill patients who are
admitted to ICUs.
► Scoring systems consists of two parts: a severity
score, which is a number (generally the higher this is,
the more severe the condition) & a calculated
probability of mortality.

Classification of Scoring Systems
► Anatomical scores: depend on the anatomical area involved.
Mainly used for trauma patients [e.g. abbreviated injury score (AIS) &
injury severity score (ISS)].
► Therapeutic weighted scores: based on the assumption that
very ill patients require more complex interventions & procedures than
patients who are less ill e.g., the therapeutic intervention scoring
system (TISS).
► Organ-specific score: similar to therapeutic scoring; the sicker a
patient the more organ systems will be involved, ranging from organ
dysfunction to failure [e.g. sequential organ failure assessment
(SOFA)].

Classification of Scoring Systems
► Physiological assessment: based on the degree of
derangement of routinely measured physiological variables [e.g.
acute physiology and chronic health evaluation (APACHE) &
simplified acute physiology score (SAPS)].
► Simple scales: based on clinical judgment (e.g. survive or die).
► Disease specific: [e.g. Ranson’s criteria for acute pancreatitis,
subarachnoid haemorrhage assessment using the World Federation
of Neurosurgeons score & liver failure assessment using Child-Pugh
or model for endstage liver disease (MELD) scoring].

Types of Scoring Systems
First day scoring systems:
► APACHE scoring systems
► SAPS (simplified acute physiology score)
► MPM (mortality prediction model)
Repetitive scoring systems:
► OSF (organ system failure)
► SOFA (sequential organ failure assessment)
► ODIN (organ dysfunction & infection system)
► MODS (multiple organs dysfunction score)
► LOD (logistic organ dysfunction)

The Ideal Scoring System
1. On the basis of easily/routinely recordable variables
2. Well calibrated
3. A high level of discrimination
4. Applicable to all patient populations
5. Can be used in different countries
6. The ability to predict functional status or quality of life after ICU
discharge.
No scoring system currently incorporates all these features

Severity scores in Medical & Surgical ICU
1980-85
• APACHE
• SAPS
• APACHE II
1986-1990
• SAPS II
• MPM
1990-95
•APACHE III
•MODS
•MPM II
•ODIN
1996-2000
• SOFA
• CIS
2000-
current
• SAPS III
• APACHE IV

Common Scoring Systems
Acute Physiology & Chronic Health
Evaluation (APACHE)

Acute Physiology & Chronic Health Evaluation
(APACHE)
► The APACHE score is the best-known & most widely
used score with good calibration & discrimination.
► The original APACHE score was developed in 1981 to
classify groups of patients according to severity of
illness & was divided into 2 sections: physiology score
to assess the degree of acute illness & preadmission
evaluation to determine the chronic health status of the
patient.

Original APACHE score:
► 34 physiologic measures (0-4)
 Sum of all acute physiology scores (APS)
 Worst of the initial 24 hour after ICU admission
► Chronic health
 A (excellent health)
 B
 C
 D (severe chronic organ system insufficiency)
Crit Care Med 1981; 9:591

APACHE II score:
► The APACHE II scoring system was released in 1985 and
included a reduction in the number of variables to 12.
► The APACHE II scoring system is measured during the first
24 h of ICU admission with a maximum score of 71. A score
of 25 represents a predicted mortality of 50% and a score of
over 35 represents a predicted mortality of 80%.
► APACHE II score is sum of:
• Acute physiology score
• Age
• Chronic health score

APACHE II score:
► The APACHE II score (0 – 71)
► Total APACHE II = A+B+C
• A → APS points
• B → Age points
• C → Chronic Health points

APACHE II score:
► Predicted mortality = - 3.517 + (Score Apache II) * 0.146
► Predicted mortality (adjusted) = - 3.517 + (Score Apache II) *
0.146 + diagnostic category weight

The APACHE II Score
Age -score
<44 → 0
45-54 → 2
55-64 → 3
65-74 → 5
≥75 → 6 JAMA 1993;270(24):2957-2963
Physiologic Variable High Abnormal Range Low Abnormal Range
+4 +3 +2 +1 0 +1 +2 +3 +4
Rectal Temp (°C) ≥41 39-40.9 38.5-38.9 36-38.4 34-35.9 32-33.9 30-31.9 ≤29.9
Mean Arterial Pressure (mmHg) ≥160 130-159 110-129 70-109 50-69 ≤49
Heart Rate ≥100 140-179 110-139 70-109 50-69 40-54 ≤39
Respiratory Rate ≥50 35-49 25-34 12-24 10-11 6-9 ≤5
Oxygenatation
a)FIO2≥0.5 record A-aDO2
b)FIO2<0.5 record PaO2
≥500 350-499 200-349
<200
PO2>70 PO2 61-70 PO2 55-60 PO2<55
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
HCO3 (mEq/l) ≥52 41-51.9 32-40.9 22-31.9 18-21.9 15-17.9 <15
K (mEq/l) ≥7 6-6.9 5.5-5.9 3.5-5.4 3-3.4 2.5-2.9 <2.5
Na (mEq/l) ≥100 160-179 155-159 150-154 130-149 120-129 111-119 ≤110
S. Creat (mqm/dl) ≥3.5 2-3.4 1.5-1.9 0.6-1.4 <0.6
Hematocrit (%) ≥60 50-59.9 46-49.9 30.45.9 20-29.9 <20
TLC (10³/cc) ≥40 20-39.9 15-19.9 3-14.9 1-2.9 <1
GCS
GCS:
15 → 0 14 → 1 13 → 2
12 → 3 11 → 4 10 → 5
9 → 6 8 → 7 7 → 8
6 → 9 5 → 10 4 → 11
3 → 12

The Glasgow Coma Scale (GCS)
Lancet 1974;304:81-84

APACHE III score:
► APACHE III, released in 1991, was developed with the
objectives of improved statistical power, ability to predict
individual patient outcome, and identify the factors in ICU
that influence outcome variations but it is far more
complex than the 2 previous scoring systems.
► 17 physiological variables & Total score (0 – 299)
► Acid-base disturbances
► GCS score – based on the worst
► Age score
► 7 co-morbidities (cardiac, respiratory & renal failures
excluded)
Chest 1991, 100:1619 - 1636

The APACHE III Scoring for Acid-Base disturbances

The APACHE III Scoring for Age
Age -score
<44 → 0
45-59 → 5
60-64 → 11
65-69 → 13
70-74 → 16
75-85 → 17
≥85 → 24

The APACHE III Scoring for Chronic Health Condition
Chronic health condition (Co-morbid condition)
1) AIDS → 23
2) Hepatic failure → 16
3) Lymphoma → 13
4) Metastatic cancer → 11
5) Leukemia/multiple myeloma → 10
6) Immunosuppression → 10
7) Cirrhosis → 4

APACHE score
ROC
Prediction at
50%probability
Calibration
APACHE II 0.85 85.5
APACHE III version (H) 0.90 88.2 48.7
APACHE III version (I) Unpublished Unpublished 24.2
APACHE III (H) in 2003-04 cohort Unpublished Unpublished 24.2

APACHE IV score:
► The APACHE IV scoring system was published in 2006.
Limitations:
► Complexity – has 142 variables.
► But web-based calculations can be done.
► Developed and validated in ICUs of USA only.
Crit Care Med 2006; 34:1297–1310

Simplified Acute Physiology Score
(SAPS)

Simplified Acute Physiology Score (SAPS)
► The SAPS score was first released in 1984 as an alternative
to APACHE scoring.
► The original SAPS score is obtained in the first 24 h of ICU
admission by assessment of 14 physiological variables, but
no input of pre-existing disease was included.
► It has been superseded by the SAPS II & SAPS III, both of
which assess the 12 physiological variables in the first 24 h
of ICU admission & include weightings for pre-admission
health status & age.

Simplified Acute Physiology Score (SAPS)
► Predicted mortality = -14.4761 + 0,0844 * SAPS II + 6.6158 *
log (SAPS II+1)
► Area under ROC for SAPS is 0.8 where as SAPS II has a
better value of 0.86
JAMA 1993;270:2957-2963

SAPS II Score
Parameter Value (score)
HR <40 (11) 40-69 (2) 70-119 (0) 120-159 (4) >160 (7)
SBP <70 (13) 70-99 (5) 100-199 (0) >200 (2)
Temp <39°C (0) >39°C (3)
PaO2/FIO2 <100 (11) 100-199 (9) >200 (6)
UO (ml) <500 (11) >500 (4) >1000 (0)
S. Urea <28 (0) 28-83 (6) >84 (10)
TLC (10³/cc) <1 (12) 1-20 (0) >20 (3)
K <3 (3) 3-4.9 (0) >5 (3)
Na <125 (5) 125-144 (0) >145 (1)
Bicarb <15 (6) 15-19 (3) >20 (0)
Bil <4 (0) 4-5.9 (4) >6 (9)
GCS <6 (26) 6-8 (13) 9-10 (7) 11-13 (5) 14-15 (0)
Age -score
<40 → 0
40-59 → 7
60-69 → 12
70-74 → 15
75-79 → 16
≥80 → 18
Chronic disease:
Metastatic cancer → 9
Hemat.malig → 10
AIDS → 17
Type of admission:
Sched. Surgical → 0
Medical → 6
Emer.surgical → 8
JAMA 1993;270(24):2957-2963

SAPS III
► Scores based on data collected within 1st hour of entry to ICU.
► Allows predicting outcome before ICU intervention occurs.
► Better evaluation of individual patient rather than an ICU.
► Limitations:
 Time for collecting data
 Can have greater missing information
Intensive Care Med 2005; 31:1345–1355

Sequential Organ Failure Assessment
(SOFA)

Sequential Organ Failure Assessment (SOFA)
► Previously known as Sepsis-related Organ Failure
Assessment because it was initially developed in 1994 to
describe the degree of organ dysfunction associated with sepsis
in a mixed, medical-surgical ICU patients.
► Nowadays, it has since been validated to describe the degree of
organ dysfunction in various ICU patient groups with organ
dysfunctions not due to sepsis.
► The SOFA score involves six organ systems (respiratory,
cardiovascular, renal, hepatic, central nervous, coagulation), and
the function of each is scored from 0 (normal function) to 4 (most
abnormal), giving a possible score of 0 to 24.

► Mortality rate increases as number of organs with
dysfunction increases.
► Unlike other scores, the worst value on each day is
recorded.
► A key difference is in the cardiovascular component;
instead of the composite variable, the SOFA score uses a
treatment-related variable (dose of vasopressor agents).

► Maximal (highest total) SOFA score: is the sum of highest
scores per individual during the entire ICU stay. A score of >15
predicted mortality of 90%.
► Mean SOFA score (ΔSOFA): is the average of all total SOFA
scores in the entire ICU stay. ΔSOFA for 1st 10 days is significantly
higher in non-survivors.
► Delta SOFA score: maximum SOFA – admission SOFA
Crit Care Med 1998;26:1793-1800

SOFA Score
Crit Care Med 1998;26:1793-1800

Multiple Organ Dysfunction Score
(MODS)

Multiple Organ Dysfunction Score (MODS)
► The MODS scores six organ systems: respiratory (PO2/FIO2 in
arterial blood); renal (serum creatinine); hepatic (serum
bilirubin); cardiovascular (pressure-adjusted heart rate);
haematological (platelet count) & CNS (Glasgow Coma Score)
with weighted scores (0–4) awarded for increasing abnormality
of each organ systems.
► Scoring is performed on a daily basis.
► Total score ranges from 0-24.
► Area under ROC 0.936.
► ΔMODS predicts mortality to a greater extent than Admission
MODS score .
Crit Care Med. 1995; 23:1638-52

MODS
Crit Care Med. 1995; 23:1638-52
System 0 1 2 3 4
Respiratory PO2/FiO2 >300 226-300 151-225 76-150 <75
Renal Serum Creatinine (μmol/L) <100 101-200 201-350 351-500 >500
Hepatic Serum bilirubin (μmol/L) <20 21-60 61-120 121-240 >240
Cardiovascular (PAR) <10 10.1-15 15.1-20 20.1-30 >30
Hematological Platelet count (100/ μL) >120 120-80 80-50 50-20 <20
Neurological (GCS) 15 14-13 12-10 9-7 <7

MODS
Crit Care Med. 1995; 23:1638-52
Score ICU Mortality Hospital Mortality
0 0% 0%
1-4 1-2% 7%
5-8 3-5% 16%
9-12 25% 50%
13-16 50% 70%
17-20 75% 82%
21-24 100% 100%

Logistic Organ Dysfunction System
(LODS)

Logistic Organ Dysfunction System (LODS)
► Worst values in 1st 24 hrs of ICU stay.
► Worst value in each of 6 organ systems.
► Total score ranges from 0-22.
► Good calibration and discrimination (area under ROC 0.85)
JAMA 1996;276:802-810

LODS
JAMA 1996;276:802-810
System Value (Score)
Neurological GCS 14,15 (0) 13-9 (1) 8-6 (3) 5-3 (5)
Cardiovascular
HR >140 (1) 140-30 (0) <30 (5)
SBP >270 (3) 240-269 (1) 70-89 (1) 69-40 (3) <40(5)
Hematological
TLC (1000/cc) <1 (3) 1-2.4 (1) 2.4-50 (0) >50 (1)
Platelet (10³/cc) <50 (1) >50 (0)
Respiratory PO2 <150 (3) >150 (1)
Hepatic
Bilirubin (mg/dl) <2 (0) >2 (1)
PT 0-2.9 s (0) 3 s (1)
Renal
Urea (mg/dl) >120 (5) 119-60 (3) 59-35 (1) <35 (0)
Creatinine (mg/dl) >1.16 (3) 1.59-1.2 (1) <1.2 (0)
UO (L/24 hr) >10 (3) 10-0.75 (0) 0.75-0.5 (3) <0.5 (5)

Clinical Pulmonary Infection Score
(CPIS)

Clinical Pulmonary Infection Score (CPIS)
► A score developed to establish a numerical value of clinical,
radiographic, and laboratory markers of pneumonia.
► Serial measurements of the CPIS could be used to identify
survivors versus non-survivors as early as day 3 of therapy.
► The CPIS correlated with mortality rate.
► CPIS scores > 6 suggest pneumonia.
► CPIS is an important variable to monitor during VAP therapy.
Patients with VAP having CPIS ≤ 6 can safely discontinue
antibiotics after 3 days.
AJRCCM 2000;162:501-511

Clinical Pulmonary Infection Score (CPIS)
AJRCCM 2000;162:501-511
Score 0 1 2
Temperature ≥36.5 & ≤38.4 ≥38.5 & ≤38.9 ≥39 & ≤36.4
TLC ≥4 & ≤11 <4 or >12
Tracheal Secretions None Non-purulent Purulent
Oxygenation
PaO2/FIO2 mmHg
>240 or ARDS ≤240 & no ARDS
Chest Radiograph No opacity
Diffuse (patchy)
opacities
Localized opacity
Progression of
Radiograpgic Opacities
No progression
Progression (after
HF & ARDS
excluded)
Culture of Tracheal
Aspirate
Pathogenic bacteria
cultured in rare/few
quantities or no growth
Pathogenic bacteria
cultured in moderate
or heavy quantity

Mortality Probability Model (MPM)

Mortality Probability Model (MPM)
► Not applicable for patients <14yrs, patients with burns, cardiac/
cardiac surgery patients.
► MPM score:
 Admission MPM (MPM0) →11 variables
 MPM at 24 Hrs (MPM24) → 14 variables
 MPM at 48 Hrs (MPM48) → 11 variables
 MPM over the time (MPMOT) → (MPM24-MPM0)
(MPM48-MPM24)
► Probability is derived directly from these variables.
► MPMOT predicted better than MPM0 for long term patients.
Crit care med 1988;16:470-477

MPM0
Variable 1 0
Level of consciousness Coma / deep stupor No coma/deep stupor
Admission Emergency Elective
Prior CPR Yes No
Cancer Present Absent
CRF Present Absent
Infection Probable Not probable
Previous ICU admission in 6 mo Yes No
Surgery before ICU admission Yes No
SBP
HR 10 beat/min relative risk
Age 10 years relative risk

Therapeutic Intervention Scoring System
(TISS)

Therapeutic Intervention Scoring System (TISS)
► Measuring sickness severity based on type & amount of
treatment received.
► Both clinical & administrative applications:
 assessing severity of illness
 Determining resource requirements
 Assessing use of critical care facilities & function
 Not standardised
► Daily data collected from each patient on 76 possible clinical
interventions

TISS
Four classes of pt recognised: Class I < 10 points does not require ICU
Class II 10-19 points 1:2 nurse : pt ratio
Class III 20-39 points 1 ICU nurse
Class IV > 40 points 1:1 nurse : pt ratio

Other Scores
Scores for Pediatric patients:
PRISM (Pediatric RISk of Mortality)
P-MODS (Pediatric MODS)
DORA (Dynamic Objective Risk Assessment)
PELOD (Pediatric Logistic Organ Dysfunction)
PIM II (Paediatric Index of Mortality II)
PIM (Paediatric Index of Mortality)
Scores for surgical patients:
Thoracoscore (thoracic surgery)
Lung Resection Score (thoracic surgery)
EUROSCORE (cardiac surgery)
ONTARIO (cardiac surgery)
Parsonnet score (cardiac surgery)
System 97 score (cardiac surgery)
QMMI score (coronary surgery)
Early mortality risk in redocoronary artery
surgery
MPM for cancer patients
Scores for trauma patients:
Trauma Score
Revised Trauma Score
Trauma and injury Severity score (TRISS)
A Severity Characterization of trauma (ASCOT)

Which score to use?
► APACHE, SAPS, MPM → only of historic significance
► APACHE II → most widely used in USA
► SAPS II → commonly used in Europe
► APACHE III → not in public domain
► SAPS III, APACHE IV → better design
► MODS & LODS → uncommonly used

ICU Scoring Systems

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