Aim of the lecture To understand the basic principles of injury scoring systems. To review the...
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Transcript of Aim of the lecture To understand the basic principles of injury scoring systems. To review the...
Aim of the lectureAim of the lecture
To understand the basic principles of injury
scoring systems.
To review the principal of anatomical and
physiological injury scoring systems.
So we should answer the following So we should answer the following questionsquestions
Why should severity be assessed
in trauma patients
How can severity be assessed in
trauma patients
Where pre-hospital or hospital
What is advantages and dis-
advantages
Trauma has been termed the neglected
disease of modern society, is among the leading
causes of death in all age groups. Each year it is
estimated that around 5.8 million people
worldwide die as a result of trauma, with 90%
of these deaths occurring in middle- and low-
income countries.
Trauma is the third cause of death after cancer and
cardiovascular diseases in the overall population.
Hemorrhagic shock and traumatic brain injury
(TBI) remain the leading causes of death accounting
respectively for 30% and 50% in trauma patients
arriving alive at the hospital (Harrois;etal 2013)
Severity assessment in trauma patients is
mandatory. when? It started during initial
phone call that alerts emergency services when
a trauma occurred. On-call physician assesses
severity based on witness provided information,
to adapt emergency response.
Whenever information comes, it helps providing
adequate therapeutics and orientating the patient
to the appropriate hospital. Severity assessment is
based upon pre-trauma medical conditions,
mechanism of injury, anatomical lesions and their
consequences on physiology.
Why should severity be assessed in trauma patients?Why should severity be assessed in trauma patients?System for field triageSystem for field triage
Assessment of injury severity is important clinically to
Correct triage of patients to a
trauma centre
Selecting the adequate intensity of care and to
prognosticating on short-/long-term patient outcome
It is also important to the comparison of trauma centres
Three main groups of trauma
scores
Anatomical ( measure static component of injury).
Physiological (measure acute dynamic component).
Combined
Anatomical Anatomical
Traumatic patients may have normal
physiology but may have anatomical
lesions that require high level of care
Injury Severity Score (ISS)
Abbreviated Injury Scale (AIS)
New Injury Severity Score (NISS)
Anatomic Profile (AP)
PhysiologicalPhysiological
(help determining prognosis)
Revised Trauma Score (RTS).
Glasgow Coma Score (GCS).
CombinedCombined
Trauma related Injury Severity Score -
(TRISS).
International Classification of Diseases
Diseases-based ISS - (ICISS).
Abbreviated Injury Scale - (AIS)Abbreviated Injury Scale - (AIS)One of the hospital scoresOne of the hospital scores
Was developed to rate and compare blunt injuries
from road vehicle accidents.
It has undergone several modifications since its
introduction in 1971. currently updating AIS -2000.
The AIS scores individual injuries and classifies them
into one of six categories, each with an associated
severity score ranges from1 (minor) to 6 (lethal).
The severity scores were subjectively assigned by experts.
Abbreviated Injury Scale - (AIS)
Injury - AIS score
1. Minor
2. Moderate
3. Serious
4. Severe
5. Critical
6. Un-survivable (fatal).
AIS – Limitations
No comprehensive measure of severity
Subjective
Not predicting patient outcomes or mortality
Injury Severity Score (ISS) Injury Severity Score (ISS)
Hospital score
The first significant scoring system to be based
primarily on anatomic criteria was developed in 1974.
Was created to define injury severity for comparative
purposes.
The strength of this system lies in its incorporation of
anatomic indices and severity indices.
Injury Severity Score
Six body regions
Head.
Face.
Chest.
Abdomen (including Pelvis).
Extremities.
External.
Example Injury Severity Score
Regioninjury descripitionAISSquare
top 3
Head&neck
Face
Chest
Abdomen
Extremity
External
ISS
Cerebral contusion
No injury
Flail chest
Liver contusion, spleen
Fracture femur
No injury
-------------------------------
3
0
4
5
3
0
9
0
16
25
50
Injury Severity Score… 3 most severely injured body regions – score
squared and added :
ISS = a2+b2+c2
Values ( 0 : 75 )
Patient with an ISS above 15 is considered as severe trauma patient.
Any lesion with an AIS of 6 will automatically lead to increase ISS severity score.
Limitations of Injury Severity
Score
Error in AIS scoring increases ISS error
Limits total number of injuries to 3 regions
Description of patient injuries unknown
Not a triage tool
Does not take into account age or co-morbidities
Not accurate for grading penetrating trauma
New Injury Severity Score -
NISS
Modified in 1997 from ISS
It equals “The sum of the squares of the AIS
of each of the three most severe AIS
injuries, regardless of the body region in
which they occur.
New Injury Severity Score
Predicts survival
Easier to calculate than ISS
Limitations of New Injury Severity
Score
No account for physiological variables
Anatomic Profile - (AP)
Because of ISS limitations,a multidimensional
characterization was sought that considers the
number, location and severity of anatomic injuries
and their influence on outcome. Includes all the
serious and non-serious a injuries.
Anatomic Profile
To describe apatient’s injuries: It uses Four categories (variables)
A - Head and spinal cord
B - Thorax and anterior neck
C - All remaining serious injuries
D - All non serious injuries.
Serious (AIS = ≥ 3)
Anatomic Profile The scores are combined using an Euclidean
Distance Model viz. the square root of the sum of the squares of the AIS scores of all serious injuries in each region.
No injury = Zero
allowing for decreasing influence of injuries as the number of injuries increases.
Limitations
Mathematical complexity
Trauma Score 1980 (TS) The widely used pre-hospital field triage tool ,it has
stood the test of time. a useful predictor of outcome for patients with blunt
or penetrating injuries.
Components Glasgow Coma Scale (GCS) Systolic Blood Pressure (SBP) Respiratory Rate (RR ) Respiratory expansion Capillary refill Revised due to difficult to
assess in the field(particularly at night)
Triage-Revised Trauma Score 1989
(RTS)
Components
Glasgow Coma Scale (GCS)
Systolic Blood Pressure (SBP)
Respiratory Rate (RR)
The Revised Trauma Score The Revised Trauma Score
Two types of RTS:
The coded form of the RTS is more frequently used
for quality assurance and outcome prediction. The
coded RTS is calculated as follows: RTSc = 0.7326
SBPc + 0.2908 RRc + 0 .9368 GCSc
Triage RTS: Determined by adding each of the
coded values together.
TheTriage- Revised Trauma
Score
Triage-Revised Trauma Score… Ranges 0:12 Score < 11 - transfer to trauma center (specificity 82%,
sensitivity59%) Predicting mortality with RTS:
RTS Mortality(%)
12 <110 126 372 700 >99
Champion HR, Sacco WJ, Copes WS, et al. A revision of the trauma score. J Trauma 1989;29:625, with permission
Limitations of Revised Trauma Score
Not practical in field
Underestimate the severity of head injury
Problems:
Intubated patients
Influence of alcohol
Drugs
The Glasgow Coma Scale - (GCS)
Best Eye Response. (4)
Best Verbal Response. (5)
Best Motor Response. (6)
1. No eye opening.
2. Eye opening to pain.
3. Eye opening to verbal command.
4. Eyes open spontaneously.
1. No verbal response
2. Incomprehensible sounds.
3. Inappropriate words.
4. Confused
5. Orientated
1. No motor response.
2. Extension to pain.
3. Flexion to pain.
4. Withdrawal from pain.
5. Localising pain.
6. Obeys Commands.
Trauma related injury severity score Trauma related injury severity score (TRISS) 1989(TRISS) 1989
Combination scoring system
Probability of trauma survival using anatomical and physiological scores.
A logarithmic regression equation is used:
Ps = 1/ (1+e^(-b)) , The b’s are regression coefficients.
where b = bo + b1(RTS) + b2(ISS) + b3(AgeScore).
RTS = (0.9368 x GCS) + (0.7326 x BPsys) +(0.2908 x RR)
ISS calculated as above
AgeScore = 0 if <55y or 1 if >55y.
Coefficients (b0 : b3) depend on type of trauma
TRISS – Limitations
Only moderately accurate for predicting survival
Problems already noted with the ISS
Similar to RTS, it can’t include tubed patients as
RR & verbal responses not obtainable
Multiple injuries to same body region cannot
measure
ASCOTASCOT)A Severity Characteristic of Trauma(
TRISS has been the pre-eminent trauma
outcome prediction model for the past 20 years. It
is used to compare patient outcomes. Its greatest
frailty is related to the Injury Severity Score (ISS).
For that reason, ISS was replaced in the TRISS
formulation by AP to create ASCOT.
When comparing ASCOT and TRISS, the
ASCOT performs much better on outcome
prediction than TRISS. However its “complexity”
has deterred many from implementing it and
TRISS still remains the mainstay of comparative
analysis of trauma patients. A study reporting the
replacement of ISS with NISS in TRISS would be a
worthwhile contribution.
In an attempt to create a score that
assesses severity in patients with medical
prehospital care, Sartorius et al. identified
four items that should be pooled:
NEW GAP
Risk categories in new GAP(Rebecca etal; 2010)
%GAP
(Total points)
MGAP
(Total points)
Low
Medium
High
<5%
5:50%
>50%
19 :24
11 :18
3 :10
23 : 29
18 : 22
3 : 17
Kondo et al. Critical Care 2011,
They studied 35,732 trauma patients in the Japan
Trauma Data Bank from 2004 to 2009 in multicenters, as
a prospective, observational study to assess whether the
new Glasgow Coma Scale, Age, and Systolic Blood
Pressure (GAP) scoring system, better predicts in-
hospital mortality and can be applied more easily than
previous trauma scores among trauma patients in the
emergency department (ED). they concluded that: The
GAP scoring system can predict in-hospital mortality
more accurately than the previously developed trauma
scoring systems.
ConclusionConclusion
All the above-mentioned scores have been developed
to predict mortality.
Severity assessment of trauma patient helps guiding
therapeutic, as well as orientating the patient in an
adequate hospital.
the GCS , RTS and GAP recommend these as the
most reliable prehospital triage instruments.
Instruments include ISS,NISS, TRISS and ASCOT
systems for assessing outcomes and mortality.
SummarySummary
Why should severity be assessed in trauma patients?
How can severity be assessed in trauma patients?
Where pre-hospital or hospital?
What is advantages and dis-advantages?
ReferencesReferences
http.//www.ATLS.org
http.//www.ITLS.org
http://www.jhsph.edu/Research/Centers/CIRP/ The Johns
Hopkins Center for Injury Research & Policy
http://www.trauma.org/A British web web-based trauma resource center
http://www.trauma.org/scores/rtscalc.html/Revised