CRICOS No. 00213J

Dr Kirsten Vallmuur and Ms Jesani Limbong11th October 2013

Issues to consider when estimating injury severity during risk assessment

Focus of presentation• Core input into risk assessment model is the

injury severity rank and probability of occurrence

• Injury severity rank = Table of injury types and body regions grouped into 4 or 6 point scale

• Core questions:– How valid is the grouping of injuries?– How consistent are these groupings across different

severity scales?– How concordant are these groupings with other

indicators of injury severity?

Canada (Health Canada)Injury Definition

Minor Requires first aid treatment; medical attention is not necessary

Moderate Are temporary or remediable; Consequences are not life-threatening and are reversible in most instances.

Serious Irreversible; cause permanent disability or long-term illness

Death Any injuries resulting in death

Injury Definition

1 Injury or consequence that after basic treatment (first aid, normally not by a doctor) does not substantially hamper functioning or cause excessive pain; usually the consequences are completely reversible.

2 Injury or consequence for which a visit to A&E may be necessary, but in general, hospitalization is not required. Functioning may be affected for a limited period, not more than about 6 months, and recovery is more or less complete

3 Injury or consequence that normally requires hospitalisation and will affect functioning for more than 6 months or lead to a permanent loss of function.

4 Injury or consequence that is or could be fatal, including brain death; consequences that affect reproduction or offspring; severe loss of limbs and/or function, leading to more than approximately 10 % of disability.

New Zealand

Europe/Australia (RAPEX Guidelines)

Injury severity ranking systemsInjury

Minor

Moderate

Serious

Severe

Critical

Death

Comparison of RAPEX and Canadian Injury Severity Categorisation

Injury type RAPEX CanadaAbrasion/ Bruising

Internal bruising severe Never severe

Burn/Scald Burns to >16% body surface severe

Burns to >10% body surface severe

Concussion Prolonged unconsciousness severe

Prolonged time for symptoms to resolve severe

Electrical Other serious effects (burns/cardiac effects etc) of electrical exposure severe

Only electrocution severe

Fracture Rib/jaw not severe; Lower leg severe

Rib/jaw severe; Lower leg not severe

Piercing/ Puncturing

Eye/internal organ/chest wall severe

Eye/internal organ/chest wall not severe

Strangulation Never minor/moderate Bruising/swallowing/ hoarseness not severe

Implications of Different Severity Categorisation

• Injuries falling below the threshold may not be raised to an investigation level in one jurisdiction but may be in another -> inconsistent risk prioritisation

• If injuries where differences exist are very common, may lead to considerable discrepancy (i.e. severity of different fractures)

• Explore injury data to get an indication of size of problem and decide if better uniformity needed

Classifying injury data into severity categories

• Injury severity ranks are largely based on injury nature and body region

• Hospitalisation and mortality data have injury diagnoses coded (codes structured into nature of injury and body region codes)

• Assigning severity scores to injury data allows for better illustration of severity by hazard and product

Burns Severity Rank ComparisonsRANK RAPEX Canada

1 or Minor

1st degree burns up to 100 % of body surface2nd degree < 6 % of body surface

1st degree burns

2 or Moderate

2nd degree burns at 6-15 % of body surface

2nd degree burns up to ≤10% of the body not including the headChemical burns causing reversible damage

3 orSevere

2nd degree burns at 16-35 % of body surface3rd degree burns up to 35 % Inhalation burn

2nd degree burns up to >10% of the body or to the head3rd degree burnsAny burn resulting in permanent disfigurement or severe scarring

4 or Death

2nd or 3rd degree > 35 % of body surfaceInhalation burn requiring respiratory assistance

Burn/scald resulting in death

Principal code: Burn

Thickness

A B C DUnspecified Erythema Partial FullT20.0, T21.0, T22.0, T23.0, T24.0 T25.0, T29.0, T30.0

T20.1, T21.1, T22.1, T23.1, T24.1 T25.1, T29.1, T30.1

T20.2, T21.2, T22.2, T23.2, T24.2 T25.2, T29.2, T30.2

T20.3, T21.3, T22.3, T23.3, T24.3 T25.3, T29.3, T30.3

Secondary code: Body Surface Area

3rd Ch3rd Ch 0 1 2 3

1 T31.0BSA Less than 10% or unspecified

0 Unclassifiable Burn 1 Burn 1Burn 2 Burn 3

2 T31.1BSA 10-19% 1 Unclassifiable Burn 1 Burn 2

Burn 3 Burn 3

3 T31.2BSA 20-19% 2 Unclassifiable Burn 1 Burn 3 Burn 3

4 T31.3BSA 30-39% 3 Unclassifiable Burn 1 Burn 3

Burn 4Burn 3Burn 4

5 T31.4BSA 40-49% 4 Unclassifiable Burn 1 Burn 4 Burn 4

6 T31.5BSA 50-59% 5 Unclassifiable Burn 1 Burn 4 Burn 4

7 T31.6BSA 60-69% 6 Unclassifiable Burn 1 Burn 4 Burn 4

8 T31.7BSA 70-79% 7 Unclassifiable Burn 1 Burn 4 Burn 4

9 T31.8BSA 80-89% 8 Unclassifiable Burn 1 Burn 4 Burn 4

10 T31.9BSA 90% or more 9 Unclassifiable Burn 1 Burn 4 Burn 4

Example categorisation of burns data in Queensland children

Validating injury severity ranks

• Other health system-based injury severity scales:– ICD-based Injury Severity Score (ICISS) => survival risk

ratio (SRR)– Abbreviated injury score (AIS)

• Other indicators of severity:– Triage urgency– Emergency department presentation/ hospital

admission/mortality rates– Length of stay– Costs of treatment– Disability outcomes

Next steps

• Compare injury data for the injuries where ranks differ across injury severity systems

• Evaluate the validity of the ranks by comparison with other health system-based injury severity scales and with other severity indicators

• Revise and consolidate different injury severity scales to establish a single international scale for categorisation of injury severity

CRICOS No. 00213J

Questions?k.vallmuur@qut.edu.au

Reports: http://eprints.qut.edu.au/46518/http://eprints.qut.edu.au/58389/