Further supplementary memorandum from
the Ministry of Defence
SURVIVAL OF
TRAUMA CASES
ON OPERATIONS
Following our oral evidence session this
morning, I thought the Committee might appreciate sight of some
numbers that demonstrate that the survival of operational casualties
is the best ever achieved by the UK.
The Defence Medical Services monitor
the survival of trauma cases on operations. The available "Killed
in Action" data demonstrate survival rates similar to those
now experienced by US forces. Our separate detailed medical audit
of each serious casualty shows our overall approach to treating
operational casualties is resulting in "unexpected survivors".
TRADITIONAL MEASUREMENTS
Traditionally, medical "success"
on operations has been measured by a number of indicators, including
the percentage rate of those "Killed in Action" (KIA).
This illustrates the proportion of those who die before reaching
medical care, compared with the total of operational casualties
who die or are significantly wounded. Historically, KIA rates
have remained fairly constant at between 23-27%, with only rare
US and Israeli instances in the last 40 years of campaigns with
KIA rates below 20%. KIA is a measure of a combination of factors—the
lethality of the weapons used by opposing forces versus the combination
of personal protection, the effectiveness of battlefield medical
care at the point of wounding and the availability of evacuation
from the tactical setting.
We have calculated current UK rates[30]
(%KIA) for Iraq as 13.7% and for Afghanistan as 15.1%. These are
broadly similar to results claimed by the US in the current conflicts,
noting that a complication arises over US and UK definitions over
the total of personnel wounded, since the KIA value is sensitive
to the definition of overall injured, which forms the denominator
for calculating the rates. This makes precise direct comparisons
between UK and US rates unwise, and we wish to do further work
to confirm the data. However, notwithstanding these provisos,
we believe:
(a) the calculated values are the
best ever achieved by the UK; and
(b) the calculated values are of the
same order as the US.
INJURY SCORING
Another measure of medical success is
"injury scoring". This looks at seriously injured survivors
to ascertain whether their survival was unexpected, given the
wounds they received ("unexpected survivors"). A number
of internationally accepted methods exist to predict survival
following injury and allow comparison of performance with civilian
institutions and other military trauma systems. They include the
Injury Severity Score (ISS), which is a score based on the anatomical
injuries and the Revised Trauma Score (RTS) a score based on physiological
changes. RTS and ISS are combined in a complex mathematical formula
to give TRISS, or the "%Probability of Survival". As
each method carries its own limitations, DMS uses the full range
of these and other analytical tools.
ISS has a maximum score of 75. An ISS
greater than 16 is the accepted definition of "major trauma"
and relates to a predicted death of 10%. Those with a score of
60 or over are not expected to survive and thus any survivor with
a score over 60 is classified as an "unexpected survivor".
ISS methodology identified that for HERRICK
4-6 [April 2006 to September 2007] there were 18 unexpected survivors
and for TELIC 8-10 [June 2006 to date] there were four unexpected
survivors, taking all the casualties we treated into consideration
(who were a mixture of UK military, coalition military and local
civilian). The UK military subset was six unexpected survivors
for HERRICK and three for TELIC.
TRISS methodology, when applied to UK
Service casualties (hostile and non-hostile action) identified
seven unexpected survivors for HERRICK 4-6 and 1 for TELIC 8-10.
COMMENTARY ON
IMPROVED SURVIVAL
The improvement in KIA is almost certainly
a result of a combination of improved body armour and the enhancements
to the immediate battlefield medical first aid equipment issued
to all our troops and their medics, and available at or close
to the point of wounding, appropriate training in the use of these
improved items and the speed of evacuation to medical facilities.
The "unexpected survivors" are also a testimony to the
skill of our medical teams in field hospitals, and the life-saving
equipment and techniques they use to save lives that would be
lost in almost any other scenario.
SUMMARY
Our processes show that the DMS has continued
to improve its performance on deployed operations. We continue
to undertake medical audits on all our serious casualties in order
to provide assurance on our quality of care. We also continue
to liaise with the US, both in order to seek to improve our ability
to benchmark our outcomes against theirs, and to ensure that any
new developments that either of us identifies are available to
both nations, to coalition partners, and to our other patients
in theatre.
Derek Twigg MP
27 November 2007
30 Iraq data from Apr 2006 to Sep 2007, Afghanistan
January to September 2007. Back
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