Helicopters and improved trauma survival

April 18, 2012 by  
Filed under All Updates, EMS, Trauma

A large retrospective study has shown increased trauma survival associated with helicopter transport. The reason is unclear and may be multifactorial: faster speed, greater access to trauma centres, higher exposure of crews to trauma, different crew skill mix and so on are all possibilities.

An interview of less than five minutes with one of the authors describes the study:


Context Helicopter emergency medical services and their possible effect on outcomes for traumatically injured patients remain a subject of debate. Because helicopter services are a limited and expensive resource, a methodologically rigorous investigation of its effectiveness compared with ground emergency medical services is warranted.

Objective To assess the association between the use of helicopter vs ground services and survival among adults with serious traumatic injuries.

Design, Setting, and Participants Retrospective cohort study involving 223 475 patients older than 15 years, having an injury severity score higher than 15, and sustaining blunt or penetrating trauma that required transport to US level I or II trauma centers and whose data were recorded in the 2007-2009 versions of the American College of Surgeons National Trauma Data Bank.

Interventions Transport by helicopter or ground emergency services to level I or level II trauma centres.

Main Outcome Measures Survival to hospital discharge and discharge disposition.

Results A total of 61 909 patients were transported by helicopter and 161 566 patients were transported by ground. Overall, 7813 patients (12.6%) transported by helicopter died compared with 17 775 patients (11%) transported by ground services. Before propensity score matching, patients transported by helicopter to level I and level II trauma centers had higher Injury Severity Scores. In the propensity score–matched multivariable regression model, for patients transported to level I trauma centers, helicopter transport was associated with an improved odds of survival compared with ground transport (odds ratio [OR], 1.16; 95% CI, 1.14-1.17; P < .001; absolute risk reduction [ARR], 1.5%). For patients transported to level II trauma centers, helicopter transport was associated with an improved odds of survival (OR, 1.15; 95% CI, 1.13-1.17; P < .001; ARR, 1.4%). A greater proportion (18.2%) of those transported to level I trauma centers by helicopter were discharged to rehabilitation compared with 12.7% transported by ground services (P < .001), and 9.3% transported by helicopter were discharged to intermediate facilities compared with 6.5% by ground services (P < .001). Fewer patients transported by helicopter left level II trauma centers against medical advice (0.5% vs 1.0%, P < .001).

Conclusion Among patients with major trauma admitted to level I or level II trauma centers, transport by helicopter compared with ground services was associated with improved survival to hospital discharge after controlling for multiple known confounders.


Association Between Helicopter vs Ground Emergency Medical Services and Survival for Adults With Major Trauma

JAMA, April 18, 2012—Vol 307, No. 15 1602-10 Full Text

Comments

5 Responses to “Helicopters and improved trauma survival”

  1. Christopher on April 18th, 2012 08:39

    As an interesting aside Dr. Galvagno wrote a great companion pathophysiology text for EMS providers, “Emergency Pathophysiology: Clinical Applications for Prehospital Care”. Glad to see he’s still going strong!

  2. Minh Le Cong on April 18th, 2012 13:36

    thanks Cliff for higlighting that one. devil is in the detail with retrospective studies, is it not? What provided the benefit? The machine or the earlier prehospital care?
    This study from Netherlands this month in Injury showed a worsening of mortality!
    http://www.ncbi.nlm.nih.gov/pubmed/22305588

  3. Minh Le Cong on April 18th, 2012 18:13

    BUT this study from Western Australia, suggests its the prehospital care and organised trauma system that improves trauma survival…not just the aircraft!
    http://www.flyingdoctor.org.au/IgnitionSuite/uploads/docs/Fatovich%20et%20al%20Resuscitation%20(2011)%20Metro_vs_Rural%20Major%20Trauma%20in%20WA.pdf

    Fundamentally I believe in prehospital care there is a THERAPEUTIC ZONE. If a critically ill or injured patient can be placed into that zone as soon as possible and kept there, then outcomes can be improved during transport and retrieval regardless of distance and time…UP TO A THRESHOLD.

    IT IS CHALLENGING TO KEEP PATIENTS IN THE THeRAPeuTIC zoNe, hence the mixed results of lots of retrospective studies in prehospital care. THE ZONE is not one single intervention that makes the difference!

  4. Mat Oliver on April 18th, 2012 20:22

    Hi Cliff,

    This is an interesting study for me as I have spent a lot of time working with the NTDB, and have used propensity matching.
    I’m sure there is an element of truth to their conclusions but to use the NTDB and then get it published in JAMA!! and then do a Youtube video about it!!! Jeez, all I can say is well done.

    It is a very nicely, well analysed study. But if you start with a database that has large flaws in it, how can we trust the outcome?
    They had 38% with missing variables. What happened to those patients, perhaps they all died by air transport?
    Also, what about the patients that they didn’t match? Were there any differences there?

    The NTDB can be useful, but we need to be fully aware of the flaws, and therefore the message delivered from any data coming from this

  5. Tim Leeuwenburg on April 26th, 2012 07:10

    I like Minhs concept of ‘the zone’

    Is it a helicopter that brings improved survival? Or brininging a retreivalist to the patient?

    Is there scope for a UK BASICS model in Oz. – get people into a trauma system arly, but utilise the rural proceduralists who can value add even before the retrieval team arrive…