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Helicopter Emergency Medical Services for Traumatic Cardiac Arrest

Three Part Question

In [trauma patients with out-of-hospital cardiac arrest] does a [helicopter emergency medical service] improve [survival]?

Clinical Scenario

A 32 year old female was driving home on a cold winter night and lost control at the wheel. On EMS arrival, the patient is obtunded, cool, and clammy. She loses pulses at the scene and EMS personnel begin CPR. After a significant delay in extrication and travel via ambulance, the patient arrives at your hospital. She undergoes multiple rounds of CPR, bilateral chest tube placement, pericardiocentesis and was found to have a large pericardial effusion in the ED trauma bay. Unfortunately, time of death was called as it is now approaching an hour-long resuscitation without ROSC. You consider if her outcome would have changed had her out of hospital traumatic arrest been managed by a helicopter emergency medical service.

Search Strategy

Medline 1966-07/19 using PubMed, Cochrane Library (2019), and Embase
[("Air Ambulances" OR "Aeromedical" OR "helicopter" OR "aircraft") AND ("trauma" OR "traumatic") AND ("cardiac arrest" OR "heart arrest")]. Limit to English language.

Search Outcome

88 studies were identified; eight addressed the clinical question.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Di Bartolomeo S, et al
July 2009
Italy
129 blunt traumatic cardiac arrest patients Prospective cohort studyPatient characteristics, mechanism of injury, on scene CPR, ROSC and survival to dischargeThere is no significant benefit in long-term survival for blunt TCA patients undergoing advanced life support interventions with HEMS versus basic life support interventions by ground EMS.Small sample size; limited HEMS response; initial cardiac rhythms not recorded; ground transport group younger in age; unknown actual duration of TCA; lower frequency of CPR performed in ground transport group; increased number of providers on scene in HEMS group; physician on all flights
Falcone R, et al.
September 1995
USA
Injured patients requiring CPR before or during air medical transportRetrospective chart reviewSurvival to hospital admissionAir medical transport for the injured patient without signs of life following prehospital intervention appears futile.Retrospective; primarily a rural setting only; patients were primarily male; primarily blunt injured patients; differing initial heart rhythms at scene; data from 1990s; flight crew bias regarding survivability and calling time of death at scene.
Gleeson A, et al.
September 1998
UK
Adult patients who sustained a non-traumatic cardiac arrest Retrospective cohort studySurvival to hospital admission and dischargeInterventions by a hospital based flying squad have only a small effect on overall survival of patients with out of hospital cardiac arrest who have been primarily treated by ambulance crews provided with semi-automatic defibrillatorsRetrospective analysis; male predominance; only requested after EMS on scene and assessed patients condition; initial rhythm and responsiveness to defibrillation
Margolin D, et al
October 1996
USA
67 patients with out of hospital traumatic cardiac arrest transported to a Level 1 trauma centerRetrospective cohort studySurvival rate, Trauma Score, Injury Severity Score, Sinus-based cardiac rhythm at arrival, and neurological outcomesTrauma patients resuscitated to a normal sinus rhythm after OHCA should be transported to a trauma center; The revised trauma score and Injury Severity Scores do help predict survival retrospectively, however, neurological outcome cannot be predicted accurately by this model. Retrospective; small sample size; majority of patients transported from outside hospital (vs scene); flight crews with very experienced staff (nurses >5 years critical care experience, physician on every flight); primarily blunt injury; data from 1990s
Peters J, et al
September 2015
Netherlands
144 patients with traumatic cardiac arrest (TCA) having undergone thoracostomy performed by helicopter emergency services (HEMS) teamsRetrospective cohort studyNumber and outcomes of TCA patients having undergone thoracostomy performed by HEMSOutcomes of TCA in patients having undergone prehospital thoracostomy were poor. There was no objective way to identify tension pneumothorax and it is unclear whether or not unnecessary thoracic interventions could be avoidedRetrospective; external validity of study; bystander bias for arrest and recognition needed for 911 call; presumed medical cause of arrest excluded; short time-frame of case review.
Ter Avest E, et al
December 2018
UK
263 patients with traumatic cardiac arrest who were attended to by a non-urban (Kent, Surrey and Sussex Air Ambulance trust) helicopter emergency medical services (HEMS) transport crewRetrospective cohort studyNumber of patients with ROSC at the scene, number and type of HEMS specific advanced interventions occurred and how they related to ROSC and number of patients who survived to hospital dischargeHEMS teams can perform significant interventions such as blood product administration and RSI which increase ROSC in traumatic arrest patients in addition to providing additional advanced interventions such as thoracostomies and thoracotomies. Retrospective; small sample size; physician on all flights; incomplete outcome data; unable to formally identify casual relation between outcomes and HEMS interventions; ROSC as primary outcome as opposed to survival.
Wright SW, et al
January 1989
USA
Patients who experienced traumatic cardiac arrest before the arrival of the flight teamRetrospective chart review Improved survivabilityPhysician intervention at the scene and rapid aeromedical transport are not likely to improve mortality after traumatic cardiac arrest.Retrospective; primarily blunt injury; data from 1980s; male predominance
Peters J, et al.
September 2015
Netherlands
144 patients with traumatic cardiac arrest (TCA) having undergone thoracostomy performed by helicopter emergency services (HEMS) teamsRetrospective cohort studyNumber and outcomes of TCA patients having undergone thoracostomy performed by HEMSOutcomes of TCA in patients having undergone prehospital thoracostomy were poor. Retrospective; no objective way to identify tension pneumothorax in prehospital setting; incomplete documentation; too low of survival rate to evaluate post thoracotomy infections; physician staffed HEMS

Comment(s)

Seven out of eight studies included are retrospective chart reviews, speaking to the limited availability of data addressing this topic. Previous studies showed little improvement with the interventions of helicopter emergency medical services (HEMS) in traumatic cardiac arrest patient outcomes. However, more recent studies do suggest a potential benefit with HEMS teams including increases in ROSC and survival with advanced interventions (such as thoracostomy).

Clinical Bottom Line

In a specific subgroup of patients with traumatic out-of-hospital cardiac arrest, helicopter emergency medical services do improve survival.

References

  1. Di Bartolomeo S, Sanson G, Nardi G, Michelutto V, Scian F. HEMS vs. Ground-BLS care in traumatic cardiac arrest Prehosp Emerg Care 2005 Jan-Mar;9(1):79-84.
  2. Falcone RE, Herron H, Johnson R, Childress S, Lacey P, Scheiderer G. Air Medical Transport for the Trauma Patient Requiring Cardiopulmonary Resuscitation: A 10-Year Experience Air Med J 1995 Oct-Dec;14(4):197-203.
  3. Gleeson AP, Mitchell RG, Robertson CE. Advanced life support for out-of-hospital cardiac arrest--the changing role of a hospital-based flying squad Eur J Emerg Med. 1998 Sep;5(3):285-7.
  4. Margolin DA, Johann DJ Jr, Fallon WF Jr, Malangoni MA. Response after Out-of-Hospital Cardiac Arrest in the Trauma Patient Should Determine Aeromedical Transport to a Trauma Center. J Trauma 1996 Oct;41(4):721-5.
  5. Prentice C, Jeyanathan J, De Coverly R, Williams J, Lyon R. Emergency medical dispatch recognition, clinical intervention and outcome of patients in traumatic cardiac arrest from major trauma: an observational study BMJ Open 2018 Sep 5;8(9):e022464
  6. Ter Avest E, Griggs J, Prentice C, Jeyanathan J, Lyon RM. Out-of-hospital cardiac arrest following trauma: What does a helicopter emergency medical service offer? Resuscitation 2019 Feb;135:73-79
  7. Wright SW, Dronen SC, Combs TJ, Storer D. Aeromedical Transport of Patients With Post-Traumatic Cardiac Arrest Ann Emerg Med 1989 Jul;18(7):721-6.
  8. Peters J, Ketelaars R, van Wageningen B, Biert J, Hoogerwerf N. Prehospital thoracostomy in patients with traumatic circulatory arrest: results from a physician-staffed Helicopter Emergency Medical Service Eur J Emerg Med 2017 Apr;24(2):96-100.