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EMS Myth #6: Air medical helicopters save lives and are cost-effective

I love helicopters. Riding in them is both unique and exhilarating. I have spent many hours in a helicopter providing emergency medical care in between police chases and other city activities. Many have called air medical helicopters nothing more than "flying billboards" for the hospitals that operate them. In this day of dwindling healthcare dollars, we must ask ourselves some hard questions: Do helicopters really make a difference in EMS? Do they provide a significant benefit for the patient? Are the risks worth any real benefit? Why do we not see a proliferation of helicopter operations in other countries like we are seeing in the U.S.? Unfortunately, any discussion of air medical helicopter efficacy often results in an emotional response by many. I have heard flight nurses say, "I know what I do makes a difference." Flight paramedics will often relay a story about a particular patient they feel benefited from helicopter transport. But, do helicopters really make a difference in patient care and the subsequent quality of the patient's life? To answer this, let's look at what the scientific literature says.

History

The use of civilian helicopters for transport of ill and injured patients has become an integral part of modern emergency care. Helicopter transport of emergency patients in the United States evolved from experience gained in the Korean and Vietnam Wars, when injured soldiers were transported from conflict areas to military medical facilities for definitive care.1

The use of helicopters in the civilian sector began in the late 1960s, when helicopters were used in dual-purpose law-enforcement or military operations, but had a limited commitment to emergency medical response.2,3 Civilian helicopters dedicated exclusively to patient care and transport were first introduced in the U.S. in 1972.1,4 Over the last two decades, there has been a significant proliferation of helicopter operations in the U.S., most of which are hospital-based and many of which have more than one aircraft.5

The impetus for the development and proliferation of civilian helicopter ambulances was based on the concept of the "golden hour." First described by R Adams Cowley, the "golden hour" is the period immediately following injury when resuscitation and definitive care improve outcome.6,7

Although outcome is better the sooner definitive care is provided, the actual concept of the so-called "golden hour" has been called into question.8,9,10

The Scientific Evidence

Initial studies published in the 1980s were supportive of air medical transport of emergency patients.11,12 However, more detailed recent studies have shown that this may no longer be the case. Several recent studies have shown that use of helicopters for trauma patients actually benefits only a small number of patients. Furthermore, these studies indicate that many EMS providers summon medical helicopters when the patient's condition may not warrant their use.

Researchers studied helicopter usage in the Silicon Valley region of California. In a retrospective review of 947 consecutive trauma patients transported to their trauma center, they found that only 22.8% of study patients possibly benefited from helicopter transport. They further found that 33.5% of patients transported by helicopter were discharged from the emergency department and not admitted to the hospital.13

In the Los Angeles area, researchers retrospectively evaluated helicopter transport of 189 pediatric trauma patients and found that 85% of patients were considered to have minor injuries. Of the patients transported by helicopter in their study, 33% were discharged home from the emergency department and not admitted to the hospital.14

In another pediatric trauma study, researchers in Washington, DC, found that approximately 85% of air transports in their study group of 3,861 injured children were considered over-triaged.15 A Boston study of 1,523 patients transported by helicopter found that 24% of patients transported from an accident scene were deemed inappropriate.16

Similar findings were reported from an Australian study. In northern coastal New South Wales, researchers reviewed 184 medical records of patients transported from an accident scene to a hospital. An expert panel reviewed all helicopter patient retrievals. They found that only 17.3% of patients benefited from helicopter transport, while 1.7% of patients were felt to have been potentially harmed. Seven percent of patients were discharged from the emergency department and not admitted to the hospital, while 36% were discharged from the hospital within 48 hours.17 In a Hong Kong study, 34.1% of patients transferred by helicopter from a scene were discharged from the emergency department and not admitted to the hospital.18 In a Norwegian study, researchers found that only 11% of the 370 patients transported by helicopter benefited.19

British researchers found no evidence of any improvement in patient outcomes for patients transported by the London Helicopter EMS.20

When the University of Texas Medical Branch at Galveston discontinued its hospital-based air medical helicopter, they found that there was no decrease in transport time or increase in mortality for trauma patients at their facility.21

In a five-year study of blunt-trauma patients transported either by helicopter or ground ambulance, researchers in Phoenix, AZ, found no survival advantage for patients transported by helicopter in an urban setting with a sophisticated prehospital care system.22

In a North Carolina study, researchers found that only a very small subset of patients transported by helicopter appeared to have any chance of improved survival based on their helicopter transport.23

In a detailed study of 162,730 patients treated at 28 accredited trauma centers in Pennsylvania from 1987--1995, researchers found that transportation by helicopter did not affect the estimated odds of survival.24

A Houston, TX, study found that patients with penetrating trauma do not benefit from helicopter transport and scene flights are not medically efficacious.25

In an eight-year Pennsylvania study of 3,048 penetrating-trauma victims, researchers found that patients transported by helicopter had longer transport times and no significant difference in mortality compared with those transported by ground.26 Likewise, transport of patients with severe head injuries and burns do not appear to benefit from helicopter transport.27,28

When interfacility helicopter transport of patients was studied, the results were also interesting. In a study of 1,234 patients transported between facilities by helicopter, researchers found that those patients did not have improved outcomes compared with those transported by ground.29 Clearly, additional studies are needed.

A factor often overlooked is helicopter safety. There has been a steady increase in the number of helicopter accidents. In fact, over the last 10 years in the U.S., there have been 83 helicopter accidents resulting in 70 deaths and 62 injuries. Furthermore, 52% of accidents in this 10-year period occurred during the last three years of the study (2000--2002). The helicopter most frequently involved was the single-engine Bell 206 Long Ranger, followed by the twin-engine Eurocopter BK-117. Primary cause of accidents in the study period was pilot error.30,31

Conclusion

Again, we have embarked on an EMS adventure that has conflicting scientific evidence. But, medicine evolves and prehospital medicine similarly evolves. When the original studies were published regarding the effectiveness of helicopters, EMS was in an earlier developmental stage. At that time, helicopters could offer added patient care skills and interventions not available on ground ambulances. Now, with prehospital care being considerably more sophisticated, helicopters offer little more than increased speed. And, in the overall scheme of things, speed makes a difference for only a limited number of patients. The proliferation of helicopter operations in this country over the last decade cannot be supported with science. Helicopters cost between $1,500,000--$5,700,000 to purchase and up to $1,000,000 a year per aircraft to operate. Thus, a significant amount of financial resources are going into a transport modality that actually benefits few patients. These large sums of money would buy many AEDs and ground ambulances that would stand to benefit more of our citizenry. With a dwindling healthcare dollar, we will soon have to make some tough decisions.

There certainly is a role for helicopters in EMS, but we have them in the wrong places. The majority of the fleet is parked atop hospitals in urban centers where ground transport takes only minutes. They need to be positioned where they will benefit the people who need them the most--those who live in rural settings. That is, they need to be closest to the hospitals and trauma scenes where they can potentially make a difference. The literature certainly supports the role of helicopter transport of critical patients in the rural setting.32

Thus, there should be a strategically placed network of helicopters that serves rural hospitals and providers. However, as long as hospitals operate helicopters as "flying billboards," this will probably never happen. Perhaps the solution is to follow the German and Australian models and move EMS helicopters from hospitals to state-wide EMS-type governing boards based on need.33 This would certainly promote fairness for all state residents, but I'm afraid that emotion may prevail.

References
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2. Military Assistance to Safety and Traffic (MAST). Report of test program by the Interagency Study Group. DHEW publication No. HSM-72-7000. Washington, DC.
3. Proctor HJ, Acai SA, Jr. Assets and liabilities of helicopter evacuation in support of emergency medical services. NC Med J 37:25--28, 1976.
4. Baxt WG, Moody P, et al. The impact of rotorcraft aeromedical emergency care service on mortality. JAMA 249:3047--3051, 1983.
5. Collett H. Air medical helicopter transport. Hosp Aviat 7(7):5--7, 1998.
6. Boyd DR, Cowley RA. Comprehensive regional trauma/emergency medical services (EMS) delivery systems: The United States experience. World J Surg 7:149--157, 1983.
7. Cowley RA. Trauma center: A new concept for the delivery of critical care. J Med Soc NJ 74:979--987, 1977.
8. Lerner EB, Moscati RM. The golden hour: Scientific fact or medical "urban legend"? Acad Emerg Med 8(7):758--760, 2001.
9. McNicholl BP. The golden hour and prehospital trauma care. Injury 25:251--254, 1994.
10. Bledsoe BE. The Golden Hour: Fact or Fiction? Emerg Med Serv 31(6):105, 2002.
11. Baxt WG, Moody P. The impact of rotorcraft aeromedical emergency care service on trauma mortality. JAMA 249(22):3047--3051, 1983.
12. Baxt WG, Moody P, Cleveland HC, et al. Hospital-based rotorcraft aeromedical emergency care services and trauma mortality: A multicenter study. Ann Emerg Med 14:859--864, 1985.
13. Shatney CH, Homan SJ, Shrek JP, Ho CC. The utility of helicopter transport of trauma patients from the injury scene in an urban trauma system. J Trauma 53:817--822, 2002.
14. Eckstein M, Jantos T, Kelly N, et al. Helicopter transport of pediatric trauma patients in an urban emergency medical services system: A critical analysis. J Trauma 5:340--344, 2002.
15. Moront ML, Gotschall CS, Eichelberger MR. Helicopter transport of injured children: System effectiveness and triage criteria. J Pediatr Surg 31(8);1183--1186, 1996.
16. Reenstra WR, Tracy J, Hirsch E, Millham F. Evaluation of the "appropriateness" of triage requests for air transport to Level I trauma centers directly from the scene versus a community hospital. Ann Emerg Med 34(4):S73, 1999.
17. Wills VL, Eno L, Walker C, Gani JS. Use of an ambulance-based helicopter retrieval service. Aust N Z J Surg 70(7):506--510, 2000.
18. Wong TW, Lau CC. Profile and outcomes of patients transported to an accident and emergency department by helicopter: Prospective case series. Hong Kong Med J 6(3):249--253, 2000.
19 Hotvedt R, Kristiansen IS, Forde OH, et al. Which groups of patients benefit from helicopter evacuation? Lancet 347:1362--1366, 1996.
20. Brazier J, Nicholl J, Snooks H. The cost and effectiveness of the London Helicopter Emergency Medical Service. J Health Serv Res Policy 1(4):232--237, 1996.
21. Chappell VL, Mileski WJ, Wolf SE, Gore DC. Impact of discontinuing a hospital-based air ambulance service on trauma patient outcomes. J Trauma 2(3):486--491, 2002.
22. Schiller WR, Knox R, Zinnecker H, et al. Effect of helicopter transport of trauma victims on survival in an urban trauma center. J Trauma 28(8):L1127--1134, 1988.
23. Cunningham P, Rutledge R, Baker CC, Clancy TV. A comparison of the association of helicopter and ground ambulance transport with the outcome of injury in trauma patients transported from the scene. J Trauma 43(6):940--946, 1997.
24. Brathwaite CEM, Rosko M, McDowell R, et al. A critical analysis of on-scene helicopter transport on survival in a statewide trauma system. J Trauma 45(1):140--144, 1998.
25. Cocanour CS, Fischer RP, Ursic CM. Are scene flights for penetrating trauma justified? J Trauma 43(1):83--86, 1997.
26. Dula DJ, Palys K, Leicht M, Madtes K. Helicopter versus ambulance transport of patients with penetrating trauma. Ann Emerg Med 36(4):S76, 2000.
27. DiBartolomeo S, Sanson G, Nardi G, et al. Effects of 2 patterns of prehospital care on the outcome of patients with severe head injury. Arch Surg 136(11):1293--1300, 2001.
28. Slater H, O'Mara MS, Goldfarb IW. Helicopter transportation of burn patients. Burns 28(1):70--72, 2002.
29. Arfken CL, Shapiri MJ, Bessey PQ, Littenberg B. Effectiveness of helicopter versus ground ambulance services for interfacility transport. J Trauma 45(4):785--790, 1998.
30. Bledsoe BE. Air medical helicopter accidents in the United States: A five-year review. Prehosp Emerg Care 7(1):94--98, 2003.
31. Bledsoe BE. Air Medical Helicopter Accidents in the United States (in press).
32. Urdaneta LF, Miller BK, Ringenberg BJ, et al. Role of the emergency helicopter transport service in rural trauma. Arch Surg 122:992--996, 1987.
33. Weil TP. Health care reform and air medical transport services. J Emerg Med. 13(3):81--87.

Bryan Bledsoe, DO, FACEP, EMT-P, is an emergency physician, author and former paramedic whose writings include: Paramedic Care: Principles and Practice and Paramedic Emergency Care.

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