What’s New in the Patient Safety World

March 2012

Helicopter Transport and Stroke



We’ve done multiple columns pointing out inappropriate use of helicopters (or other air transport) for many medical patients and the dangerous track records of helicopter safety for patients and medical personnel. In our July 8, 2008 Patient Safety Tip of the Week “Medical Helicopter Crashes” and our October 2008 What’s New in the Patient Safety World “More Medical Helicopter Crashes” we discussed the “epidemic” of crashes of helicopters and other medical rescue aircraft in the recent past. We have been very critical that the regulatory agencies involved in oversight of the air medical industry have focused too much on proximate causes and ignored root causes (see our Patient Safety Tips of the Week for February 3, 2009 “NTSB Medical Helicopter Crash Reports: Missing the Big Picture” and September 1, 2009 “The Real Root Causes of Medical Helicopter Crashes” and our November 2010 What’s New in the Patient Safety World column “FAA Safety Guidelines for Medical Helicopters Short-Sighted). Proposed solutions to these crashes have always focused on proximate causes and recommendations have come out in favor of mandating night vision goggles, terrain warning systems, better weather information, changes in pilot training, etc.


All these solutions ignore some of the most important root causes and failed to ask an important question “Was an air medical evacuation really necessary here or could ground ambulance have been adequate?”. Even the few root cause analyses (RCA’s) we have seen following actual medical helicopter crashes have failed to ask that fundamental question “Was the helicopter transport indicated in the first place?”.


We previously noted a 2006 study done by Dr. Bryan Bledsoe and his colleagues that was a meta-analysis of helicopter transport of trauma patients (Bledsoe 2006). Using several widely-used injury severity or trauma scores, they showed that almost 2/3 of trauma patients brought by helicopter to a trauma center had minor or non-life-threatening injuries and that 25% were discharged from the hospital within 24 hours. Some helicopter services apparently have rates as high as 20% of transported patients being discharged from emergency rooms shortly after arrival (Greene 2009). Even in Maryland, where the trauma system is a model and the medical helicopter system a public one, the post-crash hearings revealed that almost half of patients transported by helicopter to trauma centers were released within 24 hours (Dechter 2008).


In our November 2010 What’s New in the Patient Safety World column “FAA Safety Guidelines for Medical Helicopters Short-Sighted” we highlighted some questions you should ask before sending your patients (and staff) off on medical helicopter transports.


Now some new studies further question the necessity of air transport for transferring some patients to tertiary medical centers. While most research on transfer of patients by air transport has dealt with trauma patients, transplant patients or transplant organs, or acute MI patients, we also see substantial numbers of patients with acute ischemic stroke transferred via helicopter or other forms of air transport. For thrombolytic therapy to be effective in reducing the morbidity and mortality from ischemic stroke, it has to be delivered within a tight time window (generally 4.5 hours from onset of symptoms). Therefore many patients were transferred via air so that they could get to a stroke center within that timeframe. However, now most communities have a “hub and spoke” stroke system in which staff at the “hub” (stroke center) can communicate via telemedicine links to the “spoke” (peripheral hospital) and thrombolysis can be initiated at the remote site and then continued in transit to the stroke center. Many (in fact probably most) patients are still transferred via air transport. Previous studies favoring transfer via helicopter (Reiner-Deitemyer 2011, Silliman 2003) have been done largely in systems where thrombolysis was only initiated on arrival at the stroke center.


A new study from the Mayo Clinic (Olson 2011) analyzed the data on patients within their stroke network. Of the 122 patients analyzed, 94 were transferred via air transport (generally helicopter) and 28 by ground transport. They found that, though the actual transport time was about 30 minutes faster by air, the overall time from activation of the system to arrival at the stroke center was only about 15 minutes faster on average. Moreover, outcomes in the two groups were similar and both modes of transportation appeared to be safe (in terms of complications, etc.). The authors conclude that ground transport should be considered for patients with acute ischemic stroke receiving intravenous rtPA unless endovascular rescue therapy is likely to be pursued. Limitations of this study include the relatively small number of patients transported via ground and the fact that the “spoke” hospitals are all within about 60 miles of the stroke center.


We’ve seen similar recommendations regarding transfer of acute MI patients as well. Percutaneous coronary intervention (PCI) had become the preferred strategy for acute STEMI because of a mortality benefit when PCI could be performed promptly. However, when data are analyzed on transferring acute STEMI patients to centers capable of performing PCI, it turns out that very few patients can get PCI within the prescribed time window even when transported via helicopter. Recent data have caused reconsideration of transfer strategies for STEMI patients (Redberg 2012). For low and intermediate-risk patients with STEMI there appears to be no mortality advantage of PCI over thrombolytic therapy. Even for high-risk patients the mortality risk of PCI over thrombolytics may be lost when there are routine delays of 1-3 hours for transport. Therefore, rather than activating the air transport system routinely, the strategy for most STEMI patients should be to administer thrombolytic therapy. Only in those high-risk patients where it is likely that transfer can take place promptly (and the receiving center by ready to do PCI) should air transport (or even ground transport) be considered.


So you really do need to take a hard look at the types of patient you are sending out to tertiary centers, make sure that they get the best evidence-based treatments available within a realistic timeframe, and make good decisions about mode of transport for those that do need transfer.







Bledsoe BE. Wesley AK. Eckstein M. Dunn TM. O'Keefe MF. Helicopter scene transport of trauma patients with nonlife-threatening injuries: a meta-analysis. Journal of Trauma-Injury Infection & Critical Care 2006; 60(6): 1257-65 http://www.jtrauma.com/pt/re/jtrauma/abstract.00005373-200606000-00015.htm;jsessionid=LzvDYgJNbkdJpBhDDCFtr3VBPJJ6WwQ1bvdXstQHvMNQ7Lk0Mygl!447927974!181195628!8091!-1?index=1&database=ppvovft&results=1&count=10&searchid=1&nav=search



Greene J. Rising Helicopter Crash Deaths Spur Debate Over Proper Use of Air Transport.

Annals of Emergency Medicine 2009; 53: A15-A17 (March 2009)




Dechter G, Jones B. Md. medevac crash raises question about trauma procedures.

The Baltimore Sun. October 1, 2008




Olson MD, Rabinstein AA. Does Helicopter Emergency Medical Service Transfer Offer Benefit to Patients With Stroke? Stroke 2011; published online before print December 8 2011




Reiner-Deitemyer V, Teuschl Y, Matz K, et al. for the Austrian Stroke Unit Registry Collaborators. Helicopter Transport of Stroke Patients and Its Influence on Thrombolysis Rates: Data From the Austrian Stroke Unit Registry. Stroke 2011; 42: 1295-1300




Scott L. Silliman SL, Quinn B, Huggett V, Merino JG. Use of a Field-to-Stroke Center Helicopter Transport Program to Extend Thrombolytic Therapy to Rural Residents. Stroke 2003; 34: 729-733




Redberg RF. Reconsidering Transfer for Percutaneous Coronary Intervention Strategy: Time Is of the Essence. Arch Intern Med 2012; 172: 98 – 99
















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