Page 92 - JSOM Spring 2026

Testing the Emergency Evacuation Hyperbaric Stretcher
for Fit in Small Military and Civilian Helicopters

Nicholas M. Studer, MD *; Kaighley D. Brett, MD 2
1

ABSTRACT
Introduction: Hyperbaric oxygen (HBO ) therapy is essential for those activities with a need for an extremely compact pre-
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for the treatment of diving injuries in the field, but typically hospital HBO treatment capability. 3
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requires larger recompression chambers with limited porta-
bility. The emergency evacuation hyperbaric stretcher (EEHS) The original version of the EEHS is a monoplace chamber, and
offers a portable solution for prehospital HBO , particularly thus only appropriate for use in patients that are conscious and
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in remote or austere environments. However, it’s compatibility can maintain their own airway. This is the primary clinical lim-
with smaller evacuation aircraft remains uncertain. Methods: itation of the product. However, if an adequate compressed
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A commercially available EEHS (Hyperlite 1) was tested for fit gas supply is available, it can complete a full TT6. The EEHS
and operational computability in both a U.S. Coast Guard Air- is shown in marketing as fitting inside the cabin of large heli-
bus MH-65 “Dolphin” and an Airbus H145 helicopter with a copters, such as the Sikorsky UH-60 “Blackhawk.” However,
configuration typical of civilian air ambulances. Results: The it was not known if the EEHS could be safely loaded into the
EEHS could not be fully accommodated in the MH-65 with- smaller aircraft utilized by the U.S. Government and common
out the side doors remaining open and obstructing the rescue to the prehospital environment. In particular, there was concern
swimmer’s seat. These limitations may pose challenges to the about the Airbus MH-65 “Dolphin” utilized by the U.S. Coast
safe transport of an EEHS during standard operational scenar- Guard (USCG) and the Airbus H145 (previously EC145) plat-
ios, necessitating additional logistical support and introducing form common to civilian helicopter ambulance use. A variant
potential safety risks. The EEHS did fit within the H145, op- of the H145 is also used by the U.S. Army for Medical Evac-
timally without a large transport cot in place. In both cases, uation. If the EEHS is not capable of being loaded on board
the required tie-down straps were unavailable. Conclusion: the transport vehicle, the medical team would be placed in the
Un anticipated airframe limitations may impede the timely unenviable position of deciding whether the patient should be
evacuation of a diving casualty to advanced care. These find- removed from their ongoing HBO treatment or would be able
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ings highlight the importance of planning for the use of the to tolerate delayed transport to higher-level care.
EEHS including careful consideration of the potential aircraft
platforms available. Further research is recommended to assess Methods
newer EEHS models and to improve aircrew and clinician fa-
miliarity with EEHS transportation requirements. An in-service SOS, Ltd., Hyperlite 1 EEHS unit was obtained
from the National Oceanic and Atmospheric Administration
Keywords: hyperbaric oxygen treatment; pressure chambers; facility in Galveston, TX, and transported to the USCG Air
military diving; diving injuries; transportation Station – Houston located at Ellington Field. Subjective and
objective evaluation was performed by both USCG personnel
and the primary author with an in-service MH-65 aircraft.
This procedure was then repeated at the Memorial Hermann
Introduction
LifeFlight facility located at David Wayne Hooks Memorial
Hyperbaric oxygen (HBO ) treatment is the cornerstone of Airport with an in-service H145 aircraft. To prevent potential
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treatment for decompression sickness (DCS) and air or gas em- damage to the EEHS or airframe, the EEHS was loaded with-
bolism/arterial gas embolism. The United States Navy (USN) out end caps in place during both evaluations.
Treatment Table 6 (TT6) is typically recommended as a start-
ing point for emergency management of diving casualties. Results
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TT6 is generally completed in large, fixed-facility or shipboard
recompression chambers (RCC). In the field environment, con- MH-65
tainerized units and other rigid portable multiplace chambers The MH-65 loads from either of two side doors. The loaded
such as the Transportable Recompression Chamber System EEHS can be seen in Figure 1. Closure of the side cabin doors
(TRCS) have been historically available for military and simi- was unsuccessful, even without the end caps in place and the
lar remote diving operations activities. An emergency evacua- EEHS fully pushed towards the rear of the aircraft. The Rescue
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tion hyperbaric stretcher (EEHS), known commercially as the Swimmer crew seat could not be occupied while the EEHS was
Hyperlite 1 (SOS Group, London, UK), has become available situated in the aircraft. While standard aircraft-rated ratchet
*Correspondence to U.S. Army Office of the Surgeon General, Falls Church, VA, USA or nicholas.m.studer2.mil@health.mil
1 Dr. Nicholas M. Studer is affiliated with the U.S. Army Office of the Surgeon General, Falls Church, VA. Dr. Kaighley D. Brett is affiliated with
2
the Canadian Forces Health Services, Ottawa, Canada.
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