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Undersea and Hyperbaric Medicine Section Newsletter - September 2011

circle_arrowLetter from the Chair - Undersea and Hyperbaric Medicine Section Newsletter, September 2011
circle_arrowA Case of AGE Presents Classically - Undersea and Hyperbaric Medicine Section Newsletter, September 2011
circle_arrowJournal Review - Undersea and Hyperbaric Medicine Section Newsletter, September 2011
circle_arrowUHM Section Meeting in San Francisco - Undersea and Hyperbaric Medicine Section Newsletter, September 2011

Letter from the Chair - Undersea and Hyperbaric Medicine Section Newsletter, September 2011

Tracy Leigh LeGros, MD, PhD, UHM, FACEP, FAAM, (FUHM…soon hopefully)   

Greetings! There was a great UHMS meeting held in Dallas/Fort Worth in June. A very productive meeting with many highlights. Here are just a few: 


We have a new indication for hyperbaric medicine therapy in the making. It is (drum roll please): Idiopathic Sudden Sensineural Hearing Loss (ISSNHL). There were actually two new indications brought before the Hyperbaric Oxygen Therapy Committee. The first was Avascular Necrosis. The second was ISSNHL. There were well prepared and well reasoned arguments brought forth from both sides. To recap the spirited debate, it went a little like this:

Potential Indication Presentation Avascular Necrosis: 

Pro-Argument Presenter: Dr. Sarah Parks (General and Oncological Surgeon, LSU UHM Fellow)

  • Sponsors: Dr. Heather Murphy-Lavoie and Dr. Tracy Leigh LeGros
  • Summary: Dr. Parks went through the pathophysiology, epidemiology, classifications, diagnoses and available treatments related to AVN. She then explained the derangements made with these availability treatments, focusing on the usual endpoint for these patients, total hip arthroplasty. She then reviewed the literature as it relates to the use of hyperbaric oxygen therapy for the treatment of AVN, including the benefits of HBOT, cost differentials, and outcomes.

Con-Argument Presenter: Dr. Richard Baynosa (Plastic Surgeon) 

  • Summary: Dr. Baynosa also reviewed the literature, detailing the limitations of the current literature and the recent advances in orthopedic surgery related to surgical interventions. Additional comments and support for this position were posited within the discussion from Dr. Michael Strauss, world renowned expert in this field and author of the largest study to date detailing the benefits of hyperbaric therapy for the treatment of AVN.
  • Final Outcome: The Hyperbaric Oxygen Committee did not accept the pro-argument for inclusion of AVN as a new indication.

Potential Indication Presentation Idiopathic Sudden Sensineural Hearing Loss:

Pro-Argument Presenter: Dr. Steve Piper (Emergency Medicine Specialist, LSU UHM Fellow)

  • Sponsors: Dr. Heather Murphy-Lavoie and Dr. Tracy Leigh LeGros
  • Summary: Dr. Piper reviewed the definition, clinical presentation, incidence, epidemiology, as well as the social and economic burden of ISSNHL. He then reviewed the rationale for HBO Therapy and the supportive literature. He detailed his literature evaluation to include the most recent Cochrane Review on the subject matter and a comparison of the strength of this potential indication versus all of the other accepted indications. He ended his presentation with a review of the insurance carriers reimbursement and the world health organization viewpoint on the profound economic and social impact of this disease.

Con-Argument Presenter: Dr. Richard Moon (Critical Care Specialist, Anesthesiologist)

  • Summary: Dr. Moon utilized several of Dr. Piper's slides to illustrate his con-argument. He also reviewed the literature and its limitations.
  • Final Outcome: The Hyperbaric Oxygen Committee accepted the pro-argument for inclusion of ISSNHL as a new indication. 

And there you have it. Now, these recommendations have been forwarded onward, for final Board of Directors / Executive Committee approval. The write up for ISSNHL is being prepared. More to come soon. 


Also news to report for all of you who like extra initials behind your name to signify your hard work and dedication to your craft. The UHMS, under the leadership of Dr. Laurie Gesell, has approved a new status for members. The criteria are being approved as we speak. The upshot of it all is that you will be able, very soon, to end your name with your fellowship status. It is very much like the FACEP or FAAEM designation assigned to Fellows in good standing with ACEP and AAEM (emergency medicine organizations). 


Dr. Laurie Gesell chaired a wonderful Plenary Session devoted to reviewing the current state of affairs for wound care certifications, board certification of UHM Fellowships, and the most recent developments in all aspects of education in our field. It was very well attended and many viewpoints were expressed. We were honored that Dr. Glen Merchant, the Executive Director of the American Board of Preventative Medicine was in attendance. He provided invaluable viewpoints and advice. He is an ardent supporter of the UHMS and spent 36 years in service to the Navy and Marine Corps. It was a great session, and many ideas were brought forth that should help positively direct the future of UHM education.  


Coming to a mailbox near you, will be the new edition of “The Rules of the Road.” This very helpful book is published by the American Academy of Emergency Medicine. This edition will feature a chapter on Undersea and Hyperbaric Medicine. It was authored by Dr. Steve Agans (LSU Fellow) and Drs. Tracy Leigh LeGros and Heather Murphy-Lavoie. Within this chapter is a description of what we learn, what we do, and how we are trained. It also includes all of the information related to UHM Fellowship with accompanying contact information. 


Now this is just in the planning stages. However, it is very exciting. The President of the UHMS, as well as the Executive Council and the Publications Committee, have been spearheading the development of a new textbook in Undersea and Hyperbaric Medicine. The audience for this text will be certifying and recertifying physicians, fellowship trainees, and hyperbaric physicians in need of a complete but concise review of all that we do. It will be accompanied by a second text, which focuses on questions encompassing Clinical Hyperbaric Medicine, Diving Medicine, Fitness to Dive, and Wound Care. Dr. Tracy LeGros, MD, PhD and Dr. Laurie Gesell will be the Editors in Chief for these texts. The section editors will be Drs. Heather Murphy-Lavoie, Christopher Logue, and Robert Sanders. It is a very exciting project. 


This is something that we are currently working on. It is a concept that has worked for other specialties, and may work very well for us. If it can be done, it will allow a physician, who is already working in Undersea and Hyperbaric Medicine, to affiliate with an established, ACGME-accredited UHM Fellowship, and obtain Fellowship training while being able to keep his job and not have to uproot to another city and forsake his income. This is a win win for everyone. The Fellowship will not have to financially support the fellow, and they gain more fellows to train. The Fellowship trainee will be able to obtain a great education and the ability to sit for the board in Undersea and Hyperbaric Medicine. Drs. Tracy LeGros and Chris Logue are working with Dr. Glen Merchant to push this through. 


And finally, the Hyperbaric Oxygen Committee and the Publications Committee of UHMS is working on conversion of the Undersea and Hyperbaric Medicine Committee Report (the indications manual) into stand alone journal articles. This is an attempt to get our great literature out there in a way that is easily retrievable by those within our specialty, and importantly, those in other specialties. These articles will be peer reviewed and obtainable through pub med. Also in the works, is the development of Indication Guidelines. These will be similar to the Wound Care and Diabetic Foot Guidelines you all know and love. The Hyperbaric Oxygen Committee is also working on the newest edition of the UHM Committee Report to be released within the next year or two. 


Well that is all the news I know. It has been my privilege to serve as your Chair for the Undersea and Hyperbaric Medicine Section of ACEP. I think we accomplished a lot and I look forward to the new leadership of Dr. Norma Cooney, as she assumes Chair. Thank you very much for your continued interest and membership in this section. I hope to see all of you, very soon. 

A Case of AGE Presents Classically - Undersea and Hyperbaric Medicine Section Newsletter, September 2011

Stephen Hendriksen, George Macris, and Robert Sanders  

I was working the morning shift in a community ED in a tropical location when the Medi-Com went off requesting physician consult “for a DCS case.” 

The Case: 

It was his first dive of the day, a solo dive, when a 20 y/o male engineering student was working in about 50fsw to set a mooring under his father’s boat. After only about 10-15 minutes, he ran out of air. He initially tried a controlled emergency swimming ascent, but feeling air starved he then bolted, this was the last thing he remembered.

The family then reports that the patient, almost immediately upon surfacing, went unconscious, and may have had a seizure; “his eyes were open, rolled back but he was not responding, but he was shaking.” 911 was activated. 

Upon arrival of the paramedics (20 minutes elapsed), the patient still had some right arm twitching and clonus, right leg flaccidity, and altered mental status. Vitals were BP 140/p pulse: 113 respirations: 30 oxygen saturation: 89% on room air, but proved to be stable in the field. Emergent interventions included the patient being placed supine, on high flow O2 by non-rebreather mask, and IV fluid (normal saline) 1 liter bolus was started. The patient rapidly regained consciousness though was initially oriented x1 in the field.  

Emergency Department Course:

By the time he reached our facility (47 minutes elapsed) he was alert and oriented x4 with a completely normal neurologic exam with normal strength, mentation, light touch, sharp dull, finger-to-nose, heel-to-shin. He was just complaining of severe headache. His vitals were reassuring with a BP of 124/62, pulse of 72. Family members also felt he was “normal”. 

Since I trusted the medics and the quality of their report was so convincing for arterial gas embolism (AGE), a life threatening emergency, I began arranging for transport to the chamber (on another Island) even prior to arrival. Per the request of the receiving physician, a “complete workup” was ordered, and the patient had a normal EKG, normal chest XR, reassuring labs (CBC, BMP) except for signs of dehydration, and a normal CT of the brain. 

At 1:29 elapsed the patient began to show signs of instability with a drop in his blood pressure to the low 100’s. We were able to keep it stable with IV fluids, but could never reverse it. 

At 1:40 elapsed, the patient began to feel nauseated and was “dry heaving” so Zofran 4mg IV was given. At 1:54 elapsed the patient stated his headache was getting worse, and Toradol, 30 mg IV was given with some relief. 

At 2:19 elapsed the patient left the ED via ALS ambulance to the airport for transport to the Hyperbaric Facility, BP holding at 100/70’s with IVF. 

Hyperbaric Facility: 

At 3:15 the pt arrived at the Hyperbaric facility. Patient only complained of feeling dizzy. On exam, patient had normal vitals, was alert and oriented x2 (did not know year). On neurological exam, he had normal strength and sensory to light touch, and sharp/dull, but patient clearly favored the right side on gait and had slowed finger to nose on the right. On a mini-mental status exam, he was unable to perform serial 5’s, recall 3 objects after 5 minutes, or copy a hexagon or draw a clock face (apraxia) (see images #1 and #2 below). The patient also had trouble performing simple tasks such as putting on his scrub pants before entering the hyperbaric chamber.  

At 3:30, patient began treatment at the John A. Burns School of Medicine Hyperbaric Treatment Center (HTC) on a 60 FSW treatment table (equivalent to a USN TT6). The decision was made to include two O2 extensions at 60 FSW during this treatment because of continued cognitive deficits. After completing an HTC 60 FSW treatment with 2 oxygen extensions, the patient had improvement in his cognitive function (AAO x4) and gait, but continued with fine motor deficits and was still unable to copy a hexagon or a clock face (see Image #3).  

The patient continued treatment as an outpatient with a total of two CO treatment tables (60 FSW treatments, similar to a USN TT5) and one HTC 47 FSW (wound care) treatment with cognitive improvements after each treatment (see Image #4). As seen below, the patient was asked to draw a clock face in a circle, copy a shape such as a hexagon or a square, or draw a smiley face.   


image3  image3 
Image 1: Day 1 Pretreatment: Clockface and hexagon,
black ink, doctor; red ink, patient
Image 3: Day 1 Post treatment, Hexagon and smiley face,
black ink, doctor; red ink, patient.


 image2 image4 
Image 2:Day 1, during treatment, Clockface and square,
black ink, doctor; red ink, patient
Image 4: Day 4, Clock face and hexagon, black ink, doctor;
red ink, patient



At the end of the final treatment the patient had returned to baseline per his mother and had no neurosensory or cognitive deficits on exam.


As the story from the paramedics was classic for a cerebral arterial gas embolism (CAGE), I felt it was in the best interest of the patient to get an aircraft in the air in route to the Kona coast to transfer the patient to the regional recompression chamber. I discussed the case with both the accepting ED physician and hyperbaric specialist and everybody worked together to expedite transfer.  

If recompression were immediately available I would have forgone the CT scan, but in this case it would not delay transport, and the receiving physician wanted a “complete workup.” Also with the possible seizure-like activity and severe headache, I do feel it was a reasonable choice. EKG and chest X-ray are indicated here to assess for stability for flight (check for pneumothorax, and cardiac involvement) and need for chest tube. 

The initial call did come in as a DCS case. If the local ED physician was not a hyperbaric specialist, treatment would have been delayed at best and might have been neglected all together as the patient was completely asymptomatic when I initially evaluated him. His dive depth and time were reasonable so I can see how this patient could have easily been discharged as he was completely symptom free, only to bounce back in severe distress, or end up with permanent, severe cognitive deficits. 

This case clearly demonstrates the “lucid interval” that we teach in diving medicine. An arterial gas embolism is a pulmonary over-pressure problem syndrome due to breath holding on ascent. The lungs overinflate, rupture and leak out air. The gas can coalesce forming large bubbles in the pulmonary venous system. As it has passed the pulmonary filter, the bubbles drain into the left atrium, get carried to the left ventricle and then to the coronary arteries (often fatal), to the brain (as in this case), or elsewhere. There have been documented 7+ cm columns of gas seen on autopsy in these cases. 

This case also demonstrates how a modified mini-mental status exam can be valuable in identifying more subtle cognitive deficits. This can also be valuable to test the patient’s response to treatment. In this case, the decision was made to extend the first treatment, and also provide multiple HTC treatments for the patient based on this simple, reliable system.  

It is important to differentiate between cerebral arterial gas embolism (CAGE) and decompression sickness (DCS), or at least identify when AGE is in your differential. The “currently asymptomatic” diver who is at risk for DCS (but not AGE) is handled very differently from the “currently asymptomatic” diver who had a loss of consciousness but might now look “normal” only because he is in the “lucid interval.” Of course if either is “symptomatic” the differentiation is not important in the ED. If you ever have questions, call your regional dive medicine specialist, or the Divers Alert Network at (919) 684-9111. 

The Players (and Authors): 

ED Physician: 
Robert W. Sanders, MD, UHM/ABEM
Assistant Clinical Professor, Dept of Surgery, Division of Emergency Medicine
University of Hawaii at Manoa
John A. Burns School of Medicine 

Hyperbaric Resident:
Stephen Hendriksen, MD, PGY-3
Emergency Medicine Department
The Warren Alpert Medical School
Brown University/Rhode Island Hospital

Hyperbaric Physician: 
George Macris, MD, UHM/ABPM
Assistant Clinical Professor, Dept of Surgery, Division of Undersea and Hyperbaric Medicine
University of Hawaii at Manoa
John A. Burns School of Medicine

Journal Review - Undersea and Hyperbaric Medicine Section Newsletter, September 2011

Jawad N. Kassem, MD 

In this edition of ACEPs Hyperbaric Section Newsletter, we review an article by Dr. Lindell K. Weaver. Dr. Weaver continues to add to the peer reviewed hyperbaric literature with his latest article in Critical Care Medicine, Hyperbaric Oxygen in the Critically Ill. We applaud Dr. Weaver in his efforts and encourage all hyperbaric physicians to follow his lead in publishing research in peer reviewed journals. 

Can We Safely and Effectively Treat Critically Ill Patients With Hyperbaric Oxygen Therapy?  

When indicated and with the use of appropriate staff and equipment; critically ill patients can be treated safely and effectively with hyperbaric oxygen therapy in monoplace and multiplace chambers.   

To evaluate this question, Dr. Weaver reviewed the aspects of hyperbaric medicine pertinent to treating critically ill patients with hyperbaric oxygen therapy (HBOT) in monoplace and multiplace chambers. The author conducted an evidence based review of the literature including MEDLINE/PubMed and the Rubicon Foundation, a repository of articles of interest to hyperbaric providers not indexed in the former. Critically ill patients were defined as intubated and mechanically ventilated. The search yielded articles and abstracts regarding the technical considerations, feasibility, risks, and patient management, which were reviewed.  

Key considerations for the safe and effective treatment of critically ill patients were divided into facility requirements and equipment selection, and managing the critically ill patient during HBOT. Each section’s subheadings and their recommendations are listed concisely below. 

Regarding facility and equipment requirements the author noted an absolute need for adherence to the National Fire Protection Association (NFPA) guidelines. Consider the following when selecting chamber type. Monoplace chambers can be located in an intensive care unit (ICU), but hands-on care cannot be administered. Multiplace chambers require significant space, are outside the ICU and subject the critically ill patient to the added risk of transport. Multiplace chambers require additional trained and experienced staff to monitor the patient. Special consideration to the health and safety of the nurse and/or attendant must be given to avoid complications including decompression sickness, albeit low. Hands-on care can be delivered in multiplace chambers. Standard ICU monitoring in either type of chamber can be readily accomplished. Ventilators compatible with the hyperbaric environment are available. Each has its pros and cons. General considerations for all ventilators include availability of high pressure oxygen and air, ensuring delivery of appropriate tidal volumes despite increased pressure (use of pressure control ventilation mitigates this), and the need to exchange air for saline in the endotracheal cuff balloon - its volume will otherwise be subject to Boyle’s Law. Suction in the chamber is driven by the pressure gradient from inside to outside the chamber.  

A number of topics pertaining to the management of the critical patient during HBOT were reviewed. Treatment protocols for the critical patient remain dependent upon the disorder. Gas exchange is influenced by lung dysfunction and this needs to be considered even during HBOT. In patients with severe lung dysfunction it may be prudent to measure PaO2 to ensure a therapeutic level is attained. If PaO2 is not > 800 torr, discontinuation of HBOT should be considered as therapeutic benefit is unlikely. Arterial blood gas monitors are available for use inside the multiplace chamber. Transcutaneous oxygen and carbon dioxide are reliable and the limited data support their use for clinical decision making in the critically ill. Restraining and sedating critically ill patients in a monoplace environment is of paramount importance. In the multiplace chamber sedation is often required. Myringotomies may reduce middle ear and inner ear barotrauma, but if it is required prophylactically in intubated, sedated patients is still a matter of debate among experts. Critically ill children can be safely and effectively treated with HBOT. Input from the pediatric ICU team is invaluable. Implanted devices are safe to use during HBOT if manufacturers confirm the implanted devices are compatible with hyperbaric compression. Defibrillators need to be interrogated before compression to determine lead integrity and frequency of defibrillation. Finally, defibrillation and cardioversion can be performed in the multiplace chamber as long as NFPA oxygen tension (23.5%) is maintained. If defibrillation is required while the patient is in the monoplace chamber; the chamber first needs to be decompressed. If available, the oxygen supply should be switched to air simultaneously while decompressing to reduce oxygen around the patient’s garments and about the hatch. Remove clothing from the patient before defibrillating to reduce the risk of fire.  


Hyperbaric oxygen therapy is used to treat a number of conditions seen in critically ill patients including carbon monoxide poisoning, crush injuries, acute thermal burns, arterial gas embolism and others. Treating these patients with HBOT requires an understanding of the physiology, as well as the risks and benefits of HBOT. In addition, treating critically ill patients with HBOT requires proper equipment, training, and critical care trained and experienced staff. When the hyperbaric physician combines the aforementioned, safe and effective HBOT can be delivered to critically ill patients.   


Weaver LK. Hyperbaric oxygen in the critically ill. J Crit Care Med 20011. Vol.39:7, 1784-1791 

UHM Section Meeting in San Francisco - Undersea and Hyperbaric Medicine Section Newsletter, September 2011

salogoMake plans to attend the Undersea and Hyperbaric Medicine section meeting at Scientific Assembly in San Francisco on Monday, October 17, 2011, Noon to 2 pm at the Hilton Union Square, Golden Gate 1. 

Come join your colleagues to discuss the issues most pertinent to UHM. 

During the section meeting, elections for Chair-elect, Secretary/Newsletter Editor, and Alternate Councillor will be held. If you have an interest in serving as an officer for the UHM Section, please notify Margaret Montgomery, staff liaison or Tracy LeGros, MD, PhD, FACEP, UHM Section Chair. Nominations from the floor will be accepted at the meeting.

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