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Undersea and Hyperbaric Medicine Section Newsletter - September 2010, Vol, 17, #3


  Undersea and Hyperbaric Medicine

circle_arrow Message from the Chair
circle_arrow Decompression Sickness Case Report
circle_arrow Acute Sensorineural Hearing Loss: Should It be Added to the List of Accepted Indications for Hyperbaric Oxygen Therapy? 
circle_arrow Journal Watch 

Newsletter Index

Hyperbaric Medicine Section

Message from the Chair

Tracy Leigh LeGros, MD, PhD, UHM/ABEM, FACEP
Program Director, LSU Undersea and Hyperbaric Medicine Fellowship 

Greetings!! An exciting new academic year has begun with all the new joys and challenges. Here in New Orleans, we have recently matriculated three outstanding Fellows, and have just welcomed four new Fellows into our Program. These new Fellows have just returned from the NOAA Physician’s Training Course in Diving Medicine in Seattle. Having been inspired, they are very eager and industrious. We hope to maintain this momentum throughout the year! 

  • Undersea and Hyperbaric Medicine Meeting at Scientific Assembly

Please make plans to attend this section meeting at the Scientific Assembly.
Thursday, September 30, 2010
Noon to 2 pm
Room Tradewinds D, Mandalay Bay Resort Casino

Come join your colleagues to discuss the issues most pertinent to UHM. Be sure to check the schedule on-site as meeting times and locations can change. The section will be holding elections for Chair-elect, Secretary/Newsletter Editor, and Alternate Councilor. If you have an interest in serving as an officer, please notify Margaret Montgomery . Nominations from the floor will also be accepted. 

  • More Good News From Our Section

Membership is up!! We now have 172 members. This is up from 136 members a year ago. It should be a wonderful meeting with a lot of things to discuss! 

  • UHMS and ACEP Join Forces to Support UHM Fellowship Training

At the UHMS meeting in St. Petersburg, FL, members of the Undersea and Hyperbaric Medicine Section of ACEP met to discuss the future of the Accreditation Council for Graduate Medical Education (ACGME) accreditation of UHM fellowships. This discussion was initiated by several events. The first event was the soon to be conducted review of the UHM specialty by the Residency Review Committee (RRC) and the American Board of Medical Specialties (ABMS). This review was supposed to be conducted several years ago, but was postponed at the request of the American Board of Emergency Medicine (ABEM) and the American Board of Preventative Medicine (ABPM). The second event was the statement by the Monitoring Committee of the ACGME relating concern about the lack of growth in UHM fellowships. 

To analyze our growth, Dr. Marina Wilder, Dr. Heather Murphy-Lavoie, and myself conducted a year-long survey of the academic hyperbaric medicine landscape. We presented our findings in St. Petersburg in both oral and poster presentations. The results were well received. We were able to show significant growth in our fellowships, as well as tremendous potential.  

The leadership of the UHMS joined forces with our section to develop a proposal in advocacy of UHM Fellowships. This was a huge undertaking that was lead by our immediate past UHMS President (Dr. Laurie Gesell) and Dr. Robert Sanders. These two leaders held discussions with the Executive Director of the RRC, Dr. Lynne Meyer, and laid out a plan for our proposal. Dr. Enoch Huang developed the outline of our proposal, and many hands became involved with the development of our work. The UHM fellowships at Duke, Penn, LSU, and UCSD worked together to assemble an impressive document. The final proposal was a 50 page document that contained all the information Dr. Meyer requested as well as 30 letters (and counting) of support from ACEP, UHMS, AAEM, the Surgeon General of the Navy, The Canadian Military Forces, the Surgeon General of the Air Force, and many letters of support from around the country from institutions.  

This packet will be reviewed by the RRC board at their annual meeting this September, and our proposal will be reviewed. If any of you have plans to start a UHM fellowship and have not yet submitted a letter of intent to the RRC, please do so ASAP. If you need assistance, I would be happy to send you a template letter and ensure that your letter gets to the correct place. 

  • Fellowship Forms, Surveys, and Evaluations Available

If any of you need assistance with the ACGME application process for fellowship development, I am happy to share our documents with you. It is easy enough to download the program information form (PIF), a labor intensive form required by all ACGME accredited programs. However, it is quite another thing to stay on top of the serial evaluations required to run a fellowship. In an effort to ease this load, for all programs, but especially the new ones, our fellowship in New Orleans is making our guidelines and forms available to all. They are in word format. The forms available to you will include: patient satisfaction surveys, multiple fellow evaluations (inclusive of duty hours and all the core competencies), multiple attending evaluations, rotation evaluations, multiple ways to continually monitor and assess your fellowship as a whole, and even ways to measure the effectiveness of your program director. An updated PIF from our institution will be made available to new programs, as well as tips to help any new program navigate these academic waters.  

  • Undersea and Hyperbaric Medicine Board Examination Review Courses

Two board review courses were offered again this year. There was a one day course available in San Antonio. The faculty are nationally known for their exemplary lecturing skills and this course is always well received. Additionally, there was a three day course available in Philadelphia. It was presented by hyperbaric medicine faculty from the University of Pennsylvania, USCD, Ohio State, LSU, and Syracuse. It has also been very well received. This examination can be difficult; however, following the institution of these courses last year, the pass rates improved dramatically. 

  • Monthly Diving Medicine Conference Update

There are monthly diving medical video conferences that fellowships from around the country (Duke, San Diego, Hennepin, U Penn, San Antonio, and LSU) have been partaking in during the previous year. They occur on the first Wednesday of each month, at 4 pm central standard time. If you are interested in starting a fellowship or enhancing your staff’s knowledge of diving medicine, feel free to tune in. Please email me and I will have you put on the email list.  

  • Congratulations to Our Newest fellowship!

Please join me in congratulating SUNY Syracuse on their new ACGME accredited fellowship program. Interested parties may contact Marvin Heyboer at (315) 464-4363. Also, congratulations to Brooks AFB UHM fellowship for completing the ACGME application process and site visit, official approval is pending.

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Decompression Sickness Case Report

Robert W. Sanders, MD
Assistant Clinical Professor
University of Hawaii at Manoa
John A Burns School of Medicine
Hyperbaric Center, Honolulu, Hawaii


Decompression sickness (DCS) is often a delayed diagnosis; adversely affecting outcomes. We present a case where suspicion and emergency department (ED) access ensured prompt recompression and a favorable outcome. The presenting complaints, however, mimic several life-threatening maladies that require timely workups.  

The Case:

A 55 year-old experienced diver presented to the ED via USCG helicopter with a chief complaint of severe abdominal pain. The patient made five dives to 90 - 95 feet of salt water (fsw). As this was his “routine,” he was unsure of dive times or surface intervals. Traditionally he dives “until [his] shoulder hurts,” and then stops. On this day, however, after the 5th dive, he began to experience a rapid onset of severe abdominal pain and “coldness.” The local 911 was called and paramedics were dispatched, but the patient seemed to rapidly worsen, so the Coast Guard was called. The patient was air-lifted directly from the boat, and flown to our facility.  

In the ED, the patient was found to be hypotensive (61/39) and complaining of abdominal pain and weakness. He had diffuse abdominal tenderness, cold extremities, and slowed mentation. The initial workup included an EKG showing ST elevations, S wave in lead I, Q wave and inverted T wave in lead III. The chest x-ray and laboratory studies were unremarkable. 

The Differential Diagnosis:

The presentation of abdominal pain, hypotension and ST-elevation in a 55 y/o male is concerning for aortic dissection, ruptured aortic aneurysm, pulmonary embolus (PE) and/or heart attack (MI), all of which are emergent and life threatening. As hyperbaric physicians we also included DCS in the differential for this patient based on the dive history alone.

click image for larger view



Resuscitation was begun immediately. Because of the emergent nature of these maladies, rapid diagnosis and treatment is essential. Though the history is concerning for DCS, the other issues must be “ruled-out” to ensure safe treatment. Cardiac Echo was performed at the bedside; with no wall motion abnormalities, and normal filling. The diagnoses of MI and PE become less likely. The patient was then rushed to the CT scanner for CT angiogram of the chest abdomen and pelvis. Thought to be rarely indicated in the diagnosis of DCS (Carson 2005), there are times when CT scanning is the gold standard.



These images show cuts through the liver, 
notice gas bubbles in the left lobe, and post
treatment resolution.





These images show cuts through the mid
abdomen, notice the 7cm gas bubble in the
mesenteric vasculature, and post treatment





These images show cuts through the pelvis,
notice gas bubbles in the bladder wall &
acetabulum, and post treatment resolution.





These images show cuts through the femurs, 
notice gas bubbles in the bone marrow, and
post treatment resolution.



The Outcome:

The patient was transferred emergently to the Hyperbaric Treatment Center where he was treated on a Treatment Table 60 (TT60) with extensions (comparable to USN Table 6). Because of hemodynamic instability, his blood pressure required the use of Dopamine. Diving any deeper would have been unsafe. After the first dive, the patient’s abdominal pain was significantly improved, but he was still complaining of weakness, boring leg pain, and unsteady gait. 

The patient was treated daily with TT60s and remained in the ICU for an additional 48 hours. After the 3rd treatment, the patient had complete recovery from the diving issues, and was downgraded from the ICU. On day 3, however, he developed gastrointestinal bleeding, recovered, and was discharged home on day 5. At two-month follow-up, the patient had a normal colonoscopy, was back to free diving, but not scuba diving. 


Though CT scanning is rarely indicated in the diagnosis of DCS, there are times, however, when it can prove useful and even diagnostic, speeding transfer to the recompression chamber. This modality should remain in the arsenal of the hyperbaric physician.


Carson WK, Mecklenburg B. The role of radiology in dive-related disorders. Mil Med. 2005 Jan;170(1):57-62.

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Acute Sensorineural Hearing Loss: Should It be Added to the List of Accepted Indications for Hyperbaric Oxygen Therapy?

Heather Murphy-Lavoie, MD

Acute sensorineural hearing loss is defined as a loss of 30 decibels (dB) hearing in more than 3 contiguous frequencies for more than 3 days. It is a syndrome, not a diagnosis, with a wide variety of etiologies, but usually it is idiopathic. The incidence is somewhere between 5 - 20/100,000 persons annually, with a peak incidence in the 6th decade of life. The significance of a 30 dB hearing loss is the 25 - 40% of missed speech that occurs with a loss of this magnitude.  

The most common presentation is that of a patient noticing a unilateral hearing loss upon awakening. Tinnitus is present in varying degrees and may precede the hearing loss. Associated aural fullness is common and vertigo is present in approximately 40% of cases. Standard treatment for this syndrome includes treatment of any identified underlying cause, oral steroids, vasodilators and diuretics. Complete spontaneous recovery rates range from 32% - 65%. Vertigo and tinnitus correspond with a worse prognosis. 

Experimental studies have shown that perilymph oxygen partial pressures are reduced with sensorineural hearing loss. Therefore, the final goal of any treatment modality should be the restoration of oxygen tension in the cochlea. This is the basis for the theory that hyperbaric oxygen (HBOT) may be of benefit for these patients. 

As of 2007, when the Cochran Database Review was conducted on the use of "Hyperbaric Oxygen for Idiopathic Sudden Sensorineural Hearing Loss and Tinnitus", six randomized controlled trials had been published (308 subjects). Pooled data from two of these trials involving 114 patients showed a significantly increased chance of a 25% increase in the pure tone average (PTA) when HBOT was used. There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was five (95% CI 3 to 20). A single trial involving 50 subjects also suggested significantly more improvement in the mean PTA threshold with HBOT. The significance of any improvement following HBOT in a subjective rating of tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study that examined chronic presentations (six months) of idiopathic sensineural hearing loss (ISSHL) and/or tinnitus.  

The authors therefore concluded: “For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear.” This is curious conclusion since the clinical significance of the decibel scale has been quite clearly defined. 

The degree of improvement in dB in the above studies ranged from 22 - 39dB when HBOT use was compared to controls. After treatment, the controls were in the 50 - 60dB range and the HBOT groups were in the 20 - 30dB range. This is quite an important difference. 

The decibel scale is logarithmic. Every 10 dB increase in sound intensity is actually a ten-fold increase. The zero is not the absence of sound, but the lowest intensity that the normal sensitive ear can hear. A sound intensity of 20 dB is not twice as loud as a sound intensity of 10 dB, but is 10 times as loud; a sound intensity of 30 dB is 100 times as loud as a sound intensity of 10 dB. 

Normal hearing                     -10 to 15 dB
Slight hearing loss 16 to 25 dB
Mild hearing loss 26 to 40 dB
Moderate hearing loss 41 to 55 dB
Moderately severe loss 56 to 70 dB
Severe hearing loss 71 to 90 dB
Profound hearing loss 91 to 120 dB
Deaf below 120 dB

Since the Cochrane review, three additional controlled trials have been published, all of which have shown positive results. It seems there is adequate data to warrant reassessment of this syndrome to see if it should be added to the list of accepted indications for hyperbaric oxygen therapy.


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Journal Watch

Jawad Kassem, MD

Londahl M, Nilsson A, Katzman P, et al. Hyperbaric oxygen therapy facilitates healing of chronic foot ulcers in patients with diabetes. Diabetes Care. 2010; 33: 998-1003. 

Diabetic foot ulcers are a common and serious complication of diabetes that cause a significant amount of morbidity, and tax both the patient and the healthcare system alike. These wounds are difficult to heal. Centers of excellence report 19-35% of these wounds as non-healing.  

Hyperbaric oxygen therapy (HBO) is known to have antimicrobial effects, increase oxygenation of hypoxic wounds, enhance neutrophil killing, stimulate angiogenesis as well as fibroblast activity and collagen synthesis. As such, HBO was studied as an adjunctive treatment for these wounds in a number of small studies. Despite the reported success, the Cochrane Collaboration reviewed the topic and found a need for further study, particularly large, randomized, placebo-controlled trials.  

This study is a large, randomized, double-blinded, placebo-controlled clinical trial. The study looks at the potential benefit of hyperbaric oxygen therapy (HBO) as an adjunct to standard therapy in patients with chronic (>3 months) non-healing diabetic ulcers (Wagner Grade 2, 3, 4). All patients were diabetics that did not respond to standard therapy for over 2 months. All patients were assessed by a vascular surgeon and only patients with adequate perfusion were enrolled. There were no significant differences between the placebo or treatment group in terms of over 60 factors including age, smoking, hemoglobin A1c, medications, co-morbidities, ulcer size/location, peripheral circulation. 

 Wagner Ulcer Grading System 

Grade 1: Superficial Diabetic Ulcer
Grade 2: Ulcer extension
  • Involves ligament, tendon, joint capsule or fascia
  • No abscess or osteomyelitis 

Grade 3: Deep ulcer with abscess or osteomyelitis
Grade 4: Gangrene to portion of forefoot


The primary end point was healing of the index ulcer, the ulcer with the largest area and duration of at least 3 months. Healing was defined as complete coverage with epithelium. Intention to treat analysis (evaluating all comers whether or not they finished the protocol) showed complete healing in 25/48 (52%) of patients in the HBO group and 12/42 (29%) in the placebo group (P = 0.03). Per protocol (those patients that completed the course of HBO as intended) analysis showed complete healing in 23/38 (61%) in HBO group and 10/37 (27%) in the control group. The numbers needed to treat to heal a chronic foot ulcer were 4.2 and 3.1 according to the intention to treat and per-protocol analysis, respectively.

No patients suffered from oxygen toxicity, seizure or pneumothorax. Two patients in each group required myringotomy tubes. Two and four patients, in the HBO and placebo groups respectively, became hypoglycemic. There were four deaths, three in the placebo group and one in the HBO group (an 87 year old with comorbidities including myocardial infarction and heart failure). 

Capsule summary  

This large, randomized, double-blinded, placebo controlled study evaluated the use of HBO in the treatment of diabetic foot ulcers that were Wagner grade 2, 3, 4. Their results showed a statistically significant difference between those receiving HBO and those receiving placebo in terms of the primary endpoint, the healing of the index ulcer. There was no significant difference in adverse events in either group. This study gives further credence to what others have shown – HBO hastens the healing of diabetic foot ulcers and is a safe and effective adjunctive medical therapy.  

How this may change your practice   

This may change your practice in two important ways. First, the dive profile in this study may be different from the one used at your institution and therefore, one may consider changing to the profile described in the literature. Second, this study was the first to look at HBO as an adjunct in Wagner grade 2 ulcers, which currently do not meet criteria for treatment with HBO. The research showed a statistically significant difference in the healing of Wagner grade 2 ulcers treated with HBO when compared to placebo.

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This publication is designed to promote communication among emergency physicians of a basic informational nature only. While ACEP provides the support necessary for these newsletters to be produced, the content is provided by volunteers and is in no way an official ACEP communication. ACEP makes no representations as to the content of this newsletter and does not necessarily endorse the specific content or positions contained therein. ACEP does not purport to provide medical, legal, business, or any other professional guidance in this publication. If expert assistance is needed, the services of a competent professional should be sought. ACEP expressly disclaims all liability in respect to the content, positions, or actions taken or not taken based on any or all the contents of this newsletter.

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