Simon Mitchell

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Simon Mitchell returns from the 2002 world record dive to the wreck of the SS Kyogle. The dive re-opened the file on the AHS Centaur Simon Mitchell.jpg
Simon Mitchell returns from the 2002 world record dive to the wreck of the SS Kyogle. The dive re-opened the file on the AHS Centaur

Simon Mitchell (born 1958) is a New Zealand physician specialising in occupational medicine, hyperbaric medicine and anesthesiology. [1] Trained in medicine, Mitchell was awarded a PhD for his work on neuroprotection from embolic brain injury. [2] Mitchell has also published more than 45 research and review papers in the medical literature. [3] Mitchell is an author and avid technical diver. He also wrote two chapters of the latest edition of Bennett and Elliott's Physiology and Medicine of Diving, is the co-author of the diving textbook Deeper Into Diving with John Lippmann and co-authored the chapter on Diving and Hyperbaric Medicine in Harrison's Principles of Internal Medicine with Michael Bennett. [4] [5] [6] [7]

Contents

Background

Mitchell received a Bachelor of Human Biology (BHB) in 1988 and later a Bachelor of Medicine and Bachelor of Surgery (MB ChB) in 1990 from the University of Auckland. In 2001, he received a Diploma in Occupational Medicine (DipOccMed) from the South Pacific Underwater Medicine Society. Mitchell then went on to complete a Doctor of Philosophy in Medicine (PhD) in 2001 [8] and Diploma in Diving and Hyperbaric Medicine (DipDHM) in 1995 from the University of Auckland. Mitchell received his Australian and New Zealand College of Anaesthetists (ANZCA) Certificate in Diving and Hyperbaric Medicine in 2003, and became a Fellow of the Australian and New Zealand College of Anaesthetists (FANZCA) in 2008. [1] He is currently Associate Professor of Anaesthesiology and Head of the Department of Anaesthesiology at the University of Auckland.

Mitchell is a former vice president of the Undersea and Hyperbaric Medical Society (UHMS) and currently serves as the chairman of the organisation's diving committee. [9] He became a Fellow of The Explorers Club of New York in 2006. [10]

Mitchell has dual Australian and New Zealand citizenship. He lives in Auckland, New Zealand, with his wife Siân. [3]

In 2010, Mitchell was awarded the Albert R. Behnke Award by the UHMS for his outstanding scientific contributions to advances in undersea biomedical activity. [11]

On 23 August 2017 Mitchell delivered his inaugural lecture (as a full professor) [12] at the Grafton Campus, Auckland, New Zealand.

Diving

Mitchell began diving in 1972. [3] His diving primarily involves the use of rebreather technology to explore shipwrecks at extreme depths. [3]

Mitchell was a member of "The Sydney Project" in 2004 and located the letters U, M, and E that helped with the positive identification of the SS Cumberland. [13] In 2007, Mitchell and Pete Mesley were responsible for identification of the Port Kembla including recovery of the ship's bell. [14] Mitchell attempted to recover a Robinson 22 helicopter engine from the poor underwater visibility of Lake Wānaka for use in the Transport Accident Investigation Commission investigation of the death of Morgan Saxton. [15] [16]

AHS Centaur

AHS Centaur was a hospital ship which was attacked and sunk by a Japanese submarine off the coast of Queensland, Australia, on 14 May 1943. Of the 332 medical personnel and civilian crew aboard, 268 were killed. Following World War II, several searches of the waters around North Stradbroke and Moreton Islands failed to reveal Centaur’s location. It was believed that she had sunk off the edge of the continental shelf, to a depth the Royal Australian Navy did not, and still does not, have the capability to search for a vessel of Centaur’s size. [17]

In 1995, it was announced that the shipwreck of Centaur had been located in waters 9 nautical miles (17 km) from the lighthouse on Moreton Island, a significant distance from her believed last position. [18] [19] The finding was reported on A Current Affair , during which footage of the shipwreck, 170 metres (560 ft) underwater, was shown. [18] Discoverer Donald Dennis claimed the identity of the shipwreck had been confirmed by the Navy, the Queensland Maritime Museum, and the Australian War Memorial. [18] A cursory search by the Navy confirmed that there was a shipwreck at the given location, which was gazetted as a war grave and added to navigation charts by the Australian Hydrographic Office. [17] [18]

Over the next eight years, there was growing doubt about the position of Dennis' wreck, due to the distance from both Second Officer Rippon's calculation of the point of sinking and where USS Mugford found the survivors. [20] During this time, Dennis had been convicted on two counts of deception and one of theft through scams. [20] Two wreck divers, Trevor Jackson and Simon Mitchell, used the location for a four-hour world record dive on 14 May 2002, during which they examined the wreck and took measurements, claiming that the ship was too small to be Centaur. [21] Jackson had been studying Centaur for some time, and believed that the wreck was actually another, much smaller ship, the 55-metre (180 ft) long MV Kyogle, a lime freighter purchased by the Royal Australian Air Force and sunk during bombing practice on 12 May 1951. [18] [21] The facts gathered on the dive were inconclusive, but the divers remained adamant it was not Centaur, and passed this information onto Nick Greenaway, producer of the newsmagazine show 60 Minutes . [21]

On the 60th anniversary of the sinking, 60 Minutes ran a story demonstrating that the wreck was not Centaur. [18] It was revealed that nobody at the Queensland Maritime Museum had yet seen Dennis' footage, and when it was shown to Museum president Rod McLeod and maritime historian John Foley, they stated that the shipwreck could not be Centaur, as the rudder was incorrectly shaped. [18] Following this story, and others published around the same time in newspapers, the Navy sent three ships to inspect the site over a two-month period; HMA Ships Hawkesbury, Melville, and Yarra, before concluding that the shipwreck was incorrectly identified as Centaur. [17] An amendment was made to the gazettal, and the Hydrographic Office began to remove the mark from charts. [17]

In April 2008, following the discovery of HMAS Sydney, several parties began calling for a dedicated search for Centaur. [22] By the end of 2008, the Australian Federal and Queensland State governments had formed a joint committee and contributed $2 million each towards a search, and by February 2009, the tender for the project had received eleven expressions of interest. [23] [24]

Awards

In 2015, Mitchell was awarded a Bravo award by the New Zealand Skeptics for his rebuttal of claims in a The New Zealand Herald article about a Hyperbaric machine entitled ”Hope is in the air: Hyperbaric chambers – the real deal or a placebo?. [25]

Related Research Articles

<span class="mw-page-title-main">Nitrogen narcosis</span> Reversible narcotic effects of respiratory nitrogen at elevated partial pressures

Narcosis while diving is a reversible alteration in consciousness that occurs while diving at depth. It is caused by the anesthetic effect of certain gases at high partial pressure. The Greek word νάρκωσις (narkōsis), "the act of making numb", is derived from νάρκη (narkē), "numbness, torpor", a term used by Homer and Hippocrates. Narcosis produces a state similar to drunkenness, or nitrous oxide inhalation. It can occur during shallow dives, but does not usually become noticeable at depths less than 30 metres (98 ft).

<span class="mw-page-title-main">Decompression sickness</span> Disorder caused by dissolved gases forming bubbles in tissues

Decompression sickness is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompression. DCS most commonly occurs during or soon after a decompression ascent from underwater diving, but can also result from other causes of depressurisation, such as emerging from a caisson, decompression from saturation, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness.

<span class="mw-page-title-main">Hyperbaric medicine</span> Medical treatment at raised ambient pressure

Hyperbaric medicine is medical treatment in which an increase in barometric pressure over ambient pressure is employed increasing the partial pressures of all gases present in the ambient atmosphere. The immediate effects include reducing the size of gas embolisms and raising the partial pressures of all gases present according to Henry's law. Currently, there are two types of hyperbaric medicine depending on the gases compressed, hyperbaric air and hyperbaric oxygen.

<span class="mw-page-title-main">Oxygen toxicity</span> Toxic effects of breathing oxygen at high partial pressures

Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures. Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lungs, and eyes. Historically, the central nervous system condition was called the Paul Bert effect, and the pulmonary condition the Lorrain Smith effect, after the researchers who pioneered the discoveries and descriptions in the late 19th century. Oxygen toxicity is a concern for underwater divers, those on high concentrations of supplemental oxygen, and those undergoing hyperbaric oxygen therapy.

In-water recompression (IWR) or underwater oxygen treatment is the emergency treatment of decompression sickness (DCS) by returning the diver underwater to help the gas bubbles in the tissues, which are causing the symptoms, to resolve. It is a procedure that exposes the diver to significant risk which should be compared with the risk associated with the available options and balanced against the probable benefits. Some authorities recommend that it is only to be used when the time to travel to the nearest recompression chamber is too long to save the victim's life; others take a more pragmatic approach and accept that in some circumstances IWR is the best available option. The risks may not be justified for case of mild symptoms likely to resolve spontaneously, or for cases where the diver is likely to be unsafe in the water, but in-water recompression may be justified in cases where severe outcomes are likely if not recompressed, if conducted by a competent and suitably equipped team.

<span class="mw-page-title-main">Diving medicine</span> Diagnosis, treatment and prevention of disorders caused by underwater diving

Diving medicine, also called undersea and hyperbaric medicine (UHB), is the diagnosis, treatment and prevention of conditions caused by humans entering the undersea environment. It includes the effects on the body of pressure on gases, the diagnosis and treatment of conditions caused by marine hazards and how aspects of a diver's fitness to dive affect the diver's safety. Diving medical practitioners are also expected to be competent in the examination of divers and potential divers to determine fitness to dive.

Rubicon Foundation, Inc. is a non-profit organization devoted to contributing to the interdependent dynamic between research, exploration, science and education. The foundation, started in 2002, is located in Durham, North Carolina and is primarily supported by donations and grants. Funding has included the Office of Naval Research from 2008 to 2010. Gibson, Dunn & Crutcher has provided pro bono services to assist in copyright searches and support.

The Undersea and Hyperbaric Medical Society (UHMS) is an organization based in the US which supports research on matters of hyperbaric medicine and physiology, and provides a certificate of added qualification for physicians with an unrestricted license to practice medicine and for limited licensed practitioners, at the completion of the Program for Advanced Training in Hyperbaric Medicine. They support an extensive library and are a primary source of information for diving and hyperbaric medicine physiology worldwide.

In physiology, isobaric counterdiffusion (ICD) is the diffusion of different gases into and out of tissues while under a constant ambient pressure, after a change of gas composition, and the physiological effects of this phenomenon. The term inert gas counterdiffusion is sometimes used as a synonym, but can also be applied to situations where the ambient pressure changes. It has relevance in mixed gas diving and anesthesiology.

Hydrox, a gas mixture of hydrogen and oxygen, is occasionally used as an experimental breathing gas in very deep diving. It allows divers to descend several hundred metres. Hydrox has been used experimentally in surface supplied, saturation, and scuba diving, both on open circuit and with closed circuit rebreathers.

<span class="mw-page-title-main">Decompression (diving)</span> Pressure reduction and its effects during ascent from depth

The decompression of a diver is the reduction in ambient pressure experienced during ascent from depth. It is also the process of elimination of dissolved inert gases from the diver's body which accumulate during ascent, largely during pauses in the ascent known as decompression stops, and after surfacing, until the gas concentrations reach equilibrium. Divers breathing gas at ambient pressure need to ascend at a rate determined by their exposure to pressure and the breathing gas in use. A diver who only breathes gas at atmospheric pressure when free-diving or snorkelling will not usually need to decompress. Divers using an atmospheric diving suit do not need to decompress as they are never exposed to high ambient pressure.

<span class="mw-page-title-main">Robert William Hamilton Jr.</span> American physiologist and researcher in hyperbaric physiology.

Robert William Hamilton Jr., known as Bill, was an American physiologist known for his work in hyperbaric physiology.

<span class="mw-page-title-main">Gene Hobbs</span> American technical diver and co-founder of the Rubicon Foundation

Eugene Weston Hobbs II, known as Gene Hobbs is an American technical diver and founding board member of the non-profit Rubicon Foundation. Hobbs has served as medical officer for the Woodville Karst Plain Project since 2004 and was named the 2010 Divers Alert Network/ Rolex Diver of the year. Hobbs was a hyperbaric technologist and simulation coordinator at Duke Medical Center before taking a position as the Director of Simulation for the University of North Carolina School of Medicine and Clinical Instructor in the Department of Pediatrics. As of 2018, Hobbs is the business manager for the UNC Health Care Department of Neurosurgery.

<span class="mw-page-title-main">Neal W. Pollock</span> Canadian researcher in diving physiology and hyperbaric medicine

Neal Pollock is a Canadian academic and diver. Born in Edmonton, Canada he completed a bachelor's degree in zoology; the first three years at University of Alberta and the final year at the University of British Columbia. After completing a master's degree he then served as diving officer at University of British Columbia for almost five years. He then moved to Florida and completed a doctorate in exercise physiology/environmental physiology at Florida State University.

Richard Deimel Vann is an American academic and diver.

Inner ear decompression sickness, (IEDCS) or audiovestibular decompression sickness is a medical condition of the inner ear caused by the formation of gas bubbles in the tissues or blood vessels of the inner ear. Generally referred to as a form of decompression sickness, it can also occur at constant pressure due to inert gas counterdiffusion effects.

The US Navy has used several decompression models from which their published decompression tables and authorized diving computer algorithms have been derived. The original C&R tables used a classic multiple independent parallel compartment model based on the work of J.S.Haldane in England in the early 20th century, using a critical ratio exponential ingassing and outgassing model. Later they were modified by O.D. Yarborough and published in 1937. A version developed by Des Granges was published in 1956. Further developments by M.W. Goodman and Robert D. Workman using a critical supersaturation approach to incorporate M-values, and expressed as an algorithm suitable for programming were published in 1965, and later again a significantly different model, the VVAL 18 exponential/linear model was developed by Edward D. Thalmann, using an exponential ingassing model and a combined exponential and linear outgassing model, which was further developed by Gerth and Doolette and published in Revision 6 of the US Navy Diving Manual as the 2008 tables.

References

  1. 1 2 Mitchell, Simon J. "Simon Mitchell Curriculum vitae" (PDF). Archived from the original (PDF) on 23 July 2011. Retrieved 15 June 2011.
  2. ↑ Mitchell, Simon J. (2000), Prevention of brain injury in cardiac surgery (PhD), ResearchSpace@Auckland, hdl:2292/6028, Wikidata   Q111963965
  3. 1 2 3 4 "Dr Simon Mitchell". Eurotek Diving Technologies Conference. 2008. Archived from the original on 15 November 2009. Retrieved 15 September 2009.
  4. ↑ Lippmann, John; Mitchell, Simon (2005). Deeper into Diving (2nd ed.). Victoria, Australia: J.L. Publications. p. 5. ISBN   0-9752290-1-X. OCLC   66524750.
  5. ↑ James, T; Francis, R.; Mitchell, Simon (2003). "Pathophysiology of Decompression Sickness". In Brubakk, Alf O.; Neuman, Tom S (eds.). Bennett and Elliott's physiology and medicine of diving (5th ed.). United States: Saunders Ltd. pp. 530–56. ISBN   0-7020-2571-2. OCLC   51607923.
  6. ↑ James, T; Francis, R; Mitchell, Simon (2003). "Manifestations of Decompression Disorders". In Brubakk, Alf O.; Neuman, Tom S (eds.). Bennett and Elliott's physiology and medicine of diving (5th ed.). United States: Saunders Ltd. pp. 578–99. ISBN   0-7020-2571-2. OCLC   51607923.
  7. ↑ "Hyperbaric and Diving Medicine | Clinical Gate". clinicalgate.com. Retrieved 11 December 2015.
  8. ↑ Mitchell, Simon (2000). Prevention of brain injury in cardiac surgery (Doctoral thesis). ResearchSpace@Auckland, University of Auckland. hdl:2292/6028.
  9. ↑ "UHMS committees". Undersea and Hyperbaric Medical Society. Archived from the original on 9 May 2008. Retrieved 16 August 2009.
  10. ↑ "Simon Mitchell". Australian & New Zealand chapter of The Explorers Club. Archived from the original on 4 September 2011. Retrieved 24 August 2009.
  11. ↑ "UHMS Monthly Updates to our Members - June 2010". Undersea and Hyperbaric Medical Society. Retrieved 9 November 2010.[ permanent dead link ]
  12. ↑ "Bursting bubbles. How a recreational passion drove an academic career". The Underwater Marketing Company.
  13. ↑ Spencer, Mark. "The story of the Cumberland: Wartime piracy and deep water salvage" (PDF). Sport Diving Magazine. Archived from the original (PDF) on 23 July 2011. Retrieved 16 August 2009.
  14. ↑ "Diving in NZ WWI shipwreck Port Kembla". tv3.co.nz. Retrieved 16 August 2009.
  15. ↑ Cook, Marjorie (2 June 2009). "Murky water hampers search for engine". Otago Daily Times. Retrieved 24 August 2009.
  16. ↑ Cook, Marjorie (6 June 2009). "Lake dive for engine just another day at the office". Otago Daily Times. Retrieved 24 August 2009.
  17. 1 2 3 4 Department of Defence, Navy findings of search for ex Army Hospital Ship (AHS) Centaur
  18. 1 2 3 4 5 6 7 Richard Carleton (reporter) (18 May 2003). "A Grave Mistake". 60 Minutes. Nine Network.
  19. ↑ "Transcript: A Grave Mistake". Ninemsn.com.au - 60 Minutes Archive. 2003. Archived from the original on 28 August 2006. Retrieved 2 June 2009.
  20. 1 2 Wilson, Neil (10 May 2003). "Sunken hearts". Herald Sun. News Corporation. pp. 23–24 (Saturday liftout).
  21. 1 2 3 Jackson, Trevor (2007). Wreck Diving in Southern Queensland. Brisbane, QLD: Lulu. pp. 157–81.
  22. ↑ Dart, Shipwreck hunter offers to find Centaur remains
  23. ↑ Crutcher, Michael (7 December 2008). "Let Aussie shipwreck hunters find the Centaur". The Courier Mail. News Corporation. Archived from the original on 19 May 2009. Retrieved 2 June 2009.
  24. ↑ Atkinson, Bruce (18 February 2009). "Companies show interest in Centaur search". ABC Brisbane. Retrieved 2 June 2009.
  25. ↑ "Bravo Awards". New Zealand Skeptics. Retrieved 7 November 2016.

Bibliography

Works

Refereed journal articles
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