Hyperbaric hyperoxia induces a neuromuscular hyperexcitability: assessment of a reduced response in elite oxygen divers

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Nascholing Capita Selecta Duikgeneeskunde, AMC, February 11, 2012

PROGRAMME

Capita Selecta Duikgeneeskunde
Medical aspects of compressed air work at sea level and altitude
A refresher course for physicians of NVAB and NVD and others care professionals.
Date: Saturday February 11, 2012.

Location: Ziedses des Plantes Zaal, B1-120, AMC, Amsterdam.
Chairman: Dr. G.H. Visser, neurologist, chairman Med. Committee Dutch Underwater Federation
8h45 Welcome and registration

9h15-9h20 Dr. N.A.M. Schellart, Opening address.

9h20-9h35 T.P. van Rees Vellinga, MD, Delta Medicine BV and AMC. An introduction to caisson medicine; learned from the past.

9h35-10h05 Dr. N.A.M. Schellart, Assoc. Prof., Biomed Eng & Physics, Decompression theory.

10h05-10h45 J.Cl. Le Péchon, MSc, MEng, JCLP Hyperbarie, Paris, Risk assessment when working under pressure in the dry.

10h45-11h00 Questions and case studies (speaker and participants)

Coffee-tea break

11h15-11h55 Prof. Dr. W. Sterk, Dadcodat, The use of gas mixtures during deep caisson and tunnel labour.

11h55-12h10 Questions and case studies (speaker and participants)

12h10-12h50 J.C. Le Péchon, MSc, MEng, JCLP Hyperbarie Paris, Altitude problems in pressure exposure.

12h50-13h05 Questions and case studies (speaker and participants)

Lunch break

14h00-14h40 Prof. Dr. W. Sterk, Dadcodat, Long (de)compression in caisson and tunnelling work.

14h40-14h55 Questions and case studies (speaker and participants)

14h55-15h35 T.P. van Rees Vellinga, MD, Delta Medicine BV and AMC. The prevention of infections and microbiological hygiene.

15h35-15h50 Questions and case studies (speaker and participants)

Coffee-tea break

16h20-16h50 Examination

16h50-17h15 Evaluation of the examination.

17h15 Closing address and refreshments.

For fees and accreditation see the registration form at the last page.

Accessibility AMC:

By car via highways A9 or A2 (in both directions turn off at Amsterdam Z-O, exit S111/A9) and follow “AMC” road signs. You can park free of charge at one of the parkings without barrier located at the east or west side of the buildings.

By subway: line 50 or 54, direction Gein, get off at Holendrecht. Signs point to AMC

By rail: line Amsterdam-Utrecht, get off at NS station Holendrecht.

After leaving train or metro: AMC is to the right in front of you (it is a 12 min walk to room G4-123.)

Route to room B1-120:

Take the main entrance (clinic), go straight; pass through the main hall and then turn left to the elevators (and stair case) of building B. Go to the first floor and, after leaving the elevator, turn left. You will find B1-120 directly in front of you.

Foreword

The general mission of the “AMC Capita Selecta Duikgeneeskunde”.
The Capita Selecta Duikgeneeskunde, refresher courses in dive medicine, are given by the Academic Medical Centre (AMC), which is a one-board cooperation of the medical faculty of the University of Amsterdam (UvA) and the academic hospital with the UvA. This hospital has a special position amongst the Dutch academic hospitals; it is the seat of the Boerema tank, the cradle, of Dutch and even European hyperbaric medicine.

This new type of refresher courses, offered to all professionals concerned with diving medicine, has a typical ‘Alma Mater’ character.

Primarily, the Capita Selecta of the AMC present comprehensive education in dive and caisson medicine arranged by medical discipline. Additionally, new developments and insights are taught as they occur in the academic hospitals and medical faculties globally. This implies that, in the lessons, the characteristics of disorders are discussed, including their differential diagnostics and treatment, from the point of view of the present academic state of the art.

Resuming, the Capita are marked by a natural mix of education in specific fields of dive medicine and to bring the participants up-to-date with the latest developments in the discipline, for instance in cardiology, ophthalmology etc. Also, the Capita will pay attention to the requirements for the medical examination of the divers.

The Capita are aimed at “basisartsen” (non-specialized physicians), first line physicians, sport- and occupational-physicians, dive and hyperbaric-physicians, clinical doctors and hyperbaric paramedics.

In general, the lecturers are affiliated with academic hospitals and medical faculties, and have an international reputation in patient care. They have experience with academic education, are active in research and have an international reputation as is evident from their papers.

To maintain a low participatory threshold, the venue is easily to reach and centrally located. Moreover the course is set up to be low-budget.
Aim of Caisson and hypobaric medicine

This course aims to offer insight to the dive physician in how to medically supervise caisson and tunneling projects irrespective of the ambient pressure, in such a manner that DCS and other medical risks are minimized. The course can be seen as an advanced refresher course. Therefore having previous knowledge of elementary diving medicine is a distinct advantage, though not an absolute prerequisite.

Responsibility

This refresher course is given under the responsibility of the Academic Medical Centre, Univ. of Amsterdam (Nico Schellart, course director and Tjeerd van Rees Vellinga, adjunct course director and AMC). The organization is undertaken by the Stichting Duik Research (SDR)¹⁾ and Biomedical Engineering & Physics, AMC (Prof. Dr. Ir. A.G.J.M. van Leeuwen, chair).

Accreditation

An application for accreditation will be submitted to the NVD and NVAB, and NDC (under reserve). The content of the course fulfils the requirements of DMAC&EDTC&ECHM 2010.

The program comprises 6.0 of oral contact hours.
More info

More information and the application form can be found at www.duikresearch.org.

¹⁾ SDR is a non-profit organisation aimed to promote dive safety in the widest sense. The SDR is an organisation run exclusively by volunteers.


The Lessons
Tjeerd van Rees Vellinga An introduction to caisson medicine; what we have learned from the past

A comprehensive review is given about the medical history of caisson and tunnelling work with emphasis on what went wrong and the lessons that were drawn from DCS incidents.

Nico Schellart Decompression theory

A quick refresher will be given on the physics (gas laws) and physiology (perfusion and diffusion) of decompression theory and phenomena. Then, models for the assessment of DCS risk and models of venous gas embolism will be discussed. Single phase (Neo-Haldanian; parallel and serial models) and dual phase (gas and liquid) theory will be treated, such as VPM.

Jean-Claude Le Péchon Risk assessment for working under pressure in the dry

Occupational safety precautions should be based on risk assessment. Working in the dry under pressure requires that workers breathe compressed gases in hyperbaric chambers as well as in a pressurized working environment. There are two major sources of danger to cope with. The first relates to the consequences of breathing under pressure and the changes on human physiology this will cause. The second one is dealing with the dangers created by the hyperbaric environment and the tools used in a confined situation that may hamper emergency responses to accident at the worksite. Both these lines are reviewed in a logical order, actual cases will be used to illustrate the safety responses. A set of basic safety rules that can be brought together to ensure safe working conditions is proposed.

Wouter Sterk The use of gas mixtures during deep caisson and tunneling labour

Conventional compressed air work is done to 4 bar (absolute). However, the need for ever deeper caisson and tunnelling work is growing, particularly in our densely populated river deltas. Because of nitrogen narcosis and increasing risks for DCI, alternative gases and gas mixtures have to be used. The use of oxygen, nitrogen, helium and trimix and their limitations will be discussed. Also incidents with tunnelling labour will be discussed.

Jean-Claude Le Péchon Altitude problems in pressure exposure

We consider the environment normobaric when the pressure ranges between 0.1 bar above the local pressure (or 1 m underwater and about 0.1 bar below the standard sea level pressure of 1 bar, or at 1000 m of altitude. The 1 bar (absolute) mark is not a threshold; however it is used as reference for normal living condition for most of humans on Earth. When one needs to live or work at low pressure, specific adaptations and/or procedures are required. When one needs to work under increased pressures, equally specific techniques and precautions must be implemented (see Risk assessment….). When one wants to work at increased pressures from a low pressure environment, all the procedures discussed in the previous lessons need to be revisited. Similarly all these concepts apply to lower pressures than previous exposed to, such as happen with acute mountain sickness, aviation, space exploration and EVA, tunnelling (diving) at altitude or flying after hyperbaric exposure (or after diving). Practical examples of such situations are used to demonstrate the physiological mechanisms involved and to clarify how these issues should be considered when preparing the appropriate working safety rules.

Wouter Sterk Long (de)compression in caisson and tunnelling work

To allow for efficiency, working in compressed air conditions, requires long exposure times. This also means long decompression times and an increased risk of DCS.

Furthermore decompression tables for compressed air work need to be more conservative than for diving. To reduce decompression times and to decrease the risk of DCS, in the last decades the use of oxygen has been introduced. But oxygen too has its limitations. Also, work at even higher pressures needs alternative gas mixtures. Furthermore, modern diving techniques like saturation diving have to be used to enable this work. The pro’s and con’s of “bounce diving” versus saturation techniques will be discussed. Studious cases will be discussed. Some possible late damage to compressed air workers will be mentioned as well.
T. P. van Rees Vellinga The prevention of infections and microbiological hygiene

The DMAC protocol for Saturation Diving Chamber Hygiene will be discussed. This protocol is the basis for chamber hygiene but its scope is too limited as will be made clear. The implementation of ear inspections, swabs and environmental swabs on every third day will be discussed in relation to the prevention and to therapeutic interventions. The extended protocol allows for an early warning system to prevent problems. Cases of own practice and the literature will be discussed.

The lecturers

Jean-Claude Le Péchon graduated as a biochemical engineer from INSA in Lyon in 1963 and as a marine biologist from Nice University. He has been employed at the Musée Océanographique of Monaco as a scientific diver as well as in the Conshelf III Experiment (the undersea habitat sponsored by Jacques-Yves Cousteau). Later he joined CEMA in Marseilles (J.Y. Cousteau) to do research on breathing gases and to develop procedures for very deep dives (1000 m with animals; 500 m with humans) and was a test diver in the Saturation II simulated dive at 400 msw. From 1973 to 1986, he served with CG DORIS, an offshore and civil engineering diving company. In 1986 he founded JCLP Hyperbarie, a global consultancy agency/ bureau specialized in questions related to life support and safety under pressure (commercial diving, tunneling, space and hyperbaric medicine). He has been involved in more than 75 tunneling projects with compressed gas mixtures, up to 6.9 bar and as well as in saturation "diving" technology. Although retired, he is still teaching physiology and the technology of diving- and hyperbaric medicine at several universities in France and all over the world. He is a National Instructor for SCUBA diving (Air, Nitrox and Trimix) and holds a deep sea commercial diver certification since 1974. He has published many papers in magazines, books and international congresses etc., and often speaks at international congresses on different topics concerning diving, hyperbaric medicine and compressed gas work.
T. P. van Rees Vellinga obtained his MD at the Free University of Amsterdam and has specialized in occupational medicine. He is a Dive Physician B (with the National Dive Centre) and has published papers about several medical aspects of caisson and tunneling work. He is research fellow at the Coronel Institute (for Occupational Medicine) of the Academic Medical Centre of the University of Amsterdam. He is president of the Society for Dive Medicine (NVD) and an avid recreational diver. Founder and director of Delta Medicine BV, operating with a hyperbaric chamber in the hospital of Goes.
Nico Schellart received his MSc (c.l.) in Biology at the University of Amsterdam (UvA) and has specialized in physiological biomedical physics. He investigated visual information processing of the retina, resulting in a PhD in 1973 (UvA). He is an associate professor with the dept. of Biomedical Engineering and Physics of the AMC and is currently serving as associate editor of “Medical and Biological Engineering and Computation”. He has investigated multi-sensory information processing in the brain, both animal and human. Since 1998 he lead a research group concerned with basic and clinical EEG and MEG research of the visual and auditory system. He has studied the brain and the visual system under hypoxic and hyperoxic conditions both in the lab and in the field and introduced HBO treatment for patients with cerebral radiation damage. He published these dysbaric and HBOT studies in addition to his neuroscience papers and has contributed to a number of textbooks. He was publisher of a free electronic Textbook on Medical Physics and teaches diving physiology. He has tested the technical and physiological performance of dozens of dive computers (www.duikresearch.org), and is a recreational scuba- and freediver.
Wouter Sterk (1938) obtained his MD at the University of Amsterdam in1966 and joined the Diving Medical Centre of the Royal Dutch Navy until 1975. In 1973 he received a PhD at the University of Utrecht with the thesis entitled: “Respiratory mechanics of diver and diving apparatus”. In 1975 he registered as anesthesiologist after obtaining his training at the Academic Hospital of the University of Utrecht. From 1975 on he is DMO for diving companies, caisson and tunneling projects and director of Dadcodat.

In 1993 he was appointed as Professor in Underwater Physiology at Leiden University. From 1995 to 2009 he was medical director of the Institute for Hyperbaric Medicine with several settlements in the Netherlands and afterwards until 2010 Interim medical director at the DDRC Hyperbaric Medical Centre, Plymouth, UK. Worldwide, he supervised various tunneling projects and is one of the most experienced students of the precordial Doppler technique. He developed the current professional diving tables in use by the Dutch National Dive Center (NDC) and was an enthusiastic recreational diver.