BENDS EXPLAINED: HOW TO PLAN A SAFE DIVE - Hardcover

RUDELL, MD, JEFFREY H.

Hardcover

ISBN 10: 1440153302 ISBN 13: 9781440153303

Verlag: iUniverse, 2009

Inhaltsangabe

Ideas about bends have changed from the concept that a bubble formed in the nervous system or the joint by cavitation-negative pressure. Rapid ascent or joint motion caused the culprit to appear and pressure would make the bubble go away. Now we are treating tissue damage with oxygen. But, we are still using pressure and oxygen to increase the partial pressure of oxygen in the affected tissue. The treatment of choice is the 5 hour long USN Treatment Table 6 which washes out the nitrogen in the tissue and washes in the oxygen. Careful understanding of how my patients got bent and how they responded makes the diver more cautious regarding repetitive diving and a multi-day series of dives. Pressure, the deepest part of the dive washes in the nitrogen over time. Fatty tissue, that includes the central nervous system and peripheral nerves, absorbs more nitrogen than watery tissues such as muscle. Shaping-up to dive includes weight loss, abstinence during the duration of the series of dives, and improving lung function. Physical conditioning such as walking 20 or more minutes a day for several weeks before diving is as important as paying for the trip. Dive accidents sometimes do not have a treatable solution.

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Über die Autorin bzw. den Autor

I attended Bronx Science HS and Columbia College in NYC before attending the University of Louisville School of Medicine. After a Straight Surgical Internship and a year of Neurological Surgery at NY's Mt. Sinai Hospital under Dr. Leonard I. Malis, I served in the USNR and was a Lt. Commander, I was a Fellow at the Cleveland Clinic in Neurology, Neurosurgery and Internal MEdicine. I also completed a year of Internal Medicine residency at Brookdale Medical Center and less than a year of a Nephrology Fellowship at St. Lukes Hospital both in NYC. Andre Galerne appointed me a consultant at the North American Hyperbaric Center.I treated SCUBA diving accidents and a variety of medical conditions in the Iglu which was 20 feet tall with a wet pot in the lower half. It is 10 feet diameter and I have been an inside tender with as many as nine patients at once. The Diver's Alert Network referred most if not all of the patients that I treated for Bends.My intention is to pay tribute to Andre by continuing to serve the diving community with my outlook on diving accidents. As most divers I have had brushes with bends myself. A little insight may help divers recognize bends early and perhaps avoid more serious episodes. For example, if on the third day diving on air to 80-100 fsw one starts vomiting after breakfast it might be a good idea not to dive that day. I relocated to Kissimmee to enjoy a more relaxed retirement and raise Lilian in a country environment. However Poinciana where I live has grown into a city-same zip code. I enjoy movies, outdoor swimming, and my wife's cooking. Her specialty is oatmeal cookies.

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BENDS EXPLAINED

HOW TO PLAN A SAFE DIVEBy JEFFREY H. RUDELL

iUniverse, Inc.

Copyright © 2009 JEFFREY H. RUDELL, MD
All right reserved.
ISBN: 978-1-4401-5330-3

Contents

Introduction: Predict Bends, Decompression Illness, and Avoid An Accident...........................xiChapter 1: Bubbles and Foam.........................................................................1Chapter 2: The Joys of Diving.......................................................................7Chapter 3: Dive Risk Analysis.......................................................................9Chapter 4: Submergence Factors......................................................................11Chapter 5: Causes of the Bends, From Common to Unusual..............................................15Chapter 6: The High Tech Human Submarine............................................................21Chapter 7: 20 Cases of Bends and Analysis...........................................................23Chapter 8: What Are Certifications?.................................................................51Chapter 9: Repetitive Diving........................................................................53Chapter 10: Histories Explained: 40 Episodes That I Evaluated For Recompression.....................63Appendix 1: A Rational Linear Table That Uses Mental Arithmetic.....................................101Appendix 2: Blog Posts..............................................................................103Appendix 3: Problems................................................................................105Appendix 4: Concluding Statements...................................................................108Appendix 5: Reference Materials.....................................................................112Appendix 6: Glosslary of Terms, Abbreviations, and Formulas.........................................114Appendix 7: Hyperbaric Treatment Record.............................................................116Appendix 8: Quiz or Assessment......................................................................117Appendix 9: Photos..................................................................................118Acknowledgements....................................................................................131

Chapter One

BUBBLES AND FOAM

The first requirement for bends to occur is that the diver has to have been breathing a gas that can cause bends, namely nitrogen, under greater pressure than ambient pressure for some time to allow for on-gassing of the tissue (for the tissue to absorb the nitrogen). There has to be some history of a long dive under a substantial amount of pressure or depth. Repetitive dives, more than one a day, or flying (reducing the ambient pressure) are the culprits most often responsible for bends. Deep dives on air have other limiting physiological consequences such as blindness under pressure, increased viscosity of the pressurized air as well as regulator problems interfering with breathing. Increased partial pressures of oxygen constrict the blood vessels nourishing the retina, as well as vessels in the heart and brain. The visual field is narrowed and then disappears at great depths breathing air or another air and nitrogen mix. Nitrogen interferes with sight under high pressures also. Tissue oxygen tension may be directly measured. Tissue nitrogen concentrations are calculated, measured indirectly.

There is usually a history of extreme exertion before, during or after the dive. Other events sometimes noted are rapid ascent, extreme cold, unusual warm temperature, and past surgery at the point of symptoms. In the patient's history, it is often noted that they were aware that something was going on, but the significance of the sensation was not appreciated and it was not considered a bends symptom. Almost always someone other than the diver has helped (or insisted that) the diver request an evaluation for the need for a chamber treatment. Divers show "la belle indifference" or denial of the realization that their internal milieu has changed and that they have gotten bent.

The term "bends" derives from a condition that tunnel workers developed while working 12 hour shifts at 60 fsw; 60fsw multiplied by 0.445 lbs/sq inch/foot of sea water (1.46 lbs/sq in/meter of sea water) or 26.7psi gauge approximates the working pressure of air compressors during the 1860's. Their extremities would be fixed in position and could not be straightened due to bubbles destroying the bone in shoulder, knee, and other joints

Most divers and many insurance companies I have dealt with expect that the diver will know that bends has occurred if there is an ictus such as paralysis of an extremity or sudden blindness on ascent to the surface. Often, if a diver is limping on arrival at the dive boat, it is passed off as a swimmer's cramp, a weight belt shifted and bruised a muscle, or fatigue. The diver may just stand around for a while before taking off their gear, which includes 35 pounds of scrap metal called a SCUBA tank, a twelve pound or more weight belt to compensate for the buoyant wet suit and the buoyancy of the empty air tank, assorted tools, knives, gauges, harnesses, buoyancy compensating vest, et cetera. The buddy's responsibility is to note if the affected diver sort of collapses on sitting down. A diver rarely says that he/she cannot work today despite glassy eyes, inability to concentrate and focus their attention.

An interested observer may only be looking for focal weakness of an extremity and does not grasp the significance of the complaint that concentration on a task is impossible. A diver may complain of pain. Pain is a type one bends complaint and could be ascribed to a muscle pull. Neurological complaints of weakness are considered bends type two. Inability to pay attention and recite their name, address, phone number, date of birth, birth place, and the number of their favorite credit card may not even be assessed. It would be a type two cerebral symptom. Inability to wake up, speak, stand, or answer are more serious bends symptoms that may be due to a subdural hematoma or other injury. Observed bruises and tenderness on deep palpation may suggest a broken bone or organ rupture.

Pneumothorax may be difficult to diagnose right after a dive and should always be considered if the diver has any impairment. I have seen divers who had active pneumonia diagnosed after they went diving. This is a risk factor for pneumothorax and bacterial or air embolism. Divers tend to pass off or rationalize pain as a sprain. I cannot remember any diver that told me that they were off the no-decompression limit of the dive table that they were using. Unfortunately, many divers only learn how to use the tables after they have symptoms of bends, and then they often alter their logs to be in compliance with the tables. Divers try to justify by shaving their depths and times that they were in the safe table limits considering the decompression stops they were supposed to take on ascent. They may count 75fsw as 70 fsw because they were at 70 fsw most of the time.

With a buoyant tank on your back and without an extra six pounds of weight on your belt, decompression stops are impossible to take. Holding onto an anchor line converts the hypotenuse described by the line to the y axis. Straightening the anchor line to a bottom-to-surface line because of your buoyancy is what actually happens. A separate decompression line with a float is better. However, the current also "hypotenuses"...

Details zur Ausgabe

• Verlag: iUniverse
• Erscheinungsdatum: 2009
• Sprache: Englisch
• ISBN 10: 1440153302
• ISBN 13: 9781440153303
• Einband: Gebundene Ausgabe
• Anzahl der Seiten: 148
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: gpsr@libri.de; gpsr@libri.de; ; Europaallee 1; Bad Hersfeld; 36244; Deutschland