BENDS IS NOT A DIRTY WORD A Practical Look at Decompression Illness Joel Silverstein, VP COO Tech Diving Limited Scuba Training and Technology Inc.

We will explore…. What is The Bends? Myths Emotional Issues DCI Signs and Symptoms Treatment Delays Incident Management How Recompression Works Treatment Schedules Bends Prevention Training

What is The Bends? It is the syndrome of joint pain, numbness, paralysis and other symptoms caused by the release of gas dissolved in tissues, which forms bubbles in the blood upon surfacing after a scuba dive. Bubbles forming in tissues near joints cause the pain of classical “bends.” When high levels of bubble formation occur, complex reactions take place, which can cause other symptoms.

History 1870s - “caisson workers” would stoop over at the end of the day after working on the footings of the Brooklyn Bridge It got named “the bends” after the Grecian Bend, a fashion style of the times

Bends in diving was not recognized until the late 1800’s when a diving company was doing salvage work on the HMS Rhone in the BVI in 90 feet of water. J.S. Haldane was enlisted by the British Royal Navy to help solve this problem. Haldane’s work lead to modern day decompression theory. Today not only do we use Haldane’s theories of compartments but bubble models as well.

When does the Bends show up? Symptoms and signs can appear within 5 minutes to 48 hours after surfacing from any compressed gas dive. Severe cases can show symptoms “in-water” or immediately upon surfacing.

Who is thought to be a “Bent Diver?” Divers who exceed no-stop limits Deep divers Cold water divers Inexperienced divers Divers with “risky” profiles “Stupid” divers “Bad” divers

Sources of Myths Instructors Poor Press Coverage Retailers Resort Operators Medical Personnel Training Agencies Poor Press Coverage Peer Pressure Uninformed Divers Divers In Denial

CITY ISLAND CHAMBER 1994-1995 STATISTICS 0 % Technical Diver 17% > than 130 fsw 17% No Timing Device 41% Multi-day Trips 48% Caribbean/Mexico 52% Fly < 24 hrs. after diving 42% No Safety Stops 52% Computer Users 55% < 100 fsw 79% Repetitive Diving 79% No-Stop Dives Note: CIC is no longer in operation. Population n = 45 divers

What the Statistics Mean Of divers who required treatment, most of the dive profiles themselves should not have warranted treatment. However, neurological examinations showed significant deficits which required treatment. Most divers who required treatment believed that they were “within tables” but were really way off the required table times. Divers who dive often and have additional training are better prepared to prevent DCI.

DCI Treated Cases ‘87-’99

Emotional Issues Divers Face Anxiety Shame Humiliation Guilt Incompetence Fear of treatment Fear of inability to dive again Real concern for their physical well-being

Diver Denial “The diver may mobilize defenses and engage in behaviors that temporarily ease the psychological burden.” Jennifer C. Hunt, Ph.D. aquaCorps, N5

Injured Diver’s First Reactions “Not me, I’m a good diver.” “Only bad divers get bent.” “It’s only a sprain.” “I probably have the flu.” “I’m just tired.” “I’m within the tables.” “My computer says I’m O.K.” “I didn’t want to ruin the trip.”

Secondary Reactions “Maybe I am hurt.” “It will probably go away.” “I don’t want to go to a chamber.” “Can I afford treatment?” “Am I insured?” “If I am bent can I ever dive again?” “I’m probably not bent.”

DCI Signs and Symptoms Disorientation Dizziness Fatigue Hearing Difficulties Muscle Pain Numbness Joint Pain Paralysis Skin Rash Slurred Speech Agitation Tingling Vision Problems Weakness

Treatment Delays 55 % of divers delayed treatment for 48 hours or longer. 38 % had signs and symptoms that forced them to seek treatment in under 24 hours. 14 % had significant delays due to seeking help from non-diving medical personnel. 1995 Bends Report n = 52

Delaying Treatment % of Divers with Post-Treatment Residuals as a Function of Treatment Delay Treat Early Don’t Delay The sooner the treatment the better the outcome 1995 DAN Accident Report

Incident Management At first sign - 100 % Oxygen. Tell someone (buddy, boat captain, etc.) DO NOT let anyone minimize your urgency. Monitor your changes. Call for help - EMS - USCG - DAN. Drink plenty of non-alcoholic fluids. DO NOT take minor signs lightly. Never re-enter the water. Get to a recompression facility fast.

How Recompression Works A room is pressurized with air while a diver and a medical tender relax inside. Most treatments are done at 60 fsw - 2.8 atm pressure. The diver breathes 100 % oxygen by a mask/hood, producing a surface equivalent of 280% oxygen. Oxygen eliminates nitrogen in the body and maximizes bubble resolution. Oxygenation of areas with compromised blood flow promotes healing.

Multiplace Hyperbaric Chamber A multiplace chamber is the preferred choice. Mono-place chambers offer few treatment options.

Mono-place Chambers Usually used for clinical hyperbaric treatments Can be used for limited diver treatment

Treatment Schedules Average initial time at a hyperbaric facility 8 hours Repeat oxygen treatments last 2 hours each. Depending on severity, treatments can be from 2 to 36 hours. US Navy Treatment Table 5 60 fsw 2 hours US Navy Treatment Table 6 60 fsw 4 - 6 hours COMEX 30 Treatment Table 100 fsw 7 - 9 hours US Navy Treatment Table 6a 165 fsw 5 - 7 hours

Bends Prevention Dive within your training level. Always do a safety stop on no-stop dives. Limit decompression dives to one a day. Use conservative dive tables. Take a day off every two on long trips when air diving Reverse profiles “ok” as long as decompression is sufficient for the exposure 24 hours before flying. Stay well hydrated. Limit Alcohol

What you can do now Training / Attitude Community Participation Peer Support Organization Support

Training CPR / First Aid Oxygen Provider Certification NSC, Red Cross, AHA, SDI/TDI Oxygen Provider Certification DAN, SDI, TDI Nitrox Certification SDI/TDI, IANTD Introduction To Hyperbarics (Hyperbarics International – Key Largo ) Advanced Scuba Diver Certifications Rescue Diver Certifications

Why Nitrox ? Longer no-stop dive times Shorter surface intervals some 100% longer Shorter surface intervals Longer repetitive dives Less nitrogen absorbed (oxygen displaces it) Lower risk of decompression illness when same dives are done compared to air dives.

Repetitive Dive Air Example 36% Nitrox Example Dive # 1 90 fsw / 20 min no-stop One hour surface interval Group F > G Dive # 2 80 fsw / 12 min no-stop 36% Nitrox Example One hour surface interval Group E > D Dive # 2 80 fsw / 36 minutes no-stop time Enriched air provided 24 minutes more no-stop dive time.

US Navy - Hamilton Research Survey Air and Oxygen with Air Procedures 43 organizations surveyed for their use of air and nitrox diving tables and procedures Military (10) Commercial diving companies (14) Government regulators (4) Scientific diving organizations (10) Scuba and recreational organizations (5)

Total dives reported on From all sources the report compiles data from a little more than 1.5 million dives. 1 million are no-stop air and nitrox dives. ½ million are from commercial air decompression or sur-d O2 25k were from a variety of rebreathers

Air diving Big users of US Navy air tables by the book NOAA, UNC Wilmington, Woods Hole, etc. Some others had no hard data but observations Many smaller companies & navies ALL USE AN ASCENT LINE Many use US Navy tables but have modified them with table jumps, next greater depth etc. Many use nitrox to supplement the decompression 50/50 nitrox is most common

Air diving with No Bends Depth FSW USN no-stop 60% no stop minutes 60 36 80 40 24 100 25 15 No-stop dives reported were on average at 60% of no-stop limit. This was a significant finding Why? -- single tank diving does not have enough air to do lengthy square profiles These dives resulted in an insignificant bends rate. Average depth < 100 fsw A key to lowering recreational bends rate if the procedure is ever applied.

Shorter no-stop dives are not new Many dive tables have shorter no-stop times than the USN does, but there is still high recreational bends rates the key is to change the shape of the ascent (decompression) and …….. do the Safety Stop on all no-stop dives …. 3-5 minutes @ 15 fsw.

Ways to plan safer dives Use a good dive computer read the directions do the safety stops do the decompression stops use the proper gases watch the “shape” Use planning software allows for realistic profiles multi level and repetitive dives

Change the Shape “Square models” “Shaped Models” By changing the shape of the ascent from a geometric shape to a smoother more “biological” shape the bubbles have more time so slowly come out of solution. The shape allows the pressure reduction to be in much smaller increments, thereby doing less damage. The result is a cleaner and less stressful decompression. Square profile reduces the pressure of the inert gas too fast. Shaped profile reduces the pressure of the inert gas slowly.

Community Participation Dive club meetings Tours of hyperbaric facilities Encourage oxygen availability Promote Responsible Diving Display safety signs and phone #’s

Peer Support Learn signs of diver denial Encourage early treatment Don’t promote myths Take “bends” out of the closet

“ Decompression sickness is not an accident; a certain incidence of it is expected from practical diving” R.W. Bill Hamilton, Ph.D

“The strong negative social reaction and stigma surrounding DCI increases the trauma, and jeopardizes the healing process.” Jennifer C. Hunt, Ph.D. aquaCorps , N5

More Information www.nitroxdiver.com www.diversalertnetwork.org www.UHMS.org

BENDS IS NOT A DIRTY WORD This presentation is a public safety message of Scuba Training and Technology Inc. Extended Range Diving Organization Inc. Hamilton Research Ltd. Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2005, 2006, 2007, 2008