Sight Search

Getting Decompression Sickness while Freediving

TEXT By Andrew Khvetkevich
Images: DAAN VERHOEVEN


Getting Decrompression sickness (DCS) while freediving is uncommon. Unlike when breathing compressed gas, freedivers typically do not accumulate enough nitrogen to provoke DCS. Over the past few years only a few cases of DCS during freediving have been reported, and they all were associated with repeated deep dives over a short time. Since there is little information, statistics or research about DCS occurring while freediving, most freedivers pay little attention to the problem. Until recently, I did not take seriously the possibility of DCS happening to me.

During 2019 I dedicated myself to training and participating in freediving competitions, and I set several U.S. national records. The season was intense, and I hoped to set three more records that fall at the last competition of the year in Indonesia, where I planned to dive to 328 feet (100 meters) using bifins.

Arriving in advance, I had enough time for my usual one or two days of training followed by a rest day. Five days before the competition I planned three challenging dives without a day of rest, which was a mistake.

To give myself confidence, I wanted to repeat my current record dives in training. The three-day plan was to freedive to 325 feet (99 meters) using bifins, 233 feet (71 meters) without fins and 312 feet (95 meters) pulling the rope, and then have two days of rest before the competition. Everything went according to plan, but after the third day I began to feel weird.

I failed my surface protocol by showing the OK sign and saying, “I am OK” after 22 seconds, when the time allowed is 15 seconds. The delay occurred because I was hypoxic, meaning that my body had inadequate oxygen. After getting to the platform, I felt weak and immediately began to breathe oxygen, which is a routine practice after a deep dive. The doctor noticed that something was  wrong and told me to continue breathing the oxygen for about 30 minutes instead of the usual five minutes.

I returned to shore, where my pulse, blood pressure and oxygen saturation levels were checked and found to be a bit off but still within normal limits. I felt tired and returned to my hotel, where I soon noticed numbness and tingling in the entire left side of my body and the thumb and forefinger of my right hand. I didn’t know much about DCS and didn’t understand the seriousness of the situation, so I decided to try to sleep it off, but the weird sensations did not disappear with rest.

While showering a little later, I noticed that the left side of my body did not recognize the water temperature. The next morning, my left hand stopped tingling, and the numbness subsided, so I decided to sleep all day, expecting that all the symptoms would soon pass. But my symptoms remained the same the following morning. Understanding that I wouldn’t be able to compete now, I told the organizer about my problem.

The symptoms indicated DCS, which meant that I needed to start a hyperbaric chamber treatment as soon as possible. I have DAN cover so the competition’s organizers immediately contacted DAN. No evacuation could happen that day since the local airport closed at 5 p.m., so I would depart the next morning.

An ambulance took me straight from the hotel to the airport, and I was on a plane 72 hours after my dive. The aircraft was a private medical jet, and the staff and pilots understood that I had DCS, so the plane flew at the lowest possible altitude. During the flight they monitored my oxygen saturation, and the medical staff was ready to provide oxygen if needed. The flight and
transportation to the Kuala Lumpur hospital took about three hours. About 80 hours after my symptoms began, I was in a hyperbaric chamber in Kuala Lumpur. Now I know that if DCS symptoms appear, it is critical to start a chamber treatment as soon as possible.

I spent nine days in the Management and Science University Medical Centre in Kuala Lumpur, and during that time I had six sessions in a hyperbaric chamber for a total of 23 hours and 32 minutes of treatment. I felt better after each session, and by the end of the sixth session my symptoms had almost disappeared.

After I returned home, my symptoms worsened, and I called DAN again. I received five more sessions in the chamber at Mercy Hospital in Miami, Florida. My symptoms have almost disappeared again, and the doctors expect the symptoms will be gone within three months. I spent a total of 47 hours and 17 minutes in hyperbaric chambers over 11 sessions, and if I did not have DAN dive accident coverage, the medical bills would have been more than $20,000.

Now that I better understand the risks of developing DCS while freediving, I intend to be more careful by doing the following:

  • not diving to my maximum depth for more than two days in a row
  • taking as many rest days as necessary to fully recover between deep dives
  • avoiding repeated dives to my maximum depth on the same day
  • not taking a static breath-hold at a depth several times in a row
  • not doing any depth freediving after scuba diving or any deep dives after static training or consuming recovery oxygen underwater
  • breathing oxygen for five minutes at a depth of 16 feet (5 meters) after any dive deeper than 197 feet (60 meters) to dissolve the accumulated nitrogen in the tissues.

Full lung packing leads to injuries associated with the rupture of lung tissue. I can fully pack my lungs with 25 extra breaths, but during deep dives I take 20 breaths to leave about 20 percent less than my maximum free for extra safety. Remember that for recreational freediving, lung packing is not necessary, and you must have specialized training to pack the lungs.

I learned that I should immediately call DAN when DCS symptoms appear, because the probability of a full recovery depends on how quickly you get your first hyperbaric treatment. I can rely on DAN for valuable help with evacuation, travel and dive-related medical expenses — and you can, too.

Article from Alert Diver Magazine 1st Quarter, 2020

Categories

 2022
immersion and bubble formation 232bar AGE AIDA Accident management Accidents Acid reflux Acute ailments Advanced courses Rescue diver Aerobic exercise After anaesthesia Aged divers Air Quality Air exchange centre Air hose failure Air supply Airway control Air Alert Diver Magazine Algorithms Alice Cattaneo Alice Modolo Alternate Airsources use Alternater Air Source Alternative gas mix Altitude changes Altitude diving Altitude sickness Aluminium Oxide Ama divers Amino acids Amos Nachoum Anaerobic Metabolism Animal life Annual renewal Antarctica Anxiety Apea Apex predators Apnea Apnoea Aqua corps Aquatic creatures Aquatic life Aquatics and Scuba Diving Archaeology Argonaut octopus Argonauts Argon Arrythmia Arterial Gas Embolisms Arterial gas embolism Arthroscopic surgery Aspirin Audible signals Aurel hygiene Australian Flat backed Australia BCD BHP BLS BWARF Baacterial infections Back adjustment Back pain Back treatment Backextensors Backmount CCR Badages Bag valve mask Bahamas Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Basslets Batteries Beach entry Beached coral Becky Kaga Schott Becky Kagan Schott Beluga whales Bench press Bends Benign prostate hyperplasia Benzophenones Beth Neale Beyond Standards Big Sur Bilikiki Tours Biophysics Black Blood flow Blood pressure Blood thinners Blue Desert Blue Wilderness Blue economy Blue heron Bridge Blurred vision Boat diving Boat safety Bobbit worm Boesmans gat Boesmansgat Bonaire Bone fractures Bouyancy compensators Bouyancy controls Boyle's Law Boyle\'s Law Bradycardia Brain Brandon Cole Breast Cancer Breath Hold Diving Breath hold diver Breath holding Breath hold Breath-hold Breathing Gas Breathing gas contamination Breathing Breathold diving Bright Bank Broken bones Bruising Bubble detection Bubbleformation Buddy Exercise Buddy checks Buoyancy Burnshield CCR CGASA CMAS CO2 COVID-19 Updates COVID-19 COVID CPR Cabin pressure Caissons diseas California Camera equipment Camera settings Cameras Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Town Dive Festival Cape Town Dive Sites Cape Town CapeTown Carbon Monoxide Carbon dioxide Cardiac research Cardiaccompromise Cardio health Cardiological Cardiomyopathy Caribbean Carmel Bay Carribean Conservation Catalina Island Cave diving Cave exploration Caves Cave Cenotes Ceotes Challenging Environments Chamber Safety Chamber science Chamber treatment Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Charlie Warland Chemotherapy Chest compressions Children diving Chiropractic Chlorophll Chokka Run Christina Mittermeier Citizen Conservation Citizen sciences Citizen science Clean Air Cleaning products Climate change Closed Circuit Rebreathers Closed Circuit Rebreather Cmmunity partnership Coastal diving Coastalexcursion Cold Water Cold care Cold sores ColdWater Cold Commercial Fishing Commercial diving Commercial schools Common consideration Common understanding Communication Composition Compressed Air Compressed gas Compressor operators Compressors Concussion Congestive heart Faiture Consercation Conservation Photographer Conservation photography Conservation Contact lenses Contaminants Contaminated air Coping with cold Coral Bleaching event Coral Conservation Coral Reefs Coral Restoration Coral bleaching Coral preservation CoralGroupers Corals Core strength Corona virus Coro Coservation Costamed Chamber Courtactions Cozumel Cradiac valvular Cristina Mittermeier Crohns disease Crowns Crystal build up Crystallizing hoses Cubs Cutaneous decompression Cylinder Ruptures Cylinder capacity Cylinder handwheel Cylinder safety Cylinder valves Cylinder weight DAN Courses DAN Profile DAN Researchers DAN medics DAN members DAN report DANTraining DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DReams Daan verhoeven Dahab Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Danel Wenzel Dangerous Marinelife Dauin island Dave McCowan David Doubilet Dean's Blue Hole Dean\'s Blue Hole Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression chamber Decompression illsnes Decompression ilness Decompression limits Decompression treatment Decompression Decorator crabs Deep Freediving Deep diving Deep water exploration Deepest SCUBA Dive Delayed Offgassing Dental Depth limits Dever Health Diadema Response Team Diagnosis Diaphragms Diopter Diseases Disinfection Dive Buddy Dive Chamber Dive Chmber Dive Computer Dive Destinations Dive Destination Dive H Dive Industry Dive Instruction Dive Instructor Dive Medical Form Dive Medical Dive Practices Dive Professionals Dive Pros Dive Rescue Dive Research Dive Safari Dive Safety Tips Dive South Africa Dive Training Dive Travel Wakatobi Dive Travel Dive accidents Dive buddies Dive caves Dive computers Dive courses Dive cover Dive cylinder Aluminium Dive excursions Dive exercise Dive exeriences Dive experience Dive fitness Dive gear Dive heallth Dive health Dive in Africa Dive insurance Dive medical insurance Dive medicals Dive medicines Dive medicine Dive operators Dive opportunities Dive planning Dive procedures Dive safety 101 Dive safety Dive safe Dive skills Dive staff Dive travels DiveLIVE DiveTravel Diveleader training Diveleaders Diver Food Diver Health Diver Profile Diver Travel Diver education Diver infliencers Diver on surface Diver recall Diverover 50 Divers Alert Diversafety Divesites Diving Divas Diving Family Diving Fatalities Diving Feet Diving Helmets Diving Kids Diving Programs Diving Trauma Diving career Diving emergencies Diving emergency management Diving fit Diving guidelines Diving history Diving injuries Diving science Diving suspended Diving Dizziness Dolphins Domestic Donation Doug Perrine Dowels Dr Rob Schneider Drift diving Drysuit diving Drysuit valves Drysuits Dynamic environment Dyperbaric medicines EAPs EAP EMS Ear barotrauma Ear pressure Ear wax Ears injuries Eco friendly Ecowise Education Electronic Embolisms Emergency Action Plan Emergency Planning Emergency action planning Emergency decompression Emergency plans Emergency treatments Emergency underwater Oxygen Recompression Emergency Endurance Entry Envenomations Enviromental Protection Environmental factors Environmental impact Environmental managment Environmental stewardship Equalisation Equalization Equipment care Equipment failure Equipment inspection Equipment significance Evacuations Evacuation Evaluations Even Breath Evironmetaly friendly Exercise Exercising Exhaustion Exposure Protection Extended divetime Extinction Extinguisher Extreme treatments Eye injuries FAQ Face computer Factor V Leiden Failures FalseBay Diving Fatigue Faulty equipment Feet Femal diver Female divers Fenivir Fetus development Filling stations Fillings Fin Foot Fire Coral Fire Safety Fire extinguisher Firefighting First Aid Equipment First Aid Kit First Aid Trainig First Aid Training First Aid kits First Aid Fish Identification Fish Life Fish Fit to dive Fitness Levels Fitness Training Fitness evaluation Fitness to dive Fitnesstrainng Fitness Flying Focus lights Food Footissues Foundations Fractures Francesca Diaco Francois Burman Fred Buyle Fredive Free Student cover Free diving Free flow Freedive Competition Rules Freedive Competiton Freedive INstructor Freedive Safety Freedive Training Freedive computer Freedive rescue procedures Freediver Freedive Freediving Instructors Freediving performance Freediving Fur rade Gar Waterman Gardens of The Queen Gas Density Gas consumption Gas emboli Gas laws Gas mixes GasPerformance Gasblends Gases Gass bubbles Gastoeusophagus Gastric bypass Gastroenterologist Gas Gear Servicing Germs Geyer Bank Giant Kelp Forest Giant Kelp Giant stride Girls that Scba Gobies Golden fish Gordon Hiles Great White Sharks Green sea turtle Greenlings Guinness World Record Gutt irritations HBOT HCV HELP HIRA HMLI HMS Britanica Haemorhoid treatment Hand signals Harry Chammas Havanna Hawaii Hawksbill Hazard Description Hazardous Marine life Hazardous marinelife Head injuries Headaches Health practitioner Healthy Food Heart Attack Heart Health Heart Rate monitor Heart fitness Heart rates Heart rate Heart Heat stress Heliox Helium Gas Helium Hematoma Hemodynamic Hepatitis C Hepatitus B Hiatal Hernia High Pressure vessels High pressure hoses High temperatures Hip strength Hip surgery Hippocampus History Hole in the heart Hood Hot Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hygiene Hyperbaric Chamber Hyperbaric Oxygen Treatments Hyperbaric Oxygen Hyperbaric research Hyperbaric treatment Hyperbarics Hypertension Hypothermia Hypoxia I-52 found INclusivity IdentiFin Imaging Immersion Immine systems In Water Recompression Increased pressure Indemnity form Indian Ocean Indigo SCuba Indonesia Inert gas Infections Infra red Imaging Injections Inner ear Instinct Instruction Instructors Insurance policy Insurance Integrated Physiology International travel International Internship programs Internship Interval training Irritation Irukandji Syndrome Isotta housing Itchy Rash Jellyfish Jill Heinerth Joanna Wyrebek Joint pain Journal for Technical Diving Junior Open Water Diver KZN South Coast KZN Karen van den Oever Kate Jonker KateJonker Kenya Kidneys Kids scubadiver Komati Springs KwaZulu Natal LED lights Labour laws Lake Huron Lara Lambiase Laryngospasm Lauren Arthur Learning to dive Leatherback Legal Network Legal advice Legislation Lembeh Straights Lenses Leslie Lwaney Leukemis Liability Risks Liability releases Liability Life expectancy Lifestyle Lighting Lightroom editing Lionfish Live aboard diving Liveaboard Liver Toxicity Liver diseas Liz Louw Loss of consciousness Lost at sea Low Visability Low blood pressure Low pressure deterioration Low volume masks Lumpsuckers Lung Irritation Lung flexibility Lung function Lung injuries Lung squeeze Lung surgery Lung MOD MOzambique diving MPA Macro photography Mafia Island Maintenance Malaria Mammalian Dive Response Mammalian effect Manatees Mandarin Fish Marfan syndrome Marine Biologist Marine Biology Marine Mega fauna Marine Science Marine Scientists Marine conservation Marine parks Marine plants Marinelife Marinescience Markus Dirschi Marlin Marne protecte areas Mask clearing Masks Master scuba diver Matty Smith Maximum operating depth Medical Q Medical emergencies Medical questionaire Medical statement Medical team Medicalresearch Medicalstudents Medication Mehgan Heaney-Grier Membership benefits Menopause Menstruation Mermaid Danii Mesophotic Metotrexate Mexico Michael Aw Microbubbles Middle ear pressure Mike Bartick Military front press Misool Resort Raja Ampat Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Motionsickness Mount Kilimanjaro Mozambique Muck Diving Muscle pain Mycobacterium marinum NDL limits Narcosis National Geographic Nature Nausea Nautilus Ndibranchs Neck pain Neoprene layers Neuro assessments Neurocognitive research Neurological assessments Neuromotor exercises New Caledonia Nichola Bird Nicorette Nicotine Nitrogen Narcosis Nitrogen build up Nitrox No Decompression Limits No-decompression limits No-decompression Non-nano zinc oxide Non-rebreather Mask Non-smoking Nondiving related illness Nonrebreather masks Normal Air North Sulawesi Nosebleeds Nudibranchs Nuno Gomes Nutrition O2 oxygen provider. O2 providers O2 servicing O2treatments OOxygen maintenance Ocean Projects Ocean Research Ocean animals Ocean conservation Ocean mammals Ocean migrations Ocean pollution Oceangate Octopus Oil contamination Olive Ridley Open Ocean Open water divers Optical focus Oral contraseptives Orbital implants Oronasal mask Osteonecrosis Otters Out and about Out of air Outer ears Outreach Overhead Envirenments Oxygen Administration Oxygen Cylinder Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen kit Oxygen masks Oxygen providers Oxygen supplies Oxygen supply Oxygen systems Oxygen therapy Oxygen treatment Oxygen P J Prinsloo PADI Freedivers PFI PFO PJP Tech Paper Nautilus Paralysis Parentalsupervision Part 3 Partner Training Patent foramen ovale Pemba Island Peri-peri Divers Perspective Peter Lindholm Philippine Islands Philippines Phillipines Photographers Photographer Photography tips Photography Physical Fitness Physioball Physiology Physiotherapy Pills Pilot Whale Pistons Planning Plastic Plimsoll Interface Pneumonia Pneumothorax Poison Polka Dot Bat fish Pollution Pool Diving Pool chemicals Pool maintenance Pool workout Pools Post-dive Potuguese man-of-war Pre-dive Predive check Pregnancy Pregnant divers Preparation Prepared diver Press Release Preventions ProDive Port Elizabeth Professional rights Provider course Psycological Pulmanologist Pulmonary Barotrauma Pulmonary Bleb Pulmonary Edema Pulmonary Hypertension Pulse Punture wounds Pure Air Pure Apnea Purge Quit Smoking Q RAID South Africa RCAP REEF Radio communications Range of motion Rashes Rebreather diving Rebreatherdive Rechargeable batteries. Recompression chamber Recompression treatment Recompression Recycle Red SEA Reef Chcek Reef Conservation Reef Environmental Education Foundation Reef protection Reef safe Reef surveyors Refractive correction Regal Sea Goddesses Regulator failure Regulators Regulator Remote areas Remote islands Renewable Report incidents Rescue Divers Rescue Procedure Rescue breathing Rescue breaths Rescue diver Rescue skills Rescue skill Rescue training Rescue Research Resume diving Return To Diving Return to diving Reuseable items Risk Assessments Risk assesments Risk assessment Risk elements Risk management Risks of Seizures Riviera Maya Roatan Marine Park Roatan SABS 019 SMB SafariLive Safe diving practices Safety Concerns Safety Gear Safety Stop Safety in Air Safety SaherSafe Barrier Salish Seas Salty Wanderer Sanitising Sanne Volja Sara Andreotti Sara Banderby Sara Campbell Sardine Run Sargassum sea Saturation Diving Save our seas Schrimps Science Scoliosis Scombroid Poisoning Scorpion Fish Scuba Air Quality Scuba Guru Scuba Injury Scuba Instructor Scuba children Scuba divers Scuba dive Scuba education Scuba health Scubalearners Scubalife Sea Horses Sea Turtles Sea slugs Seagrass Sealcolonies Sealife Seals Seasickness Seaweeds Seaweed Sea Self Rescue Shallow Water Blackout Shallow dives Shark Protection Shark Research Shark conservation Shark diving Sharks Shipwrecks Shit Happens Shore entries Shoulder strength Sidemount Sideplank Signs and Symptoms Silty bottoms Sit-ups Sixgill Sharks Skills in action Skin Bends Skin outbreak Skin rash Smart phone photography Snells Window Snorkeling Snorkels Social Distancing Sodwana Bay Solomon Islands Sonnier bank South Africa Southern Sea Otters SpareAir Sperm Whales Spinal Bend Spinal bends Spinal cord DCS Spinal dura Spinal pain Spinner dolphins Spleen Splits Sports medicine Squeezes Squid Run Stability exercise Standars Statin Mediction Stay Fit Stay Warm Steel Stefan Randig Stents Step ups Stephen Frink Stepping up Stockton Rush Stonetown Stretch band exercise Stretch bands Strobe Lighting Strobes Stroke Submerge tech Submerged Sudafed Sulawesi Sun protection Sun screen Sunscreen Supplemental oxygen Surface Marker Buoys Surface supplied Air Surfaced Surgeries Surgery Suspension training Swim Fitness Swimmers health SwimmingIn wateractivities Swimming Sylvia Earl Symbiosis Symbiosys TRavel safety Tabata protocol Talya Davidoff Tanzania Tattoes Tec Clark Tech diving Technical Diving Technical divng Temperature Homeostatis The Bends The Cavettes The Titanic Wreck The Wild Coast The greatest Shoal The truth Thermal Notions Thermoregulation Thomas Peschak Thunder Bay National Marine Sanctuary Tides Tips and trick Tonga Tooth squeeze Transplants Travel destinations Travel smarter Travel tips Travel Tropical Coastal Management Tulamben Tullum Tulum. Tunnelling Turks and Caicos Turtles Tweezers Ultrsound Umkomaas Unconscious diver Unconsciousness Underground waterways Underground work Underseaa world Underwaater Photos Underwater Photography Underwater Photograper Underwater Photograpgraphy Underwater Photographer Manirelife Underwater Research Underwater critters Underwater floral Gardens Underwater hockey Underwater imaging Underwater photographer Underwater photography Underwater pho Underwater sound Underwatercommunications Underwater University of Stellenbosch Unresponsive Urchins Urinary retention. VGE Vacations Vaccines Vagus nerve Valsalva manoeuvers Valve stem seals Vape Vaping Vasopressors Vasvagal Syncope Venous gas emboli Ventilate Venting Verna van Schak Veterinarian Videography Vincenzo Ferri. Virus infections Volatile fuels WWII wrecks War stories Washout treatments Wastewater Watchman device Water Resistance Water Weakness Weigang Xu Weights West Papua Western Cape Diving Wet Lenses Wet diving bell Wetsuit fitting Wetsuites Wetsuits White balance Whitetpped Sharks Wide Angle Photos Wide angles Wildlife park Wildlife Winter Wits Underwater Club Wolf Eels Woman and diving Woman in diving Womans health Woman Women In Diving SA Women and Diving Women in Freediving Women in diving Womens Month Womens health Work of Breathing Workout World Deeepst Dive Record World Records Wound dressings Wreck History Wreck divers Wreck dive Wreck diving Wreck exploration Wreckdiving Wrecks Yoga Youth diver Zandile Ndholvu Zanzibar Zoology Zooplankton \ Blennies abrasion absolute pressure acoustic neuroma excision adverse seas air-cushioned alert diver altitude alveolar walls anemia antibiotics anticoagulants antiseptics bandages barodontalgia bent-over barbell rows bioassays biodiversity bloodcells blue carbon body art breathing air calories burn canal blockage carbon dioxide toxicity cardiovascular career developments cerebrospinal fluid cervical spine checklist chemo port children child chronic obstructive pulmonary disease clearances closed circuit scuba coral growth corrective lenses currents cuts cylinder filling dead lift decompression algorithms decongestants decongestion deep dive training dehydration dive injuries dive medicing dive ready child dive reflex dive tribe divecomputers diver in distress diver rescue diver training dive diving attraction doctors dolphns domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces elearning electrolyte imbalance electroytes emergency action plans emergency assessment emergency training environmentally friendly equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fish watching fitness Balance fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn histidine hospital humidity hypobaric hypoxia immersion and bubble formation immersion pulmonary edema (IPE informal education isopropyl alcohol jaundice join DAN knee lanyard laparoscopic surgery life jackets longevity lower stress lox oxygen level lungs malaise mamalian effect marielife marine pathogens medical issues medical procedures medical risk assesment medications mental challenge mental preparedness micro-organisims micro minor illness mucous membranes multilineage dysplasia myelodysplasia nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles off-gassed operating theatre operations orthopeadic otitis media out planting outgas pain parameters perforation phillippines phrenic nerve physical challenges pinched nerves plasters pneumoperitoneum polyester-TPU polyether-TPU post dive posture prescription mask preserve prevention professional emergency responders proper equalization psychoactive pulmonary barotrauma. pulmonary injury. pulmunary barotrauma radiation rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba sea goddesses single use sinus infections situationalawarenes smoking snorkeling. spearfishing sterilising stings strength sub-aquatic sunscreen lotion swimmers ears tattoo care tecnical diver thermal protection tissue damage toxicity trachea training trimix unified standards upwelling virtual coach vision impaired vomiting warmers water quality zinc oxide