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COLD WATER IMMERSION

Discover the physiology of entering cold water, how it can lead to hypothermia and drowning, and ways to prevent and survive such incidents. Learn about submersion, drowning, and the stages of an immersion incident.

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COLD WATER IMMERSION

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  1. COLD WATER IMMERSION

  2. Cold Water Immersion

  3. The Cold Facts - Hypothermia and Drowning • Physiology - What happens when we enter cold water • Why and how does it kill • How can it be prevented • What can we do to help

  4. Setting the StageCase History – P04 0589 April 23, 2004 - Duke Point • Accidental Immersion in cold water can be a terrifying experience. “We’re going down. We have 2 kids on board” “You gotta get out here. It’s bloody cold. We aren’t going to last long” • This incident fortunately had a happy ending – rescue of family of four by “Sea Shuttle” after approx 30 minutes in water

  5. Hypothermia • Results from the body’s inability to adequately replace heat lost to the surrounding environment • Factors influencing heat loss include water temperature, sea state/water circulation, degree of immersion, insulating garments, rate of energy expenditure, body type, psychological factors • To err on side of safety, we assess as either mild or severe

  6. Submersion Incidents – Drowning and Near Drowning • Drowning is defined as death through suffocation by submersion, especially in water • Near Drowning has been defined as survival, at least temporarily, after aspiration of fluids into lungs • Hypothermia is likely biggest factor in survival of near drowning/submersion patients

  7. Drowning • Laryngeal Spasm – May offer some early protection from aspiration but hypoxia causes relaxation of the vocal cords allowing water into the lungs • Drowning does not occur without fluid aspiration – immersion victims without fluid in lungs probably did not drown

  8. Drowning • Drowning can occur at surface due to wave splash over mouth and nose • Type of water – salt water (hypertonic) draws fluid into lungs, while fresh water (hypotonic) results in osmotic passage of some aspirated water into circulation

  9. Drowning • Males and children have the highest drowning mortality rates • Prevention works – Prevention initiatives in developed countries have been successful • According to the Lifesaving Society of Canada, two thirds of drowning victims had no intention of entering the water

  10. Stages of an Immersion Incident • 1. Cold Shock – first few minutes • 2. Swimming Failure – 3-30 minutes • 3. Long term – Hypothermia becoming severe • 4. Post Rescue

  11. The Cold Facts – Surviving Sudden Cold Water Immersion

  12. 1. Cold Shock • Responses, triggered by cold receptors in the skin, last just a few minutes (peaking at about 30 seconds) • Large inspiratory gasp upon immersion – may trigger drowning • Uncontrollable hyperventilation and reduced breath hold • Coordination of swimming stroke and breathing very difficult

  13. 1. Cold Shock • Survival activity often fails • Aspiration of water is likely – leading to near drowning or drowning • Massive increase in heart rate and blood pressure may trigger cardiac arrest in older or less healthy individual

  14. 2. Swimming Failure • Cold incapacitates within 3 – 30 minutes of immersion, even before hypothermia sets in • Water temperatures below 20C result in degradation of swim performance • Peripheral cooling leads quickly to the loss of manual dexterity and muscle strength, with resultant inability to self rescue

  15. 2. Swimming Failure • Even short swims may be impossible – many who drown are reported to have been “good swimmers”

  16. 3. Hypothermia • Water conducts heat away 25 times faster than air of same temperature • Predications of survival times are possible, but many variables make these unreliable • If airway is protected (no drowning), death will occur somewhere below 24C, although the casualty is considered vulnerable below 30C • Lowest recorded survival is core temperature of 13.7C

  17. 4. Post Rescue • Vulnerable time for the casualty – up to 20% of immersion deaths • Circum-rescue collapse – drop in blood pressure as result of release of hydrostatic pressure and vertical positioning during rescue • Afterdrop – the continued decline in core tissue temps after removal from cold stress

  18. 4. Post Rescue • Physical effort by survivor may trigger collapse or death • Rough handling may trigger cardiac arrest (VF) • VF responds poorly to defibrillation at core temps below 28C

  19. Sometimes not everyone makes it May 1, 2004 – Cape Beale • 5 persons in the water from over-turned 18’ pleasure craft, spotted by light-keeper • 1 swam ashore, later recovered by EHS helicopter

  20. Sometimes not everyone makes it May 1, 2004 – Cape Beale • 4 recovered from water by RHIOT 1 and 2 • despite prolonged resuscitation attempt 1 person did not survive (core temp measured at Bamfield - 22C)

  21. Prevention and Survival

  22. Prevention and Survival • Training, Preparation, Attitude and Experience • Avoid entering water unless necessary – stay with your boat • Floatation and Insulation – objective is warm and dry • A dry suit or immersion suit is best if you must enter water

  23. Rescue of Survivors • Assess survivor as being either mildly or severely hypothermic - based on history, level of responsiveness, vital signs and if possible temperature If possible; • Recover horizontal and keep horizontal during transport • Handle gently - do not allow survivor to aid in own rescue

  24. Rescue of Survivors Remember that concerns at point of rescue include; • Circum-Rescue Collapse – due to drop in blood pressure on removal from water • Core Temperature Afterdrop – the continued decline in core temperature after removal from cold stress

  25. Treatment • Remove wet clothing, provide shelter and insulate against further heat loss • Avoid rapid full surface re-warming, alcohol or caffeine, and inappropriate speech • Add heat to high heat loss areas (head and neck, chest, groin)

  26. Treatment • Evacuate to medical, monitoring continuously

  27. Resuscitation • Expect fluid in airway to be a problem – foaming may be present • Stiffness may be due to cold rather than rigor mortis • Prior to resuscitation, check carotid pulse for up to 45 seconds

  28. Resuscitation • Recovery following prolonged submersion is possible – don’t give up “The casualty is not considered dead until they are warm and dead”

  29. Summary • Hypothermia, Drowning and Near Drowning • Four stages of an immersion incident • Prevention and Survival • Rescue of Survivors

  30. Summary • Treatments issues, including resuscitation • Questions?

  31. For more information • World Congress on Drowning – www.drowning.nl • Essentials of Sea Survival – Dr. Frank Golden, Dr. Michael Tipton – Human Kinetics, 800-465-7301, orders@hkcanada.com • The Cold Facts – Surviving Sudden Cold Water Immersion (A Canadian Forces Production) • Dr. Chris Brooks – Survival in Cold Waters, TP 13822E http://www.tc.gc.ca/MarineSafety/TP/Tp13822/menu.htm

  32. With thanks to Bob Ayres CCG

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