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COLD WATER IMMERSION

COLD WATER IMMERSION. Cold Water Immersion. 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. Setting the Stage Case History – P04 0589 April 23, 2004 - Duke Point.

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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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