Drowning and Scuba Emergencies

Drowning and Scuba Emergencies

Drowning Definition

• At the 2002 World Congress on Drowning in Amsterdam, experts proposed a unified definition of drowning to eliminate confusion stemming from various terms.
• Definition: Drowning is a process resulting in primary respiratory impairment from submersion in a liquid medium.
• The following terms are proposed for discontinuation:
  • Wet drowning
  • Dry drowning
  • Active drowning
  • Passive drowning
  • Near-drowning
  • Secondary drowning
  • Silent drowning

Submersion Events

• Following breath-holding, laryngospasm occurs due to liquid presence in the oropharynx or larynx.
• As the urge to breathe increases, laryngospasm relaxes, leading to gasping, and potential aspiration of liquid.
• Asphyxia induces airway relaxation, allowing water intake into lungs; typically, individuals aspirate less than 4 ext{ mL/kg} of fluid.

Progression of Drowning

• Laryngospasm Outcomes:
  • Dry Drowning: 10-15%
  • Wet Drowning: 85-90%
• Consequences include:
  • Aspiration leading to cerebral hypoxia, acidosis, possible cardiac arrest, and subsequent brain injury or death.

Drowning Statistics (2018 Alberta Drowning Report)

• Where do drownings occur?

  • Lakes: 28%
  • Rivers: 29%
  • Bathtubs: 19%
  • Pools: 8%
  • Hot Tubs: 4%
  • Other: 13%

• Gender:

  • Women: 28%
  • Men: 72%

• Time of Year:

  • Drownings are distributed unevenly throughout the year.

Risk Factors by Activity

• Factors involved in drowning incidents include:
  • No Personal Flotation Device (PFD)
  • Capsizing
  • Alcohol consumption
  • Swimming alone
  • Poor swimming ability

Secondary Drowning

• Defined as pulmonary function deterioration after deficient gas exchange, linked to surfactant loss or inactivation.
• The term is gradually becoming obsolete due to better understanding.

Laryngospasm

• Laryngospasm: A sudden spasm of the vocal cords causing breathing difficulties.
• In drowning scenarios, this simulates airway obstruction.
• Usually resolved with a forceful ventilation.

Cold Water & Hypothermia

• Hypothermia onset times vary based on temperature exposure:
  • Belief information indicates expected effects in intervals from 0-30 minutes in cold water.

1-10-1 Principle for Cold Water

• 1 minute: To gain breathing control.
• 10 minutes: Of meaningful movement before exhaustion.
• 1 hour: Until loss of consciousness from hypothermia.

Emergency Responder Protocol

1. Standard approach includes:
   • Clear airway, apply oxygen.
   • If patient requires transport post-submersion, they must go to the hospital regardless of apparent injury.
   • Specific protocols for dealing with hypothermic cardiac arrest vary based on water temperature.
   • Always ensure patient safety by monitoring vital signs and readiness for potential advanced interventions.

Scuba Emergencies

The Physics of Pressure and Gas

• Gas Characteristics: Gases are compressible, but liquids are not.
• Pressure increases with depth, impacting air-filled cavities like the lungs and sinuses.

Barotrauma

• Definition: Injuries caused by pressure changes on air-filled body cavities.
• Common forms include middle ear and pulmonary barotrauma which occur due to rapid pressure changes (elevation in pressure on descent or rapid ascent).

Types of Barotrauma

• Inner Ear Barotrauma: Damage linked to pressure differences across ear windows; symptoms include vertigo and nausea.
• Pulmonary Barotrauma: Can lead to air embolism, pneumonia, or pneumothorax when ascending too quickly or holding breath.

Nitrogen Narcosis

• Definition: Altered mental state due to high nitrogen partial pressure, typically at greater depths underwater.
• Anesthesia-like effect on consciousness, with potentially serious safety implications.

Decompression Sickness

• Known as The Bends; develops from nitrogen bubble build-up during rapid ascent.
• Treatment includes immediate oxygen therapy followed by recompression therapy.

Vocabulary

• Barotrauma
• Embolism
• Hypoxemia
• Laryngospasm
• Hypothermia
• Drowning Morbidity
• Mortality