Diving Medicine (HAP 11)

Talk by Rob Stafford

Notes by Tim Slade

diver-108881_1280

  • SCUBA – self contained underwater breathing apparatus. May be Air, Nitrox, Heliox or (if military) re-breather
  • At sea level pressure is 1 atmosphere or 100 kPa. For every 10m descent pressure will increase by 1 atmosphere or 100 kPa.

Medical issues with diving:

Exposure & Submersion: Covered in cold emergencies


Dysbarisms:

Due to pressure changes:

  • Middle ear barotrauma
  • External ear canal barotrauma if excessive wax
  • Barosinusitis
  • Facial barotrauma if mask not equalised – normally novice
  • TMJ dysfunction
  • Pulmonary barotrauma due to holding breath and rapid surfacing
  •  Rupture of major airway

Nitrogen narcosis:

Nitrogen becomes toxic at partial pressures achieved at approximately 30m depth. Euphoria and disinhibition. Similar sensation to using medical entonox. Can result in bizarre behaviour such as offering fish to the regulator!


Oxygen toxicity:

At high partial pressures (at around 60m depth) oxygen becomes toxic and will result in seizures @ approx 60 m. This is likely to be fatal.


Contaminated air:

If diving in poorly regulated areas, need to be careful of generators’ exhaust fumes contamination of compressor’s air intake. It may be possible to be adding carbon monoxide to the tanks resulting in poisoning on use.


Decompression Sickness:

  • Caused by formation of Nitrogen bubbles in blood and tissues.
  • Increased chance with increased length of dive and increased depth.
  • Risks – increased age, obesity, fatigue, dehydration, diving at altitude, flying post diving
  • 2.6x greater chance in males
  • Can reduce risk by sticking to dive tables or dive computer.

T1 – Skin, muscles and lymphatics

T2 – any other organ

  • Can be at risk of CVA if PFO. Even if closed at birth this can reopen at depth. Can only tell only tell by hyperbaric bubble echo!

Symptoms:

  • Joint pains
  • Puritis, erythema or mottling
  • Limb weakness or paralysis
  • Parasthesia or numbness
  • Bladder Sympotms, incontinence
  • Priapism

History:

  • Depth of 1st Symptoms
  • Dive location
  • Recommended dive limits
  • Decompression stops
  • Water decompression attempted?
  • Time delay in dive to air time?
  • On surface/delayed/progressive?

Treatment:

  • High flow O2
  • Consider urgent decompression
  • Contact diving centre for advice:
Environmental Emergencies HAP 11
Environmental Emergencies HAP 11
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