Scuba diving emergencies

Background

Diving Physiology

• Pascals Law applies to the diving body (without air filled areas such as lungs) states that the pressure applied to any part of the enclosed liquid will be transmitted equally in all directions through the liquid.
• Boyles Law applies to the diving body's air filled areas such as lungs, sinuses, middle ear, and states that the volume and pressure of a gas at a given temperature are inversely related.
  • At 2 ATA (10m/33ft) a given gas would be 1/2 it's volume, at 3 ATA (20m/66ft) it would be 1/3 it's volume and so on.

Boyle's Law

Differential Diagnosis

• Facial/Ear/Eye Pain:
  • Sinusitis
  • Otitis Media and Otitis Externa
  • Subconjunctival Hemorrhage
  • Corneal Abrasion or Corneal Ulcer
  • Facial bone fracture
• Dyspnea:
  • Pneumonia
  • Congestive Heart Failure
  • Acute Asthma Exacerbation
  • COPD Exacerbation
• Chest Pain:
  • Acute myocardial infarction
  • Pericarditis
  • GERD
• Altered Mental Status:
  • Stroke
  • Meningitis or Encephalitis
  • Intracerebral Hemorrhage
  • Toxic Ingestion

Diving Emergencies

• Barotrauma of descent
  • Otic barotrauma
  • Pulmonary barotrauma
  • Sinus barotrauma
  • Mask squeeze
  • Barodentalgia (trapped dental air causing squeeze)
• Barotrauma of ascent
  • Pulmonary barotrauma (pulmonary overpressurization syndrome)
  • Decompression sickness (DCS)
  • Arterial gas embolism
  • Alternobaric vertigo
  • Facial baroparesis (Bells Palsy)
• At depth injuries
  • Oxygen toxicity
  • Nitrogen narcosis
  • Hypothermia
  • Contaminated gas mixture (e.g. CO toxicity)
  • Caustic cocktail from rebreathing circuit

Water-related injuries

• Hypothermia
• Immersion pulmonary edema
• Marine toxins, envenomations, and bites
• Scuba diving emergencies
• Submersion injury (drowning and near-drowning)

Management

Barotrauma of Descent

• Gradual Ascent, avoidance of diving deeper if experiencing pain
• Decongestants for sinus pain
• Antibiotic ear drops for TM rupture (choose a formulation such as ofloxacin suspension that is safe in the middle ear)

Barotrauma of Ascent

• Gradual ascent, safety stops imperative
• Pulmonary barotrauma may manifest in many ways
  • Local pulmonary injury and pneumomediastinum require supportive care only
  • Treat Pneumothorax according to severity, does not require recompression on its own
  • If any of the above conditions present with altered mental status, presume arterial gas embolism and recompress the patient
  • Arterial gas embolism is the most dreaded complication of diving. It can manifest in many ways depending on where the emboli travel (i.e. stroke, seizure, acute myocardial infarction, or arrythmia. The treatment is immediate hyperbaric oxygen therapy.
  • Decompression sickness (aka the bends) is due to the gas (usually nitrogen) coming out of solution in the blood and tissues secondary to too rapid of an ascent/depressurization. It can present with a myriad of findings, but the most common systems affected are neurologic and musculoskeletal. Those suspected to have this condition should be referred for urgent hyperbaric therapy.

At Depth Injuries

• Oxygen Toxicity usually results from high FiO2 at several atmospheres of pressure. It can cause pulmonary injury manifesting as chest pain, pleurisy, or even pulmonary edema/hemorrhage. It can also cause CNS pathology manifesting as nausea, auditory changes, convulsions, sweating, twitching, or tunnel vision. Treatment for any of these injuries is ascent and inhalation of lower FiO2 at decreased pressure. More severe presentations of pulmonary injury may require intubation.
• Nitrogen Narcosis results from inhaling nitrogen containing gas mixtures at high pressures (specialized gas mixtures exist for work at depth that have decreased amounts of nitrogen). It manifests as altered mental status. Treatment is gradual ascent.
• Hypothermia: re-warm
• Carbon Monoxide Toxicity: see main section; oxygen, consider hyperbaric therapy
• Caustic Cocktail: supportive

See Also

• Diving medicine
• Hyperbaric medicine