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Impaired consciousness when scuba diving associated with vasovagal syncope
Peter Wilmshurst1,2, Margaret Clamp3
1Royal Stoke University Hospital, Stoke-on-Trent, United Kingdom.
Diving and Hyperbaric Medicine
|December 16, 2020
Summary
Vasovagal syncope, a common cause of fainting on land, may also cause impaired consciousness in scuba divers. This condition can lead to drowning if not properly identified and managed.
Area of Science:
- Diving Medicine
- Cardiology
- Neurology
Background:
- Impaired consciousness during scuba diving can lead to drowning.
- Potential causes include breathing gas toxicity (nitrogen narcosis, oxygen toxicity) and arterial gas embolism.
Purpose of the Study:
- To investigate the cause of impaired consciousness in scuba divers when other known causes are ruled out.
Main Methods:
- Retrospective review of medical records of scuba divers experiencing underwater impaired consciousness.
- Exclusion of toxic effects of breathing gas and arterial gas embolism as causative factors.
Main Results:
- Four scuba divers experienced impaired consciousness at shallow depths (8-18m).
- Episodes were similar in description.
- Three divers had a history of recurrent vasovagal syncope on land.
Conclusions:
- Vasovagal syncope is the probable cause of impaired consciousness in these scuba divers.
- This finding suggests vasovagal syncope should be considered in divers with unexplained underwater blackouts.
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