Decompression Illness and PFO

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SCUBA divers who suffer from decompression illness are extremely likely to have a Patent Foramen Ovale (PFO) or Atrial Septal Defect (ASD).

In addition, divers who suffer from migraine with aura have a higher incidence of PFO than other divers.

Decompression illness (DCI) or the ‘Bends’ is due the nitrogen gas accumulation in the blood stream, tissues and joints whilst diving at depth.

Recreational SCUBA diving has a very good safety record because there is a strict adherence to dive tables and more recently advanced dive computers. However, there is a strong relationship between decompression illness (DCI) and the presence of a large patent foramen ovale (PFO) even in those diving conservatively.

During and after resurfacing nitrogen off-gassing occurs mostly in the tissues and joints and venous circulation. In the presence of a PFO/ASD there is a direct communication to the arterial circulation so the bubbles have no chance of being expelled from the lungs.  

The more serious DCI such as Cerebral Arterial Gas Embolism (CAGE) or neurological/spinal DCI is more likely to be directly related to divers with a PFO or ASD.

Are you at risk?

We recommend that all commercial divers performing saturation dives, as well as advanced and technical recreational divers, be screened for PFO.   

Anyone wishing to take up diving with a history of migraine with aura, unexplained stroke or heart attack should also be assessed and screened for a PFO – as per section A4.8(c) of the South Pacific Underwater Medical Society (SPUMS) guidelines for recreational divers.

In 2015, SPUMS released this joint position statement:

2015 Joint position statement on persistent foramen ovale (PFO) and diving:  

South Pacific Underwater Medicine Society (SPUMS) and the United Kingdom Sports Diving Medical Committee (UKSDMC). 2015).

Consideration should be given to investigating for a PFO under any of the following circumstances: 

  • A history of decompression illness (DCI) with cerebral, spinal, vestibulocochlear or cutaneous manifestations 
  • A current or past history of migraine with aura  
  • A history of cryptogenic stroke  
  • A history of PFO or atrial septal defect (ASD) in a first degree relative 

What do I do next?

If you fit the above criteria, visit your GP for a referral to Heartbrain Private Clinic.

After an initial assessment, we will likely perform a simple 15 minute, non-invasive ‘bubble test’ to see if you have a PFO or ASD. This test is called a Transcranial Doppler (cTCD) and we are pioneering this screening method in Australia.

For more information see Screening for a PFO.

Decompression Illness and PFO
Decompression Illness and PFO

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