A Small Pfo

[DocVikingo]

[NOTE: A correction in anatomy before the discussion: Patent foramen ovale (PFO) is an abnormality between the upper chambers of the heart (atria), not between the lower chambers (ventricles).]

You are correct that the majority of persons with a small PFO are without symptoms and don't have more than a trivial shunting of blood from the right to the left upper heart chamber (e.g., from the lower pressure side to the higher pressure side).

However, most persons with a small PFO are not scuba divers and therefore do not with any frequency perform common equalization techniques, like the Valsalva maneuver, that can cause brief increases in pressure within the right atrium. Nor do these individuals experience the increased uptake of nitrogen inherent in recreational scuba and the related potential for decompression illness (DCI).

Given a 13 year old scuba student with a known PFO of any size, it cannot even be suggested that she probably is at no risk until clearance is received from a cardiologist, preferably one with some degree of diving medicine knowledge.

Best regards.

DocVikingo

 

[IndigoBlue]

...Given a 13 year old scuba student with a known PFO of any size, it cannot even be suggested that she probably is at no risk until clearance is received from a cardiologist, preferably one with some degree of diving medicine knowledge.

Best regards.

DocVikingo

Thanks, DocV.

It was abundantly clear to me that she would need clearance from a medical professional. What surprises me is that any degree of PFO is permissible for scuba diving??

And if permissible, would I now certify her with limitations, such as the newest handicapped-diver requirements for certification endorse?

For the record, she dropped out of my class. Her parents who were divers were unaware of the scuba issues of PFOs, although acutely aware of the girl's own PFO from her early childhood. So they took her out of the class upon becoming aware of the issue during my class presentation.

For future reference, this is an interesting issue.

 

[IndigoBlue]

Very few disease are unconditionally 'safe', such as color blindness or acne, and the like. Most instructors I know, if they see any disease checked in those boxes, will ask for medical opinions.

All your items are not absolute contraindications to dive, they are relative contraindications that is, it depend on the severity of each type of diseases and whether they are active or not.

There are many kinds of cerebral palsy, seizure types beyond epilepsy, 'chronic heart disease', various sizes of PFOs, diabetes and asthma. Its best and easiest to just get a medical sign-off concerning these disease from a dive physician.

You may review each disease here in detail:

http://diversalertnetwork.org/medical/faq/index.asp

Doc Saturation, here is my dilemma with the "classic" approach.

The "classic" approach refers all medical issues to a medical diving doctor. This then gives momentum to allow the potential student into the class if the medical diving doctor agrees. That might not always be the right answer. And sending the person to a medical diving doctor sets up this expectation.

Additionally, our store owner does not want any fatalites of any kind from any kind of mistakes. Asthma and diabedes are ripe areas for potential fatalities. The owner is proud of our 20 year record of no fatalites. The cross-town competition cannot say the same thing.

Currently I do not have an asthma or diabedes issue. My issue is/was with a "small PFO." It is now for the moment at least academically moot. The student's parents withdrew her from the scuba course.

 

[Saturation]

Doc Saturation, here is my dilemma with the "classic" approach.

The "classic" approach refers all medical issues to a medical diving doctor. This then gives momentum to allow the potential student into the class if the medical diving doctor agrees. That might not always be the right answer. And sending the person to a medical diving doctor sets up this expectation.

Additionally, our store owner does not want any fatalites of any kind from any kind of mistakes. Asthma and diabedes are ripe areas for potential fatalities. The owner is proud of our 20 year record of no fatalites. The cross-town competition cannot say the same thing.

Currently I do not have an asthma or diabedes issue. My issue is/was with a "small PFO." It is now for the moment at least academically moot. The student's parents withdrew her from the scuba course.

Hi IndigoBlue:

I understand. In the end, you, as instructor, have full control over whom you wish to take to class, regardless of any medical clearances your students have. Medical clearance is not a right to dive, its a risk assessment of the likelihood of the student encountering a problem because of medical conditions. Instructors are, and alway have been, the boss with the final say when taking a student into their classes.

 

[DocVikingo]

Yes, some divers with PFO are medically cleared to dive, although the research evidence suggests that they are anywhere from 3 to 5 times more likely to develop DCI under recreational dive profiles than divers with normal cardiac anatomy.

Despite this, several diving medicine experts have stated that the individual risk in divers with asymptomatic PFO remains so low that it does not justify the exclusion of 25-30% of the population from diving. Nonetheless, I rather strongly suspect that a number of cardiologists do feel that PFO of any size is an absolute contraindication to scuba.

It is recommended that cleared divers with PFO avoid long deep dives, repeated ascents & descents during the same dive, and diving several times a day. While I am unaware of any research bearing on the effectiveness of profile restrictions in reducing the risk of DCI in divers with PFO, conservatism does seem prudent & I suspect that it well may reduce risk.

If a diver with PFO does experience an incident of DCI, I'd venture that most diving medicine specialists would say that it's time to find another recreation.

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.

Best regards.

DocVikingo

 

[IndigoBlue]

Thanks to you both, Gentlemen. I am honored to have access to your professional views in real-time on these isues. I think its great that you contribute your time to us here on Pete's board, for the benefit of all of us and for our students as well. Thanks again.