PFO screening guidelines - and an Instagram post

New recommendations for screening cardiac right-to-left shunts - especially for persistent foramen ovale (PFO) - in divers have recently been published. They reaffirm what has long been established and for which SUHMS has played a leading role. In keeping with this, I was sent a social media post by recreational divers that vividly portrays the topic.

No routine screening - but targeted evaluation after DCS

The following still applies: general screening for PFO is not indicated. However, if certain forms of decompression sickness (DCS) are suspected, a diagnostic work-up should be performed. These include

• Central (e.g. brain, spinal cord),

• Cardiovascular,

• vestibulo-cochlear (inner ear) and

• Cutaneous (skin) manifestations of DCS.

  
  

The Instagram post mentioned above shows an example: The symptoms described in the post are clearly severe DCS with cutaneous and neural involvement. The attending physician does not seem to have recognized this either. The assumption of a lack of oxygen as the cause of the clinical picture is of course humbug. Such cases are indicators of a possible PFO.

For this reason, the person involved should receive diving medical advice and be examined for PFO. The guidelines also recommend a diving ban until the examination. Continuing to dive immediately after a one-day break was certainly not a good idea and the risk of a new DCS is high. If a PFO is found, it can be discussed whether it should be closed. However, closure is not mandatory.

However, the internationally recognized recommendations on low bubble diving published by the SUHMS years ago are crucial.

These include all measures to prevent the formation of gas bubbles during ascent and the opening of the PFO, such as

• Do not exceed no-decompression limits.

• A maximum of two dives per day.

• Safety stop at a depth of 3-5 m for at least 5-10 minutes.

• At least 4 hours surface interval until the next dive.

• No exertion in the first 2 hours after the dive.

• Avoid pressing maneuvers:

  • No exertion at the end of the dive.

  • Do not inflate DSMBs by mouth.

  • Removing the scuba in the water.

Important: Nitrogen reduction in the breathing gas plays a central role. Nitrox is strongly recommended for intensive vacation diving - leave the dive computer in air mode to ensure maximum safety.

Knowledge can save - and is often lacking

Unfortunately, the Instagram post also shows that we diving doctors and instructors fail to communicate the necessary knowledge to recognize a DCS and react correctly - even in obvious cases.

Conclusion

• The PFO remains a key risk factor for DCS.

• The proven rules of low bubble diving must be observed.

• PFO closure is possible, but not mandatory.

• Consistent implementation of the rules of conduct is crucial - see SUHMS flyer.

• Diver training urgently needs to be improved, especially with regard to recognizing and correctly assessing a DCS.