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PFO CONCERNS IN DIVE INJURY MANAGEMENT
Q: I recently took DAN’s online Basic Life Support: CPR and First Aid and Emergency Oxygen for Scuba Diving Injuries courses. I’ve heard it is best to put an injured diver in the recovery position on their left side because of the possibility of a patent foramen ovale (PFO). Is this true, and what would be the benefit? A: A PFO is undoubtedly a concern with diving because about 25 percent of the population has one. The recovery position supports and maintains an open airway in an unconscious person or injured diver. The left-side preference was based on anatomy, not PFO concern. Blood from the venous system returns to the right atrium via the superior and inferior vena cava, so the idea of putting a diver on the left side was to alleviate unnecessary weight that might compress these large vessels and impede circulation. Recent studies and recommendations from the International Liaison Committee on Resuscitation (ILCOR), however, suggest there is no benefit to placing someone on their left side instead of their right side when using the recovery position. In the case of suspected decompression sickness (DCS), place the injured diver in a position of comfort, or if they are unconscious, one that allows you to monitor them as necessary. PFO concern is not a factor in this case. If the diver is symptomatic and you are rendering care, then you need to treat the symptoms. Give them the highest concentration of oxygen available and get them to definitive health care and treatment. Remember that many conditions show symptoms that may mimic DCS. Just because someone was diving does not mean they have a dive-related illness. When creating your emergency action plan, note the location of the nearest emergency room or where and how to access local emergency services.
What is a PFO?
A PFO is a very small hole in the heart (often closed under normal circumstances) and which, during or after diving, can enable nitrogen bubbles to pass back into circulation in the blood rather than being expelled by the lungs, leading to DCI. If a PFO is suspected, the treating physician will often refer the diver to be tested. A negative result on the test does not necessarily mean there is no PFO, however, if one is present it is likely to be very small. A positive test indicates there is an obvious route that bubbles in the venous blood can pass through the heart and enter the arterial blood, from where it can be taken to the brain, spine and elsewhere in the body. The PFO can often be repaired surgically, and some divers elect to have the hole closed. As with any surgical procedure there are associated risks and these need to be balanced against the desire to continue diving and the risk of diving without having the PFO repaired. Many divers continue to dive despite a small PFO and reduce the chances of a problem by limiting depths, repetitive diving, extending surface intervals, doing slow ascents and safety stops and using nitrox (with dive times based on air). DANAP.org
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