A quarter of the population have a PFO (small hole on the heart) without ever knowing, and can live quite happily with it for the rest of their lives. It can have serious implications for divers, though. Read what happened to one of our members …
It was a normal dive on a normal day, not that deep, not that long, a couple of minutes of deco and a generally relaxing day. We had completed two, hour long dives on the Zenobia in Cyprus. A relaxed day at the end of the season with friends, what could go wrong…?
About 2 hours after getting out of the water I started to feel tired, I put this down to not eating for a while, and if I was honest I was actually probably a bit dizzy. I put this down to low sugar level. I also had an itchy stomach; again this I put this down to several hours in a dry suit, which I had had before.
The long and short was that I decided to sleep on it despite the nagging feeling that all was not quite right.
Next morning things were still not quite right so I went to be checked only to be told by a very nice Russian hyperbaric doctor that I was bent, a typical type 1 DCS skin bend. Bit of a surprise given that nothing had gone wrong.
I had two sessions in the chamber, US Navy table 6 and table 5, this means a 5 hour and 2 ½ hour session at 20 metres on oxygen. The treatment cleared the bend but the reason for it remained a topic for discussion given the circumstances.
The view of the doctors at the chamber was that I had a PFO and I got bent getting out of the water. More of that later.
Back in the UK I went for a bubble test and it was confirmed that I had a grade 4 PFO, no sizing bigger than a grade 4. So I had the option, give up diving or get it fixed. I am going through the process , have had further tests and a operation to fill the hole , all going well and hopefully will be cleared to dive again in a couple of months.
The fixing of the problem is a bit of a side issue, the bigger issue is how and why and managing the risk.
PFO, or patent foramen ovale to give it the full name is the hole / flap/ tunnel that links the 2 lower heart cavities. When in the womb and our lungs are not needed our bodies circulate blood through this hole. At birth the hole is meant to seal naturally but for up to 25% of the population this doesn’t happen. For normal life this is generally not an issue but evolution had not foreseen diving. The right side of the heart receives blood from the body and pumps it to the lungs.
For divers this is blood full of dissolved gas that needs to be exhaled. The left side of the heart gets clean oxygenated blood from the lungs to pump around the body. So a hole between the 2 chambers will allow dissolved gas to be re-circulated back to the body. It is this process that leads to a skin bend. This is know as a right-left shunt.
Depending on the size of the PFO this can occur continually or intermittently; it is more significant when stressed. Imagine the action of clearing your ears, this is a process of sealing and pressurising your lungs, this process stresses the heart and should you have a PFO will cause the flow through it to be increased. It is this type of stress that shunts blood across the PFO and puts blood with dissolved gas straight back into your arterial system.
This type of stress can be caused by exertion getting out of the water, struggling to get fins off etc. So the key thing is take it easy at the end of the dive.
1 About a quarter of divers have a PFO and so are at an increased risk of a skin bend.
2 You can still get a skin bend even if you don’t have a PFO.
3 The PFOs vary from the small to the significant.
4 Avoid physical stress getting out of the water and immediately after. This is something we are told, but I for one did not make the connection with increased risk of skin bends for those divers with PFOs.
5 The Hyperbaric doctors in Cyprus believe that tiredness contributes to a bend just like dehydration; I was tired when I got bent.
6 Skin bends and other bends can occur even when following good practise and planned dive profiles – they can happen; if you think you have a bend get it seen to.
7 Should you get tested for a PFO – tricky question, the NHS does not nationally recognise the connection between DCS and PFOs (England.nhs.uk reference: NHSCB/A09/PS/a) which means that you may or may not be able to get treated on the NHS. The policy on treatment varies area to area so there is a risk that if tested positive treatment to resolve it may not be forthcoming which will mean that as far as travel insurance companies are concerned you now have a pre-existing condition so will not get cover for diving abroad. From my own experience I suggest you keep diving and if you do get bent deal with it then. If you have private health insurance resolution is more straight forward if not then use your GP to push the issue.