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Catfish Dive & Safari
Dive Medical questions & answers for common scuba diving conditions and illness provided in conjunction with the doctors at the London Diving Chamber and Midlands Diving Chamber.
All Categories » Respiratory Problems » Pulmonary Oedema


I am a fit, healthy 25 year old who plays a lot of sport. I have done 70 dives with 60 being in temperate waters around Britain and Ireland. I have done all my dives in a wetsuit.

I developed what I believe now to be cold water induced pulmonary oedema on my 50th dive. The oedema occurred at the end of the dive. I had a chest injury at the time and I felt that that it was due to this. After a year break from diving and consulting a cardiologist, I returned to diving. I had all manners of medical tests: ECG, PFO test, exercise test, CT scan and all showed that I was in good condition.

I kept on diving in my wetsuit. I am cold on my dives but I tend to grin and bear it. Since my return to diving I have done 25 dives. Recently I was doing some deeper and longer dives and on my 70th dive, it happened again, at above 3m. I recognised it immediately, dekitted, got in the boat and put myself on oxygen. Again it cleared in 15 minutes. I went back to see my cardiologist and he suggested that I refrain from diving.

From what I have read in the literature on immersion/cold water induced pulmonary oedema it seems to me that there is a lack of consensus as to whether someone should refrain from diving or not. A diver I know back in Ireland had two cases 17 years ago but has been diving since. I find the advice to refrain from diving a little conservative. The UKSDMC say that since people have begun using drysuits that the number of cases of pulmonary oedema have dropped. I feel that the cold was a critical factor and that if I was using a drysuit this may well not have happened. I don't think you will find many people who have done as much diving as myself in a wetsuit in these waters.

I would like to return to diving but I would definitely be more conservative as regards temperature. Any advice is welcome.


This seems to be a case of pulmonary oedema associated with cold water immersion. The main mechanism behind this is as follows. On land, quite a lot of blood sits in peripheral veins, but when the body is immersed in water, the peripheral veins shut down, and the blood in them physically shifts to the deeper vessels, moving centrally. If the water is cold, the effect is more pronounced. This increases the amount of blood reaching the heart with each pump, as well as increasing the resistance against which the heart is pumping (as the peripheral vessels are shut down). Sort of like a water pump trying to squeeze water through furred up pipes. There is also a theory that the chest constriction caused by a tight wetsuit might contribute. The net effect of all this is to cause fluid to leak out into the lungs.

Bizarrely, the patchy pattern of lung changes seen in pulmonary oedema in divers is very similar to patients who have overdosed on cocaine. But that’s not important right now. What is, is that the changes resolve very quickly with appropriate treatment. The body somehow cleverly shunts blood away from the fluid-filled (non-functioning) alveoli, towards the ones that are still working, so that the lungs can still do their job while the damaged alveoli heal.

Although it often resolves with no long term complications, to have had it twice at your age does suggest some predisposition to it. Interestingly this is similar to high altitude pulmonary oedema (HAPE), in which there is a definite genetic component. Your investigations sound pretty thorough so I would assume they have found no cardiac or pulmonary cause for it.

Certainly this is a grey area in terms of recommendations for future diving. Obvious measures such as dry suit diving and steering clear of cold water would be mandatory. Other than that, however, one of the issues is that the onset of pulmonary oedema is often acute and unpredictable. Personally I would be reluctant to consider diving again other than in very safe and non-challenging conditions.


Hello Doctor, can you give me some general advice please. 2 months ago, my brother undertook a trek to Aconcagua, a 7000m peak in Argentina. His trek had to be aborted when he was diagnosed as suffering from high altitude pulmonary oedema (HAPE). Since he returned to the UK he has recovered quickly and appears fit and well. Like all our family he is a keen scuba diver and had scheduled to go diving in Thailand next month. Do you think his lungs will have recovered enough for him to dive?


Despite being at the opposite end of the pressure spectrum, the pulmonary oedema that affects mountaineers is very similar to that which affects divers. The mechanisms by which fluid accumulates are different, but one effective treatment is to put the sufferer in a recompression chamber, just as with DCI. Happily, the changes of HAPE also resolve very quickly when the victim descends, and within 2 or 3 weeks the lungs are fully functional again. So after 3 months I would imagine he’d be fine to dive again. A set of lung function tests wouldn’t go amiss though, just to be on the safe side.

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