DIVE DOCTOR: Medical Q&A
Dr Oliver Firth has gained considerable experience in the field of diving and hyperbaric medicine since joining LDC in 2006. He is an Approved Medical Examiner of Divers for the UK HSE, and a medical referee for the UK Sport Diving Medical Committee. He is involved in the management of all types of diving-related illness, including recompression treatment, as well as providing hyperbaric oxygen therapy for non-diving conditions. He remains a passionate diver and has participated in various expeditions and conservation projects throughout the globe.
Q: Hi. I’ve recently started tech diving and have just done the TDI extended range course and am diving around 45m - 65m on air. I have noticed something rather strange when I go beyond 45m: I hear a very loud beat in my head. If I clear my ears with a small blow, the sound disappears, and once I ascend, it stops. I’ve just done a couple of 30m dives and no beat in my head. It has only started since I’ve done deep dives - I’d never heard it before. The sound is like a propeller: thud, thud, thud. It sounds like it’s my heart beat or pulse, but really loud, and it gets louder the deeper I go (below 45m). Is this narcosis, O2 toxicity or (as my buddy thinks) could my Eustachian tube be pressing on a vein due to the increased pressure? Do you have any other ideas as to what it could be?
A: From your description of the sound, it would appear to be a heightened awareness of your pulse, technically termed pulsatile tinnitus. Quite why this should have arisen now and not on previous dives is anyone’s guess, but with increasing depth your Eustachian tubes are likely to be compressed nearer to the blood vessels that are causing the sound, and so I can see some merit in your buddy’s explanation. It tends to be louder with exertion (as your blood is being pumped around with more force), which would also tie in with deeper diving. If you have any middle ear congestion, then the sound will get louder too, as the congestion conducts sound much better than air. It can sometimes be due to high blood pressure, or rarely to vascular tumours in the middle ear – but in these cases I’d expect you to be aware of the symptoms much more frequently, including at night, and when you’re not diving. So on balance I don’t think you need worry unduly. A lot of people get this from time to time, non- divers as well as divers, and it is simply an elevated perception of the big arteries pulsing away in the neck. It is, basically, nothing to worry about.
Q: I’ve been getting some symptoms during and after diving which are worrying me. I went on a Red Sea liveaboard a month ago, which I’ve done many times before. The first couple of days were fine, great in fact, but from day 3, after each dive I started to notice slight bubbling/gurgling sounds in my chest. These got worse over the week, and I started getting burning pains as well. By the end I had to bail out of the last 2 dives as my chest was so sore. I felt sick too, and half the time couldn’t sleep as lying down made it worse. I’m only 40 years old so I was looking forward to a lot more diving. Hopefully this doesn’t mean the end?
A: Don’t panic, this is actually quite a common complaint and thankfully it’s unlikely to end your diving career. These are the typical symptoms of gastro-oesophageal reflux disease (GORD), which are often exacerbated by diving. Think of your stomach as a wine bottle filled with acid, and your oesophagus (food pipe) the long neck of the bottle. Normally a handy little sphincter at the base of the bottle neck stops acid entering the oesophagus. However, in some situations (like being horizontal in the water), the acid refluxes through this sphincter, up the long neck of the bottle, and causes heartburn and nausea. Pretty unpleasant during a dive. The risk factors for GORD are numerous: certain foods, certain drugs, obesity, advancing age and tight clothing are those most prevalent in the diving community. If any of these apply then address them. Luckily there are also plenty of medicines to help. Some coat the lining of the oesophagus, others stop the acid secretion from the stomach, and sometimes a course of “triple therapy” will eradicate pesky bacteria that can contribute to the symptoms. So before your next dive ask your GP to give your gullet the once-over.