Decompression Sickness a personal experience

Decompression Sickness

Decompression Sickness

The following was written by an Instructor who, at first hand, had the unfortunate experience of a “Bend” and Decompression Sickness.

As a Open Water Scuba Instructor, I know that anxiety and stress are things to look out for in my students, not just specifically about the diving but also generally. Stress raises your heart rate and increases your circulation. An increase in circulation will result in more nitrogen being absorbed in the body tissues. I was not stressed about the diving. Far from it. It was a welcome distraction to my personal situation. However, I was under emotional duress and therefore experiencing stress.

A key factor to consider, and we are all warned of it, is Decompression Sickness.


I did what people do. I got busy! My weekend had started with a run round a very hilly, woody circuit. Normally I run alone a couple of times a week at a comfortable pace and for about 40 minutes. In need of social contact, I joined some friends and ended up running “at pace” for over an hour. It was a push for me, and the hills were a challenge, but I was pleased I had been able to keep up with the others. Running dehydrates you and dehydration makes your blood thicker. This reduces blood flow (“perfusion”) and increases the risk of Decompression Sickness by reducing the body’s ability to release nitrogen.

FACTOR 2: DEHYDRATION (Physical exercise pre diving)

After a large bacon butty (salty!) and a mug of tea (a diuretic), I got a quick shower, changed and then headed off to the pool. As there wasn’t much going on student wise, myself and two other instructors got together in the pool and practiced skill demos for an hour and a half. Diving itself dehydrates you. If you are in a wet suit, your body is in contact with water and the brain sends signals to reduce the actual content of water in your body. You pee more and lose water through the skin.

FACTOR 3: DEHYDRATION (Immersion Diuresys)

My evening was spent with a friend talking. This was accompanied by a few glasses of red wine. It was a valuable evening spent putting my topsy turvy world to rights. I crawled into bed at 12.30pm, pleased to have achieved much in the day and relieved to have talked.

FACTOR 4: DEHYDRATION (Alcohol Consumption)


The arrangements for Sunday’s “fun diving” had been to meet up at Stoney Cove for 10.20am (ish). I was diving with 3 guys I regularly dive with and another guy that I had dived with once a year before. I got a text message from him at 7am. He was already at Stoney! I was awake so I decided to get up there a bit earlier too. I sprang into action Lara Croft style. After some decisive packing, tea and toast to go and (oh dear!) just enough fuel in the tank to get me there, I was on my way up the M1. By 8.35am I was queuing up for the top car park, and by 9.30pm was jumping in the water for my first dive.

Our first dive was to the Stanegarth, a sunken Tug that sits on the 22 metre shelf of the quarry. From there we managed to find the Armoured Personnel Carrier and then it was slowly back up the cliff to the 7 metre shelf for a potter around and safety stop. We were down for 36 minutes. The water temperature was 7 degrees!


The absorption of nitrogen into the body tissues may be slower in colder conditions due to a narrowing of the blood vessels (vasoconstriction). It also means that the release of nitrogen from the bloodstream is also slower, particularly in “slower” body tissues such as fat, nerves and bones which do not receive a large supply of blood.

The other three guys arrived at about 10.30am to find us enjoying our first surface interval with bacon and egg cobs and tea (salty food, diuretic drink!). After 1 hour and 45 minutes on the surface we went down for a dive with the others to the Hydro Box, which sits on the 32 metre shelf.


The second dive was 10 metres deeper than the first dive. This is known as a “reverse profile”. Some textbooks recommend that a second dive should not be more than 12 metres deeper than the first dive. There is no evidence to prove that reverse profiles increase the risk of DCS. However talking afterwards to the dive physician and to the Hyperbaric team, anecdotal evidence is to the contrary.

During the second surface interval I felt tired so, after carrying my tank to the compressor room, I enjoyed a twenty minute power nap lying on the grass in the Winter sun. I was peckish but didn’t bother getting any food and didn’t drink water as I would normally.


FACTOR 9: DEHYDRATION (Not drinking enough water)

After a 2 hour surface interval, we went in for our third dive. We went back to the Stanegarth (22 metres) and I took some photos of the guys on the deck. I am a very slow mover when I dive, but I was moving around more than usual to go in and out of the tug’s hold and to take the photos.


After about 20 minutes I started to feel really cold. I signalled to my buddy that I wanted to go back and we signalled to the others to go on without us. We headed slowly back up the cliff and then, after a safety stop, ascended super slowly up the steps to “the bus stop” to get out.

When I got out I felt really cold. I also felt that my breasts had gone really hard and my nipples were sore. I assumed that this was the effect of having been in the cold water. I now know that this was because my lymphatic system was not draining properly and the lymph nodes under my armpits had swollen up as a result. Swelling is a symptom of DCS.

The classic Symptoms

Key Symptoms of Decompression Sickness.

SYMPTOM 1: SWELLING (Lymphatics not draining)

I ditched my kit, grabbed my bag and swiftly headed for the changing rooms. I used the toilet and then started to get changed. I suddenly felt very weak and light headed. I sat down and asked a lady for water. Then I really started to feel bad so I lay down on the bench and asked her to get my friend from the car park. She used my mobile phone, and when he came in I asked for a sweet cup of tea, thinking that was all I needed!

What happened after that is a bit of a blur. I drifted off. Whilst I remember hearing voices and was vaguely aware of what was happening, I couldn’t command my body to react and respond properly.


I stayed lying on the bench and was put on O2. Then I started wretching and vomiting quite violently.


Someone was asking me to open my eyes. Then they were asking me to touch my nose. I tried to but could hardly move. They were using my name alot. I remember that much. Then there were new voices in the room. The ambulance crew had arrived. They put a drip in (so I’m told) and moved me to the ambulance using a chair. I remember feeling very cold and very tired. I couldn’t move my limbs and I couldn’t open my eyes.

The ambulance took me the short distance to the waiting helicopter and the West Midlands Air Ambulance team took over from there. I heard more new voices, and then bleeping sounds as they hooked me up to the monitors. Whirring blades, and then a ride that seemed to last an eternity to the Hull and East Riding Hospital. I missed seeing the team in their red boiler suits with the very useful pockets. My friend later told me all about it.

Another ambulance took me to the hospital once we’d landed. By the time I was moved to the bed in the assessment room, I was able to string a few sentences together in explanation and could open my eyes to see the people around me. I was beginning to feel more lucid but still didn’t want to move my head as the feelings of dizziness and disorientation were overwhelming.


I had to use a bed pan – lying down, but that’s another story!

Within 3 hours of getting out of the water, I was being wheeled on a trolley into a Hyperbaric Chamber. The first evening I spent 4.75 hours in the company of Darren, a hyperbaric nurse and under the watchful eyes of Angela and Helen who were “manning the submarine” from the outside. My head was enclosed in a small oxygen tent connected to a plastic ring with a rubber neck seal and for most of the time while I as in there I breathed 100% Oxygen. I just lay there feeling like a limp rag doll. My friend and my daughter drove 3 hours to bring my bag and peer at me through the glass porthole. I think I might have waved at them at one point before they headed off back to Milton Keynes.

Afterwards, when they moved me onto the bed in my room, I threw up again, but felt better afterwards!

The following morning I felt better but still couldn’t move my head without feeling really dizzy. My treatment in the chamber was with other patients and so I had to go in a wheelchair. This involved moving which wasn’t a pleasant experience. I was in for 90 minutes this time. All I wanted to do was lie down and keep still.

I want my family and friends to know that the phone calls I received on that Monday and the visit from Kate were a real boost when I was feeling very low indeed.

By the Tuesday morning, I’d managed to get myself up, have a bath and get dressed. This was major progress. I had another treatment and then went home in the afternoon with my daughter and friend. I was still feeling very disorientated and was given drugs to help with this.


Back at home on the Wednesday I was walking around as if I was half drunk. I kept forgetting what I was doing or saying. I stopped taking the drugs as they were making me feel really “spaced out”. On the advice of a friend, I phoned Dr King the following morning. He had seen me only 2 weeks before for my annual dive medical. By 2pm I was sitting in his office in Harley St, London, escorted by my daughter, and by 3.30pm I was in the London Diving Chamber.

The diagnosis was Type 2 Decompression Sickness

The cerebral nerve tissues had been starved of oxygen by the nitrogen bubbles that had formed and the tissues were damaged. This explained my “fuzzy head”. It was like my brain had had some of its “leads” disconnected! The Hyperbaric Oxygen Therapy I received in the Chamber was helping to radically speed up the healing process. On session in the chamber is the equivalent of 3-4 weeks normal healing time.

After the first session in the LDC, this time with an oxygen mask over my mouth and O2 supplied “on demand”, I came out feeling euphoric! I went back down to London on the Friday for a further 2 x 90 minute sessions. This time I came out feeling really queasy and slightly unsteady. I was told this was a normal effect of breathing the O2. Dr Ollie did a few tests. Apparently my “sharpened Rombergs were a bit off”!

I went back on Monday and yesterday (Tuesday) for another 2 sessions a day. When I woke up on the Tuesday morning I felt as though a cloud had lifted from my head. I felt human again! The nausea from the oxygen lasted a couple of hours after the end of each session, but the healing effects were well worth it.

Today is Wednesday. I’ve written this whilst in the chamber for what I hope is my last session. I’m off to see Dr King shortly and I hope that he can see how much of a difference the treatment has made.

Continued Treatment

Quick and repeated HBOT treatment has meant that I have recovered so much quicker than I would have done. I have learnt a great deal about DCS. You have alot of time to read when you are in the chamber. When I’m teaching again I will be much more aware of the risks. Whilst I would never seek to put anyone off diving, particularly novices, I will be reinforcing the education for prevention of DCS as part of my classroom presentations.

This is a highlight why it is valuable for all club members to be able to use and admister Oxygen O2 where Decompression Sickness is suspected or proven.

BSAC have a Skill Developement Course for this.

More Skill Developement Course information may be found Here Many can be actioned within the club. If there are others you wish to attend BSAC opperate national training sessions and advertise via the website.

Under normal circumstances we meet on Sunday nights at One Leisure St Ives (the St. Ives Recreation Centre), with theory lessons starting at 6:30PM and the pool is available exclusively for our training from 8:15PM. One Leisure St Ives Recreation Centre Westwood Road, St. Ives Cambs. PE27 6WU.  

Due to Covid 19 we have suspended all Pool training and Try Dive activities.

St Ives Sub Aqua Club is affiliated with BSAC (British Sub Aqua Club)

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