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Wayne Ford Chamber Supervisor.

Here at DES we are always looking for things to blog about. So this time we thought we would blog about our staff. Most of the staff here work on a part time basis and therefore have other jobs and hobbies. I thought we would start off with Wayne.


Wayne Ford

CHT, DMT, ALST Supervisor, Instructor & Diver

Wayne has been with the company for about 7 1/2 years. Starting off as a student on our Hyperbaric Operator/Attendant course. Following on, he was offered a few days a month working at our hyperbaric facility in East London. Over the years, the amount of shifts he works have increased, alond with his knowledge of the work. He is now one of our supervisors and works at the unit three days a week. However, he is on call 24/7 – meaning that he can be called in to deal with any of our out-of-hours emergency cases.

Dry Dives

Wayne also coordinates the educational 40 meter dry dives that we run throughout the Winter period.

Topics covered include:
-banned items and why they are banned.
-the clothes we wear and why.
-possible barotrauma damage, O2 toxicity, DCI, nitrogen narcosis and how to avoid these.


We will also talk about the dive profile and the experiments that we will do inside the chamber at pressure. We will discuss when we go on O2 and the different gases we can use such as Heliox 50/50.  There are various experiments inside the chamber show how the pressure affects air and water. We visually show gas bubbles being drawn back into solution, air density and a narcosis test. We use 100% O2 at 9 metres; this is to show the divers what it’s like if they would ever need treatment.

It’s a 40 metre dive, bottom time 15mins and a total dive time of 32mins.Dive computers, cameras/video equipment with housing can be taken in to the chamber; this makes the experience something you can share or use as a promotional tool for your club.

Other Activities

This kind of schedule works well for Wayne. He is also a PADI instructor and a safety diver working with The Underwater Studio based in Basildon.

He can’t always tell us about the different shoots he works on, owing to confidentiality agreements. Although when he is allowed to, we never tire of hearing about the films, pop videos, TV series and varied other projects he has been part of.

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Multi-agency training day

From time to time we take part in ‘Multi-Agency Training Days’. These are full-scale tests of our systems and processes; they help ensure that the various agencies involved can effectively co-ordinate the response to different emergencies.

Decompression Illness Treatment Scenario

The day started with a call from a Police Dive Supervisor advising us of an incident; one of their divers had a rapid, uncontrolled ascent from a depth of 22 metres. Decompression Illness treatment was required quickly; the Police had informed the Coast Guard and a Sea King helicopter had been dispatched for pick-up.

This call was received by the Duty Supervisor at London Hyperbaric Medicine  based at Whipps Cross University Hospital.

Seaking landing in Epping Forest.

Seaking landing in Epping Forest.

Team clearing the area looking for foreign objects

Team clearing the area looking for foreign objects

Diving Emergency – A Logistical Response

When we receive a call of this nature, advising of a diving emergency coming to us by helicopter, the Hyperbaric Supervisor must inform various agencies:


The police need to be contacted as they are responsible for crowd control at the landing zone (LZ) in Epping Forest; this is a public area that’s well used during summer months with picnicking families.


Ambulance crews need to be on site to transport the patient from the LZ to Whipps A+E

Forest Rangers

Epping forest rangers will open up the locked gates around the area to allow access for the ambulance and police, they also help with clearing the area.

Hyperbaric Crew

The hyperbaric crew need to be mobilised to get the chamber ready to receive the patient.

This all needs to be done in a very short space of time; a Sea King helicopter can fly from the South coast to the LZ in about 30 minutes.


The whole exercise can be stressful but also very rewarding when everything goes like clockwork just as it did on this day. The outcome was that the patient was transferred efficiently with no problems and minimal disruption.

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Two weeks in the Red Sea, February 2014

Mattijn’s dive blog – two weeks in the Red Sea, February 2014


Despite the recent political unrest, the Red Sea is still a good place for recreational and technical diving. It’s close to home, cheap and warm! Up till now there has been no violence in the Red Sea towns. Let’s keep our fingers crossed…

This was going to be a two tiered diving holiday. Joran (my 16 years old son) and Emiliano (long-time friend) joined me to do their courses. I finally persuaded Emi to do his OWC and this was the week it was going to happen (I thought). Joran was here to do his advanced nitrox course with Cat from Tekstreme.

We checked in at the old familiar Seagarden hotel in Hurghada. It was 3 yrs ago but they still remembered us. Must have been the tipping… The next day we were surprised to find the recently opened Hurghada Emperor Divers resort in Tia heights in the process of closing down. Declining tourist numbers has had its toll. It did not affect our diving but it was funny to see Joran clinging to the fridge to get a last coke while the whole thing was shifted out. Joran did very well in his advanced nitrox course. See you tube video. He has a natural build in buoyancy and had no trouble at all doing all the skills Cat Braun from Tekstreme threw at him. “Make him eighteen” was all she said. Both father and son can’t wait for that to happen so that Joran can do his tech courses and become an OC or CCR diver as well. Joran loved making dive plans, calculating SAC rates, OTU’s and a theoretical decompression plan. His SMB deployment is excellent. Yes, I am a proud father. I can’t wait for him to be eighteen so he can start with his tech courses OC or CCR.

Emiliano was a different story. He did all his skills but could not get further down then 1.2 meter. His ears just could not equalize. He had a history of glue ears and grommets but both of us thought he had grown out of it. Unfortunately this was not the case. After 3 days of trying he had a grade 2-3 barotrauma and he had to surrender. As there is absolutely nothing to do in Hurghada besides diving, he changed his flight and flew back the next morning.

My challenge was getting used to the combination off a dry suit and a CCR. I had been avoiding it for years but finally I bought a Bare trilaminate dry suit. In February even the Red Sea is cold at 60 msw. The first dives were OK. But my first zodiac entry was ehh….. Experienced dry suit divers can guess what happened. Slowly but surely my buoyancy control got better and after I had learned to squeeze out most of the air before rolling off the zodiac, I started to like my new suit.

The Emperor Elite

Friday I boarded the Emperor Elite for the technical safari. Joran played hideaway for one night in my cabin and flew back to Schiphol very early in the morning. At 9 AM the boat left for Gota Abu Ramada to do our check out dive. I use an Evolution plus with PLDT travel frame.  Two x 3 litre cylinders,  2 x 10 L bail cylinders and the dry suit created the need for 12 kg of lead. Who said that CCR is less heavy compared to OC….

Tekstreme is a red sea based company. Apart from doing technical courses the whole year round, they organize technical safari’s 3 times a year. I have done practically all of my OC and CCR training with them. This time there were 13 divers plus 3 Tekstreme staff members. A German, a Fin, Brits, a Russian and the odd Dutchman. Experience varied from a recreational CCR diver up to very experienced hard core OC divers who do 120 m plus. It is a bit like a floating hotel. This time there were two chefs in the little kitchen, one was a pastry chef! Everybody has put on weight, that’s for sure. The dive deck is very impressive. Loads of equipment, cylinders and a blending panel.

Time to set up my equipment, check the rebreather. Oh no…. cell failure of nr 3! Before leaving Holland I had replaced all of my cells as they were getting old. Now I had no spares left. Cat Braun was kind enough to give me a replacement cell. Scrubber changed, zipper waxed and fluid repleted, I was ready for the safari’s first dive.

Date Location Max depth Run time Dil mixture  
22-2-14 Gota Abu Ramada (reef) 13 44 air Check out dive
22-2-14 Umm Gamar (reef) 40 51 air  
23-2-14 Rosalie Muller (wreck bombed in 1941) 40 61 air Explored stern section
23-2-14 Rosalie Muller bow section 43 69 air Bow section, engine room too silted out to enter
24-2-14 The Lara (wreck) 60 20 min @ 60 msw, TRT 71 min Tx 16/35 Searched for 10 min!, could only explore the top part
24-2-14 Reef dive       Skipped the second dive because of N2 load
25-2-14 Thomas canyon 60 20 min “60msw, 10 min@45msw, TRT 80min Tx 16/35 Very nice dive!

See you tube video

25-2-14 The Dunraven (wreck sunk in 1876)       Grrrr

Cell failure again, no dive…..

26-2-14 Jolanda and shark reef 34 61 Tx 18/25 No deco dive, see you tube video for all the bath tubs and toilets
26-2-14 Abu Nuhas 30 110 Tx 18/25 Crazy dive
27-2-14         Very strong wind and waves, skipped the dive

The last dive was a memorable one. My two dive buddies, Ron and Craig wanted to do all four wrecks at Abu Nuhas in one two-hour dive! Kimon M, Chrissola K, the Carnatic  and the Giahannis D (all in the 20-30 msw range) We spent 15 min at each of the first three wrecks and all was fine. However, it was the swim between the wrecks that got us. After 90 min, with the Giahannis D looming in the distance, Ron was knackered (at least that was what he wrote on his slate) and it was time to abort the dive. He went up and then it I found out that Craig still had 25 min of deco to do. He was on OC, me and Ron were on CCR and had no deco time! LOL.  See Abu Nuhas: The Movie

Dive medicine

I had brought my V-scan (a very portable transthoracic echo machine) to get experience in doing post-dive TTE’s to look for bubbles. As the resolution of this midget machine is not as good as that of his big brothers I needed an echogenic diver with a considerable nitrogen load to begin with. Guess who was the Guiney pig. Joran did an air dive very close to his NDL. Fourty minutes post-dive some bubbles were discernable in his right ventricle. Then I echoed two technical divers 40-60 min post-dive. No bubbles! Perhaps not surprising as they had a thorough decompression with 80% oxygen.  Next step is to look at a technical diver at the end of a week of repetitive diving. Most technical divers are very interested in dive medicine. I gave a talk about decompression theory/ physiology and pre-dive optimisation strategies. Especially pre-dive exertion and the use of post-dive oxygen got their attention.

It was a very good trip. I have learned to dive with a dry suit and I have made new friends.  The after party was memorable as well! See Tekstreme diving blog. My next tech safari will be in September this year.

Mattijn Buwalda, anaesthesiologist-intensivist DMP DESA EDIC

Hyperbaric physician @ London Hyperbaric Medicine

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Oxygen Toxicity: Too much of a good thing.

Oxygen is necassary for life, but as divers we are exposed to higher partial pressures of oxygen (pO2 or ppO2) than normal. A partial Dr Oliver Sykespressure is simply the fraction of the total pressure that an individual gas takes up in a mixture of gases. Therefore 21% oxygen at sea level has a pO2 of 0.21 bar.

There are 2 main types of oxygen toxicty that we need to limit, which are pulmonary (lung) and neurological oxygen toxicity. In order to obtain energy from food, oxygen is used to break strong molecular bonds at the cellular level and is necessarily a fairly reactive species. As humans, we have evolved to use oxygen at 0.21 bar and even a pO2 of 0.5 bar begins to overwhelm the body’s repair mechanisms very slightly. This pO2 is only 50% O2 at sea level or 25% O2 at 2 bar or 10m. Therefore 50% oxygen is not recommended for over 24hrs in healthcare settings due to lung oxygen toxicity. Unless absolutely necassary. With much larger increases over shorter periods, such as a pO2 of over 1.4 bar during diving, neurological oxygen toxicity becomes the main worry. This is manifested in violent fitting (uncontrolled movements of the arms and legs) and is often fatal when diving. Unfortunately drowning is common and ascent is dangerous due lung barotrauma from a closed wind pipe. Therefore even a full face mask is not safe and the only treatment is to reduce the high pO2. Unfortunately stressors make neurological oxygen toxicity more likely during diving and include exercise, cold, poor vis, nitrogen narcosis, raised blood carbon dioxide levels and psychological stress. These are present on all dives and for everyone to some degree.

During recompression treatment, the chamber environment does not risk drowning and we minimise the stressors. We also use air breaks to limit the time spent at high pO2 levels and therefore use 100% O2 to greater depths than in water.

Overall, neurological oxygen toxicity is a very rare event in chambers and simply requires the diver to be taken off oxygen. Given that recompression is a treatment, the additional risk from oxygen toxicity is therefore acceptable and the pO2 limit is significantly higher in chamber treatments. But only with good reason.


Question 1:

What do you do if a diver fits underwater?

100% O2 should not be breathed below 4-6m, as this gives a pO2 of 1.4 to 1.6 bar. If a diver is using breathing gas mixes enriched with oxygen and then fits at depth, the cause is likely to be oxygen toxicity and switching to the wrong mix can cause this. Ascent is clearly dangerous due to lung over expansion injury, but may be the only way to ensure help can be given. Make sure you are aware of this problem and are able to cope with it. Essentially, follow the guidence from your training agency at all times.


Question 2:

Are there any preceding symptoms prior to an oxygen toxicty fit?

Yes there are. These include blurred vision, ringing in the ears, nausea, twitching, irritability (anxiety, restlessness) and dizziness, which can progress to convulsions (fitting). These can be remembered with the letters VENTID-C  and can be difficult to pick up when diving. (Vision, Ears, Nausea, Twitching, Irritability, Dizziness, Convulsions)


Question 3:

What happens if someone has an oxygen fit in the chamber?

Our chamber attendants are trained to recognise the preceding symptoms and will take the diver off oxygen. If there is a convulsion, then they will pad the moving limbs and the fit will stop once off oxygen. Chamber pressure must not be altered during a fit. There is no long term damage, it is not epilepsy and has no impact on future diving or driving. We would then decide whether to continue the treatment or shorten it, depending on the reason for treatment and the state of the patient.


Question 4:

What is pulmonary (lung) oxygen toxicity?

The airways become narrower as a result of inflammation. There is often midline chest pain, cough and reduced lung function tests. Diving is unlikely to produce sufficient oxygen exposure. However some of the more extensive treatments for decompression illness may cause a degree of pulmonary oxygen toxicty. Thankfully this is often completely reversible.


Question 5:

Are air breaks useful in preventing oxygen toxicity at sea level?

Important: Do not use air breaks when using oxygen at the surface in an emergency situation, this is unnecessary and deprives the diver of a very important treatment.


A video from Divers Alert Network DAN follow the link below :

CNS Oxygen Toxicity – Richard Vann PhD