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Dry Diving With St Ives and Bramston Sub-Aqua Clubs

The St Ives and Bramston Sub-Aqua Clubs recently attended one of the Dry Diving sessions at our Hyperbaric Chamber in London. And they kindly made the following report of their day:

A Dive to 40m with Ocean Divers in East London!

Our branch, St Ives SAC (Cambs) 0833, and Bramston SAC attended a Dry Dive SDC at Whips Cross Hyperbaric facility in August.

The intention of the SDC is to remove some of the mythology and apprehension about recompression treatment. The hope is that divers will be more likely to admit the possibility of decompression illness (a bend) and present earlier at the chamber for treatment. Early treatment greatly improves the likelihood of a full recovery and reduces the amount of treatment required.

After the usual form filling (signing away your life), we where separated into two groups. Those from the Bramston club where decked out in hospital scrubs to ensure that there was no risk of introducing combustible contaminants into the oxygen rich environment. Those entering the chamber also needed to be free of makeup, aftershave, hairspray etc. To complete the preparation, each person was fitted with an oral-nasal masks which were to be used on the 9m and 6m decompression stops at the end of the dive.

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So like medical extras from Casualty, the first group of divers from the Bramston branch entered the chamber and had their ‘dive briefing’. The rest of us watched the show from the outside.

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The chamber is controlled via a pre-programmed computer profile of the intended ‘dive’. The chamber operator has overall control and can interrupt or modify the profile if required.

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A peculiarity of a ‘dry dive’ is that you need to clear your ears more frequently during the descent compared with a ‘wet dive’ – basically, once every breath! For the Bramston group this proved to be more of a problem as they halted the descent a number of times as individuals experienced difficulty in clearing their ears. Because of this, the chamber operator modified the profile and ran the chamber in ‘manual mode’. This allowed him to reduce the bottom time to compensate for the longer descent time.

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Next, it was SISAC’s turn to don the green scrubs, fit the oral-nasal masks and take their seats in the chamber. We had the briefing and the oral-nasal masks were each plugged in to their own demand value which would supply 100% oxygen on the stops. Our descent proceeded smoothly and once on the bottom we took part in some exercises to demonstrate the effects of pressure and nitrogen narcosis.

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This included the ‘parachutist’ which took about 2 seconds to fall to the ground outside the chamber and around 10 seconds when we were at 40m where the air was 5 times more dense.

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Then there was the beach ball which compressed as we descended, expanded on our ascent, returning to its original shape at the end of the dive.

The bottle of coke which was shaken violently at 40m and then opened failed to spray everyone demonstrating the effect of gas compression at 40m.

At 40m, we also blew up a balloon and watched it expand during the ascent.

We also carried out a few simple reasoning exercises, reaction tests and puzzles to demonstrate the effects of narcosis on concentration, coordination and task narrowing.

Prior to the ascent phase, we filled a bottle with water and sealed it tightly.

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During the ascent we stopped at 9m where we all put on our oral-nasal masks. Looking like extras in an air force movie, we all started breathing 100% oxygen. There was an initial stop at 9m for 2 minutes followed by the continued ascent to 6m where we continued to breathe 100% oxygen for a further 11minutes. Once we returned to the ‘surface’ we opened the bottle of water which fizzed a little demonstrating the effect of a rapid ascent on the gas dissolved in a fluid.

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 On completion of the dive we had a presentation about DCI, the chamber and the treatments it could be used for – both diving and non-diving related. The presentation was entertaining and educational and we had the chance to ask questions and clear up any misconceptions that we may have had.

Those attending the dry dive had a wide range of diving experience and qualifications – Ocean Dives through to First Class, instructors, nitrox through to trimix, open circuit and rebreathers. We all agreed that it was very reassuring to have seen and experienced the chamber in action and that if we are subsequently unlucky enough to need recompression treatment, a lot of the apprehension would be reduced.

I believe that diver training has ensured that those with obvious decompression or diving related issues directly after a dive are evacuated for treatment quickly, resulting in a high likelihood of a positive outcome. The area that divers are poor at identifying are issues relating to late-presenting symptoms – aches and pains that occur hours after diving.

During the day, the chamber staff reinforced that all divers should be more conscious of those niggles that they may suffer hours after a dive and that they would prefer to be contacted sooner rather later if a diver suspects there is a problem. Whipps Cross Chamber is at its busiest with diving-related treatments, not over the weekend, but three to four days later, when the discomfort from that niggle from the weekend becomes more than an irritation and divers finally acknowledge that it could be more serious!

You can now find out about the Dry Dive sessions we run and even book online on our website

Believe it or not, they are actually a friendly bunch, and the chamber operators are all divers.

I would like to thank all those at Whipps Cross for the time and enthusiasm, and for making the SDC both enjoyable and informative.

Article and pictures, G J Leyshon and S J Miller.

The contact at Whips Cross Univeristy Hospital Hyperbaric Unit was Wayne
wayne@londonhyperbaric.com

 St Ives Sub-Aqua Club (Cambs). Branch 0833

Website www.sisac.co.uk
Forum www.sisac.co.uk/forum
Contact can be made through the website via email.
The Branch meets every Sunday evening (with the exception of bank holidays) from 20:15 – 21:15 at the St Ivo recreation centre swimming pool.

Bramston SAC.
Website http://www.bsac.com/clublanding.asp?section=000140000034

The branch meets every Thursday evening 20:30 at the Bramston Sport Centre.