Dry Dive London Hyperbaric Medicine 26/02/11

Report by Steve & Jacqui Mudie  

The five intrepid BUDC dry divers including Simon and his natty bag of important ‘diving papers’ arrived at the centre in wonderful Whipps Cross at 10.00am on a cold rainy Saturday morning and were introduced to the in-house team, two (PADI) strangers joining us for the dive and as much tea, coffee and water that we could drink.

Wayne Ford, our instructor and experienced diver (PADI), gave us an in depth briefing about the chamber and what would happen during the procedure. He explained that because of the increase in oxygen levels, fire risk posed a potential hazard so only cotton underwear and scrubs were to be worn. Makeup had to be removed because it always contains some oil. This caused some distress among those chaps who felt ‘naked’ without their mascara!  We were warned about the noise during descent and the heat and subsequent cold on ascent.

We were measured up for oxygen masks and given our scrubs to change into and then all took our seats in the chamber. Wayne had us put on our masks to make sure they were a perfect fit and were then hung beside each of us. Our computers were all placed in a bucket of water within the chamber because they are tested under pressure in water not air and might be damaged otherwise. Wayne then explained we would have to clear our ears almost continuously on the descent because it is a reasonably rapid process. It was and we did until he explained how you can take a large breath and while holding it keep pressure on your ears which equalized pressure constantly while you held it. This made the descent more comfortable.

When we reached 40m the noise stopped and we were all given a sheet of questions to answer before taking a speed reaction test. This involved Wayne holding a ruler against the door and us holding an index finger level with the bottom. When we confirmed ‘ready’ Wayne let go of the ruler and we had to stop it with our finger, with Wayne measuring the distance traveled. We all managed the task with varying reaction distances but, according to Wayne, all were very quick, even the PADI divers!

At 40m, our voices all sounded like we had sucked helium from a balloon, or according to Steve and Paul made them sound like George Formby. Without needing any encouragement they rattled off a couple of the great man’s ‘classics’ including; ‘When I’m cleaning windows!’

It is fair to say that we experienced different levels of narcosis, however for Steve and Paul this was hard to tell as they always seem to act as though they are ‘narced!’ Ironically, Wayne seemed to be the worst affected, although he had predicted this would potentially happen. It was interesting to observe how his thinking time slowed, especially when he asked Jacqui if she was left or right handed for the reaction test but didn’t seem to understand which was right until Jacqui showed him which finger she would use and so which side she would stand on.

We all felt a little tipsy when we reached 40m but in the main all felt clear headed almost immediately. That said one wouldn’t have attempted driving if it was the effect of alcohol we were feeling. We had 5mins bottom time then began the ascent. We put on our oxygen masks and blankets were handed around for protection from the sudden drop in temperature. With not enough blankets to go round, Simon demonstrated that his reaction times were not unduly affected by sharing with Jacqui. A possible reason why his bag seems to go missing! 

We were told to breathe deeply into the masks as this would help get the oxygen into our systems and the nitrogen out during our accelerated decompression. We took 5mins to reach 9m, the chamber was very cold and quite noisy with all our heavy breathing. There was also a lot of fine mist making the air very damp. We stayed at 9m for 2mins then had a 1min ascent to 6m where we stayed for 10mins. We took 1min to ascend to the surface and we all took our masks off.

The total ‘dive’ lasted 35mins and it was interesting to observe that our computer depth readings varied from 40.1m to 40.4m, despite that they were all Suunto. The temperature rose from 22°C to 35°C on descent and dropped to 18°C on ascent, hence the mist and thermocline experienced.

Another interesting aspect of the ‘dive’ was observing the pressure impact upon a plastic bottle hanging from the ceiling during descent and ascent and the expansion and contraction of a balloon. Wayne made the mistake of trying to be helpful by giving a general explanation of the pressure impact upon air volume in the balloon, only to be confronted by BUDC’s very own Dr. Dave Witcher studying ‘physics,’ who took the discussion to another level and of course was proved to be right.   

We then changed back to our civvies and had a debrief and presentation on how the chamber is used on a day-to-day basis and the types of treatment available. We were very interested to learn that hyperbaric chambers are used to treat much more than decompression illness (DCI) and carbon monoxide poisoning, especially compared to treatments offered in Europe and the US. Wayne’s passion for his work made the presentation hugely enjoyable and with a doctor also in attendance to elaborate upon discussion points, the whole experience was thoroughly worthwhile and to be recommended to all divers, whatever their qualifications.

Whilst we as divers are aware of DCI, it was again interesting to hear of DCI examples, with a large proportion of ‘sufferers’ not acknowledging that their aches and pains were caused by DCI. If there was one big lesson from the outing, it was; ‘If in doubt, call the centre.’ Do not feel embarrassed if you think you might have DCI. I can happen to anybody.

The visit concluded with a brief tour of the facility, seeing first hand how the chamber works before saying our thank you’s and goodbyes after having had to wait for Simon to find his missing bag (shouldn’t have got cosy with Jac then should he?).

The fun boy three of FJ, Dr. Witcher and Blanket Boy headed off to make use of public transport for their return journey, whilst the Mudie’s set the sat nav for home via the Olympic Park and athletes village site seeing route.

A very worthwhile day out.