Narked at 50

This is a strange report to write…we went diving but didn’t get wet! Well, our computers got wet but were left forgotten outside the chamber door and we can’t blame being narked! For those uninitiated, a 50m dry dive is as it sounds and is completed inside a hypobaric chamber—it gives the “divers” an opportunity to feel the effect of a deep dive on air without the risks of DCI. It also allows the diver to feel the full effects of nitrogen narcosis without having to concern oneself with safety…so really, we all went to get drunk without the hangover!!!

Seven of us entered the chamber on the 10th November at Midland Dive Chamber after a very interesting presentation from Robbie on the other uses of HBOT (Hybobaric Oxygen Therapy), which include treatment for long COVID and non-healing wounds. We all changed into very fetching scrubs after the safety warnings of polyester clothing (the ladies amongst us got a little paranoid at the composition of our undergarments—we were assured we did not need to remove them!), doffed our shoes and sat down.

A few of us were concerned about the speed at which we would descend and the pressure on our ears but we were very surprised to find that the initial drop to 3m takes longer than you think, the next progression down to our intended 50m was rapid. We all commented on the change of temperature when it reached 33 degrees on the way down – the effects of Charles’ Law. Our in-chamber guide Andy drew our attention to the various balls and balloons which shrank/changed shape, Boyles law was implosively demonstrated with ping pong balls!

…I think most of us began to feel the effects of narcosis about 30m but boy does it hit you at 50! We were all giggling at the effect on our voices! We all sounded like we were on helium due to the pressure squashing our vocal chords. We were set simple alphabet challenges in pairs which we were all incapable of completing due to fits of giggles! Great fun! I personally also experienced feelings of dizziness and nausea which in honesty made me glad I haven’t experienced it during a dive where prior to this I wouldn’t have understood what was happening.

Our 10 minute bottom time seemed to fly by and it was time to start ascending—the noise from purging air meant we donned ear defenders and again noted the change in temperature. This time the temp plummeted to 15 degrees leaving condensation on the skin and a mist in the air. We stopped at 12m for our first safety stop of 1 minute, then continued up to 9m where we transferred to 100% oxygen for 4mins and then up to 6m. Here we had 22 minutes whilst breathing 100% so Andy talked us through some of the interesting aspects of the chamber itself and relayed some instances of note when treating patients. The idea of spending up to 8 hours at a time for treatment of a bend was quite thought provoking sitting in this slightly claustrophobic tank but its clear that the guys at the chamber make it as comfortable and entertaining as possible with DVD’s, books and an encyclopaedic list of recommended takeaways.

Once back at surface pressure, we tumbled out and spent some time with Robbie around the back of the chamber trying to understanding the intricacies of its operation, the fail safes for fire (which is a very, very scary prospect) and the tables by which treatment is governed. It was also an opportunity to further discuss the effects we’d experienced and why.

It really was a great evening—interesting and entertaining. A great opportunity to giggle with fellow divers, I’m positive Josh didn’t regret inviting us all (he’d originally planned to join a group and go on his own!) Our logbooks signed, the award for the “Squeakiest Voice” given (to me—I literally sounded like a cartoon character!) and changed into our souvenir t-shirts, we wandered into the night! I really would recommend it to anyone!


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