two 'undeserved hits' in 7 days - help

[Rick Inman]

And, in the process, divers would become more educated and perhaps others would not have to repeat the same mistakes. Instead, we hear "undeserved hit" and we accept it, learn nothing, and move on.

You're off topic. But I like it, so I'll chime in.

I got what many called an "undeserved hit" some time ago. Yes, my computer said I was within NDLs. What it didn't know was that I was dehydrated, middle aged, it was cold water (40's), that I was freezing cold, that I had to urinate badly (all that coffee I'd had all day prior to the dive), that I exerted myself immediately following the dive (ran with my gear on up a hill and over to the porta-potty), and that I went right home and took a hot shower.

An undeserved hit... right? Actually, I can't think of a recipe for deserving it more. Which is why I now disagree with the prevailing concept of riding a computer that knows nothing about your age, your weight, the water temp, or a hundred other things that might contribute to DCS.

I'd really like to rename "undeserved hit" to "computer-rider hit".

 

[DeepSeaExplorer]

I had a buddy that got a 'Computer-rider hit' on his first post-training deco dive when we missed the wreck at 165ft and had to abort. On descent, I couldn't clear my ears quickly enough and got separated, left behind actually. I continued down at a slower pace expecting to find the other divers on the wreck. No luck. We ended up doing our ascent alone and didn't have the benefit of buddy communication. During my ascent, I switched to deco gas and was okay. He stayed on back gas thinking he wasn't in deco, according to his computer, and came up quickly hoping for a second drop. We didn't know at the time that apparently some computers won't calculate deco correctly for deep bounce dives.

My big hit a few years back was due to dehydration. I decided to have a soft drink the morning of the dive instead of water since I was up late the night before getting mix. Then, I ended up deeper and longer than planned and over-exerted myself on the dive wrestling with the anchor. Some told me it was undeserved, but when I started thinking about it, I knew it wasn't. Of course, I continued to let them believe it was...

 

[TekDiveGirl]

I once took an "undeserved hit" --- I had classic DCS symptoms and rode the chamber for a straight table 6 after a 30 minute 40' dive. Well turns out it wasn't so undeserved as many years later and a lot of diving I ended up taking another much more severe "undeserved hit" --- after this it was pretty obvious that I had a PFO so I asked to be tested and sure enough bubbling was clear as day! So some "undeserved hits" may just be masking other issues and truly be deserved.

 

[Dr Deco]

Hello readers:

“Underserved”

The term “underserved hit” refers basically to tissue gas loading. In actuality, decompression bubbles do NOT form during decompression but rather grow from preformed micronuclei. These nuclei are incorporated into the RGBM, and they determine the position of the deep stops. Preformed nuclei are not a part of virtually any other commn decompression tables. Likewise, the idea of them is not taught – unfortunately.

My Decompression Physiology class and this ASK DR DECO forum are the only places where the concept appears with regularity.

Nuclei

In the RGBM, nuclei are generated - and regenerated - by thermal activity over a period of days. Dr Wienke has algorithms to calculate this. These micronuclei are then incorporated into the decompression algorithm, taking into account gas tensions, bubble radii, and the surface tension of the body fluid.

I the system that I developed for NASA, the nuclei are generated by musculoskeletal activity, i.e., physically moving around and lifting.

Current Tables

Because virtually all dive tables are based on gas loading ONLY, they attempt to explain everything in terms of uptake and elimination. This means that we have water temperature, dehydration, and underwater swimming. These play a role, but they are not big players.

NASA

Based on research by others and me, NASA does not consider, weight, age or gender in its decompression calculations for EVA astronauts. It only considers gas loads and physical activity.

Take a clue.

Dr Deco :doctor:


The next class in Decompression Physiology for 2007 is August 18-19. :1book:
This class is at the USC campus in Los Angeles.
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[LavaSurfer]

Hello readers:

“Underserved”

The term “underserved hit” refers basically to tissue gas loading. In actuality, decompression bubbles do NOT form during decompression but rather grow from preformed micronuclei. These nuclei are incorporated into the RGBM, and they determine the position of the deep stops. Preformed nuclei are not a part of virtually any other commn decompression tables. Likewise, the idea of them is not taught – unfortunately.

My Decompression Physiology class and this ASK DR DECO forum are the only places where the concept appears with regularity.

Nuclei

In the RGBM, nuclei are generated - and regenerated - by thermal activity over a period of days. Dr Wienke has algorithms to calculate this. These micronuclei are then incorporated into the decompression algorithm, taking into account gas tensions, bubble radii, and the surface tension of the body fluid.

I the system that I developed for NASA, the nuclei are generated by musculoskeletal activity, i.e., physically moving around and lifting.

Current Tables

Because virtually all dive tables are based on gas loading ONLY, they attempt to explain everything in terms of uptake and elimination. This means that we have water temperature, dehydration, and underwater swimming. These play a role, but they are not big players.

NASA

Based on research by others and me, NASA does not consider, weight, age or gender in its decompression calculations for EVA astronauts. It only considers gas loads and physical activity.

Take a clue.

Dr Deco :doctor:


The next class in Decompression Physiology for 2007 is August 18-19. :1book:
This class is at the USC campus in Los Angeles.
http://wrigley.usc.edu/hyperbaric/advdeco.htm

Thanks Doc, I get it loud and clear.
Yours and Dr Wienke's information is a great contribution.
You simplify the information well. Reading Dr Wienke's book almost causes me to get the mental bends and my brain bubbles up.

When I read the initial posters post my first thought was sciatic nerve.
Lugging these tanks around, even under water, can aggrivate the nerves if they are on the edge.
Taking a hit in the exact same place seemed like a real odds buster.

Is there any information on physical condition in relation to decompression.
I run distance and imagine thats a good thing when it comes to cardiovascular health and decompression.

 

[JahJahwarrior]

decompression theory and all that is quite confusing and that's why it's not well understood, even by the experts. However, I think we all know that "undeserved hit" in the vernacular of the diving community means getting bent when you were well within your NDLimits. If you dive a very conservative profile and make a deep stop and a safety stop and you still get bent, we call it "undeserved" even though that might not be the technical term. Maybe it should be called "computer caused hit" instead, but heck, that won't happen until we stop calling Cuttlefish a fish.....

 

[tinglinglegs]

Thanks for your input everybody. Today I went to a neurologist. He ordered an echocardiogram (sp?) to check for 'hole in heart' as well as a brain MRI 3T magnet(?). He had me do some 'exercises' and discovered that my right arm is 'significantly' weaker than my left arm, which I was unaware of. Bottom line - the 2 'hits' may have caused a slight stroke in brain if there is in fact a hole in the heart. Weird. Of course he has to cover his butt, but I'll go ahead and do the tests. He said he would do it sooner than later. I'll let you know. Thanks

 

[TekDiveGirl]

Wow --- I'm so sorry to hear this. After you have your PFO test please let us know the results.

 

[pipedope]

I am going to suggest that all divers learn the 5 minute neuro exam and use it regularly.

If you and your buddy do the 5 min neuro before diving and after, any changes will be easy to spot.
This will give you something solid to work from to say, "I'm fine" or "I'm bent!"
It also gives you something to hang your hat on when activating EMS.

The exam is found at;
http://wrigley.usc.edu/hyperbaric/neuro/neuro.htm

 

[rockjock3]

Off topic.