Take a pill to find off the bends

[ppo2_diver]

I'm curious about what the Doc thinks about this article....


http://story.news.yahoo.com/news?tmpl=story&cid=585&e=1&u=/nm/20040324/sc_nm/science_divers_bends_dc

 

[rmediver2002]

I'm curious about what the Doc thinks about this article....


http://story.news.yahoo.com/news?tmpl=story&cid=585&e=1&u=/nm/20040324/sc_nm/science_divers_bends_dc

I wonder if the pill will give me a six pack as well as mimik exercise?

The Navy Experimental Diving Unit has been working on something similar but I think they were looking at specific enzymes. I do not have a specific reference for the research though...

Jeff Lane

 

[Dr Deco]

Hello jhnsndn:

The “Tablet Approach”

This is reminiscent of the news flash that appeared a couple of years ago that indicated that bacteria could prevent the bends. We certainly are folks that love drugs – while at the same time looking for “all natural.”

The study refers to a finding from the laboratory of Dr Alf Brubakk in Norway concerning exercise one day prior to decompression. There was a reduction in DCS in the rats that exercise compared to those who rested. This has been repeated (with Doppler bubbles as the biomarker) in humans. It is truly fascinating work if nitric oxide ( not nitrous oxide) is implicated, as the authors suggest.

The “Exercise Approach” :sprite10:

The truth is, if you have exercised one day prior to diving, you are doing what is suggested by the authors. Far be it from me to say that I also found this (earlier), but for those interested, the Reference is below.

What is of more importance is to avoid strenuous activity during and after the dive, since that will produce micronuclei and DCS could well result.

Dr Deco :doctor:

References :book3:
MR Powell. Exercise and physical fitness decrease gas phase formation during hypobaric decompression. Undersea Biomed. Res., 18 (Suppl.), 61, (1991).

 

[oleras]

may be a better link:
http://www.newscientist.com/news/news.jsp?id=ns99994809

 

[Dr Deco]

Hello Readers:

Comments on the New Scientist article

“This is a totally novel approach," says Brubakk. Until now, all the ways of preventing the bends, such as staying within safe limits, ascending in stages or breathing gas mixtures with less nitrogen, have been designed to limit or reduce the levels of nitrogen in the body. But if you can get rid of the nuclei, bubbles cannot form even when the blood is supersaturated with nitrogen.

Readers of this FORUM for the past several years will recognize that I have stressed the aspect of micronuclei concentration reduction. It is absolutely true that, if you can get rid of the nuclei, bubbles cannot form. That is why I continually return to the topic of reducing physical stress while diving and after returning to the boat. All of the “table and meter techniques” used to rid the body of dissolved inert gas will work less effectively if you then nucleate yourself when climbing back into the boat.

But Brubakk thinks such a drug would allow divers to go deeper or stay down longer. "It's not dangerous if you can prevent bubble formation," he says. A drug would not prevent bubbles forming in other tissues such as cartilage, he admits, but it is in the blood that bubbles cause the most serious forms of decompression sickness.

Most likely the drug would not reduce bubble formation in extravascular regions (= outside of the capillaries and larger blood vessels). That remains to be tested. In such a case, you must then practice good technique and avoid stress-assisted nucleation.

The good news is that this is free; the bad news is that you must actually do it yourself.

Dr Deco :doctor:

 

[dtdiver]

nitric oxide is one of the potent vasodilators known.
it is presently used to dilate blood vessels in the pulmonary circulation by inhalation.
if it gets to the arterial circulation it will such dangerous drops in the blood pressure as to make it unusable.
the reason it can be used by inhalation is that it's half life is so short it doesn't get to the systemic arteries.
sorry no magic bullet here.

dt

 

[kelpdiver]

are already on the market, heavily advertised on sports shows. However, if you want to see why NOT to dive with one, check out
http://www.scubadiving.com/article/0,7424,5-94-0-108,00.html

 

[dtdiver]

it might make it [red]hard[/red] (hehe) to get close to the reef

here's why (in a serious tone) not to:

http://circ.ahajournals.org/cgi/content/full/99/1/168

dt

 

[Saturation]

Hello Readers:

Comments on the New Scientist article

“This is a totally novel approach," says Brubakk. Until now, all the ways of preventing the bends, such as staying within safe limits, ascending in stages or breathing gas mixtures with less nitrogen, have been designed to limit or reduce the levels of nitrogen in the body. But if you can get rid of the nuclei, bubbles cannot form even when the blood is supersaturated with nitrogen.

Readers of this FORUM for the past several years will recognize that I have stressed the aspect of micronuclei concentration reduction. It is absolutely true that, if you can get rid of the nuclei, bubbles cannot form. That is why I continually return to the topic of reducing physical stress while diving and after returning to the boat. All of the “table and meter techniques” used to rid the body of dissolved inert gas will work less effectively if you then nucleate yourself when climbing back into the boat.

But Brubakk thinks such a drug would allow divers to go deeper or stay down longer. "It's not dangerous if you can prevent bubble formation," he says. A drug would not prevent bubbles forming in other tissues such as cartilage, he admits, but it is in the blood that bubbles cause the most serious forms of decompression sickness.

Most likely the drug would not reduce bubble formation in extravascular regions (= outside of the capillaries and larger blood vessels). That remains to be tested. In such a case, you must then practice good technique and avoid stress-assisted nucleation.

The good news is that this is free; the bad news is that you must actually do it yourself.

Dr Deco :doctor:

Without a doubt, and although I've practiced the same for several years it was Dr. D who emphasized the physiologic basis to me and led me to search the older literature for added examples, both in humans and animal studies as far back as the 1940s [many of these papers are now emphasized in the current edition of Bove's 2004 Diving Medicine.]

Several approaches to NO release and bubbles have been published in the past, but Brubakk's work makes it very convincing clear in animal studies enough to make it ripe for human testing, especially considering the drug used in the study itself, isosorbide mononitrate. This is an angina adjunct drug, is relative toxicity free and can be managed by normal people in the right dose. What needs be done now are human trials and an evaluation of an effective human dosage.

Brubakk's results open doors to testing a host of NO reducing drugs and for basic researchers, a source of funding from a drug company eager to find a new market for these drugs.

Together with motion reduction strategies, the drugs offer a adjunct to further lower risk of bubbling in dives, and possibly EVA, you think Dr. D?

 

[Dr Deco]

Dear Readers:

Bubble Reduction :inlove:

As Dr Brubakk states, this medication might reduce the bubbles in the blood stream. Arterialization (other than from barotrauma) results from bubbles in the venous return, either through a PFO or pulmonary shunts. With fewer venous bubbles, the risk of arterialization is reduced. Certainly any problems, e.g. neurological DCS from embolization, would be reduced.

It is very possible that this compound could aid divers and astronauts during EVA as well. Whether exercise immediately prior to or during the dive negates the effect of the medication remains to be seen. It certainly indicates that some degree of chemical manipulation of bubble concentration appears to be possible.

Dr Deco :doctor: