Getting bent again...what's the story

[miketsp]

..snip..
Because age is a factor, in those cases where persons dove for decades but never got bent, then perhaps due to age, weight (that comes with age), injuries (as bones become more frail, and other bodily problems occur more frequently) , these factors and others cause them to get that first hit.
..snip..

I was not aware that age as a factor has been proven, other than the fact that there may be an increased obesity and lack of physical conditioning with age.
AFAIK studies purely on the age factor are inconsistent.

 

[Dr Deco]

Hello readers:

Physical fitness is related to DCS susceptibility. Weight and age are debated. References are given below.

Dr Deco :doctor:

References (reduced for this FORUM) :book3:

[1] Webb JT, Pilmanis AA, Balldin UI, Fischer JR. Altitude decompression sickness susceptibility: influence of anthropometric and physiologic variables. Aviat Space Environ Med. 2005 Jun;76(6):547-51.

INTRODUCTION: There is considerable variability in individual susceptibility to
altitude decompression sickness (DCS). METHODS: There were 240 subjects who participated in at least 4 of 70 exposure profiles in which between 5 and 95% of all subjects tested developed DCS symptoms. An index was used to identify the relative susceptibility of subjects for use in analyzing possible relationships between DCS susceptibility and the variables of height, weight, body mass index, age, percent body fat, and aerobic capacity. RESULTS: The DCS incidence was 46.5% during 1879 subject-exposures by subjects exposed at least 4 times. A significant relationship existed between higher DCS susceptibility and the combination of lower aerobic capacity and greater weight (p < 0.05). DISCUSSION: Despite a correlation, less than 13% of the variation in DCS susceptibility was accounted for by the best combination of variables, weight and VO2max. CONCLUSION: Differences in DCS susceptibility cover a wide range and appear to be related to some anthropometric and physiologic variables. However, there was insufficient correlation to allow prediction of an individual's susceptibility.


[2] Conkin J, Powell MR, Gernhardt ML. Age affects severity of venous gas emboli on decompression from 14.7 to 4.3 psia. Aviat Space Environ Med. 2003 Nov;74(11):1142-50.

INTRODUCTION: Variables that define who we are, such as age, weight and fitness
level influence the risk of decompression sickness (DCS) and venous gas emboli
(VGE) from diving and aviation decompressions. METHODS: Our data are from 7 different NASA tests where 188 men and 50 women performed light exercise at 4.3 psia for planned exposures no less than 4 h. Subjects were monitored for VGE in the pulmonary artery using a Doppler ultrasound bubble detector for a 4-min period every 12 min. RESULTS: Age was significantly associated with VGE. CONCLUSIONS: Our selection of tests produced a wide range of the explanatory variables, but only age,and height was helpful in various combinations to model the probability of DCS and VGE.

 

[mnj1233]

This really was a thorough response from Dr. Deco. But I felt I never got closure ... so after searching around and not finding a thread that really nailed this down I'm going to try rephrasing the question:

Does getting bent once increase susceptiblity even in the absence of all other "Trouble Spots"?

Is there a case where a non-susceptible diver who was bent previously for hitting a "Trouble Spot", later got bent again but no "Trouble Spot" or susceptibility could be identfied?

I had a situation I was concerned about within the last couple months. Called DAN, asked all the questions your asking and was told there was NO increase in susceptibility. Who ya gonna believe???? I personally think the jury is out. That said Im erring on the side of caution.

 

[Dr Deco]

Hello readers:

In the absence of provocative events (eg, heavy exercise, large dissolved nitrogen dose, dehydration, etc.), an incident of DCS might indicate that one is a more susceptible-to-DCS diver. In that case, one case of DCS might indicate that conservative diving is in order.

I am not aware that one case of DCS, of and by itself, makes one susceptible to another case. In other words, you do not become &#8220;sensitized.&#8221;

Dr Deco :doctor:

 

[mnj1233]

Hello readers:

In the absence of provocative events (eg, heavy exercise, large dissolved nitrogen dose, dehydration, etc.), an incident of DCS might indicate that one is a more susceptible-to-DCS diver. In that case, one case of DCS might indicate that conservative diving is in order.

I am not aware that one case of DCS, of and by itself, makes one susceptible to another case. In other words, you do not become “sensitized.”

Dr Deco :doctor:

Doc why the angry face on the post???

 

[Dr Deco]

That is supposed to be a "questioning face."

 

[kraken]

Is it correct that once you have been bent in an area if you are bent again it will be harder to treat?

 

[sky50960]

Hum and what about PFO in 25 to 30% of the divers...?

 

[sky50960]

Many people do dive with unknow PFO... but DCS is not that frequent.
If you get bent and having a PFO, Does it mean that the DCS is due to the PFO???????????

 

[DiverBuoy]

Hello readers:

In the absence of provocative events (eg, heavy exercise, large dissolved nitrogen dose, dehydration, etc.), an incident of DCS might indicate that one is a more susceptible-to-DCS diver. In that case, one case of DCS might indicate that conservative diving is in order.

I am not aware that one case of DCS, of and by itself, makes one susceptible to another case. In other words, you do not become “sensitized.”

Dr Deco :doctor:

Thank you sir. I respect your work in this field. This answer, derived from your knowledge and experience on this subject, assuages my curiosity and resolves the debate for me. I am deeply grateful for such a ludicly articulated response.