Am I bent???

[Dr Deco]

Dear Readers:

You can certainly get some forms of decompression sickness in shallow water. These are of the pulmonary barotrauma variety when one does not exhale on ascent to the surface. This barotrauma is not DCS of the “tissue gas bubble” variety to be sure, but it can occur in shallow water. Four feet is the record for dying from an ascent when one does not exhale the gas.

DCS from gas bubble formation (growth, actually) in tissues generally is very difficult at shallow depths unless one dives repeatedly or has surface-supplied gas.

Following the tables or a meter is like the good use of a road map. It will generally tell you where you are in the “pressure realm,” but it not a guarantee that everything will always be OK.

Dr Deco
:doctor:

 

[Uncle Pug]

Originally posted by tchil01
I want to see UP in your pink gear

Dearest Blue.... Uncle is sooooo pleased you are not bent.

 

[blue32]

Originally posted by tchil01


I want to see UP in your pink gear

Ty

T.M.I. :nono:

 

[Liquid]

DennisW-
As Haldane have noticed long time ago, One can not get bent under 10M. On that he based his wrongfull assumption that one can get from being fully saturated at certain depth to half that depth with enough safety. Today we know the ratio is not 1/2, but becouse of the longer compartment is about 1/1.6. Still, within rec.dive limits, getting bent at under 10M is close to imposibble, and the shalower you get it becomes imposible. That, ofcourse, has nothing to do with over-expansion injuries! these injuries are most likely to happen in shalower depths, as Dr Deco pointed out.

 

[Dr Deco]

Dear Readers:

The following indicates that decompression sickness from saturation is shallower than expected by Haldane.

Eckenhoff RG, Osborne SF, Parker JW, Bondi KR. Direct ascent from shallow air saturation exposures. Undersea Biomed Res 1986 Sep;13(3):305-16

Thirty-four healthy human subjects were exposed to shallow air saturation for 48 h [(25.5 fsw) n = 19; (29.5 fsw) n = 15] and then decompressed to 1 ATA (0 fsw) in about 2 min. Symptoms included fatigue, limb and joint pain, headache, myalgias, and pruritus. No subject of 19 was diagnosed as having decompression sickness (DCS) after the shallower exposure, but 4 of 15 were diagnosed and treated for DCS subsequent to the deeper exposure. Almost all subjects in both groups had Doppler-detectable venous gas emboli (VGE) lasting up to 12 h postdecompression. Treated subjects had a recurrence of VGE several hours after the hyperbaric oxygen treatment. Only the duration of VGE, and not the VGE score, correlated with symptoms; and only the subjects body weight and age correlated with the VGE variables. This study indicates that hyperbaric air exposures of this magnitude are not as benign as previously thought.


This is of course for saturation diving, that is, at depth for longer than 24 hours. Shorter exposures would not produce problems from tissue gas loadings.

Dr Deco:doctor:

 

[Liquid]

The Doc, ofcourse (like always) is right. What I said was STRICKTLY for rec diving. As I said, Haldane's assumption was wrongfull, but within limits of rec diving up to 10M is still about right.