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maj75:
Hi maj75,
What is pictured is cutis marmorata, an often intensely itchy area in which the skin becomes pale with dark mottling, giving a marbled appearance.
Helpful?
Regards,
DocVikingo
Pictures of Skin Bends
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Hi maj75,
What is pictured is cutis marmorata, an often intensely itchy area in which the skin becomes pale with dark mottling, giving a marbled appearance.
Helpful?
Regards,
DocVikingo
Nudgeroni
Contributor
As much as the description of the ailment, I appreciate your candor about the denial you had concerning condition. I am amazed at how many accidents happen because we choose to ignore evidence that something is seriously wrong. Ironically, those of us who are the most careful, and plan the most, are sometimes the least likely to pick up on clues that things are not going as planned.
BTW, an excellent book on errors in adventure sport is _Deep Survival: Who Lives, Who dies, and Why_ (by Laurence Gonzales). In a nut shell: many accidents happen because our plan becomes a mental picture in our heads; we invest so much in this picture, that sometimes we choose *it* over reality (especially if reality tells us we can't have as much fun as we were hoping for).
BTW, an excellent book on errors in adventure sport is _Deep Survival: Who Lives, Who dies, and Why_ (by Laurence Gonzales). In a nut shell: many accidents happen because our plan becomes a mental picture in our heads; we invest so much in this picture, that sometimes we choose *it* over reality (especially if reality tells us we can't have as much fun as we were hoping for).
Dr Deco
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Hello poco:
Skin Bends
These are generally thought to arise from gas bubbles that have arterialized (entered the arterial blood circulation) from the venous return (the major venous circulation, the vena cava). It is often suggested that this arterialization occurs through a PFO, and it can also occur from passage through blood vessels in the lungs. Thus, lack of a PFO in an individual does not offer immunity from arterialization.
Bubble Formation
A major requirement is the presence of decompression bubbles in the vena cava. These will arise primarily from capillaries in muscle and fat tissues. Muscle activity contributes to their formation/growth. Underwater this can be intense swimming, which also increases blood flow and gas loading.
It has also been reported that bubbles are released from cutaneous tissue when it is warmed by a hot shower. Warm air was less successful. [1]
Methods of Arterialization
The commonest contributor is a Valsalva maneuver – or a Valsalva-like maneuver. Curiously, straining and coughing produce bigger blood flow changes than a normal Valsalva maneuver [2]. These changes can lead to a reversal of the normal left-over-right pressure gradient in the atria of the heart; arterialization of bubbles results. This has been known for decades [3]. A study [4] reported that 60% of patients with transient global amnesia (TGA) (from arterialization through a PFO) reported a precipitating activity, such as lifting heavy furniture, digging out roots of a tree, strenuous defecation, filling a concrete mixer, and pumping bicycle tires immediately before the TGA occurred. This hypothesis could explain the frequent observation of preceding Valsalva-like activities in patients with TGA.
Another bad maneuver is straining, exerting, and breath holding while climbing a ladder to reboard a boat following the dive.
At NASA, we noted a tendency for recumbent test subjects to arterialize compared to seated ones. [5]
A Problem
One problem for the scuba community is that this information is not being passed along. Possibly many professional hyperbaricists are unaware or do not believe this hypothesis. Instead they drag out that old chestnut “keep hydrated.”
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
References :book3:
[1] Mekjavic IB, Kakitsuba N. Effect of peripheral temperature on the formation of venous gas bubbles. Undersea Biomed Res. 1989 Sep;16(5):391-401.
[2] Balestra C, Germonpre P, Marroni A. Intrathoracic pressure changes after Valsalva strain and other maneuvers: implications for divers with patent foramen ovale. Undersea Hyperb Med. 1998 Fall;25(3):171-4.
[3] Little RC, Opdyke DF, and Hawley JG (1949). Dynamics of experimental atrial septal defects. Am. J. Physiol. 158, 241 -250.
[4] Klotzsch C, Sliwka U, Berlit P, Noth J. An increased frequency of patent foramen ovale in patients with transient global amnesia. Analysis of 53 consecutive patients. Arch Neurol. 1996 Jun;53(6):504-8.
[5] Powell MR, Norfleet WT, Kumar KV, Butler BD. Patent foramen ovale and hypobaric decompression. Aviat Space Environ Med. 1995 Mar;66(3):273-5.
Skin Bends
These are generally thought to arise from gas bubbles that have arterialized (entered the arterial blood circulation) from the venous return (the major venous circulation, the vena cava). It is often suggested that this arterialization occurs through a PFO, and it can also occur from passage through blood vessels in the lungs. Thus, lack of a PFO in an individual does not offer immunity from arterialization.
Bubble Formation
A major requirement is the presence of decompression bubbles in the vena cava. These will arise primarily from capillaries in muscle and fat tissues. Muscle activity contributes to their formation/growth. Underwater this can be intense swimming, which also increases blood flow and gas loading.
It has also been reported that bubbles are released from cutaneous tissue when it is warmed by a hot shower. Warm air was less successful. [1]
Methods of Arterialization
The commonest contributor is a Valsalva maneuver – or a Valsalva-like maneuver. Curiously, straining and coughing produce bigger blood flow changes than a normal Valsalva maneuver [2]. These changes can lead to a reversal of the normal left-over-right pressure gradient in the atria of the heart; arterialization of bubbles results. This has been known for decades [3]. A study [4] reported that 60% of patients with transient global amnesia (TGA) (from arterialization through a PFO) reported a precipitating activity, such as lifting heavy furniture, digging out roots of a tree, strenuous defecation, filling a concrete mixer, and pumping bicycle tires immediately before the TGA occurred. This hypothesis could explain the frequent observation of preceding Valsalva-like activities in patients with TGA.
Another bad maneuver is straining, exerting, and breath holding while climbing a ladder to reboard a boat following the dive.
At NASA, we noted a tendency for recumbent test subjects to arterialize compared to seated ones. [5]
A Problem
One problem for the scuba community is that this information is not being passed along. Possibly many professional hyperbaricists are unaware or do not believe this hypothesis. Instead they drag out that old chestnut “keep hydrated.”
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
References :book3:
[1] Mekjavic IB, Kakitsuba N. Effect of peripheral temperature on the formation of venous gas bubbles. Undersea Biomed Res. 1989 Sep;16(5):391-401.
[2] Balestra C, Germonpre P, Marroni A. Intrathoracic pressure changes after Valsalva strain and other maneuvers: implications for divers with patent foramen ovale. Undersea Hyperb Med. 1998 Fall;25(3):171-4.
[3] Little RC, Opdyke DF, and Hawley JG (1949). Dynamics of experimental atrial septal defects. Am. J. Physiol. 158, 241 -250.
[4] Klotzsch C, Sliwka U, Berlit P, Noth J. An increased frequency of patent foramen ovale in patients with transient global amnesia. Analysis of 53 consecutive patients. Arch Neurol. 1996 Jun;53(6):504-8.
[5] Powell MR, Norfleet WT, Kumar KV, Butler BD. Patent foramen ovale and hypobaric decompression. Aviat Space Environ Med. 1995 Mar;66(3):273-5.
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