Mailing List Archive

Mailing List: techdiver

Message Display

On Wed, 4 May 1994, Jolie Bookspan wrote:

(lots of stuff about the relationship between CO2 & haemoglobin, which I
won't repeat here)

Jolie,

	Many thanks for taking the time to spell-out your knowledge on
this subject.  You've cleared a lot of it up for me.  That's why I enjoy
this forum so much - I learn new things on a daily basis!

Regarding:

> There are several parts to understanding this. First, it is not true that  
> diving deeper, by itself, increases pCO2 in a diver's  body. You do not  
> produce any more CO2 merely for being  underwater. It's not like  
> nitrogen that you are breathing in increased density with increased   
> depth. You ordinarily, and again - note the qualifier 'ordinarily',  
> produce the  same amount of CO2, so pCO2 does not change  with  
> change in ambient pressure as does pN2  and pO2. It is also not true 
> that the exercise of ordinary diving causes CO2 to  build up in a 
> diver's  body in ordinary conditions. Your breathing speeds up 
> during exercise to breathe off the excess and your blood  has 
> powerful buffers to control CO2 level. Increased  CO2 with skip 
> breathing and equipment dead space in helmets, full  face  masks, 
> and rebreathers is another story, as is increased work of breathing at 
> depth and increased gas density. These things may increase CO2 
> retention - another story for another time.          

What effect does hyperoxic concentrations in the blood have on restriction
of bloodflow?  I understand oxygen is a vasoconstrictor - shouldn't
excessively elevated dissolved PPO2 result in constricted perhipheral
vessels & consequently a build-up in CO2? 

> --------
> It ain't so much what we don't know that gets us into trouble, it's 
> what we know that ain't so.  
>         -Will Rogers

Along the lines of my favorite quote:

"A little knowledge is a dangerous thing"


Aloha,

Rich

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]