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To: deepreef@bi*.bi*.ha*.or*
Subject: Re: some CO2 and hemo info
From: stibolt@oh*.ED* (Tom Stibolt)
Cc: techdiver@opal.com
Date: Wed, 4 May 94 19:18:53 PDT

>>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 seems to me (I'm just talking off the top of my head right now...) that
>the oxygen concetration at an inspired PPO2 of 2 ATM is high enough above
>"normal" that it would lead to a vascular constriction effect that could
>only be countered by proportionally high CO2 concentrations (i.e., CO2
>
>Yes? No? Maybe?

Not really.  Hypoxia causes vasodilation and hyperoxia removes the
vasodilatory effect.  Hyperoxia does not cause significant systemic
vasoconstriction (people don't lose legs and arms breathing 2.0 ATA O2
in a chamber for instance) as you are assuming so there is no effect to be
"countered" by CO2.

Tom

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