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Re: Respiration rate and thumps



Hi Lynn,

Does an elevated respiration rate due to thermoregualtory needs have the
same effect as described in your post quoted below?

Ramey and Cynthia Peticolas-Stroud
Cascade Endurance Center
Lyons, Oregon


LYNN M. Crespo wrote:
> 
> Just had to jump in here and offer a little physiology lesson.  With
> regards to the question as to whether or not a high respiration rate could
> induce thumps the answer is yes.
> 
> When the respiration rate is high carbon dioxide is being eliminated from
> the body.  In the blood some carbon dioxide is converted to carbonic acid.
> This acid helps to balance the pH of the body.  When carbon dioxide is
> quickly eliminated the body is losing its natural acid and becomes
> alkaline, in other words a respiratory alkalosis has been induced.
> 
> A key point is that when alkalosis is induced, potassium in the
> bloodstream is shifted to the inside of the cells, so that even though no
> total potassium is really lost from the body it is in the wrong place, and
> the metabolic consequences are the same as if the horse was deficient in
> potassium, in other words hypokalemic.
> 
> In addition, the change in serum pH also affects the binding of calcium in
> the bloodstream also complicating the situation.  The net effect is a
> respiratory induced clinical situation presenting as thumps.
> 
> When respiratory rates induce these changes in the pH of the blood, there
> will be compensatory changes in how the kidneys operate to try to
> normalize the situation.  Any change in pH, whether it originates in the
> lungs or the kidneys will lead to other compensations.
> 
> Thumps (synchronous diaphragmatic flutter) has been induce experimentally
> in animals through either making them potassium deficient, or by changing
> their pH.  By the way, when horses do become potassium deficient, the loss
> of electrolytes will also induce a change in pH, making them alkalotic.
> It's the chicken and the egg story,  potassium deficiency leads to
> alkalosis, and alkalosis leads to potassium deficiency.  In endurance
> horses there are both metabolic and respiratory influences occuring
> simultaneously.
> 
> To manage the situation electrolytes are an absolute necessity, and for
> those horses that are rapid breathers or panters, slowing their
> respiratory rate is also important.
> 
> Lynn
> 
> L. M. Crespo, Ph.D.
> Associate Professor and Chair
> Department of Pharmacology
> Nova-Southeastern University
> 
> lynn@hpd.acast.nova.edu



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