M.A.S
Forum Senior
Topics: 28
Posts: 56
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As I know, if ECF volume decreased then acidosis tends to occur; if ECFV increased there will be an alkalosis.
There are special cases (such as: nausea ---> HCl loss and decreased ECF ---> metabolic alkalosis)
But now I have read a different things about renal acid-base control:
In general:
decreased ECFV ---> increased tubular reabsorption of Na ---> increased Na+/H+ exchange ---> increased HCO3- reabsorption ---> METABOLIC ALKALOSIS
increased ECFV ---> decreased tubular reabsorption of Na ---> decreased Na+/H+ exchange ---> dencreased HCO3- reabsorption ---> METABOLIC ACIDOSIS
Which is correct?
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| Larry
Forum Newbie
Topics: 8
Posts: 21
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Both are right.
Large ECF volume decreased, e.g. acute blood loss in trauma or burn, Cardiac output decreased, less tissue perfusion systemically. Meanwhile, Renin-aldosterone system activated, vasoconstriction all over the body. If in lungs, due to vascular constriction, perfusion and ventilation mismatch, shunting increase, leading hypoxia.
Each acid-base imbalance is an overall manifestation from a series of underlying pathophysiologies.
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| meg
Forum Guru
Topics: 62
Posts: 806
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M.A.S.,
acidosis or alkalosis are not all the time based on ECF volume changes but rather changes in ions. So rather than connecting ECF volume changes with acidosis/alkalosis, start from the main pathogenesis for each state, like Larry has mentioned.
Meg
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