Pages

Saturday, November 10, 2012

Laboratory findings in metabolic acidosis:


Bicarbonate concentration have been used to estimate pH and pCO2.
E.g. if HCO3- = 10 mmol/L

Then for pH determination,
10 + 15 = 25, Thus pH = 7.25

For estimating pCO2 (mm Hg), following formula is used:
pCO2 ± 2 = 1.5 (cHCO3-) + 8
1.5 (10) + 8 or 23 ± 2 is pCO2.

Electrolytes are also altered depending upon the cause of metabolic acidosis. Eg. in diabetic ketoacidosis (DKA), the increase in organic acids caused by increased ketone bodies is reflected by decrease in plasma bicarbonate and sometimes chloride. Plasma sodium and potassium are also decreased due to polyuria and coexcretion with acetoacetate and beta hydroxy butyrate. Fruthermore, because of high glucose, there is dilutional effect as a result of osmotically induced increase in vascular volume. When glucose concentration decreases following insulin treatment, water leaves the vascular compartment and sodium concentration increases.

Chronic metabolic acidosis enhances mobilization of calcium from bones; the decrease in plasma pH increases dissociation of plasma proteins bound calcium so that more calcium is filtered through the glomerulus and less is reabsorbed. 

No comments:

Post a Comment