The hypocalcemic effect of inorganic sulfate infusions.
Inorganic sulfate is a divalent anion that forms a soluble ion-pair complex with serum calcium, but the extent to which infusions of sulfate salts may depress the concentration of ionized calcium has never been quantitated. In a study of 9 patients who received sodium sulfate infusions as part of a standard diagnostic workup for their renal tubular acidosis, we observed a decrease in mean ionized calcium (adjusted to pH 7.40) from 1.15 +/- 0.01 to 1.04 +/- 0.02 mmol/l (p less than 0.01). The changes in ionized calcium were highly correlated with those in serum sulfate (r2 = 0.95; p less than 0.01). Quantitatively, an increase of 1 mmol/l in serum sulfate was associated with a decrease of 0.017 mmol/l in ionized calcium, a result that is in close agreement with in vitro data based on simple salt solutions. Diagnostic sulfate infusions should be used with caution in any patient predisposed to hypocalcemia.
Cole
D E
DE
Department of Pediatrics, Dalhousie University, Halifax, N.S., Canada.
McPhee
M D
MD
Crocker
J F
JF
D000141:Acidosis, Renal Tubular / Q000097:blood*; D000293:Adolescent; D002118:Calcium / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D006996:Hypocalcemia / Q000139:chemically induced*; D007223:Infant; D007262:Infusions, Intravenous; D013431:Sulfates / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood; D013997:Time Factors
D013431:Sulfates; D002118:Calcium