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.
Department of Pediatrics, Dalhousie University, Halifax, N.S., Canada.
D E
DE
Cole
M D
MD
McPhee
J F
JF
Crocker
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