Abstract
This retrospective study was performed to investigate the changes in plasma ionized calcium (iCa) and magnesium (iMg) concentrations, and their proper supplementation in 16 adult patients whose intraoperative blood loss exceeded 4, 000ml.
Despite occasional supplementation, iCa concentrations (mmol/l) decreased from 1.06±0.06 to 0.71±0.13 during surgery, and returned toward baseline values by the end of surgery. iMg concentrations (mmol/l) decreased from 0.46±0.06 to 0.19±0.07, and returned to 0.27±0.07 at the end of surgery and to 0.38±0.06 in the first post-operative day without any supplementation.
A plausible cause of the decreases in plasma iCa and iMg concentrations was hemodilution due to administration of fluid with low concentrations of Ca2+ and Mg2+ to maintain circulation during surgery.
The volume and electrolyte concentration of fluid administered during surgery must be considered to maintain normal plasma iCa and iMg levels in patients with massive intra-operative bleeding.
