Hypocalcemia in trauma patients receiving massive transfusion

Ionised calcium levels in major trauma patients who received blood en route to a military medical treatment facility

“…This supports the findings of previous in-hospital studies that have demonstrated that blood product administration reduces calcium levels 6 7. These studies disagree on the cut-off point with Giancarelli et al advocating that over 5 units of blood is needed to produce a clinically relevant reduction,6 while others argue that even 1 unit of blood reduces calcium levels below the accepted normal value, consistent with our findings 7…”

“…Levels <0.8 mmol/L have been associated with adverse cardiac effects, and Kraft et al 13 proposed 0.9 mmol/L as a trigger for supplementary calcium therapy. In line with Giancarelli  et al ’s recommendation, a working definition of hypocalcaemia in this study was a blood assay of <1.12 mmol/L 6. This lower limit of normal is also the recommended limit for the i-stat blood monitoring system14 used at the time of the study, which recommended a normal value range of 1.12–1.32 mmol/L.…”

“…Giancarelli et al 6 postulated that a threshold level of 0.9 mmol/L of iCa should be used to start calcium therapy. This is a useful strategy in hospital with accurate testing capability, but in the prehospital environment, without POC testing facilities, this cut-off is of no practical use.…”

“…There are limited studies regarding the dose response of calcium supplementation needed after administration of blood products 6. Elmer et al suggest the use of 2 g of calcium gluconate for every 2 to 4 units of blood,9 and another13 suggested a strategy of 290 mg of calcium gluconate or 96 mg of calcium chloride for every 100 mL of blood received, although the effects of these two strategies have not been reported.…”

“…Ionised hypocalcaemia has been defined as serum iCa <1.12 mmol/L;6it has been further defined as severe at levels <0.9 mmol/L, and this has been associated with increased mortality in critically ill adults 12. Levels <0.8 mmol/L have been associated with adverse cardiac effects, and Kraft et al 13 proposed 0.9 mmol/L as a trigger for supplementary calcium therapy.…”