Impact of a calcium replacement protocol during massive transfusion in trauma patients at a level 2 trauma center.

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PURPOSE: Hypocalcemia is associated with increased mortality in trauma patients with hemorrhagic shock who require massive transfusion protocols (MTPs). Despite known risks of potentiating hypocalcemia with blood product administration, there is little research discussing appropriate calcium replacement. The purpose of this study was to evaluate the ability of a standardized calcium replacement protocol to reduce the incidence of hypocalcemia in trauma patients undergoing MTP.

METHODS: This retrospective, single-center, pre-post study evaluated the use of a calcium replacement protocol during MTP. Adult trauma patients with MTP orders who received at least one "round" of product transfusion were included. Patients were excluded if their ionized calcium (iCa) levels were unavailable or they were transferred to a higher level of care within 4 hours of presentation. The primary outcome was incidence of hypocalcemia (iCa of <1.1 mg/dL) within 24 hours of MTP initiation. Secondary endpoints included the incidence of severe hypocalcemia (iCa of <0.9 mg/dL), time to first calcium dose, total calcium dose administered (mEq), resolution of hypocalcemia within 24 hours, hypercalcemia, adherence to the calcium replacement protocol, and mortality.

RESULTS: The incidence of hypocalcemia within 24 hours was significantly lower in the postprotocol group (63% vs 95.2%; P = 0.006). There was not a significant difference in the incidence of severe hypocalcemia between the groups (39.1% vs 69.1%; P = 0.083). Time to first calcium dose was significantly shorter in postprotocol patients compared to preprotocol patients (median [interquartile range], 5.5 [0-21] minutes vs 43 [22.8-73] minutes; P < 0.0001), and postprotocol patients were administered more calcium during MTP (40.8 [27.2-54.4] mEq vs 27.2 [14-32.2] mEq; P = 0.005). Adherence to the protocol was seen in only 37% of patients in the postprotocol group. There was no difference in the rate of adverse events or overall mortality.

CONCLUSION: Trauma patients who received massive transfusion of blood products had a significantly lower incidence of hypocalcemia after a calcium replacement protocol was implemented.