Purpose: Historically, trauma resuscitation has focused on three main complicating factors known as the “lethal triad”: hypothermia, acidosis, and coagulopathy. However, recent literature has begun to recognize hypocalcemia as a fourth pillar in mortality rates. Data has shown up to 97% of patients can experience an exacerbation of hypocalcemia during massive transfusion protocol (MTP), of which 71% may experience severe hypocalcemia (ionized calcium < 0.9 mmol/L). The purpose of this study is to evaluate the effect of a standardized protocol for calcium repletion in trauma patients requiring MTP. Methods: This was a single center, retrospective, descriptive, observational study among trauma patients who presented to Wellstar Kennestone Regional Medical Center Emergency Department (WKRMCED). Data was collected prior to implementation of a calcium repletion protocol from July 1, 2023 to May 31, 2024, and post-protocol implementation from August 1, 2024 to June 30, 2025. Patients were included if they presented to WKRMCED during the specified treatment dates as a tier 1 trauma requiring activation of MTP for administration of blood products. Patients were excluded if they were pregnant, ≤ 15 years old, had activation of MTP for a non-trauma related reason, did not have documentation of calcium levels after transfusion, or if the calcium replacement protocol was not followed after transfusion of blood products. The primary outcome was calcium levels up to 24h following the last documented blood product given post-transfusion. Secondary outcomes included total amount of blood products transfused within 24h of MTP initiation, hospital length of stay, intensive care unit length of stay, and in-hospital mortality. Results: Of the 6217 patients screened for inclusion in this study, 122 met inclusion criteria. Patients were screened further based on the predefined exclusion criteria and a total of 98 patients were included in the study (pre-protocol n=62; post protocol n=36). Although this study was observational, and descriptive statistics were used, there did not appear to be any vast differences, numerically in demographic information. The primary outcome increased nearly 25% from pre-protocol (51.5%) to post-protocol (75%). Regarding the secondary outcomes, more elemental calcium was given in the post-protocol group, and there was a decrease from pre- to post-protocol in the time difference between the first unit of blood being given and the first dose of calcium being administered (pre-protocol: median 1.17 hours, IQR 3.21 hours; post-protocol: median 0.45 hours, IQR 0.65 hours). In the pre-protocol group, the baseline to follow up iCAL was 1.07 to 1.1. Comparatively, the difference in baseline to follow up iCAL in the post-protocol group was 0.195 mmol/L, which is a 6.5 times greater increase than the pre-protocol of 0.03 mmol/L. Conclusions: The implementation of a calcium repletion protocol during MTP in trauma suggests maintenance of higher serum calcium levels and thus may decrease the risk of complications during trauma resuscitation. Future studies should focus on the inclusion of larger populations for better generalizability and defining a dose of calcium (gluconate, chloride, or both) that is most efficacious among any trauma patient requiring massive transfusion protocol.
