Early calcium replacement after minimal blood transfusion is associated with adverse outcomes.

PURPOSE: Calcium disturbances are common in patients with traumatic injuries, exacerbated by shock and blood product resuscitation. Recently, empiric calcium supplementation has been recommended with the first unit of blood transfusion, despite a lack of data supporting this practice. We hypothesize that there are risks associated with calcium administration in patients receiving small volume transfusion. METHODS: This is a retrospective review of patients admitted to our Level 1 trauma center from 2018 to 2024 who received 1-3 units of red blood cells (RBCs). Patients were stratified by calcium levels and whether they received early calcium supplementation. A logistic regression was used to estimate odds ratios for the association between calcium levels, calcium supplementation, and outcomes. The primary outcome was in-hospital mortality. Secondary outcomes included acute kidney injury, myocardial infarction, acute respiratory distress syndrome, and venous thromboembolism. The model was adjusted for age, sex, ISS and shock index. RESULTS: A total of 2,680 patients were included. When stratified by calcium levels and supplementation status, patients were similar in terms of age, sex, mechanism and injury severity score, but shock index was higher among patients receiving calcium supplementation. After adjustment, hypocalcemic patients who received calcium supplementation had higher odds of developing acute kidney injury, acute respiratory distress syndrome, deep vein thrombosis, and pulmonary embolism (all p < 0.05). CONCLUSION: In trauma patients who received 1-3 units of RBCs, early calcium supplementation was associated with adverse outcomes. The use of early, empiric calcium supplementation in conjunction with minimal transfusion should be carefully considered.