Impact of hypocalcemia on mortality in pediatric trauma patients who require transfusion

BACKGROUND: Admission hypocalcemia has been associated with poor outcomes in injured adults. The impact of hypocalcemia on mortality has not been widely studied in pediatric trauma. METHODS: A pediatric trauma center database was queried retrospectively (2013-2022) for children younger than 18 years who received blood transfusion within 24 hours of injury and had ionized calcium (iCal) level on admission. Children who received massive transfusion (>40 mL/kg) prior to hospital arrival or calcium prior to laboratory testing were excluded. Hypocalcemia was defined by the laboratory lower limit (iCal <1.00). Main outcomes were in-hospital mortality and 24-hour blood product requirements. Logistic regression analysis was performed to adjust for Injury Severity Score (ISS), admission shock index, Glasgow Coma Scale (GCS) score, and weight-adjusted total transfusion volume. RESULTS: In total, 331 children with median (IQR) age of 7 years (2-3 years) and median (IQR) ISS 25 (14-33) were included, 32 (10%) of whom were hypocalcemic on arrival to the hospital. The hypocalcemic cohort had higher ISS (median (IQR) 30(24-36) vs. 22 (13-30)) and lower admission GCS score (median (IQR) 3 (3-12) vs. 8 (3-15)). Age, sex, race, and mechanism were not significantly different between groups. On univariate analysis, hypocalcemia was associated with increased in-hospital (56% vs. 18%; p < 0.001) and 24-hour (28% vs. 5%; p < 0.001) mortality. Children who were hypocalcemic received a median (IQR) of 22 mL/kg (7-38) more in total weight-adjusted 24-hour blood product transfusion following admission compared to the normocalcemic cohort ( p = 0.005). After adjusting for ISS, shock index, GCS score, and total transfusion volume, hypocalcemia remained independently associated with increased 24-hour (odds ratio, 4.93; 95% confidence interval, 1.77-13.77; p = 0.002) and in-hospital mortality (odds ratio, 3.41; 95% confidence interval, 1.22-9.51; p = 0.019). CONCLUSION: Hypocalcemia is independently associated with mortality and receipt of greater weight-adjusted volumes of blood product transfusion after injury in children. The benefit of timely calcium administration in pediatric trauma needs further exploration. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level III.