The observed incidence of hypocalcemia in traumatically injured patients is lower than previously reported

Incidence of hypocalcemia in trauma patients has been reported as 23% to 56% in small studies with strict inclusion criteria. We aim to describe the incidence of hypocalcemia in a larger set of patients with an ionized calcium level drawn in the trauma bay. We also aim to corroborate the association of calcium levels with mortality, blood product administration, emergent procedural intervention, and coagulopathy by thromboelastography (TEG).

We performed a retrospective review of patients 15 years or older who presented as a trauma activation over 1 year. We describe the incidence of hypocalcemia and compare normal (ionized calcium, >4.0 mg/dL) versus low (3.0-4.0 mg/dL) versus very low (<3.0 mg/dL) cohorts with regard to mortality, number of emergent procedures performed, blood product transfusion, overall incidence, and type of TEG derangements.

Of 2,275 included trauma activations, 57 patients presented with hypocalcemia (2.5%; 95% confidence interval, 1.9-3.1), and 2,272 patients (97.4%) were normocalcemic. Forty-eight patients (2.1%) had moderate hypocalcemia, and nine (0.4%) had severe hypocalcemia. Hypocalcemic patients had decreased maximum amplitude both as citrated functional fibrinogen measures and citrated RapidTEG. Clot lysis at 30 minutes was significantly prolonged in severely hypocalcemic patients, but reaction time was not different in hypocalcemic patients. Mortality was significantly higher for the hypocalcemic group and differed significantly between each subgroup of calcium levels. Hypocalcemic patients received significantly more of all components of blood product transfusions and higher number of emergent procedures.

In a large, inclusive population, the incidence of presenting hypocalcemia is almost 20-fold lower than previous reports. Hypocalcemia was associated with increased mortality, blood product transfusions, and emergent procedures. Hypocalcemia was associated with TEG derangements in maximal amplitude and clot lysis, but not reaction time.

Prognostic and Epidemiologic; Level IV.