Massive transfusions and severe hypocalcemia: An opportunity for monitoring and supplementation guidelines

Abstract

Background Massive transfusion protocols (MTPs) are associated with severe hypocalcemia, contributing to coagulopathy and mortality in severely injured patients. Severity of hypocalcemia following massive transfusion activation and appropriate treatment strategies remain undefined. Study design and methods This was a retrospective study of all MTP activations in adult trauma patients at a Level 1 trauma center between August 2016 and September 2017. Units of blood products transfused, ionized calcium levels, and amount of calcium supplementation administered were recorded. Primary outcomes were ionized calcium levels and the incidence of severe ionized hypocalcemia (iCa ≤1.0 mmol/L) in relation to the volume of blood products transfused. Results Seventy‐one patients had an MTP activated during the study period. The median amount of packed red blood cells (PRBCs) transfused was 10 units (range 1–52). A total of 42 (59.1%) patients had periods of severe hypocalcemia. Patients receiving 13 or more units of PRBC had a greater prevalence of hypocalcemia with 83.3% having at least one measured ionized calcium ≤1.0 mmoL/L (p = .001). The number of ionized calcium levels checked and the amount of supplemental calcium given in patients who experienced hypocalcemia varied considerably. Discussion Severe hypocalcemia commonly occurs during MTP activations and correlates with the number of packed red blood cells transfused. Monitoring of ionized calcium and amount of calcium supplementation administered is widely variable. Standardized protocols for recognition and management of severe hypocalcemia during massive transfusions may improve outcomes.

The Incidence, Degree, and Timing of Hypocalcemia From Massive Transfusion: A Retrospective Review

“…Giancarelli et al only looked at ionized calcium at one moment in time whereas we looked over a period to review a trajectory and assess for potential timing of intervention. Several recent studies have measured the incidence of hypocalcemia during massive transfusion and found similarly high incidences [7,[9][10][11].…”

“…Clinical signs of hypocalcemia include heart failure, prolonged QT interval, sinus tachycardia, paresthesia, muscle spasms, cramps, tetany, circumoral numbness, and seizures [8]. Given the integral role that calcium plays in coagulation and hemodynamics, it is no surprise that several studies have shown a correlation between hypocalcemia and mortality [7,[9][10][11].…”

Trauma‐induced hypocalcemia

“…1,2 Decreased cardiac contractility occurs when ionized calcium levels drop below 0.8-0.9 mmol/L, 31 levels that have been demonstrated postinjury and are associated with increased mortality. 7,12,17,32 Administration of calcium chloride temporarily improves refractory shock by increasing cardiac contractility. 2,17 In states of decreased contractility, blood pressure is normally maintained by increasing afterload through vascular smooth muscle contraction.…”

“…39 This could explain the increased ventilation duration and decreased survival that has been reported in hypocalcemic patients. 6,13,17,32 Indeed, the profound shock state induced after a severe injury is a mix of hypovolemic, cardiogenic, and distributive shock which is intricately linked to hypocalcemia.…”

“…This increased vascular endothelial permeability complicates the resuscitation of injured patients and may potentiate multiple organ failure later in the hospital course 39 . This could explain the increased ventilation duration and decreased survival that has been reported in hypocalcemic patients 6,13,17,32 . Indeed, the profound shock state induced after a severe injury is a mix of hypovolemic, cardiogenic, and distributive shock which is intricately linked to hypocalcemia.…”