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

A Case of Severe Hypocalcemia During JAK1/2 Inhibitor Therapy for Myelofibrosis in a Patient with Liver Cirrhosis

We herein report a 56-year-old man with severe hypocalcemia during ruxolitinib therapy for myelofibrosis transitioning from JAK2 mutation-positive polycythemia vera. Blood transfusions were administered every one to two weeks for ruxolitinib-induced anemia. Blood tests revealed hypocalcemia with low TRACP-5b, 25-hydroxyvitamin D (25 (OH) D), and 1,25-dihydroxyvitamin D3 (1,25 (OH) 2 D3) levels within the lower reference range. Intact-PTH levels were relatively low compared to calcium levels. Severe hypocalcemia with ruxolitinib is rare and may be caused by a combination of factors, impaired vitamin D activation due to liver or renal insufficiency, accumulation of calcium-chelating agents from blood transfusions, and inadequate compensatory response to PTH.

Multicenter analysis of massive transfusion practices demonstrates variabilities across trauma centers in the Southwestern Surgical Congress

BACKGROUND

This study's purpose is to investigate emergent blood (EB) usage, massive transfusion protocols (MTP), and the use of pharmacologic adjuncts to resuscitation across trauma centers in the Southwestern Surgical Congress (SWSC).

METHODS

Anonymous, voluntary 26-question survey conducted by the SWSC multicenter trials group. Descriptive statistical analysis was performed.

RESULTS

36 institutions across 14 states responded. EB is immediately available at 27 institutions. 53 ​% have LTOWB available. LTOWB is incorporated into MTP at 39 ​% of institutions and is the primary MTP product used at 4 centers. 65 ​% of institutions use thromboelastography to guide resuscitation. 70 ​% of institutions reported using TXA and 11 ​% used fibrinogen concentrate. 36 ​% of responding institutions routinely draw ionized calcium values. Four institutions have a calcium replacement protocol. Only 6 centers report redosing antibiotics during MTP.

CONCLUSION

EB availability and MTP practices are evolving with variability across the SWSC. Pharmacologic therapies remain poorly incorporated into the MTP.

Hypocalcaemia upon arrival (HUA) in trauma patients who did and did not receive prehospital blood products: a systematic review and meta-analysis

PURPOSE

Hypocalcaemia upon arrival (HUA) to hospital is associated with morbidity and mortality in the trauma patient. It has been hypothesised that there is an increased incidence of HUA in patients receiving prehospital transfusion as a result of citrated blood products. This research aimed to determine if there was a difference in arrival ionised calcium (iCa) levels in trauma patients who did and did not receive prehospital transfusion.

METHODS

We conducted a systematic review and meta-analysis of patients with an Injury Severity Score (ISS) > / = 15 and an iCa measured on hospital arrival. We then derived mean iCa levels and attempted to compare between-group variables across multiple study cohorts.

RESULTS

Nine studies reported iCa on arrival to ED, with a mean of 1.08 mmol/L (95% CI 1.02-1.13; I2 = 99%; 2087 patients). Subgroup analysis of patients who did not receive prehospital transfusion had a mean iCa of 1.07 mmol/L (95% CI 1.01-1.14; I2 = 99%, 1661 patients). Transfused patients in the 3 comparative studies had a slightly lower iCa on arrival compared to those who did not receive transfusion (mean difference - 0.03 mmol/L, 95% CI - 0.04 to - 0.03, I2 = 0%, p = 0.001, 561 patients).

CONCLUSION

HUA is common amongst trauma patients irrespective of transfusion. Transfused patients had a slightly lower initial iCa than those without transfusion, though the clinical impact of this remains to be clarified. These findings question the paradigm of citrate-induced hypocalcaemia alone in trauma. There is a need for consensus for the definition of hypocalcaemia to provide a basis for future research into the role of calcium supplementation in trauma.

Calcium supplementation during trauma resuscitation: a propensity score-matched analysis from the TraumaRegister DGU®

BACKGROUND

In major trauma patients, hypocalcemia is associated with increased mortality. Despite the absence of strong evidence on causality, early calcium supplementation has been recommended. This study investigates whether calcium supplementation during trauma resuscitation provides a survival benefit.

METHODS

We conducted a retrospective analysis using data from the TraumaRegister DGU® (2015-2019), applying propensity score matching to balance demographics, injury severity, and management between major trauma patients with and without calcium supplementation. 6 h mortality, 24 h mortality, and in-hospital mortality were considered as primary outcome parameters.

RESULTS

Within a cohort of 28,323 directly admitted adult major trauma patients at a European trauma center, 1593 (5.6%) received calcium supplementation. Using multivariable logistic regression to generate propensity scores, two comparable groups of 1447 patients could be matched. No significant difference in early mortality (6 h and 24 h) was observed, while in-hospital mortality appeared higher in those with calcium supplementation (28.3% vs. 24.5%, P = 0.020), although this was not significant when adjusted for predicted mortality (P = 0.244).

CONCLUSION

In this matched cohort, no evidence was found for or against a survival benefit from calcium supplementation during trauma resuscitation. Further research should focus on understanding the dynamics and kinetics of ionized calcium levels in major trauma patients and identify if specific conditions or subgroups could benefit from calcium supplementation.

The Impact of Ca2+ on Intracellular Distribution of Hemoglobin in Human Erythrocytes

The membrane-bound hemoglobin (Hb) fraction impacts red blood cell (RBC) rheology and metabolism. Therefore, Hb-RBC membrane interactions are precisely controlled. For instance, the signaling function of membrane-bound deoxy-Hb and the structure of the docking sites in the cytosolic domain of the anion exchanger 1 (AE-1) protein are well documented; however, much less is known about the interaction of Hb variants with the erythrocyte's membrane. Here, we identified factors other than O2 availability that control Hb abundance in the membrane-bound fraction and the possible variant-specific binding selectivity of Hb to the membrane. We show that depletion of extracellular Ca2+ by chelators, or its omission from the extracellular medium, leads to membrane-bound Hb release into the cytosol. The removal of extracellular Ca2+ further triggers the redistribution of HbA0 and HbA2 variants between the membrane and the cytosol in favor of membrane-bound HbA2. Both effects are reversible and are no longer observed upon reintroduction of Ca2+ into the extracellular medium. Fluctuations of cytosolic Ca2+ also impact the pre-membrane Hb pool, resulting in the massive transfer of Hb to the cellular cytosol. We hypothesize that AE-1 is the specific membrane target and discuss the physiological outcomes and possible clinical implications of the Ca2+ regulation of the intracellular Hb distribution.

Standardized Calcium Replacement in Massive Transfusion: A Quality Improvement Project

BACKGROUND

Hypocalcemia is common in trauma patients receiving massive transfusion protocol and often leads to worsening coagulopathies. Despite the identified problem and recommendations for replacement, few institutions have implemented a standardized calcium replacement protocol.

OBJECTIVE

This study aims to assess whether a revised massive transfusion protocol, including standardized calcium replacement, increases the incidence of calcium administration in trauma patients receiving massive transfusion protocol.

METHODS

This quality improvement project used a retrospective pre-/postdesign to study the revision of the current facility's massive transfusion protocol to include calcium replacement and ionized calcium monitoring at an urban Level I academic trauma center. Pre- and postintervention data were collected from January 2022 through October 2022 to determine the number of times massive transfusion protocol was ordered, ionized calcium monitoring, and calcium administration rates. Feedback regarding the protocol was collected throughout the monitoring period and was utilized in the final analysis.

RESULTS

A total of 40 patients received massive transfusion protocol, preintervention, 18 of 23 (78%) received calcium supplementation, postintervention, 15 of 16 (98%) were treated. The majority of protocol activations occurred in the trauma bay (79%) and postintervention; ionized calcium monitoring dropped by 14%.

CONCLUSION

This study found that the addition of standardized calcium replacement improved administration rates of calcium in this patient population. Ongoing research will ensure the recommended changes improve the identified shortcomings and that patients maintain adequate ionized calcium levels with the current dosing parameters.

Impact of Transfused Citrate on Pathophysiology in Massive Transfusion

This narrative review article seeks to highlight the effects of citrate on physiology during massive transfusion of the bleeding patient.

DATA SOURCES

A limited library of curated articles was created using search terms including "citrate intoxication," "citrate massive transfusion," "citrate pharmacokinetics," "hypocalcemia of trauma," "citrate phosphate dextrose," and "hypocalcemia in massive transfusion." Review articles, as well as prospective and retrospective studies were selected based on their relevance for inclusion in this review.

STUDY SELECTION

Given the limited number of relevant studies, studies were reviewed and included if they were written in English. This is not a systematic review nor a meta-analysis.

DATA EXTRACTION AND SYNTHESIS

As this is not a meta-analysis, new statistical analyses were not performed. Relevant data were summarized in the body of the text.

CONCLUSIONS

The physiologic effects of citrate independent of hypocalcemia are poorly understood. While a healthy individual can rapidly clear the citrate in a unit of blood (either through the citric acid cycle or direct excretion in urine), the physiology of hemorrhagic shock can lead to decreased clearance and prolonged circulation of citrate. The so-called "Diamond of Death" of bleeding-coagulopathy, acidemia, hypothermia, and hypocalcemia-has a dynamic interaction with citrate that can lead to a death spiral. Hypothermia and acidemia both decrease citrate clearance while circulating citrate decreases thrombin generation and platelet function, leading to ionized hypocalcemia, coagulopathy, and need for further transfusion resulting in a new citrate load. Whole blood transfusion typically requires lower volumes of transfused product than component therapy alone, resulting in a lower citrate burden. Efforts should be made to limit the amount of citrate infused into a patient in hemorrhagic shock while simultaneously addressing the induced hypocalcemia.

Hypocalcemia in Trauma is Determined by the Number of Units Transfused, Not Whole Blood Versus Component Therapy

INTRODUCTION

Blood component resuscitation is associated with hypocalcemia (HC) (iCal <0.9 mmol/L) that contributes to coagulopathy and death in trauma patients. It is unknown whether or not whole blood (WB) resuscitation helps mitigate the risk of HC in trauma patients. We hypothesized that calcium homeostasis is maintained and mortality improved in patients who only receive WB.

MATERIALS AND METHODS

This is a retrospective review of all adult trauma patients who received WB from July 2018 to December 2020. Variables included transfusions, ionized calcium levels, and calcium replacement. Patients were characterized as follows based on blood products received: WB or WB with other blood components. Groups were compared with respect to HC, correction of HC, 24 h, and inpatient mortality.

RESULTS

Two hundred twenty-three patients received WB and met the inclusion criteria. 107 (48%) received WB only. HC occurred in 13% of patients who received more than one WB unit compared to 29% of WB and other blood component patients (P = 0.02). WB patients received less calcium replacement (median 250 mg versus 2000 mg, P < 0.01). HC and total units transfused within 4 h were associated with mortality in the adjusted model. HC significantly increased after 5 units of blood products were transfused, regardless of product type. WB was not protective against HC.

CONCLUSIONS

HC and failure to correct HC are significant risk factors for mortality in trauma. Resuscitations with WB only and WB in combination with other blood components are associated with HC especially when more than 5 units of any blood product are transfused. Calcium supplementation should be prioritized in any large volume transfusion, regardless of blood product type.

Continuum of Care: A Multiagency Approach to Seamless Warmed Prehospital Whole Blood Resuscitation of a Patient with Noncompressible Truncal Hemorrhage

BACKGROUND

Prehospital transfusion capabilities vary widely in the United States. Here we describe a case of prehospital resuscitation using warmed, whole blood in a patient with penetrating torso trauma and associated hemorrhagic shock.

CASE REPORT

A 68-year-old man sustained a single gunshot wound to the left chest and was found to have a shock index of 1.5 at the time of emergency medical services (EMS) arrival. Rapid peripheral intravenous and central venous access enabled the infusion of warmed low-titer O-positive whole blood. The EMS crew intentionally resuscitated the patient before managing the airway by means of rapid sequence intubation. An air medical services helicopter crew assumed patient care from the ground EMS crew and continued the warmed, whole blood transfusion during the flight to a regional Level I trauma center. The patient went directly to the operating room from the helipad, underwent definitive operative management, and was ultimately discharged home on hospital day nine.

CONCLUSION

Early recognition of hemorrhagic shock, implementation of prehospital transfusion protocols that emphasize transfusion of warmed blood without interruption, and an organized, regional approach to trauma care are critical for improving patient survival.