Citrate toxicity during massive blood transfusion

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.

Defining the optimal calcium repletion dosing in patients requiring activation of massive transfusion protocol

PURPOSE

Massive transfusion protocols (MTP) commonly result in severe hypocalcemia due to the calcium-binding affinity of citrate in blood components. The purpose of this study is to determine the optimal grams (g) of citrate to repletion calcium (Ca) milliequivalents (mEq) (Citrate:Ca) ratio to reduce 30-day mortality.

METHODS

This was a retrospective, single-centered, cohort study at a level 1 trauma center evaluating trauma and surgical patients in need of MTP activation from January 1, 2010-July 31, 2021. Patients with severe hypocalcemia at baseline, defined as ionized calcium (iCa) <0.9 mmol/L, were compared to patients without severe hypocalcemia. The primary endpoint was to determine the optimal ratio of grams of citrate to calcium mEq to reduce mortality in patients receiving a MTP. Secondary endpoints included mortality at 24 h and 30 days, blood components used in MTP, and type of calcium used.

RESULTS

Overall, 501 patients were screened for inclusion. Of these patients, 193 were excluded, leaving 308 patients, of which 165 patients (53.6%) had an iCa <0.9 mmol/L within 24 h and 143 patients (46.4%) had iCa ≥0.9 mmol/L within 24 h. The ratio of Citrate:Ca for each patient was not significantly associated with mortality at 24 h (P = 0.79) or 30 days (P = 0.91) at a repletion Citrate:Ca ratio of median 1.97 (IQR 1.14-2.91). The rate of mortality was lowest at a Citrate:Ca of 2 in both <24-h mortality and 30-day mortality.

CONCLUSIONS

There were no differences in 24 h or 30 day mortality based on repletion ratios seen in this study. A Citrate:Ca ratio between 2 and 3 in patients undergoing MTP was sufficient to obtain a normalized iCa within 24 h of MTP activation regardless of baseline iCa level. Further prospective studies will be needed to determine the optimal Citrate:Ca ratio.

A guide to the collection of T-cells by apheresis for ATMP manufacturing-recommendations of the GoCART coalition apheresis working group

Autologous chimeric antigen receptor-modified T-cells (CAR-T) provide meaningful benefit for otherwise refractory malignancies. As clinical indications for CAR-T cells are expanding, hospitals hitherto not active in the field of immune effector cell therapy will need to build capacity and expertise. The GoCART Coalition seeks to disseminate knowledge and skills to facilitate the introduction of CAR-T cells and to standardize management and documentation of CAR-T cell recipients, in order to optimize outcomes and to be able to benchmark clinical results against other centers. Apheresis generates the starting material for CAR-T cell manufacturing. This guide provides some initial suggestions for patient's apheresis readiness and performance to collect starting material and should thus facilitate the implementation of a CAR-T-starting material apheresis facility. It cannot replace, of course, the extensive training needed to perform qualitative apheresis collections in compliance with national and international regulations and assess their cellular composition and biological safety.

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.

Adverse transfusion reactions and what we can do

INTRODUCTION

Transfusions of blood and blood components have inherent risks and the ensuing adverse reactions. It is very important to understand the adverse reactions of blood transfusion comprehensively for ensuring the safety of any future transfusions.

AREAS COVERED

According to the time of onset, adverse reactions of blood transfusion are divided into immediate and delayed transfusion reactions. In acute transfusion reactions, timely identification and immediate cessation of transfusion is critical. Vigilance is required to distinguish delayed responses or reactions that present non-specific signs and symptoms. In this review, we present the progress of mechanism, clinical characteristics and management of commonly encountered transfusion reactions.

EXPERT OPINION

The incidence of many transfusion-related adverse events is decreasing, but threats to transfusion safety are always emerging. It is particularly important for clinicians and blood transfusion staff to recognize the causes, symptoms and treatment methods of adverse blood transfusion reactions to improve the safety. In the future, at-risk patients will be better identified and can benefit from more closely matched blood components.

Plasma exchange in the intensive care unit: a narrative review

In this narrative review, we discuss the relevant issues of therapeutic plasma exchange (TPE) in critically ill patients. For many conditions, the optimal indication, device type, frequency, duration, type of replacement fluid and criteria for stopping TPE are uncertain. TPE is a potentially lifesaving but also invasive procedure with risk of adverse events and complications and requires close monitoring by experienced teams. In the intensive care unit (ICU), the indications for TPE can be divided into (1) absolute, well-established, and evidence-based, for which TPE is recognized as first-line therapy, (2) relative, for which TPE is a recognized second-line treatment (alone or combined) and (3) rescue therapy, where TPE is used with a limited or theoretical evidence base. New indications are emerging and ongoing knowledge gaps, notably regarding the use of TPE during critical illness, support the establishment of a TPE registry dedicated to intensive care medicine.

Serial monitoring of ionised calcium levels in plateletpheresis donors: A study from tertiary care oncology centre in India

BACKGROUND

Plateletpheresis is a safe procedure, and the most common reaction is hypocalcemia which is transient and self-limiting, but it can have an impact on donor experience and donor return rate.

AIM

To serially monitor the ionized calcium levels of the plateletpheresis donors and to correlate with symptoms of hypocalcemia if any.

METHODS

It was a prospective observational study in 126 healthy voluntary donors eligible for plateletpheresis as per the Departmental SOP and after taking written informed consent. Procedures were conducted on continuous flow centrifugation (CFC) and intermittent flow centrifugation (IFC) cell separators. Donor blood samples were collected in pre-heparinized syringes at different intervals to measure ionized calcium levels (iCa++) by venous blood gas analysis (Cobas 221).

RESULTS

There was a continuous and gradual decrease in iCa++ from start to 30-45 minutes during the procedure; while the levels showed a gradual increase at end of the procedure and reached near the baseline values after 15-30 min of completion of the procedure. The change in iCa++ was statistically significant at 30 min and 45 min (p < 0.05), which was correlated with symptoms of hypocalcemia observed in 32.5 % (41/126) of the donors. Females experienced more symptoms of hypocalcemia as compared to males (p < 0.01). Donors who underwent plateletpheresis on the IFC machine experienced more symptoms of hypocalcemia as compared to the CFC machine (p < 0.05).

CONCLUSION

For donors with persistent symptoms of hypocalcemia which are unrelieved by procedural modifications (reducing blood return rate, citrate infusion rate, etc.) measurement of iCa++ and administration of oral calcium tablets may be considered.

Why may citrate sodium significantly increase the effectiveness of transarterial chemoembolization in hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) represents the third cause of cancer death in men worldwide, and its increasing incidence can be explained by the increasing occurrence of non-alcoholic steatohepatitis (NASH). HCC prognosis is poor, as its 5-year overall survival is approximately 18 % and most cases are diagnosed at an inoperable advanced stage. Moreover, tumor sensitivity to conventional chemotherapeutics (particularly to cisplatin-based regimen), trans-arterial chemoembolization (cTACE), tyrosine kinase inhibitors, anti-angiogenic molecules and immune checkpoint inhibitors is limited. Oncogenic signaling pathways, such as HIF-1α and RAS/PI3K/AKT, may provoke drug resistance by enhancing the aerobic glycolysis ("Warburg effect") in cancer cells. Indeed, this metabolism, which promotes cancer cell development and aggressiveness, also induces extracellular acidity. In turn, this acidity promotes the protonation of drugs, hence abrogating their internalization, since they are most often weakly basic molecules. Consequently, targeting the Warburg effect in these cancer cells (which in turn would reduce the extracellular acidification) could be an effective strategy to increase the delivery of drugs into the tumor. Phosphofructokinase-1 (PFK1) and its activator PFK2 are the main regulators of glycolysis, and they also couple the enhancement of glycolysis to the activation of key signaling cascades and cell cycle progression. Therefore, targeting this "Gordian Knot" in HCC cells would be of crucial importance. Here, we suggest that this could be achieved by citrate administration at high concentration, because citrate is a physiologic inhibitor of PFK1 and PFK2. As shown in various in vitro studies, including HCC cell lines, administration of high concentrations of citrate inhibits PFK1 and PFK2 (and consequently glycolysis), decreases ATP production, counteracts HIF-1α and PI3K/AKT signaling, induces apoptosis, and sensitizes cells to cisplatin treatment. Administration of high concentrations of citrate in animal models (including Ras-driven tumours) has been shown to effectively inhibit cancer growth, reverse cell dedifferentiation, and neutralize intratumor acidity, without apparent toxicity in animal studies. Citrate may also induce a rapid secretion of pro-inflammatory cytokines by macrophages, and it could favour the destruction of cancer stem cells (CSCs) sustaining tumor recurrence. Consequently, this "citrate strategy" could improve the tumor sensitivity to current treatments of HCC by reducing the extracellular acidity, thus enhancing the delivery of chemotherapeutic drugs into the tumor. Therefore, we propose that this strategy should be explored in clinical trials, in particular to enhance cTACE effectiveness.

Metabolic Strategies for Inhibiting Cancer Development

The tumor microenvironment is a complex mix of cancerous and noncancerous cells (especially immune cells and fibroblasts) with distinct metabolisms. These cells interact with each other and are influenced by the metabolic disorders of the host. In this review, we discuss how metabolic pathways that sustain biosynthesis in cancer cells could be targeted to increase the effectiveness of cancer therapies by limiting the nutrient uptake of the cell, inactivating metabolic enzymes (key regulatory ones or those linked to cell cycle progression), and inhibiting ATP production to induce cell death. Furthermore, we describe how the microenvironment could be targeted to activate the immune response by redirecting nutrients toward cytotoxic immune cells or inhibiting the release of waste products by cancer cells that stimulate immunosuppressive cells. We also examine metabolic disorders in the host that could be targeted to inhibit cancer development. To create future personalized therapies for targeting each cancer tumor, novel techniques must be developed, such as new tracers for positron emission tomography/computed tomography scan and immunohistochemical markers to characterize the metabolic phenotype of cancer cells and their microenvironment. Pending personalized strategies that specifically target all metabolic components of cancer development in a patient, simple metabolic interventions could be tested in clinical trials in combination with standard cancer therapies, such as short cycles of fasting or the administration of sodium citrate or weakly toxic compounds (such as curcumin, metformin, lipoic acid) that target autophagy and biosynthetic or signaling pathways.

Hypocalcemia in trauma patients: A systematic review

BACKGROUND

During hemorrhagic shock and subsequent resuscitation, pathways reliant upon calcium such as platelet function, intrinsic and extrinsic hemostasis, and cardiac contractility are disrupted. The objective of this systematic review was to examine current literature for associations between pretransfusion, admission ionized hypocalcemia, and composite outcomes including mortality, blood transfusion requirements, and coagulopathy in adult trauma patients.

METHODS

This review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. We searched Ovid MEDLINE and grey literature from database inception till May 3, 2020. Case series and reports were excluded. Reference lists of appraised studies were also screened for articles that the aforementioned databases might not have captured. The Newcastle-Ottawa Scale was used to assess study quality.

RESULTS

A total of 585 abstracts were screened through database searching and alternative sources. Six unique full-text studies were reviewed, of which three were excluded. Admission ionized hypocalcemia was present in up to 56.2% of the population in studies included in this review. Admission ionized hypocalcemia was also associated with increased mortality in all three studies, with increased blood transfusion requirements in two studies, and with coagulopathy in one study.

CONCLUSION

Hypocalcemia is a common finding in shocked trauma patients. While an association between admission ionized hypocalcemia and mortality, blood transfusion requirements, and coagulopathy has been identified, further prospective trials are essential to corroborating this association.

LEVEL OF EVIDENCE

Systematic review, level III.

Dose-response of intravenous calcium in the surgical intensive care unit

Background Hypocalcemia is common in patients admitted to the surgical intensive care unit and is associated with increased morbidity and mortality. Current dosing strategies do not always achieve ionized calcium (iCa) normalization, especially in patients with severe hypocalcemia. Objective The purpose of this study was to explore the association between intravenous (IV) calcium dose and change in ionized calcium. Setting Patients admitted to the surgical intensive care unit with concomitant hypocalcemia at a large academic hospital in the United States. Method This single center, retrospective cohort study evaluated the association between IV calcium dose and subsequent change in ionized calcium level in adult surgical intensive care unit patients with hypocalcemia. The primary outcome of this study was to develop a model exploring the association between IV calcium dose and change in iCa levels. Secondary outcomes included describing the average IV calcium dose required to normalize iCa levels, average time to normalization of iCa levels, and assessing the safety of IV calcium replacement. Main outcome measure Change in iCa. Results One hundred and ninety-four patients met study criteria. In the final model initial iCa level, total calcium dose, the interaction between initial iCa level and total calcium dose, age, and pancreatitis remained. The model (R² = 0.625) is expressed by the following equation: Change in iCa level = 0.462 - 0.011 × [Ca dose] - 0.0007 × [Age] - 0.259 × [Initial iCa] + 0.076 × [initial iCa × Ca dose] - 0.076 × [Pancreatitis]. Removing two patients that received > 10 grams of total calcium improved the R² to 0.769. Lastly, a simplified model removing age and pancreatitis found a similar R² of 0.756. Conclusion We observed that change in iCa level after initial calcium dose depended on the baseline iCa. Our full and simplified model excluding two outliers predicted 76.9% and 75.6% of the variation in iCa response, respectively. If validated in other settings this model could be utilized to provide more accurate calcium dosing.

Recommendations for Therapeutic Apheresis by the Section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology

The section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology (DGTI) has reviewed the actual literature and updated techniques and indications for evidence-based use of therapeutic apheresis in human disease. The recommendations are mostly in line with the "Guidelines on the Use of Therapeutic Apheresis in Clinical Practice" published by the Writing Committee of the American Society for Apheresis (ASFA) and have been conducted by experts from the DACH (Germany, Austria, Switzerland) region.

Serial measurement of electrolyte and citrate concentrations in blood-primed continuous hemodialysis circuits during closed-circuit dialysis

BACKGROUND

For continuous renal replacement therapy in small infants, due to the large extracorporeal volume involved, blood priming can be necessary to prevent hypotension and hemodilution. Because packed red blood cells (RBCs) have high levels of potassium and citrate, closed-circuit dialysis is often performed. We assessed the metrics of closed-circuit dialysis and serial citrate concentration changes.

METHODS

We performed dialysis of closed circuits primed with expired human packed RBC solution and 5% albumin. Blood and dialysate flow rates were 70 and 33.3 mL/min, respectively. The extracorporeal volume was 70 mL. We measured pH, electrolytes, and citrate in the closed circuit every 3 min for 15 min. We also assessed the adequacy of closed-circuit dialysis using the formula: [dialysate flow rate (mL/min) × time of dialysis (min)]/extracorporeal volume (mL) and we assessed the correlation between citrate and ionized calcium concentrations.

RESULTS

To reach normal concentrations of sodium, potassium, and chloride, 2.4 times as much dialysate fluid as extracorporeal volume was needed. In contrast, for ionized calcium, bicarbonate, and citrate, 3.8 times as much dialysate fluid as extracorporeal volume was required. By simple linear regression analysis, the concentration of citrate was significantly correlated with that of ionized calcium.

CONCLUSIONS

For closed-circuit dialysis using an RBC solution, the formula [dialysate flow rate (mL/min) × time of dialysis (min)]/extracorporeal volume (mL) would be a better parameter to estimate efficacy, compared with other metrics. Additionally, the citrate concentration can be readily estimated from the ionized calcium concentration during closed-circuit dialysis.

Plasma exchange in catastrophic antiphospholipid syndrome

Plasma exchange is a well-established therapeutic procedure commonly used in many autoimmune disorders. The beneficial effects of plasma exchange are thought to occur through the elimination of pathogenic mediators found in plasma, including autoantibodies, complement components, and cytokines. The catastrophic antiphsopholipid syndrome (CAPS) is a life-threatening variant of the antiphospholipid syndrome (APS) where several thrombosis take place in a short period of time in patients with circulating antiphospholipid antibodies. The triple therapy with anticoagulation, corticosteroids and plasma exchange or intravenous immunoglobulins has been proposed in CAPS. CAPS is a rare disease precluding the conduction of formal clinical trials. However, the observation of a better clinical course of patients who received this treatment supports their use. Plasma exchange has become an established therapeutic procedure in CAPS but there are no studies regarding the better approach and thus its use relies on the experience of the physicians in charge. The current article aims to review potential mechanisms of action of plasma exchange and the technical aspects of this procedure and will focus on its current role in CAPS, the experience published in treating this condition and the treatment protocol that we use in our institution.

Perioperative Serum Calcium and Phosphorus Levels are Associated with Hospital Costs and Length of Stay after Major Abdominal Surgery

This study aimed to identify an association between serum calcium (Ca) and phosphate (P) levels, tested during the pre- and postoperative period, with hospital costs and length of hospital stay (LOS) of patients who underwent major abdominal surgery. This retrospective cohort study analyzed the medical records of patients who underwent major abdominal surgery. A total of 3893 patients were included in the analysis, and multivariable linear regression analysis was performed. For a 1 mg/dL increase in preoperative Ca, total hospital costs decreased by 3997.9 dollars (coefficient: −3997.9, 95% confidence interval (CI): −4900.5, −30,953; p-value < 0.01), and for a 1 mg/dL increase in postoperative P, total hospital costs decreased by 702.5 dollars (coefficient: −702.5, 95% CI: −1274.5, −67.3; p-value = 0.03). Furthermore, for a 1 mg/dL increase in preoperative Ca, LOS decreased by 2.9 days (coefficient: −2.9, 95% CI: −3.7, −2.1; p-value < 0.01). For a 1 mg/dL increase in postoperative P, LOS decreased by 3.4 days (coefficient: −3.4, 95% CI: −4.2, −2.6; p-value < 0.01). This study suggested preoperative Ca and postoperative P could be useful indicators for the reduction of hospital costs and decrease in LOS from the perspective of enhanced recovery after surgery.

Transfusion Therapy in Children With Sickle Cell Disease

Hydroxyurea, blood transfusions, and hematopoietic stem cell transplantation represent the 3 disease-modifying therapies in children with sickle cell disease (SCD). Blood transfusions play an increasingly important role in both prevention and management of SCD complications in this age group. This review will focus on the indications of blood transfusion in children with SCD and modalities of its administration. It will also highlight the complications of this life-saving therapy and ways of optimizing transfusion to minimize its associated risks.

Transfusion reactions: prevention, diagnosis, and treatment

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.

Distinctive aspects of peptic ulcer disease, Dieulafoy's lesion, and Mallory-Weiss syndrome in patients with advanced alcoholic liver disease or cirrhosis

AIM: To systematically review the data on distinctive aspects of peptic ulcer disease (PUD), Dieulafoy’s lesion (DL), and Mallory-Weiss syndrome (MWS) in patients with advanced alcoholic liver disease (aALD), including alcoholic hepatitis or alcoholic cirrhosis.

METHODS: Computerized literature search performed via PubMed using the following medical subject heading terms and keywords: “alcoholic liver disease”, “alcoholic hepatitis”,“ alcoholic cirrhosis”, “cirrhosis”, “liver disease”, “upper gastrointestinal bleeding”, “non-variceal upper gastrointestinal bleeding”, “PUD”, ‘‘DL’’, ‘‘Mallory-Weiss tear”, and “MWS’’.

RESULTS: While the majority of acute gastrointestinal (GI) bleeding with aALD is related to portal hypertension, about 30%-40% of acute GI bleeding in patients with aALD is unrelated to portal hypertension. Such bleeding constitutes an important complication of aALD because of its frequency, severity, and associated mortality. Patients with cirrhosis have a markedly increased risk of PUD, which further increases with the progression of cirrhosis. Patients with cirrhosis or aALD and peptic ulcer bleeding (PUB) have worse clinical outcomes than other patients with PUB, including uncontrolled bleeding, rebleeding, and mortality. Alcohol consumption, nonsteroidal anti-inflammatory drug use, and portal hypertension may have a pathogenic role in the development of PUD in patients with aALD. Limited data suggest that Helicobacter pylori does not play a significant role in the pathogenesis of PUD in most cirrhotic patients. The frequency of bleeding from DL appears to be increased in patients with aALD. DL may be associated with an especially high mortality in these patients. MWS is strongly associated with heavy alcohol consumption from binge drinking or chronic alcoholism, and is associated with aALD. Patients with aALD have more severe MWS bleeding and are more likely to rebleed when compared to non-cirrhotics. Pre-endoscopic management of acute GI bleeding in patients with aALD unrelated to portal hypertension is similar to the management of aALD patients with GI bleeding from portal hypertension, because clinical distinction before endoscopy is difficult. Most patients require intensive care unit admission and attention to avoid over-transfusion, to correct electrolyte abnormalities and coagulopathies, and to administer antibiotic prophylaxis. Alcoholics should receive thiamine and be closely monitored for symptoms of alcohol withdrawal. Prompt endoscopy, after initial resuscitation, is essential to diagnose and appropriately treat these patients. Generally, the same endoscopic hemostatic techniques are used in patients bleeding from PUD, DL, or MWS in patients with aALD as in the general population.

CONCLUSION: Nonvariceal upper GI bleeding in patients with aALD has clinically important differences from that in the general population without aALD, including: more frequent and more severe bleeding from PUD, DL, or MWS.

An autopsy case of death due to metabolic acidosis after citric acid ingestion

A man in his 40s was found unconscious on a sofa in a communal residence for people with various disabilities. He appeared to have drunk 800 ml of undiluted citric acid from a commercial plastic bottle. The instructions on the label of the beverage specified that the beverage be diluted 20- to 30-fold before consumption. The patient was admitted to an emergency hospital with severe metabolic acidosis (pH, 6.70; HCO3(-), 3.6 mEq/L) and a low ionized calcium level (0.73 mmol/L). Although ionized calcium and catecholamines were continuously administered intravenously to correct the acidosis, the state of acidemia and low blood pressure did not improve, and he died 20 h later. Citric acid concentrations in the patient's serum drawn shortly after treatment in the hospital and from the heart at autopsy were 80.6 mg/ml and 39.8 mg/dl, respectively (normal range: 1.3-2.6 mg/dl). Autopsy revealed black discoloration of the mucosal surface of the esophagus. Microscopically, degenerated epithelium and neutrophilic infiltration in the muscle layer were observed. In daily life, drinking a large amount of concentrated citric acid beverage is rare as a cause of lethal poisoning. However, persons with mental disorders such as dementia may mistakenly drink detergent or concentrated fluids, as in our case. Family members or facility staff in the home or nursing facility must bear in mind that they should not leave such bottles in places where they are easily accessible to mentally handicapped persons.

Citrate anticoagulation: Are blood donors donating bone?

An estimated 2.4 million volunteer apheresis blood donation procedures were performed in the United States in 2010, and increases in the proportion of transfused blood products derived from apheresis blood collections have been consistently reported. Anticoagulation is required during apheresis and is achieved with citrate. Donor exposure to citrate causes an acute physiological response to maintain serum mineral homeostasis. Some data are available on the sequelae of this acute response in the days and weeks following exposure, raising questions about bone mineral density in regular apheresis donors. New research is emerging that addresses the potential long-term health outcomes of repeated citrate exposure. This article reviews the acute physiological response to citrate anticoagulation in volunteer blood donors, presents contrasting perspectives on the potential effects of citrate exposure on bone density, and identifies key knowledge gaps in our understanding of long-term health outcomes in apheresis donors. J. Clin. Apheresis 31:459-463, 2016. © 2015 Wiley Periodicals, Inc.

Autologous blood transfusion in dogs with thoracic or abdominal hemorrhage: 25 cases (2007-2012)

OBJECTIVE

To describe the use and outcome following autologous blood transfusion (ABT) in dogs.

DESIGN

Retrospective study (January 2007-July 2012).

SETTING

Private veterinary referral center.

ANIMALS

Twenty-five dogs that underwent ABT secondary to thoracic or abdominal hemorrhage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The hospital transaction database was searched using the keyword "autotransfusion" from January 2007 to July 2012. Data collected included signalment, body weight, etiology of hemorrhage, source and method of collection, volumes and method of ABT administration, use of anticoagulant, reported complications, and outcome. Twenty-five dogs were included for a total of 27 ABTs. Causes of hemorrhage included vascular trauma (14/25 dogs, 56%), ruptured tumor (8/25, 32%), and coagulopathy attributed to brodifacoum toxicosis (3/25, 12%). Autologous blood was collected from the abdominal (19/25, 76%), thoracic (5/25, 20%), or abdominal and thoracic cavities (1/25, 4%). Anticoagulant was added to the ABT blood in 13 of 25 (52%) cases. A median ABT volume of 29.3 mL/kg (range 2.9-406.9 mL/kg) was infused through either a 210 μm blood administration filter (21/27, 78%) or an 18 μm hemonate filter (6/27, 22%). Reported complications that may have been associated with ABT included hypocalcemia (4/17, 24%), hemolyzed serum (5/19, 26%), and prolonged coagulation times (4/5, 80%). These complications were considered of minimal clinical significance. Additional blood products were administered in 17 of 25 (68%) dogs. Seventeen (68%) dogs survived to discharge. Cause of death in the remaining cases was euthanasia or cardiac arrest secondary to uncontrollable hemorrhage.

CONCLUSIONS

ABT is an adjunct to volume replacement in dogs with thoracic or abdominal hemorrhage secondary to vascular trauma, ruptured tumor, or anticoagulant rodenticide toxicosis. ABT may be used as bridge to definitive hemorrhage control, particularly when other blood products are not available or affordable. Complications may include hypocalcemia, prolonged coagulation times, and hemolysis.

Adverse events related to blood transfusion

The acute blood transfusion reactions are responsible for causing most serious adverse events. Awareness about various clinical features of acute and delayed transfusion reactions with an ability to assess the serious reactions on time can lead to a better prognosis. Evidence-based medicine has changed today's scenario of clinical practice to decrease adverse transfusion reactions. New evidence-based algorithms of transfusion and improved haemovigilance lead to avoidance of unnecessary transfusions perioperatively. The recognition of adverse events under anaesthesia is always challenging. The unnecessary blood transfusions can be avoided with better blood conservation techniques during surgery and with anaesthesia techniques that reduce blood loss. Better and newer blood screening methods have decreased the infectious complications to almost negligible levels. With universal leukoreduction of red blood cells (RBCs), selection of potential donors such as use of male donors only plasma and restriction of RBC storage, most of the non-infectious complications can be avoided.

Effects of Liver Function on Ionized Hypocalcaemia following Rapid Blood Transfusion

OBJECTIVE: Hypocalcaemia detrimentally affects the cardiovascular system and massive transfusion-related hypocalcaemia is particularly severe in end-stage liver disease patients undergoing liver transplantation (LT). This study, therefore, compared the severity and duration of ionized hypocalcaemia between patients with normal and impaired liver function. METHODS: Patients ( n = 26 per group) were transfused at a rate of 10 ml/kg within 10 min with packed red blood cells (PRBCs) during LT (group LP) or spinal surgery (group SP), or were infused with 0.9% normal saline during spinal surgery (group SN). Serum levels of ionized calcium were assessed before (T0), just after (T1), and at 20 (T2) and 60 min (T3) after transfusion. RESULTS: Transfusion with PRBCs caused more severe ionized hypocalcaemia than 0.9% normal saline at T1. In contrast to the faster (20 min) normalization in group SP, ionized hypocalcaemia in group LP persisted at T3. Serum ionized calcium levels at T3 showed correlations with vital signs, blood glucose, serum potassium, base deficit and lactate. CONCLUSION: Rapid blood transfusion caused more severe and prolonged ionized hypocalcaemia in patients with liver dysfunction than in those with normal liver function.

Concentration-Dependent Effect of Hypocalcaemia on Mortality of Patients with Critical Bleeding Requiring Massive Transfusion: A Cohort Study

Mortality of patients with critical bleeding requiring massive transfusion is high. Although hypothermia, acidosis and coagulopathy have been well described as important determinants of mortality in patients with critical bleeding requiring massive transfusion, the risk factors and outcome associated with hypocalcaemia in these patients remain uncertain. This cohort study assessed the relationship between the lowest ionised calcium concentration during the 24-hour period of critical bleeding and the hospital mortality of 352 consecutive patients, while adjusting for diagnosis, acidosis, coagulation results, transfusion requirements and use of recombinant factor VIIa. Hypocalcaemia was common (mean concentrations 0.77 mmol/l, SD 0.19) and had a linear, concentration-dependent relationship with mortality (odds ratio [OR] 1.25 per 0.1 mmol/l decrement, 95% confidence interval [CI]: 1.04 to 1.52; P=0.02). Hypocalcaemia accounted for 12.5% of the variability and was more important than the lowest fibrinogen concentrations (10.8%), acidosis (7.9%) and lowest platelet counts (7.7%) in predicting hospital mortality. The amount of fresh frozen plasma transfused (OR 1.09 per unit, 95% CI: 1.02 to 1.17; P=0.02) and acidosis (OR 1.45 per 0.1 decrement, 95% CI: 1.19 to 1.72; P=0.01) were associated with the occurrence of severe hypocalcaemia (<0.8 mmol/l). In conclusion, ionised calcium concentrations had an inverse concentration-dependent relationship with mortality of patients with critical bleeding requiring massive transfusion. Both acidosis and the amount of fresh frozen plasma transfused were the main risk factors for severe hypocalcaemia. Further research is needed to determine whether preventing ionised hypocalcaemia can reduce mortality of patients with critical bleeding requiring massive transfusion.

Regional citrate anticoagulation--a safe and effective procedure in pediatric apheresis therapy

Regional citrate anticoagulation (RCA) has been considered to be a standard component of pediatric apheresis therapy for more than a decade. However, data on dosing recommendations and evaluations of the effectiveness and safety of anticoagulation are rarely found in published reports. The aim of this retrospective analysis was to present our single-center experience with RCA in pediatric apheresis therapy with the aim of developing an operating procedure. Five children aged 7-14 years underwent a total of 72 (range 3-44) therapeutic apheresis sessions with RCA in the form of immunoadsorption therapy (2 patients), low-density lipoprotein (LDL)-apheresis (1 patient), and plasmapheresis (two patients). A 3% citrate solution was used. Citrate flow was started at 4.0% of the blood flow velocity and was adapted to match post-filter ionized calcium levels ≤ 0.30 mmol/l. Once the patient's ionized calcium fell to <1.05 mmol/l, an intravenous 10% calcium gluconate solution was administered. Twenty pediatric apheresis patients who received standard heparinization, matched for age, body surface area, processed plasma volume, and blood flow velocity, were enrolled in the study as a comparison group. No side effects were experienced in 72 apheresis session. The 3% citrate solution had to be reduced gradually during the apheresis session and was infused at a mean of 2.8-3.8% of the blood flow rate. Serum bicarbonate levels before and after the apheresis session with RCA [23.9 (range 18.9-30.1) vs. 26.3 (20.2-33.0) mmol/l, respectively] were significantly different (p=0.013). All patients required intravenous calcium substitution to maintain serum calcium levels within the physiological range. Due to the administration of the 3% citrate solution and calcium, all patients significantly gained weight during the procedure, with a median weight gain of 2.5% (p<0.001). The extra fluid load caused problems in patients with kidney failure. Our regimen with RCA is safe, feasible, and effective in pediatric therapeutic apheresis therapy. For RCA in apheresis, we recommend (1) a citrate (3%) flow of 3.3% of the blood flow, (2) prophylactic intravenous calcium substitution from the beginning, and (3) a more highly concentrated citrate solution in the case of oliguric patients.

Red cell changes during storage

Red blood cells can be stored in liquid suspension in approved additive solutions for periods up to 6 weeks with 0.4% hemolysis, 84% 24-h in vivo recovery, and normal subsequent survival of the cells that persist in the circulation for at least 24h. However, while they are stored, the red cells undergo changes including the loss of adenosine triphosphate, diphosphoglycerate, and potassium, oxidative injury to proteins, lipids, and carbohydrates, loss of shape and membrane, increased adhesiveness, decreased flexibility, reduced capillary flow, and decreased oxygen delivery. Deaths have been reported related to the high potassium and lysophospholipids, but are rare.

Regional citrate anticoagulation is safe in intermittent high-flux haemodialysis treatment of children and adolescents with an increased risk of bleeding

BACKGROUND

Regional citrate anticoagulation (RCA) is strongly recommended for adults with an increased risk of bleeding complications. The objective of this retrospective analysis was to evaluate an RCA protocol concerning feasibility and safety in intermittent high-flux haemodialysis (iHD) treatment in children and adolescents.

METHODS

Eighteen children and adolescents aged 5-17 years (median 15 years) underwent 74 iHD treatment sessions with RCA. Twelve of 18 patients presented with overt local or diffuse haemorrhage before beginning the HD sessions, and six had an increased risk of haemorrhagic complications. Forty children on acute haemodialysis with general heparin anticoagulation, matched for bleeding risk, age and body surface area, served as a control group. Citrate 3% solution was begun with 3.3% blood flow rate, and calcium gluconate 10% substitution was started with 0.4% of blood flow rate. Citrate flow was adapted to achieve a post-filter ionized calcium of ≤0.30 mmol/L; calcium substitution was adapted to maintain the patients' serum calcium levels within the physiological range. Calcium-free dialysis fluid was used. The blood flow rate ranged from 3 to 5 mL per minute and kilogram body weight.

RESULTS

Regional anticoagulation was successfully achieved within the extracorporeal blood circuit, while the coagulation of all 18 patients remained within physiological parameters. No adverse effects of RCA were observed. In all 18 children, neither new haemorrhage nor worsening of the bleeding situation occurred, and in 10/12 patients, bleeding stopped during dialysis with RCA. In contrast, one-third of the control group developed new haemorrhagic complications or presented with worsening of pre-existing bleeding during haemodialysis (P = 0.006).

CONCLUSION

RCA is feasible, safe and effective in paediatric intermittent haemodialysis treatment.

Metabolic regulation of citrate and iron by aconitases: role of iron–sulfur cluster biogenesis

Iron and citrate are essential for the metabolism of most organisms, and regulation of iron and citrate biology at both the cellular and systemic levels is critical for normal physiology and survival. Mitochondrial and cytosolic aconitases catalyze the interconversion of citrate and isocitrate, and aconitase activities are affected by iron levels, oxidative stress and by the status of the Fe-S cluster biogenesis apparatus. Assembly and disassembly of Fe-S clusters is a key process not only in regulating the enzymatic activity of mitochondrial aconitase in the citric acid cycle, but also in controlling the iron sensing and RNA binding activities of cytosolic aconitase (also known as iron regulatory protein IRP1). This review discusses the central role of aconitases in intermediary metabolism and explores how iron homeostasis and Fe-S cluster biogenesis regulate the Fe-S cluster switch and modulate intracellular citrate flux.

Tolerable infusion rate of citrate based on clinical signs and the electrocardiogram in conscious dogs

BACKGROUND & AIMS

The possible clinical significance of the toxic effects of citrate has not yet been fully clarified. This study was therefore conducted to confirm the toxicity and determine the tolerable infusion rate of citrate administered by rapid intravenous infusion to conscious dogs.

METHODS

Citrate solutions were infused via the cephalic vein of 4 conscious dogs at 0.33, 0.67, or 1.33mmol/kg/h up to 1.33mmol/kg. Clinical signs and the electrocardiogram were observed during and after infusion. Serum citrate and ionized calcium levels were also measured.

RESULTS

Although the mean citrate level increased in accordance with the infusion rate, the calcium level decreased. No significant changes in clinical signs or the electrocardiogram were observed during infusion at 0.33mmol/kg/h despite an increase in the serum citrate level to 1.22+/-0.11mmol/l (pre-infusion value: 0.38+/-0.01mmol/l) and a decrease in the serum calcium level to 1.28+/-0.03mmol/l (pre-infusion value: 1.50+/-0.05mmol/l). Vomiting and QTc prolongation were observed at 0.67mmol/kg/h or higher. Salivation and tachycardia were observed at 1.33mmol/kg/h.

CONCLUSIONS

Based on clinical signs and the electrocardiogram, the tolerable infusion rate of citrate in conscious dogs is concluded to be 0.33mmol/kg/h.

Complications of donor apheresis

A decreasing blood donor pool in the presence of increasing blood transfusion demands has resulted in the need to maximally utilize each blood donor. This has led to a trend in the increasing use of automated blood collections. While apheresis donation shares many reactions and injuries with whole blood donation, because of the differences, unique complications also exist. Overall, evidence in the literature suggests that the frequency of reactions to apheresis donation is less than that seen in whole blood donation, though the risk of reactions requiring hospitalization is substantially greater. The most common apheresis-specific reaction is hypocalcemia due to citrate anticoagulation, which, while usually mild, has the potential for severely injuring the donor. Other reactions to apheresis donation are uncommon (e.g., hypotension) or rare (e.g., air embolism). More worrisome, and in need of additional study, are the long-term effects of apheresis donation. Recent evidence suggests that repeated apheresis platelet donations may adversely effect thrombopoiesis as well as bone mineralization. Granulocyte donation has also been implicated in unexpected long-term consequences.

Risks and side effects of therapy with plasma and plasma fractions

Transfusion of plasma can lead to adverse reactions or events. Immune-mediated reactions are most common--these include allergic and anaphylactic reactions, transfusion-related acute lung injury (TRALI) and haemolysis. They can range in severity from mild to fatal. Fluid overload and citrate toxicity can occur after rapid or massive transfusion. In developed countries, microbial transmission rates are low because of donor selection and testing. Pathogen reduction processes can be applied to either single-unit components (methylene blue) or plasma pools (solvent-detergent). They have the unwanted effect of reducing some coagulation factors but reduce viral transmission risk even further. Reactions associated with plasma products or fractions also include allergic reactions, although TRALI is rare. Viral transmission risk is very low because of the use of two independent viral inactivation steps. Different products have particular specific unwanted effects: intravenous immunoglobulin has been associated with thrombotic events, renal toxicity and aseptic meningitis; coagulation factors are associated with development of inhibitors and thrombotic events. The risk of transmission of variant Creutzfeldt-Jakob disease in both plasma components and pooled plasma products is as yet unknown. If anything, the low titre of prion infectivity in the blood of an infected individual (approximately 10 infectious units/ml) will be massively diluted by the thousands of units of plasma in the pool. Subsequent manufacturing processes also remove prions from the final product.

EFFECT OF WHOLE BLOOD CLOTTING TIME IN RATS WITH IONIZED HYPOCALCEMIA INDUCED BY RAPID INTRAVENOUS CITRATE INFUSION

Although the toxic effects of citrate including hemodynamic and cardiovascular changes result from a decrease in ionized calcium levels in serum due to chelating action, these effects of citrate on blood coagulation have not yet been fully clarified. The present study examines whether serum citrate and ionized calcium levels affect whole blood clotting time in rats using the test tube method in which citrate is administered by rapid intravenous infusion. Citrate was infused via the tail vein into 10 rats at 3, 4 or 5 mmol/kg/hr for 1 hr, and then whole blood clotting time, serum citrate and ionized calcium levels were determined. Whole blood clotting time did not significantly change at citrate infusion rates of 3 and 4 mmol/kg/hr. However, at 5 mmol/kg/hr, whole blood clotting time was significantly prolonged by a factor of 2.1 relative to the untreated group, when the serum citrate level was 10.03 +/- 1.39 mmol/l (59.0-fold higher than that in the untreated group) and the serum-ionized calcium level was 0.29 +/- 0.02 mmol/l (0.2-fold lower than that in the untreated group). These results suggest that whole blood clotting time is significantly prolonged in rats with severe ionized hypocalcemia.