Use of B-natriuretic peptide as a diagnostic marker in the differential diagnosis of transfusion-associated circulatory overload

CE: Recognizing Transfusion-Associated Circulatory Overload

ABSTRACT

Transfusion-associated circulatory overload (TACO) is the leading cause of transfusion-related deaths in the United States, accounting for more than 30% of fatalities reported to the Food and Drug Administration between 2016 and 2020. However, TACO is widely considered to be an underdiagnosed and underreported complication of blood transfusions, and its exact incidence is unknown. One of the reasons for this is a lack of recognition of TACO and its signs and symptoms, especially as the definition of TACO has been updated twice since 2018 without full dissemination to nurses, who are responsible for bedside care of patients during and following blood transfusions. This article seeks to bridge this gap by discussing the updated definitions and signs and symptoms of TACO, as well as the management of this treatable blood transfusion reaction.

Hemodynamics of different volumes of red blood cell transfusion in preterm infants

BACKGROUND

Although many controversies exist regarding the risk of red blood cell (RBC) transfusions, half of preterm infants born at <32 weeks of gestational age receive such transfusions because of anemia of prematurity. Because of the costs and risks associated with multiple transfusions, it has been suggested that a large transfusion volume reduces the number of transfusions. However, there have been persistent concerns that RBC transfusion might lead to volume overload.

METHODS

We examined the impacts of large (20 mL/kg) compared to standard volume (15 mL/kg) transfusions on the hemodynamic variables of stable, electively transfused, preterm infants, by serially measuring echocardiographic parameters and plasma B-type natriuretic peptide levels.

RESULTS

A total of 39 infants born at <34 weeks of gestation and aged >2 weeks at the time of enrollment were randomly allocated to either a standard volume (15 mL/kg) or a large volume (20 mL/kg) group. Significant reductions in cardiac output and transient increases in plasma B-type natriuretic peptide levels were found after RBC transfusion in both the standard and large volume (20 mL/kg) groups. However, these changes were not significantly different between the two groups.

CONCLUSIONS

Large-volume transfusions could be tolerable in stable preterm infants with anemia.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) transfusion reaction small animal consensus statement (TRACS). Part 3: Diagnosis and treatment

OBJECTIVE

To systematically review available evidence to develop guidelines for diagnosis and treatment of transfusion-associated reactions in dogs and cats.

DESIGN

Standardized and systemic evaluation of the literature (identified through Medline via PubMed and Google Scholar searches) was carried out for identified transfusion reaction types in dogs and cats. The available evidence was evaluated using PICO (Population, Intervention, Comparison, Outcome) questions generated for each reaction type. The evidence was categorized by level of evidence (LOE) and quality (Good, Fair, or Poor). Guidelines, diagnostic, and treatment algorithms were generated based on the evaluation of the evidence. Consensus on the final guidelines was achieved through Delphi-style surveys. Draft recommendations were disseminated through veterinary specialty listservs for review and comments, which were evaluated and integrated prior to final publication.

RESULTS

Medline via PubMed and Google Scholar databases were searched. There were 14 Population Intervention Comparison Outcome questions identified and corresponding worksheets were developed focusing on the diagnosis and treatment of transfusion-associated reactions in dogs and cats. Fourteen guidelines and four algorithms were developed with a high degree of consensus.

CONCLUSIONS

This systematic evidence evaluation process yielded recommended diagnostic and treatment algorithms for use in practice. However, significant knowledge gaps were identified, demonstrating the need for additional research in veterinary transfusion medicine.

Transfusion-associated circulatory overload and high blood pressure: A multicentre retrospective study in Japan

BACKGROUND

Transfusion-associated circulatory overload (TACO) is an adverse reaction associated with a high risk of mortality. The actual incidence of TACO and hypertension associated with transfusion in Japan is unknown.

METHODS

A multicentre retrospective observational study was conducted across 23 institutions during the 1-year period of 2016. Patients were included if they developed TACO or their blood pressure (either systolic or diastolic) increased by at least 30 mmHg during the transfusion. TACO was confirmed by the primary physicians and transfusion medicine teams and recorded in the data on passive surveillance, and additional data were extracted from electronic medical records.

RESULTS

In our patient cohort of 31 384 patients who underwent transfusion, the incidence of TACO and hypertension was 0·03% and 0·2%, respectively. However, 43% of the participating institutions didn't report any cases. When comparing risk factors between the TACO and hypertension groups, there were significant differences in comorbidities, such as abnormal findings on chest x-ray. Significant differences between the two groups were observed post-transfusion pulse rate, body temperature and oxygen saturation (P < 0·01). In the group of patients with hypertension, the level of BNP increased significantly after transfusion in 45% (5/11) of the patients. We identified 4 patients in the hypertension group who met the new ISBT's TACO criteria.

CONCLUSION

Our study suggests that more attention should be given to TACO in Japan, particularly in terms of improving surveillance systems. For the early diagnosis of TACO, it is crucial to carefully monitor vital signs including blood pressure.

Pulmonary complications of transfusion: Changes, challenges, and future directions

The pulmonary complications of transfusion (TACO, TRALI and TAD) are the leading cause of transfusion-related mortality and major morbidity. Advance in this area is essential in improving transfusion safety. This review describes the drivers for change in haemovigilance practice, the influence of recent key publications and future directions.

NT-proBNP levels in the identification and classification of pulmonary transfusion reactions

BACKGROUND

Consensus definitions for transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) have recently been revised; however, pulmonary transfusion reactions remain difficult to diagnose. We hypothesized that N-terminal pro-brain natriuretic peptide (NT-proBNP) levels could have utility in the identification and classification of pulmonary transfusion reactions.

STUDY DESIGN AND METHODS

We performed a secondary analysis of a case-control study of pulmonary transfusion reactions at four academic hospitals. We evaluated clinical data and measured NT-proBNP levels prior to and following transfusion in patients with TACO (n = 160), transfused acute respiratory distress syndrome (ARDS) [n = 51], TRALI [n = 12], TACO/TRALI [n = 7], and controls [n = 335]. We used Wilcoxon Rank-Sum tests to compare NT-proBNP levels, and classification and regression tree (CART) algorithms to produce a ranking of covariates in order of relative importance for differentiating TACO from transfused controls.

RESULTS

Pre-transfusion NT-proBNP levels were elevated in cases of transfused ARDS and TACO (both P < .001) but not TRALI (P = .31) or TACO/TRALI (P = .23) compared to transfused controls. Pre-transfusion NT-proBNP levels were higher in cases of transfused ARDS or TRALI with a diagnosis of sepsis compared to those without (P < .05 for both). CART analyses resulted in similar differentiation of patients with TACO from transfused controls for models utilizing either NT-proBNP levels (AUC 0.83) or echocardiogram results (AUC 0.80).

CONCLUSIONS

NT-proBNP levels may have utility in the classification of pulmonary transfusion reactions. Prospective studies are needed to test the predictive utility of pre-transfusion NT-proBNP in conjunction with other clinical factors in identifying patients at risk of pulmonary transfusion reactions.

Revised international surveillance case definition of transfusion-associated circulatory overload: a classification agreement validation study

BACKGROUND

Transfusion-associated circulatory overload (TACO) is a major cause of transfusion-related morbidity and mortality in countries with well developed transfusion services. The International Society of Blood Transfusion, the International Haemovigilance Network, and AABB (formerly American Association of Blood Banks), have developed and validated a revised definition of TACO.

METHODS

International Haemovigilance Network-member haemovigilance systems (Australia, Austria, Denmark, Finland, Greece, India, Ireland, Italy, Japan, Malta, Netherlands, New Zealand, Norway, Slovenia, United Kingdom and United States) provided cases of respiratory complications categorised by their systems, including clinical parameters listed in the 2017 draft definition (part 1). Individual transfusion professionals were then invited to assess 24 case descriptions according to the draft definition (part 2). Positive and negative agreement and inter-rater agreement (κ) were calculated. Based on validation results, cases were reanalysed and slight adjustments made to yield the final 2018 TACO definition.

FINDINGS

In part 1, 16 (44%) of 36 haemovigilance systems provided 178 cases, including 126 TACO cases. By use of the 2018 definition, 96 (76%) of 126 cases of TACO were in positive agreement. 19 (37%) of 52 cases were recognised as non-TACO respiratory complications. In part 2 (47 experts from 20 countries), moderate all-case agreement (κ=0·43) and TACO-specific agreement (κ=0·54) were observed. Excluding cases missing some clinical information (eg, N terminal pro-brain natriuretic peptide, distinctive chest x-ray findings, and relationship with existing respiratory co-morbidities like pneumonia and chronic obstructive pulmonary disease) improved all-case agreement to κ=0·50 (moderate) and κ=0·65 (good) for TACO cases.

INTERPRETATION

The two-part validation exercise showed that the revised 2018 TACO surveillance case definition captures 76% of cases endorsed as TACO by participating haemovigilance systems. This definition can become the basis for internationally consistent surveillance reporting and contribute towards increased awareness and mitigation of TACO. Further research will require reporting more complete clinical information to haemovigilance systems and should focus on improved distinction between TACO and other transfusion respiratory complications.

FUNDING

International Society of Blood Transfusion, International Haemovigilance Network, and AABB.

A consensus redefinition of transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a serious complication of blood transfusion and is among the leading causes of transfusion-related morbidity and mortality in most developed countries. In the past decade, the pathophysiology of this potentially life-threatening syndrome has been increasingly elucidated, large cohort studies have identified associated patient conditions and transfusion risk factors, and preventive strategies have been successfully implemented. These new insights provide a rationale for updating the 2004 consensus definition of TRALI.

STUDY DESIGN AND METHODS

An international expert panel used the Delphi methodology to develop a redefinition of TRALI by modifying and updating the 2004 definition. Additionally, the panel reviewed issues related to TRALI nomenclature, patient conditions associated with acute respiratory distress syndrome (ARDS) and TRALI, TRALI pathophysiology, and standardization of reporting of TRALI cases.

RESULTS

In the redefinition, the term "possible TRALI" has been dropped. The terminology of TRALI Type I (without an ARDS risk factor) and TRALI Type II (with an ARDS risk factor or with mild existing ARDS) is proposed. Cases with an ARDS risk factor that meet ARDS diagnostic criteria and where respiratory deterioration over the 12 hours before transfusion implicates the risk factor as causative should be classified as ARDS. TRALI remains a clinical diagnosis and does not require detection of cognate white blood cell antibodies.

CONCLUSIONS

Clinicians should report all cases of posttransfusion pulmonary edema to the transfusion service so that further investigation can allow for classification of such cases as TRALI (Type I or Type II), ARDS, transfusion-associated circulatory overload (TACO), or TRALI or TACO cannot distinguish or an alternate diagnosis.

Transfusion-associated circulatory overload and transfusion-related acute lung injury

Transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI) are syndromes of acute respiratory distress that occur within 6 hours of blood transfusion. TACO and TRALI are the leading causes of transfusion-related fatalities, and specific therapies are unavailable. Diagnostically, it remains very challenging to distinguish TACO and TRALI from underlying causes of lung injury and/or fluid overload as well as from each other. TACO is characterized by pulmonary hydrostatic (cardiogenic) edema, whereas TRALI presents as pulmonary permeability edema (noncardiogenic). The pathophysiology of both syndromes is complex and incompletely understood. A 2-hit model is generally assumed to underlie TACO and TRALI disease pathology, where the first hit represents the clinical condition of the patient and the second hit is conveyed by the transfusion product. In TACO, cardiac or renal impairment and positive fluid balance appear first hits, whereas suboptimal fluid management or other components in the transfused product may enable the second hit. Remarkably, other factors beyond volume play a role in TACO. In TRALI, the first hit can, for example, be represented by inflammation, whereas the second hit is assumed to be caused by antileukocyte antibodies or biological response modifiers (eg, lipids). In this review, we provide an up-to-date overview of TACO and TRALI regarding clinical definitions, diagnostic strategies, pathophysiological mechanisms, and potential therapies. More research is required to better understand TACO and TRALI pathophysiology, and more biomarker studies are warranted. Collectively, this may result in improved diagnostics and development of therapeutic approaches for these life-threatening transfusion reactions.

Cardiac stress biomarkers after red blood cell transfusion in patients at risk for transfusion-associated circulatory overload: a prospective observational study

BACKGROUND

Transfusion-associated circulatory overload (TACO) is a leading cause of serious reactions. In regard to TACO, little is known regarding biomarkers as a predictor, their most informative timing, or thresholds of significance or differentiation from other reactions.

STUDY DESIGN AND METHODS

In this study of inpatients at risk for TACO (age ≥ 50 years) receiving 1 red blood cell unit, cardiac biomarkers, brain natriuretic peptide (BNP), N-terminal pro-BNP (NT-proBNP), and high-sensitivity troponin were measured at baseline, 6 to 12 hours (except troponin) posttransfusion, and 18 to 24 hours posttransfusion. Primary outcome was a critical increase in biomarkers (>1.5-fold increase and supranormal) at 18 to 24 hours.

RESULTS

Fifty-one patients were analyzed; 29% had cardiovascular disease, 73% had one or more cardiac risk factors, and 50% took cardiac or antihypertensive therapies. Although eight (16%) developed an increase in systolic pressure of at least 30 mmHg and four (8%) reported dyspnea and/or cough, none had TACO. At baseline, BNP level was more than 100 ng/L in 59% and NT-proBNP was more than 300 pg/mL in 83%. A total of 25% had a BNP critical increase, 33% had a NT-proBNP critical increase, and 2% had a troponin critical increase at 18 to 24 hours. Overall, 38% had at least one biomarker critical increase and NT-proBNP/BNP concordance was 84%. An increase in the NT-proBNP (>1.5-fold increase and >300 pg/mL) at 18 to 24 hours was the commonest biomarker change.

CONCLUSIONS

An increase of the NT-proBNP at 18 to 24 hours may be the preferred surrogate marker for identifying a patient experiencing physiologic difficulty in handling the volume challenge. Larger studies are needed to clarify the risk of TACO for a given pretransfusion biomarker profile and the correlation between TACO and increase in biomarkers after transfusion.

Sudden intraoperative pulmonary congestion in a patient with severe anemia transfused 3 days prior to surgery

Preoperative blood transfusion is sometimes controversial. We describe a case of a 43-year-old woman who developed sudden pulmonary congestion during surgery despite a small amount of intravenous crystalloid administration. She had no allergic disorders. Preoperative examination revealed that her hemoglobin was 5.6 g/dl, and she was diagnosed as folate-deficiency anemia although she never felt any symptoms before. Therefore, blood transfusion was performed and her hemoglobin increased to 9.4 g/dl. Amid surgery, airway pressure increased suddenly and pulsed oxygen saturation dropped. Chest roentgenogram revealed that the lungs were congested and her heart was markedly enlarged indicating the state of circulatory overload. We suggest that preoperative transfusion in a patient with chronic anemia should be carefully considered, and strongly recommend the confirmation with chest roentgenogram.

TACO and TRALI: biology, risk factors, and prevention strategies

Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are the leading causes of transfusion-related morbidity and mortality. These adverse events are characterized by acute pulmonary edema within 6 hours of a blood transfusion and have historically been difficult to study due to underrecognition and nonspecific diagnostic criteria. However, in the past decade, in vivo models and clinical studies utilizing active surveillance have advanced our understanding of their epidemiology and pathogenesis. With the adoption of mitigation strategies and patient blood management, the incidence of TRALI and TACO has decreased. Continued research to prevent and treat these severe cardiopulmonary events is focused on both the blood component and the transfusion recipient.

Transfusion-associated circulatory overload-a systematic review of diagnostic biomarkers

BACKGROUND

Transfusion‐associated circulatory overload (TACO) is the leading cause of transfusion‐related major morbidity and mortality. Diagnosing TACO is difficult because there are no pathognomonic signs and symptoms. TACO biomarkers may aid in diagnosis, decrease time to treatment, and differentiate from other causes of posttransfusion dyspnea such a transfusion‐related acute lung injury.

STUDY DESIGN AND METHODS

A systematic review of literature was performed in EMBASE, PubMed, the TRIP Database, and the Cochrane Library, from inception to June 2018. All articles discussing diagnostic markers for TACO were included. Non‐English articles or conference abstracts were excluded.

RESULTS

Twenty articles discussing biomarkers for TACO were included. The majority investigated B‐type natriuretic peptide (BNP) and the N‐terminal prohormone cleavage fragment of BNP (NT‐proBNP), markers of hydrostatic pressure that can be determined within 1 hour. The data indicate that a post/pretransfusion NT‐proBNP ratio > 1.5 can aid in the diagnosis of TACO. Posttransfusion levels of BNP less than 300 or NT‐proBNP less than 2000 pg/mL, drawn within 24 hours of the reaction, make TACO unlikely. Cut‐off levels that exclude TACO are currently unclear. In critically ill patients, the specificity of natriuretic peptides for circulatory overload is poor. Other biomarkers, such as cytokine profiles, cannot discriminate between TACO and transfusion‐related acute lung injury.

CONCLUSION

Currently, BNP and NT‐proBNP are the primary diagnostic biomarkers researched for TACO. An NT‐proBNP ratio greater than 1.5 is supportive of TACO, and low levels of BNP or NT‐proBNP can exclude TACO. However, they are unreliable in critically ill patients. Other biomarkers, including cytokines and pulmonary edema fluid‐to‐serum protein ratio have not yet been sufficiently investigated for clinical use.

Transfusion-associated circulatory overload in a pediatric intensive care unit: different incidences with different diagnostic criteria

BACKGROUND

The incidence of transfusion-associated circulatory overload (TACO) is not well known in children, especially in pediatric intensive care unit (PICU) patients.

STUDY DESIGN AND METHODS

All consecutive patients admitted over 1 year to the PICU of CHU Sainte-Justine were included after they received their first red blood cell transfusion. TACO was diagnosed using the criteria of the International Society of Blood Transfusion, with two different ways of defining abnormal values: 1) using normal pediatric values published in the Nelson Textbook of Pediatrics and 2) by using the patient as its own control and comparing pre- and posttransfusion values with either 10 or 20% difference threshold. We monitored for TACO up to 24 hours posttransfusion.

RESULTS

A total of 136 patients were included. Using the "normal pediatric values" definition, we diagnosed 63, 88, and 104 patients with TACO at 6, 12, and 24 hours posttransfusion, respectively. Using the "10% threshold" definition we detected 4, 15, and 27 TACO cases in the same periods, respectively; using the "20% threshold" definition, the number of TACO cases was 2, 6, and 17, respectively. Chest radiograph was the most frequent missing item, especially at 6 and 12 hours posttransfusion. Overall, the incidence of TACO varied from 1.5% to 76% depending on the definition.

CONCLUSION

A more operational definition of TACO is needed in PICU patients. Using a threshold could be more optimal but more studies are needed to confirm the best threshold.

The practice of diagnosing and reporting transfusion-associated circulatory overload: a national survey among physicians and haemovigilance officers

OBJECTIVES

This study aims at identifying factors that disciplines consider when diagnosing and reporting transfusion-associated circulatory overload ('TACO').

BACKGROUND

TACO is a clinical diagnosis based mainly on subjective factors. Therefore, TACO could be an underreported complication of blood transfusion.

METHODS

A survey was conducted among critical care physicians, anaesthesiologists, haematologists, transfusion medicine physicians and haemovigilance officers using case vignettes and a questionnaire. Factors that may affect diagnosing TACO were investigated using conjoint analysis. A positive B-coefficient indicates a positive preference for diagnosing TACO. Participants rated factors influencing reporting TACO on a 0- to 100-point scale.

RESULTS

One hundred and seven surveys were returned (62%). Vignettes showed preferences in favour of diagnosing TACO with the onset of symptoms within 2 h [β 0·4(-0·1-1·0)], positive fluid balance [β 0·9(0·4-1·5)] and history of renal failure [β 0·6(0·1-1·2)]. Compared with transfusion of a single unit of red blood cells (RBC), respondents showed a preference for diagnosing TACO following a single unit of solvent/detergent (S/D) plasma or pooled platelet concentrate (PPC) [β 0·3(-0·2-0·7) resp. 0·5(-0·1-1·2)]. Multiple transfusion (6 RBC + 4 S/D plasma) was a strong preference for diagnosing TACO compared to 1 RBC and 1 S/D plasma [β 0·3(-0·8-1·3)]. Respondents did not fully take into account new hypertension and tachycardia when reporting TACO [median 70 (IQR 50-80) resp. 60 (IQR 50-80)]. No differences were observed between disciplines involved.

CONCLUSION

When diagnosing and reporting TACO, physicians and haemovigilance officers do consider known risk factors for TACO. Reporting could be improved by increasing the awareness of haemodynamic variables in future education programmes.

Point-of-care washing of allogeneic red blood cells for the prevention of transfusion-related respiratory complications (WAR-PRC): a protocol for a multicenter randomised clinical trial in patients undergoing cardiac surgery

INTRODUCTION

The transfusion-related respiratory complications, transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO), are leading causes of transfusion-related morbidity and mortality. At present, there are no effective preventive strategies with red blood cell (RBC) transfusion. Although mechanisms remain incompletely defined, soluble biological response modifiers (BRMs) within the RBC storage solution may play an important role. Point-of-care (POC) washing of allogeneic RBCs may remove these BRMs, thereby mitigating their impact on post-transfusion respiratory complications.

METHODS AND ANALYSIS

This is a multicenter randomised clinical trial of standard allogeneic versus washed allogeneic RBC transfusion for adult patients undergoing cardiac surgery testing the hypothesis that POC RBC washing is feasible, safe, and efficacious and will reduce recipient immune and physiologic responses associated with transfusion-related respiratory complications. Relevant clinical outcomes will also be assessed. This investigation will enrol 170 patients at two hospitals in the USA. Simon's two-stage design will be used to assess the feasibility of POC RBC washing. The primary safety outcomes will be assessed using Wilcoxon Rank-Sum tests for continuous variables and Pearson chi-square test for categorical variables. Standard mixed modelling practices will be employed to test for changes in biomarkers of lung injury following transfusion. Linear regression will assess relationships between randomised group and post-transfusion physiologic measures.

ETHICS AND DISSEMINATION

Safety oversight will be conducted under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained by the DSMB as well as the institutional review boards at each institution prior to enrolling the first study participant. This study aims to provide important information regarding the feasibility of POC washing of allogeneic RBCs and its potential impact on ameliorating post-transfusion respiratory complications. Additionally, it will inform the feasibility and scientific merit of pursuing a more definitive phase II/III clinical trial.

REGISTRATION

ClinicalTrials.gov registration number is NCT02094118 (Pre-results).

Transfusion Reactions

Transfusion reactions are common occurrences, and clinicians who order or transfuse blood components need to be able to recognize adverse sequelae of transfusion. The differential diagnosis of any untoward clinical event should always consider adverse sequelae of transfusion, even when transfusion occurred weeks earlier. There is no pathognomonic sign or symptom that differentiates a transfusion reaction from other potential medical problems, so vigilance is required during and after transfusion when a patient presents with a change in clinical status. This review covers the presentation, mechanisms, and management of transfusion reactions that are commonly encountered, and those that can be life-threatening.

Differentiating pulmonary transfusion reactions using recipient and transfusion factors

BACKGROUND

It is increasingly recognized that recipient risk factors play a prominent role in possible transfusion-related acute lung injury (pTRALI) and transfusion-associated circulatory overload (TACO). We hypothesized that both transfusion and recipient factors including natriuretic peptides could be used to distinguish TRALI from TACO and pTRALI.

STUDY DESIGN AND METHODS

We performed a post hoc analysis of a case-control study of pulmonary transfusion reactions conducted at the University of California at San Francisco and Mayo Clinic, Rochester. We evaluated clinical data and brain natriuretic peptides (BNP) levels drawn after transfusion in patients with TRALI (n = 21), pTRALI (n = 26), TACO (n = 22), and controls (n = 24). Logistic regression and receiver operating characteristics curve analyses were used to determine the accuracy of clinical and biomarker predictors in differentiating TRALI from TACO and pTRALI.

RESULTS

We found that pTRALI and TACO were associated with older age, higher fluid balance, and elevated BNP levels relative to those of controls and TRALI. The following variables were useful in distinguishing cases of pTRALI and TACO from TRALI: age more than 70 years, BNP levels more than 1000 pg/mL, 24-hour fluid balance of more than 3 L, and a lower number of transfused blood components. Using the above variables, our logistic model had a 91% negative predictive value in the differential diagnosis of TRALI.

CONCLUSIONS

Models incorporating readily available clinical and biomarker data can be used to differentiate transfusion-related respiratory complications. Additional studies examining recipient risk factors and the likelihood of TRALI may be useful in decision making regarding donor white blood cell antibody testing.

Incidence and clinical characteristics of transfusion-associated circulatory overload using an active surveillance algorithm

BACKGROUND

The concordance of haemovigilance criteria developed for surveillance of transfusion-associated circulatory overload (TACO) with its clinical diagnosis has not been assessed. In a pilot study to evaluate an electronic screening algorithm, we sought to examine TACO incidence and application of haemovigilance criteria in patients with post-transfusion pulmonary oedema.

STUDY DESIGN AND METHODS

From June to September 2014, all transfused adult inpatients at four academic hospitals were screened with an algorithm identifying chest radiographs ordered within 12 h of blood component release. Patients with post-transfusion pulmonary oedema underwent case adjudication by an expert panel. TACO incidence was calculated, and clinical characteristics were compared with other causes of post-transfusion pulmonary oedema.

RESULTS

Among 4932 transfused patients, there were 3412 algorithm alerts, 50 cases of TACO and 47 other causes of pulmonary oedema. TACO incidence was 1 case per 100 patients transfused. TACO classification based on two sets of haemovigilance criteria (National Healthcare Safety Network and proposed revised International Society for Blood Transfusion) was concordant with expert panel diagnosis in 57% and 54% of reviewed cases, respectively. Although the majority of clinical parameters did not differentiate expert panel adjudicated TACO from other cases, improved oxygenation within 24 h of transfusion did (P = 0·01).

CONCLUSIONS

The incidence of TACO was similar to that observed in prior studies utilizing active surveillance. Case classification by haemovigilance criteria was frequently discordant with clinical diagnoses of TACO in patients with post-transfusion pulmonary oedema. Improvements in oxygenation within 24 h of transfusion merit further evaluation in the diagnosis of TACO.

Transfusion-associated dyspnea--shadow or substance?

New Zealand Blood Service Haemovigilance uses International Society of Blood Transfusion/International Haemovigilance Network definitions to categorize transfusion reactions (TR). Transfusion-associated dyspnoea (TAD) is a category for TR with respiratory features (TRRF) that do not fit definitive entities. TRRF, including TAD, are clinically significant. TR classified as TAD were reviewed. We found that many TAD may have been transfusion-associated circulatory overload. Better information in TR reports and refining TR diagnostic criteria may result in less misclassification of TRRF. TAD may represent mild, atypical or overlap entities, and there may be a residuum of cases with currently unexplained pathophysiology.

Passive reporting greatly underestimates the rate of transfusion-associated circulatory overload after platelet transfusion

BACKGROUND

Transfusion-associated circulatory overload (TACO) is the second leading cause of reported transfusion-related fatalities in the United States. While its occurrence has been previously investigated after red cell and plasma transfusion, no data are available regarding its association with platelet transfusion. Our goal was to determine the rate of platelet-associated TACO at our university medical centre.

STUDY DESIGN AND METHODS

This study had retrospective and prospective analyses. The 13-year retrospective analysis served to determine the historical rate of platelet-associated TACO by passive reporting. The 30-day prospective analysis included active surveillance of all non-emergently issued and non-operative platelet recipients ≥16 years old with no transfusions in the previous 6 h determined by analysis of blood bank product issue records. Data collected included demographics, vital signs pre- and posttransfusion, fluid balances, supplemental oxygen use, reports of dyspnoea, and infusion rates. For the prospective analysis, all variables were collected within 24 h of transfusion from the medical record and, when necessary, interviews with care providers and/or patients.

RESULTS

In the retrospective analysis, 366 reactions were reported, of which 6 (1·6%) were TACO. The historical rate of TACO was 1:5997 transfused platelet units. During the prospective analysis, 225 eligible patients received a total of 334 units of platelets. The average platelet transfusion volume was 261 ± 26 ml, and the average infusion rate was 391 ± 198 ml/h. Two unreported TACO reactions were discovered and characterized by new-onset hypertension, crackles on lung auscultation, dyspnoea, hypoxia and supplemental oxygen requirements which resolved completely with diuresis. The rate of TACO during this prospective analysis was 1:167 transfused platelet units.

CONCLUSION

Platelet-associated TACO is greatly underestimated by passive reporting in the adult patient population.

Loop diuretics for patients receiving blood transfusions

BACKGROUND

Blood transfusions are associated with significant morbidity and mortality. Prophylactic administration of loop diuretics (furosemide, bumetanide, ethacrynic acid, or torsemide) is common practice, especially among people who are at risk for circulatory overload, pulmonary oedema or both.

OBJECTIVES

This review aimed to determine if the prophylactic administration of loop diuretics (furosemide, bumetanide, ethacrynic acid, or torsemide) provides a therapeutic advantage (that is, a favourable risk benefit ratio) in adults and children who are recipients of any blood product transfusion versus placebo, no treatment, or general fluid restriction measures.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 13 January 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs assessing a loop diuretic in patients receiving any blood transfusion were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Study authors were contacted for additional information. Results were to be expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Mean effect sizes were to be calculated using the random-effects models.

MAIN RESULTS

We included four studies that involved 100 participants. Furosemide was the only diuretic investigated in all four studies.None of the included studies assessed the clinically important outcomes noted in our protocol. The studies focused on various markers of respiratory function. An improvement in fraction of inspired oxygen (in favour of furosemide) was noted in one study. An improvement in pulmonary capillary wedge pressure (in favour of furosemide) was noted in two studies.

AUTHORS' CONCLUSIONS

There was insufficient evidence to determine whether premedicating people undergoing blood transfusion with loop diuretics prevents clinically important transfusion-related morbidity. Due to the continued use of prophylactic loop diuretics during transfusions, and because this review highlights the absence of evidence to justify this practice, well-conducted RCTs are needed. Given the high mortality, severe morbidity and increasing incidence of transfusion-associated circulatory overload, determining the therapeutic utility of pre-transfusion loop diuresis is an urgent need.

Damage control resuscitation

The early recognition and management of hemorrhage shock are among the most difficult tasks challenging the clinician during primary assessment of the acutely bleeding patient. Often with little time, within a chaotic setting, and without sufficient clinical data, a decision must be reached to begin transfusion of blood components in massive amounts. The practice of massive transfusion has advanced considerably and is now a more complete and, arguably, more effective process. This new therapeutic paradigm, referred to as damage control resuscitation (DCR), differs considerably in many important respects from previous management strategies for catastrophic blood loss. We review several important elements of DCR including immediate correction of specific coagulopathies induced by hemorrhage and management of several extreme homeostatic imbalances that may appear in the aftermath of resuscitation. We also emphasize that the foremost objective in managing exsanguinating hemorrhage is always expedient and definitive control of the source of bleeding.

Split Blood Products

The last 20 years have seen many advances in transfusion therapy and safety. Blood products are biological products engendering complex interactions with the immune system. Prestorage leukoreduction results in a reduced risk of febrile reactions, CMV transmission, and immune modulation, proving to be safer for patients than non-leuko reduced products.

Simple patient identification issues and clerical error continue to be the primary causes of ABO-incompatible transfusions. Rigorous donor screening as well as serologic and nucleic acid testing for transfusion transmitted infection have brought the blood supply to a very safe level, although transmission of these agents continues to be a problem in underdeveloped countries. Emerging infectious diseases, beyond current laboratory detection capabilities, combined with global travel, pose unknown imminent risks everywhere. We also briefly discuss the current risks of transfusion-transmitted infections.

We review currently available hemostatic blood products, their compositions, and their clinical indications; we mention product modifications currently in development; and we touch upon the hemostatic properties and drawbacks of whole blood, which is currently gaining popularity as an alternative to split blood products. We conclude with an in-depth overview of the risks associated with transfusion, including incompatibility, hemolytic transfusion reactions, transfusion-associated circulatory overload (TACO), and transfusion-related acute lung injury (TRALI).

Blood product transfusions and reactions

Blood product transfusions are an essential component of the practice of emergency medicine. From acute traumatic hemorrhage to chronic blood loss necessitating transfusion for symptomatic anemia, familiarity with individual blood products and their indications for transfusion is an essential tool for every emergency physician (EP). Although the focus of this article is primarily on the transfusion of red blood cells, many of the concepts are applicable to the transfusion of all blood products. EPs must be fully familiar with both the individual blood components and the potential reactions and complications of these transfusions.

Dynamic detection of N-terminal pro-B-type natriuretic peptide helps to predict the outcome of patients with major trauma

INTRODUCTION

NT-proBNP and BNP have been demonstrated to be prognostic markers in cardiac disease and sepsis. However, the prognostic value and the dynamic changes of BNP or NT-proBNP in trauma patients remain unclear. The present study was conducted to investigate the dynamic changes of NT-proBNP in patients with major trauma (injury severity score ≥16), determine whether NT-proBNP could be used as a simple index to predict mortality in major trauma patients.

METHODS

This prospective observational study included 60 patients with major trauma. Serum NT-proBNP levels were measured on the 1st, 3rd and 7th day after injury The NT-proBNP levels in survivors were compared with those in non-survivors. The efficacy of NT-proBNP to predict survival was analyzed using receiver operating characteristic curves. An analysis of correlations between NT-proBNP and various factors, including injury severity score, Glasgow coma score, acute physiology and chronic health evaluation II, central venous pressure, creatine kinase-MB, cardiac troponin I and procalcitonin (PCT) was performed. NT-proBNP levels in patients with traumatic brain injury were compared with those in patients without traumatic brain injury. A comparison of NT-proBNP levels between patients with and without sepsis was also performed at each time point.

RESULTS

NT-proBNP levels in non-survivors were significantly higher than those in survivors at all the indicated time points. In the group of non-survivors, NT-proBNP levels on the 7th day were markedly higher than those on the 1st day. In contrast, NT-proBNP levels in survivors showed a reduction over time. The efficacy of NT-proBNP to predict survival was analyzed using ROC curves, and there was no difference in the area under the ROC between NT-proBNP and APACHE II/ISS at the three time points. A significant correlation was found between NT-proBNP and ISS on the 1st day, NT-proBNP and CK-MB, Tn-I and APACHE II on the 3rd day, NT-proBNP and PCT on the 7th day. There were no significant differences in NT-proBNP levels between patients with or without brain trauma at all the indicated time points. NT-proBNP levels in patients with sepsis were significantly higher than those in patients without sepsis at all the indicated time points.

CONCLUSION

These findings suggest that dynamic detection of serum NT-proBNP might help to predict death in patients with major trauma. A high level of NT-proBNP at admission or maintained for several days after trauma indicates poor survival.

Post-partum sequential occurrence of two diverse transfusion reactions (transfusion associated circulatory overload and transfusion related acute lung injury)

Transfusion associated circulatory overload (TACO) and transfusion related acute lung injury (TRALI) are two dissimilar pathological conditions associated with transfusion of blood products where the time course of the events and clinical presentation overlap leading to uncertainty in establishing the diagnosis and initiating the treatment, which otherwise differs. We encountered a case where a patient of post-partum hemorrhage developed TACO in the immediate post-operative period due to aggressive resuscitative attempts with blood products. The patient's condition was appropriately diagnosed and was managed according to the clinical scenario, and the condition abated. Subsequently, on the third post-operative day the patient again required blood product transfusions following which the patient developed TRALI, the diagnosis of which was also established and adequate treatment strategy was undertaken.

[Transfusion-related acute lung injury]

Transfusion-related acute lung injury (TRALI) developed into the leading cause of transfusion-related morbidity and mortality after the first description by Popovsky et al. approximately three decades ago. It was the most frequent reason for transfusion-related fatalities worldwide before implementation of risk minimization strategies by donor selection. Plasma-rich blood products, such as fresh frozen plasma and apheresis platelets seem to be the leading triggers of TRALI. Hypoxemia and development of pulmonary edema within 6 h of transfusion are the diagnostic criteria for TRALI. The differentiation between cardiac failure and other transfusion-related lung injuries, such astransfusion-associated circulatory overload ( TACO) is difficult and causal treatment is not available. Therapy is based on supportive measures, such as oxygen insufflationor mechanical ventilation. The exactly pathogenesis is still unknown but the most propagated hypothesis is the two-event-model. Neutrophils are primed by the underlying condition, e.g. sepsis or trauma during the first event and these primed neutrophils are activated by transfused leukoagglutinating antibodies (immunogen) or bioreactive mediators (non-immunogen) during the second-event. Transfusion of leukoagglutinating antibodies from female donors with one or more previous pregnancies is the most frequent reason. No more TRALI fatalities were reported after implementation of the donor selection in Germany in 2009.

A retrospective review of patient factors, transfusion practices, and outcomes in patients with transfusion-associated circulatory overload

Transfusion-associated circulatory overload (TACO) is a common yet underrecognized and underreported complication of transfusion associated with significant morbidity and mortality. The objective of this study was to examine patient and transfusion characteristics in a cohort of TACO cases. A retrospective medical record review of 100 consecutive TACO episodes reported at 2 academic centers was performed. Information related to demographics, medical history, radiologic and echocardiographic investigations, infusion practices, reaction features, management, and outcome were collected. Ninety-eight cases were accessible for review. A history of congestive heart failure (41%), renal dysfunction (44%), and age more than 70 years (56%) were common in TACO patients. Suboptimal fluid status management and inappropriate infusion practices were often seen (eg, verbal orders, double red cell transfusions, rapid infusion rates, lack or improper timing of preemptive diuretics). The median volume of blood ordered was 500 mL, and the median volume of crystalloid or colloid (preceding 24 hours) was 2200 mL. A physician order specifying the infusion rate was documented in 50% of transfusion orders. Preemptive diuretics were ordered in only 29% of cases, most commonly introduced midway or after the transfusion at a dose of furosemide 20 mg intravenously. After TACO, 18% of patients required transfer to the intensive care unit, 8% suffered a major complication, and 2% died. Suboptimal ordering and infusion practices may be contributing to the high incidence and severity of TACO. Research in TACO prevention strategies, such as slow rates of infusion and preemptive diuretics, is warranted.

Approach of using established and new laboratory tests to more comprehensively investigate noninfectious and nonhemolytic transfusion reactions--along with the experience in Japan

BACKGROUND AND OBJECTIVES

Noninfectious and nonhaemolytic transfusion reactions are the most common type of transfusion reactions. Several new tests have been made, helping diagnosis and understanding of their pathogenesis. This manuscript provides a review of the literature on currently available tests in association with the approach in Japan.

MATERIALS & METHODS

Primarily by using key words, more than 100 pertinent articles in the Medline database were identified and reviewed.

RESULTS

Numbers of laboratory tests are available including those for plasma protein levels, plasma protein antibodies, leucocyte and platelet antibodies, serum N-terminal-pro-brain natriuretic peptide levels, serum tryptase levels and genetic microchimerism. Cross-match tests, such as basophil activation test and neutrophil activation test, are also available to determine a causal relationship between the reaction and transfusion.

CONCLUSIONS

Several tests should help to confirm diagnosis and determine causal relationship between adverse reactions and transfusion and to gain an insight into the mechanism of the reaction in some cases, although some of the recently developed tests have not been completely validated.

Adverse effects of plasma transfusion

Plasma utilization has increased over the past two decades, and there is a growing concern that many plasma transfusions are inappropriate. Plasma transfusion is not without risk, and certain complications are more likely with plasma than other blood components. Clinical and laboratory investigations of the patients suffering reactions after infusion of fresh-frozen plasma (FFP) define the etiology and pathogenesis of the panoply of adverse effects. We review here the pathogenesis, diagnosis, and management of the risks associated with plasma transfusion. Risks commonly associated with FFP include: 1) transfusion-related acute lung injury, 2) transfusion-associated circulatory overload, and 3) allergic and/or anaphylactic reactions. Other less common risks include 1) transmission of infections, 2) febrile nonhemolytic transfusion reactions, 3) red blood cell alloimmunization, and 4) hemolytic transfusion reactions. The effects of pathogen inactivation or reduction methods on these risks are also discussed. Fortunately, a majority of the adverse effects are not lethal and are adequately treated in clinical practice.

Benefits and risks of IgA in immunoglobulin preparations

The case of Immunoglobulin A (IgA) in transfusion medicine is unsettled: on one hand IgA is an important component of adaptive immunity and its deficiency may cause disease, on the other its presence in blood products might induce, in rare instances, allergy-like symptoms if not anaphylaxis. The practice with i.v. immunoglobulins currently changes as up to 10% concentrated preparations are given at fast rates hence even trace amounts of IgA contained in these IgG preparations can cause unexpected (side-) effects. Fortunately, the spectrum of sensitive IgA assays, along with anti-IgA screening assays now permits laboratories to narrow down IgA-dependent transfusion reactions to the real cases, in which IgA was the decisive trigger of anaphylaxis, proven or not by the presence of anti-IgA of the IgG or even IgE class. Tolerance to allogenic IgA has recently been reported. The known association of HLA with IgA deficiency (IgAD) has now been completed with an association to the nonsynonymous variant in IFHI1, allowing physicians to more precisely spot recipients at risk for an IgA-dependent transfusion reaction. Our review, along with our own experience here in Switzerland, allows us to conclude that IgA is a beneficial antibody rather than an allergen to be placed at the end of the list of non-infectious transfusion complications such as TRALI, febrile non-hemolytic reactions, purpura or volume overload.

Risks of transfusion

Each year, more than 4 million patients receive a blood transfusion in the United States to control symptoms associated with anemia, coagulopathy, thrombocytopenia, or some combination thereof. In each of these cases, the physician and the patient must weigh the potential benefits of the transfusion along with the associated risks. To assess accurately the risk:benefit ratio and to discuss this with the patient, the physician must be familiar with the range of adverse transfusion outcomes and the current estimates of their frequency. Most important, during the past decade the risk profile of transfusion has changed significantly. Transfusion-transmitted disease, although still a rare outcome of transfusion, is no longer an overriding concern in transfusion safety considerations; however, risks such as hemolysis, transfusion-related lung injury, and anaphylaxis continue to represent significant concerns and are relatively more common than the transmission of infectious diseases after transfusion. Against this background, the development of a national hemovigilance system, designed to evaluate more accurately transfusion adverse outcomes in the United States, will require greater precision and reliability in the assessment of adverse transfusion outcomes by clinicians if the proposed benefits of this system are to be realized.

Brain natriuretic peptide measurement in pulmonary medicine

Serum levels of natriuretic peptides are well established as important biomarkers in patients with cardiac disease. Less attention has been placed on the role of natriuretic peptides in patients with pulmonary conditions. In several well-defined groups of patients with pulmonary disease natriuretic peptides provide the clinician with clinically valuable information. A limitation of the interpretation of natriuretic peptides in pulmonary disease is the confounding effect of concurrent conditions such as heart failure, hypoxia, sepsis and renal failure. The present paper reviews the role of natriuretic peptides for diagnosis, risk stratification and prognosis of several pulmonary disorders.

Transfusion-associated circulatory overload after plasma transfusion

BACKGROUND

In 2010, transfusion-associated circulatory overload (TACO) was the second most common cause of transfusion-related mortality reported to the Food and Drug Administration. We sought to determine the rate of TACO caused by plasma transfusion.

STUDY DESIGN AND METHODS

This study was conducted in two parts: 1) A retrospective analysis to determine the prevalence of TACO reactions caused by plasma at a tertiary care hospital from 2003 to 2010 was performed by analyzing the blood bank's electronic transfusion reaction records and 2) active surveillance of plasma recipients to determine if unreported TACO reactions had occurred over a 1-month period at the same hospital.

RESULTS

Eighty-seven reactions to plasma had been reported to the blood bank from 2003 through 2010. Of these reactions 23% (20/87) were TACO. The historical prevalence rate of TACO was 1 in 1566 (95% confidence interval [CI], 1:2564-1:1014). During the prospective 1-month surveillance period, 84 patients received a total of 272 units of plasma, and four TACO reactions in separate patients (4.8%) were identified, none of which were reported to the blood bank. The prevalence rate of TACO in the prospective study was 1 in 68 (95% CI, 1:250-1:27). In total, most patients (14/24) were in the intensive care unit when they experienced TACO and on average they had received 4.0±2.3 units of plasma at an average rate of 647±315 mL/hr before the TACO reaction.

CONCLUSIONS

Passive reporting of TACO grossly underestimates its actual prevalence. Educational efforts are needed to enhance physician recognition of TACO reactions.

Transfusion in the critically ill: does it affect outcome?

Anemia and red blood cell (RBC) transfusions are common in critically ill and injured, trauma, and surgical patients. Tolerance of anemia is highly variable, depending on the presence of cardiovascular and other comorbid diseases that may diminish the hemodynamic response to a lower hemoglobin (Hb) level. The quest to define a minimum threshold Hb concentration at which patients achieve significant benefit to improve outcome has not yet been identified. Complications related to RBC transfusion are related to RBC storage and intrinsic properties of donor allogeneic RBCs, including bacterial contamination, transfusion-related acute lung injury, and transfusion-related immunomodulation. The best evidence related to transfusion-related outcome involves titrating transfusion requirements to parameters of severity of illness rather than arbitrarily defined Hb levels.