Transfusion-related acute lung injury after transfusion of maternal blood: a case-control study

Transfusion-Related Acute Lung Injury: 36 years of Progress (1985-2021)

The term transfusion-related acute lung injury (TRALI) was coined in 1985 to describe acute respiratory distress syndrome (ARDS) after transfusion, when another ARDS risk factor was absent; TRALI cases were mostly associated with donor leukocyte antibody. In 2001, plasma from multiparous donors was implicated in TRALI in a randomized controlled trial in Sweden. In 2003 and in many years thereafter, the FDA reported that TRALI was the leading cause of death from transfusion in the United States. In 2003, the United Kingdom was the first among many countries to successfully reduce TRALI using male-predominant plasma. These successes are to be celebrated. Nevertheless, questions remain about the mechanisms of non-antibody TRALI, the role of blood products in the development of ARDS in massive transfusion patients, the causes of unusual TRALI cases, and how to reduce inaccurate clinical diagnoses of TRALI in clinical practice. Regarding the latter, a study in 2013-2015 at 169 US hospitals found that many TRALI diagnoses did not meet clinical definitions. In 2019, a consensus panel established a more precise terminology for clinical diagnosis: TRALI type I and TRALI type II are cases where transfusion is the likely cause, and ARDS are cases where transfusion is not the likely cause. For accurate diagnosis using these clinical definitions, critical care expertise is needed to distinguish between permeability versus hydrostatic pulmonary edema, to determine whether an ARDS risk factor is present and, if so, whether respiratory function was stable within the 12 hours before transfusion.

Mortality in civilian trauma patients and massive blood transfusion treated with high vs low plasma: red blood cell ratio. Systematic review and meta-analysis

Introduction: Massive bleeding in civilian trauma patients leads to dilutional coagulopathy. Transfusion with high plasma: red blood cell (RBC) ratio has been effective in reducing mortality in war trauma patients. However, in civilian trauma the evidence is controversial. Objective: To assess the impact on mortality of high vs low plasma: RBC ratio transfusion, in civilian trauma patients with massive bleeding. Methods: A systematic review and meta-analysis, including observational studies and clinical trials, was conducted. Databases were systemically searched for relevant studies between January 2007 and June 2019. The main outcome was early (24-hours) and late (30-day) mortality. Fixed and random effects models were used. Results: Out of 1295 studies identified, 33 were selected: 2 clinical trials and 31 observational studies. The analysis of observational trials showed both decreased early mortality (odds ratio [OR] 0.67; 95% confidence interval [CI], 0.60–0.75) and late mortality (OR 0.79; 95% CI, 0.71–0.87) with the use of high plasma:RBC ratio transfusion, but there were no differences when clinical trials were evaluated (OR 0.89; 95% CI, 0.64–1.26). The exclusion of patients who died within the first 24hours was a source of heterogeneity. The Injury Severity Score (ISS) altered the association between high plasma: RBC ratio and mortality, with a reduced protective effect when the ISS was high. Conclusion: The use of high vs low plasma: RBC ratio transfusion, in patients with massive bleeding due to civil trauma, has a protective effect on early and late mortality in observational studies. The exclusion of patients who died within the first 24 hours was a source of heterogeneity.

Recommendations on RBC Transfusions in Critically Ill Children With Acute Respiratory Failure From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with bleeding developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations as well as research priorities for RBC transfusions in critically ill children. The respiratory subgroup included six experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Transfusion and Anemia Expertise Initiative experts developed seven recommendations focused on children with acute respiratory failure. All recommendations reached agreement (> 80%). Transfusion of RBCs in children with respiratory failure with an hemoglobin level less than 5 g/dL was strongly recommended. It was strongly recommended that RBCs not be systematically administered to children with respiratory failure who are hemodynamically stable and who have a hemoglobin level greater than or equal to 7 g/dL. Experts could not make a recommendation for children with hemodynamic instability, with severe hypoxemia and/or with an hemoglobin level between 5 and 7 g/dL. Specific RBC transfusion strategies using physiologic-based metrics and biomarkers could not be elaborated.

CONCLUSIONS

The Transfusion and Anemia Expertise Initiative Consensus Conference developed specific recommendations regarding RBC transfusion management in critically ill children with respiratory failure, as well as recommendations to guide future research. Clinical recommendations emphasize relevant hemoglobin thresholds. Research recommendations emphasize the need to identify appropriate physiologic thresholds, suggest a better understanding of alternatives to RBC transfusion, and identify the need for better evidence on hemoglobin thresholds that might be used in specific subpopulations of critically ill children.

A Clinical Trial to Detect Subclinical Transfusion-induced Lung Injury during Surgery

BACKGROUND

Transfusion-related acute lung injury incidence remains the leading cause of posttransfusion mortality. The etiology may be related to leukocyte antibodies or biologically active compounds in transfused plasma, injuring susceptible recipient's lungs. The authors have hypothesized that transfusion could have less severe effects that are not always appreciated clinically and have shown subtly decreased pulmonary oxygen gas transfer in healthy volunteers after transfusion of fresh and 21-day stored erythrocytes. In this study, the authors tested the same hypothesis in surgical patients.

METHODS

Ninety-one patients undergoing elective major spine surgery with anticipated need for erythrocyte transfusion were randomly allocated to receive their first transfusion of erythrocytes as cell salvage (CS), washed stored, or unwashed stored. Clinicians were not blinded to group assignment. Pulmonary gas transfer and mechanics were measured 5 min before and 30 min after erythrocyte transfusion.

RESULTS

The primary outcome variable, gas transfer, as assessed by change of PaO2/FIO2, with erythrocyte transfusion was not significant in any group (mean ± SD; CS: 9 ± 59; washed: 10 ± 26; and unwashed: 15 ± 1) and did not differ among groups (P = 0.92). Pulmonary dead space (VD/VT) decreased with CS transfusion (-0.01 ± 0.04; P = 0.034) but did not change with other erythrocytes; the change from before to after erythrocyte transfusion did not differ among groups (-0.01 to +0.01; P = 0.28).

CONCLUSIONS

The authors did not find impaired gas exchange as assessed by PaO2/FIO2 with transfused erythrocytes that did or did not contain nonautologous plasma. This clinical trial did not support the hypothesis of erythrocyte transfusion-induced gas exchange deficit that had been found in healthy volunteers.

Transfusion-related lung injury in children: a case series and review of the literature

BACKGROUND

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. The majority of the literature involves adult patients. The main objective of this study was to characterize the demographic features, clinical presentation, patient outcomes, and antibody profiles of TRALI patients reported to the Canadian Blood Service (CBS) and to assess similarities and differences between adult and pediatric TRALI cases.

STUDY DESIGN AND METHODS

A retrospective review of cases of TRALI submitted to the CBS from 2001 to 2011 was performed. Information collected included recipient demographics, event details, blood component transfused, morbidity and mortality data, and donor antibody results.

RESULTS

A total of 284 cases of definite, possible, or probable TRALI were reported. Six percent (n = 17) occurred in children. There were no significant differences between pediatric or adult patients with TRALI. Most of the children who presented with TRALI were either teenagers or less than 1 year of age. The incident rate of reported TRALI cases in Canada per 100,000 red blood cell transfusions was estimated at 5.58 for children and 3.75 for adults.

CONCLUSIONS

This study is the largest case series of reported TRALI cases in children. Crude modeling suggests that the incidence of TRALI in children is similar to that of adults. Although the numbers are small, there do not appear to be differences in presentation or outcome between adults and children with TRALI. TRALI is associated with significant morbidity and mortality and pediatricians need to consider this diagnosis in children who experience respiratory distress after transfusions.