Transfusion of blood components containing ABO-incompatible plasma does not lead to higher mortality in civilian trauma patients

Outcomes of massive transfusion recipients administered ABO-incompatible fresh frozen plasma

BACKGROUND

The provision of ABO-incompatible fresh frozen plasma (FFP) in massive transfusion (MT) has become accepted to conserve AB FFP stock. There is an evidence gap in non-trauma settings. We compare characteristics of patients who received ABO-compatible or ABO-incompatible FFP during an MT episode due to any cause of critical bleeding, and assess the impact of incompatible FFP transfusion on inhospital mortality.

METHODS

Using the Australian and New Zealand Massive Transfusion Registry, data were extracted for patients aged ≥18 years who received an MT (defined as ≥5 red cell units in 4 h) between April 2011 and October 2018. Incompatible FFP was defined as transfusion of ≥1 unit of FFP with a bidirectional or minor ABO-mismatch in the first 24 h from MT initiation.

RESULTS

A total of 7340 patients from 28 hospitals were included. Seventy-seven (1%) patients received incompatible FFP (26 trauma, 51 non-trauma). Those who had incompatible FFP received a median of seven units of FFP, compared to those who only received compatible FFP receiving five units, p = .005. A total of 226 units of incompatible FFP were provided overall. Incompatible FFP provision was not independently associated with inhospital mortality in MT (HR of 1.40 [95% CI 0.84-2.26, p = .2]). Variables independently associated with inhospital mortality included increased FFP volume in the first 24 h, age, Charlson Comorbidity Index score, and lower pre-transfusion fibrinogen and peri-transfusion pH values.

CONCLUSION

Transfusion of incompatible FFP in MT in our cohort was not independently associated with higher inhospital mortality, although the number of patients who received incompatible FFP was small.

Type-specific whole blood still has a role in the era of low-titer O universal donor transfusion for severe trauma hemorrhage

ABSTRACT

Whole blood can be ABO-type specific (type-specific whole blood (TSWB)) or low-titer O universal donor (low-titer O whole blood (LTOWB)). Having previously used LTOWB, the US Armed Forces Blood Program began using TSWB in 1965 as a method of increasing the donor pool. In contrast to military practice, the Association for the Advancement of Blood and Biotherapies formerly the American association of blood banks (AABB), from its first guidelines in 1958 until 2018, permitted only TSWB. Attempting to reduce time to transfusion, the US military reintroduced LTOWB in the deployed environment in 2015; this practice was endorsed by the AABB in 2018 and is progressively being implemented by military and civilian providers worldwide. Low-titer O whole blood is the only practical solution prehospital. However, there are several reasons to retain the option of TSWB in hospitals with a laboratory. These include (1) as-yet ill-defined risks of immunological complications from ABO-incompatible plasma (even when this has low titers of anti-A and -B), (2) risks of high volumes of LTOWB including published historical advice (based on clinical experience) not to transfuse type-specific blood for 2 to 3 weeks following a substantial LTOWB transfusion, (3) uncertainty as to the optimal definition of "low titer," and (4) expanding the potential donor pool by allowing type-specific transfusion. Several large randomized controlled trials currently underway are comparing LTOWB with component therapy, but none address the question of LTOWB versus TSWB. There are sufficient data to suggest that the additional risks of transfusing LTOWB to non-group O recipients should be avoided by using TSWB as soon as possible. Combined with the advantage of maintaining an adequate supply of blood products in times of high demand, this suggests that retaining TSWB within the civilian and military blood supply system is desirable. TSWB should be preferred when patient blood group is confirmed in facilities with a hematology laboratory, with LTOWB reserved for patients whose blood group is unknown.

Associations between ABO non-identical platelet transfusions and patient outcomes-A multicenter retrospective analysis

BACKGROUND

Due to platelet availability limitations, platelet units ABO mismatched to recipients are often transfused. However, since platelets express ABO antigens and are collected in plasma which may contain ABO isohemagglutinins, it remains controversial as to whether ABO non-identical platelet transfusions could potentially pose harm and/or have reduced efficacy.

STUDY DESIGN AND METHODS

The large 4-year publicly available Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) database was used to investigate patient outcomes associated with ABO non-identical platelet transfusions. Outcomes included mortality, sepsis, and subsequent platelet transfusion requirements.

RESULTS

Following adjustment for possible confounding factors, no statistically significant association between ABO non-identical platelet transfusion and increased risk of mortality was observed in the overall cohort of 21,176 recipients. However, when analyzed by diagnostic category and recipient ABO group, associations with increased mortality for major mismatched transfusions were noted in two of eight subpopulations. Hematology/Oncology blood group A and B recipients (but not group O) showed a Hazard Ratio (HR) of 1.29 (95%CI: 1.03-1.62) and intracerebral hemorrhage group O recipients (but not groups A and B) showed a HR of 1.75 (95%CI: 1.10-2.80). Major mismatched transfusions were associated with increased odds of receiving additional platelet transfusion each post-transfusion day (through day 5) regardless of the recipient blood group.

DISCUSSION

We suggest that prospective studies are needed to determine if specific patient populations would benefit from receiving ABO identical platelet units. Our findings indicate that ABO-identical platelet products minimize patient exposure to additional platelet doses.

The Use of Whole Blood Transfusion in Trauma

Purpose of Review

This review illustrates the current benefits, limitations, ongoing research, and future paths for Low Titer O Whole Blood compared to Component Therapy in massive transfusion for trauma patients.

Recent Findings

Many studies show that compared to Component Therapy, Low Titer O Whole Blood transfusion is associated with better patient outcomes and simplified transfusion logistics among others. There are, however, issues with cost, supply/demand and handling of Whole Blood that limit its use, but experience in the military setting has shown that these limitations can be easily overcome.

Summary

The use of Whole Blood has increased in the civilian trauma population and there is a growing body of evidence to support its current use. More research looking at Whole Blood in females of child-bearing age, pediatric populations, and cold-stored platelets is underway.

THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Risk of ABO-Incompatible Plasma From Non-ABO-Identical Components

The last several decades have seen significant changes in the approach to resuscitation of bleeding patients. These include the adoption of ABO-incompatible plasma transfusion in the form of group A plasma and/or low titer group O whole blood for trauma patients of unknown ABO group. Studies to date have examined the impact of these practices on patient outcomes and clinical markers of hemolysis in recipients of ABO-incompatible plasma compared to those for whom the plasma is ABO-compatible. Risk for increased mortality and/or overt hemolysis appear to be low among recipients of ABO-incompatible plasma; however, nearly all of studies are retrospective and most have focused only on adult trauma patients so results may not be generalizable to other bleeding patients. Work continues to evaluate the role of various titer thresholds in decreasing hemolytic risk and opportunities remain to improve our understanding of anti-A and anti-B antibody interactions with complement/endothelium and identify strategies to minimize risk.

The rebirth of the cool: a narrative review of the clinical outcomes of cold stored low titer group O whole blood recipients compared to conventional component recipients in trauma

There has been renewed interest in the use of low titer group O whole blood (LTOWB) for the resuscitation of civilian casualties. LTOWB offers several advantages over conventional components such as providing balanced resuscitation in one bag that contains less additive/preservative solution than an equivalent volume of conventional components, is easier and faster to transfuse than multiple components, avoids blood product ratio confusion, contains cold stored platelets, and reduces donor exposures. The resurgence in its use in the resuscitation of civilian trauma patients has led to the publication of an increasing number of studies on its use, primarily amongst adult recipients but also in pediatric patients. These studies have indicated that hemolysis does not occur amongst adult and pediatric non-group O recipients of a modest quantity of LTOWB. The published studies to date on mortality have shown conflicting results with some demonstrating a reduction following LTOWB transfusion while most others have not shown a reduction; there have not been any studies to date that have found significantly increased overall mortality amongst LTOWB recipients. Similarly, when other clinical outcomes, such as venous thromboembolism, sepsis, hospital or intensive care unit lengths of stay are evaluated, LTOWB recipients have not demonstrated worse outcomes compared to conventional component recipients. While definitive proof of the trends in these morbidity and mortality outcomes awaits confirmation in randomized controlled trials, the evidence to date indicates the safety of transfusing LTOWB to injured civilians.

Safety profile of low-titer group O whole blood in pediatric patients with massive hemorrhage

BACKGROUND

Low-titer Group O Whole Blood (LTOWB) is used with increasing frequency in adult and pediatric trauma and massive bleeding transfusion protocols. There is a risk of acute hemolytic reactions in non-group O recipients due to the passive transfusion of anti-A and anti-B in the LTOWB. This study investigated the hemolysis risk among pediatric recipients of LTOWB.

STUDY DESIGN AND METHODS

Blood bank records were queried for pediatric recipients of LTOWB between June 2016 and August 2020 and merged with clinical data. The primary outcome was laboratory evidence of hemolysis as manifested by changes in lactate dehydrogenase (LDH), haptoglobin, total bilirubin, reticulocyte count, potassium, and creatinine. Per protocol, these values were collected on hospital days 0-2 for recipients of LTOWB. Transfusion reactions were reported to the hospital's blood bank.

RESULTS

Forty-seven children received LTOWB transfusion between 2016 and 2020; 21 were group O and 26 were non-group O. The groups were comparable in terms of the total volume of transfused blood products, demographics, and clinical outcomes. The most common indication for LTOWB transfusion was hemorrhagic shock due to trauma. There were no clinically or statistically significant differences in baseline, post-transfusion day 1, or post-transfusion day 2 hemolysis markers between the group O and non-group O LTOWB recipients. There were no adverse events or transfusion reactions reported.

DISCUSSION

Use of up to 40 ml/kg of LTOWB appears to be serologically safe for children in hemorrhagic shock.

Injured recipients of low-titer group O whole blood have similar clinical outcomes compared to recipients of conventional component therapy: A single-center, retrospective study

INTRODUCTION

Low-titer group O whole blood (LTOWB) is being increasingly transfused to injured patients. This study evaluated a range of clinical outcomes to determine if receipt of LTOWB predisposed recipients to worse outcomes compared to recipients of conventional component therapy (CCT).

METHODS

A retrospective analysis of trauma patients who received at least 3 units of LTOWB (LTOWB group) versus those that received at least 3 units of RBCs, 1 unit of plasma and 1 unit of platelets but no LTOWB (CCT group) during the first 24 h of their admission was performed. Causal treatment effects were explored using propensity score matching (PSM) and coarsened exact matching (CEM). Important clinical outcomes were evaluated.

RESULTS

There were 165 CCT and 155 LTOWB recipients eligible for matching. PSM and CEM reduced covariate imbalances between the CCT and LTOWB groups, with the exception that males remained over-represented in the LTOWB group due to the hospital's former resuscitation policy of not administering RhD-positive LTOWB to females <50. In both of the matched analyses, the LTOWB group received a median of 4 LTOWB units. There were no significant differences in 6-, 24-h mortality or 30-day mortality between groups, nor were there differences in the frequency of other clinical outcomes such as acute kidney injury, sepsis, venous/arterial thromboembolism; delta MODS was lower for the LTOWB recipients in the exact match group.

CONCLUSION

In both matched analyses, administration of a median of four LTOWB units did not result in a different frequency of major clinical outcomes including mortality.