Review of low titre group O whole blood use for massively bleeding patients around the world in 2019

Low titer group O whole blood and risk of RhD alloimmunization: Rationale for use in Finland

BACKGROUND

Prehospital low-titer group O whole blood (LTOWB) used for patients with life-threatening hemorrhage is often RhD positive. The most important complication following RhD alloimmunization is hemolytic disease of the fetus and newborn (HDFN). Preceding clinical use of RhD positive LTOWB, we estimated the risk of HDFN due to LTOWB prehospital transfusion in the Finnish population.

STUDY DESIGN AND METHODS

We collected data on prehospital transfusions in Tampere and Helsinki University Hospital areas. Using the mean of reported alloimmunization rates in trauma studies (24%) and a higher reported rate representing trauma patients of 13-50 years old (42.7%), we estimated the risk of HDFN and extrapolated it to the whole of Finland.

RESULTS

We estimated that in Finland, with the current prehospital transfusion rate we would see 1-3 cases of severe HDFN due to prehospital LTOWB transfusions every 10 years, and fetal death due to HDFN caused by LTOWB transfusion less than once in 100 years.

DISCUSSION

The estimated risk of serious HDFN due to prehospital LTOWB transfusion in the Finnish population is similar to previous estimates. As Finland routinely screens expectant mothers for red blood cell antibodies and as the contemporary treatment of HDFN is very effective, we support the prehospital use of RhD positive LTOWB in all patient groups.

Incompatible plasma transfusion is not associated with increased mortality in civilian trauma patients

BACKGROUND

The introduction of low titer group O whole blood (LTOWB) that contains potentially ABO-incompatible plasma and the increasing use of group A plasma, due to shortages of AB plasma, in trauma patients whose ABO group is unknown could put the recipients of incompatible plasma at risk of increased morbidity and mortality. This study evaluated civilian trauma patient outcomes following receipt of incompatible plasma.

METHODS

One trauma center's patient contributions to three multicenter studies of different trauma resuscitation strategies was analyzed; these patients were separated into two groups based on receipt of only compatible plasma versus receipt of any quantity of incompatible plasma. Multivariate analysis was performed to determine if receipt of incompatible plasma was associated with 24-hour or 30-day mortality.

RESULTS

There were 347 patients eligible for this secondary analysis with 167 recipients of only compatible plasma and 180 recipients of incompatible plasma. The two groups were well matched demographically and on both prehospital and hospital arrival vital signs. The median (IQR) volume of incompatible plasma received by these patients was 684 ml (342, 1229). There was not a significant difference between the groups in 24-hour and 30-day mortality, nor in in-hospital or intensive care unit lengths of stay. In the Cox proportional-hazards regression model for both 24-hour and 30-day survival, receipt of incompatible plasma was not independently predictive of either mortality endpoint.

CONCLUSION

Receipt of incompatible plasma was not independently associated with increased mortality in trauma patients. Prospective studies are needed to confirm these findings.

Low titer Group O whole blood utilization in pediatric trauma resuscitation: A National Survey

BACKGROUND

Renewed interest in low titer group O whole blood (LTOWB) transfusion has led to increased utilization in adult trauma centers; little is known regarding LTOWB use in pediatric centers.

STUDY DESIGN AND METHODS

A survey of LTOWB utilization at American pediatric level 1 trauma centers.

RESULTS

Responses were received from 43/72 (60%) centers. These institutions were primarily urban (84%) and pediatric-specific (58%). There were 16% (7/43) centers using LTOWB, 7% (3/43) imminently initiating an LTOWB program, 47% (20/43) with interest but no current plan to develop a LTOWB program, and 30% (13/43) with no immediate interest in an LTOWB program. For the hospitals actively or imminently using LTOWB, 70% (3/10) have a minimum recipient weight criterion, 60% (6/10) have a minimum age criterion, and 70% (7/10) restrict the maximum volume transfused. Before the patient's RhD type becomes known, 30% (3/10) use RhD negative LTOWB for males and females, 40% (4/10) use RhD positive LTOWB for males and RhD negative LTOWB for females, 20% (2/10) use RhD positive LTOWB for males and RhD negative RBCs for females, and 10% (1/10) use RhD positive LTOWB for both males and females. Maximum LTOWB storage duration was 14-35 days and units nearing expiration were used for non-trauma patients (40%), processed to RBC (40%), and/or discarded (40%). The most common barriers to implementation were concerns about inventory management (37%), wastage (35%), infrequent use (33%), cost (21%) and unclear efficacy (14%).

CONCLUSION

LTOWB utilization is increasing in pediatric level 1 trauma centers in the United States.

Receipt of at least 4 units of low titer group O whole blood with titer <100 does not lead to hemolysis in adult trauma patients

BACKGROUND

The serological safety of transfusing low titer group O whole blood (LTOWB) with an anti-A and anti-B titer of <100 was evaluated in group O and non-group O trauma recipients.

METHODS

Civilian adult trauma patients who received ≥4 units of leukoreduced LTOWB during their initial resuscitation and who survived for >24 h after admission at two level 1 trauma centers were included in this retrospective study. Lactate dehydrogenase (LDH), total bilirubin, haptoglobin, potassium, creatinine were evaluated on the day of LTOWB transfusion (day 0) and on the next 3 days.

RESULTS

There were 77 injured recipients evaluated: 39 non-group O and 38 group O. The median (IQR) number of transfused LTOWB units was 4 (4-6) and 4 (4-5), respectively, and the maximum number of units was 8 and 11, respectively. The non-group O patients received a median (IQR) volume of 1710 ml (1368-2070) of ABO-incompatible plasma. Comparing non-group O to group O recipients, there were no significant differences in the median haptoglobin, LDH, or creatinine concentrations at any time point. The median concentration of total bilirubin was significantly higher amongst the non-group O recipients on days 1 and 2, while on day 0 the median potassium concentration was significantly higher amongst the group O recipients. All median elevated values were within the laboratory's normal range. Amongst the non-group O recipients there were no reported transfusion reactions.

CONCLUSION

Receiving at least four LTOWB units (anti-A&B titer <100) was not associated with biochemical/clinical evidence of hemolysis in adult trauma patients.

The Story of Blood for Shock Resuscitation: How the Pendulum Swings

Whole blood transfusion (WBT) began in 1667 as a treatment for mental illness, with predictably poor results. Its therapeutic utility and widespread use were initially limited by deficiencies in transfusion science and antisepsis. James Blundell, a British obstetrician, was recognized for the first allotransfusion in 1825. However, WBT did not become safe and therapeutic until the early 20th century, with the advent of reliable equipment, sterilization, and blood typing. The discovery of citrate preservation in World War I allowed a separation of donor from recipient and introduced the practice of blood banking. During World War II, Elliott and Strumia were the first to separate whole blood into blood component therapy (BCT), producing dried plasma as a resuscitative product for "traumatic shock." During the 1970s, infectious disease, blood fractionation, and financial opportunities further drove the change from WBT to BCT, with few supporting data. Following a period of high-volume crystalloid and BCT resuscitation well into the early 2000s, measures to avoid the resulting iatrogenic resuscitation injury were developed under the concept of damage control resuscitation. Modern transfusion strategies for hemorrhagic shock target balanced BCT to reapproximate whole blood. Contemporary research has expanded the role of WBT to therapy for the acute coagulopathy of trauma and the damaged endothelium. Many US trauma centers are now using WBT as a front-line treatment in tandem with BCT for patients suffering hemorrhagic shock. Looking ahead, it is likely that WBT will once again be the resuscitative fluid of choice for patients in hemorrhagic shock.

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.

A whole blood based resuscitation strategy in civilian medical services: Experience from a Norwegian hospital in the period 2017-2020

BACKGROUND

Civilian and military guidelines recommend early balanced transfusion to patients with life-threatening bleeding. Low titer group O whole blood was introduced as the primary blood product for resuscitation of massive hemorrhage at Haukeland University Hospital, Bergen, Norway, in December 2017. In this report, we describe the whole blood program and present results from the first years of routine use.

STUDY DESIGN AND METHODS

Patients who received whole blood from December 2017 to April 2020 were included in our quality registry for massive transfusions. Post-transfusion blood samples were collected to analyze isohemagglutinin (anti-A/-B) and hemolysis markers. Administration of other blood products, transfusion reactions, and patient survival (days 1 and 30) were recorded. User experiences were surveyed for both clinical and laboratory staff.

RESULTS

Two hundred and five patients (64% male and 36% female) received 836 units in 226 transfusion episodes. Patients received a mean of 3.7 units (range 1-35) in each transfusion episode. The main indications for transfusion were trauma (26%), gastrointestinal (22%), cardiothoracic/vascular (18%), surgical (18%), obstetric (11%), and medical (5%) bleeding. There was no difference in survival between patients with blood type O when compared with non-group O. Haptoglobin level was lower in the transfusion episodes for non-O group patients, however no clinical hemolysis was reported. No patients had conclusive transfusion-associated adverse events. Both clinical and laboratory staff preferred whole blood to component therapy for massive transfusion.

DISCUSSION

The experience from Haukeland University Hospital indicates that whole blood is feasible, safe, and effective for in-hospital treatment of bleeding.

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.

Survey of group A plasma and low-titer group O whole blood use in trauma resuscitation at adult civilian level 1 trauma centers in the US

BACKGROUND

Recently revisited products like low-titer group O whole blood (LTOWB) and novel applications of group A as a universal donor of plasma are being used for trauma resuscitation. A survey of American Level 1 trauma centers was performed to elucidate the extent to which these products are currently employed.

METHODS

A survey was written that probed into the current use of blood products in trauma resuscitation with specific emphasis on LTOWB and group A plasma. A list of adult civilian Level 1 trauma centers in the continental USA was obtained from two public surgery and trauma focused websites. An email was then sent to each center's transfusion service medical director or laboratory manager providing them with a link to the online survey.

RESULTS

Responses were received from 103/187 (55%) adult civilian Level 1 trauma centers. For the resuscitation of trauma patients, group A plasma was used at 94/103 (91%) centers, while LTOWB was used at 43/103 (42%) centers. There were 39/103 (38%) centers that used both products. At 62/94 (66%) of the centers that used group A plasma, there was no limit on the number of units that could be administered, while an unlimited number of LTOWB units could be used at 5/43 (12%) of the centers that used LTOWB. RhD-positive LTOWB could be transfused to RhD-negative or RhD-type unknown females of childbearing potential at 22/43 (51%) of centers.

CONCLUSION

The use of group A plasma and LTOWB in trauma is increasing at American Level 1 trauma centers.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.

Whole Blood is Superior to Component Transfusion for Injured Children: A Propensity Matched Analysis

OBJECTIVE

To compare a propensity-matched cohort of injured children receiving conventional blood component transfusion to injured children receiving low-titer group O negative whole blood.

SUMMARY OF BACKGROUND DATA

Transfusion of whole blood in pediatric trauma patients is feasible and safe. Effectiveness has not been evaluated.

METHODS

Injured children ≥1 years old can receive up to 40 mL/kg of cold-stored, uncrossmatched whole blood during initial hemostatic resuscitation. Whole blood recipients (2016-2019) were compared to a propensity-matched cohort who received at least 1 uncrossmatched red blood cell unit in the trauma bay (2013-2016). Cohorts were matched for age, hypotension, traumatic brain injury, injury mechanism, and need for emergent surgery. Outcomes included time to resolution of base deficit, product volumes transfused, and INR after resuscitation.

RESULTS

Twenty-eight children who received whole blood were matched to 28 children who received components. The whole blood group had faster time to resolution of base deficit [median (IQR) 2 (1-2.5) hours vs 6 (2-24) hours, respectively; P < 0.001]. The post-transfusion INR was decreased in whole blood vs component cohort [median (IQR) 1.4 (1.3-1.5) vs 1.6 (1.4-2.2); P = 0.01]. Lower plasma volumes [median (IQR) = 5 (0-15) mL/kg vs 11 (5-35) mL/kg; P = 0.04] and lower platelet volumes [median (IQR) = 0 (0-2) vs 3 (0-8); P = 0.03] were administered to the whole blood group versus component group. Other clinical variables (in-hospital death, hospital length of stay, intensive care unit length of stay, and ventilator days) did not differ between groups.

CONCLUSIONS

Compared to component transfusion, whole blood transfusion results in faster resolution of shock, lower post-transfusion INR, and decreased component product transfusion. Larger cohorts are required to support these findings.

Effects of the COVID-19 pandemic on supply and use of blood for transfusion

The COVID-19 pandemic has major implications for blood transfusion. There are uncertain patterns of demand, and transfusion institutions need to plan for reductions in donations and loss of crucial staff because of sickness and public health restrictions. We systematically searched for relevant studies addressing the transfusion chain-from donor, through collection and processing, to patients-to provide a synthesis of the published literature and guidance during times of potential or actual shortage. A reduction in donor numbers has largely been matched by reductions in demand for transfusion. Contingency planning includes prioritisation policies for patients in the event of predicted shortage. A range of strategies maintain ongoing equitable access to blood for transfusion during the pandemic, in addition to providing new therapies such as convalescent plasma. Sharing experience and developing expert consensus on the basis of evolving publications will help transfusion services and hospitals in countries at different stages in the pandemic.

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

BACKGROUND

This study investigated the effect on mortality of transfusing ABO-incompatible plasma from all sources during trauma resuscitation.

METHODS

Demographic, transfusion, and survival data were retrospectively extracted on civilian trauma patients. Patients were divided by receipt of any quantity of ABO-incompatible plasma from any blood product (incompatible group) or receipt of solely ABO-compatible plasma (compatible group). The primary outcome was 30-day mortality, while other outcomes included 6- and 24-hour mortality. Mixed-effects logistic regression was used to model the effect of various predictor variables, including receipt of incompatible plasma, on mortality outcomes.

RESULTS

Nine hospitals contributed data on a total of 2618 trauma patients. There were 1282 patients in the incompatible group and 1336 patients in the compatible group. In both the unadjusted and adjusted models, the 6-hour, 24-hour, and 30-day mortality rates were not significantly different between these groups. The patients in the incompatible group were then divided into high volume (>342 mL) and low volume (≤342 mL) incompatible plasma recipients. In the adjusted model, the high-volume group had higher 24-hour mortality when the Trauma Injury Severity Score survival prediction was >50%. Mortality at 6 hours and 30 days was not higher in this model. The low-volume group did not have increased mortality at any of the time points in this adjusted model.

CONCLUSION

The transfusion of incompatible plasma in civilian trauma resuscitation does not lead to higher 30-day mortality. The finding of higher mortality in a select group of recipients in the secondary analysis warrants further study.

Optimizing blood bank resources when implementing a low-titer group O+ whole blood program: an in silico study

INTRODUCTION

Low-titer group O+ whole blood (LTOWB) is becoming commonly used in massive bleeding resuscitation, but the impact on blood center O+ RBCs has not been studied. This in silico model simulated a variety of different LTOWB production and utilization patterns.

METHODS

Collections and distributions data from a large blood collector were scaled to vary the total number of O+ red blood cell (RBC) collections, the O+ RBC collection: import ratio, and the O+ RBC apheresis: whole blood (WB) collection ratio. Daily LTOWB demand was determined by the daily number of LTOWB recipients, average number of LTOWB units transfused per patient, maximum number of LTOWB units a single patient can receive, and seasonality of LTOWB use. LTOWB program factors included the high-titer exclusion %, the LTOWB expiry, and whether LTOWB units were reclaimed as O+ RBC units on the date of expiry. Simulations using unique combinations of the above input parameters were performed.

RESULTS

For the 1,224,720 unique combinations of input parameters simulated, the average increase in the fraction of additional O+ RBC units required to meet hospital demand was only 0.02%. Higher daily LTOWB demand resulted in more LTOWB shortages. Increasing the minimum LTOWB inventory threshold reduced LTOWB shortages without increasing the number of required additional RBC units. LTOWB wastage was minimal but was lower with longer LTOWB shelf life or manufacture of RBC units from unused LTOWB on Day 14.

CONCLUSION

Implementing an LTOWB program does not have a major impact on the blood collectors' needs for additional RBC units to meet hospital demands.

Hemolytic markers following the transfusion of uncrossmatched, cold-stored, low-titer, group O+ whole blood in civilian trauma patients

BACKGROUND

Low-titer group O whole blood (LTOWB) is increasingly being used in the civilian trauma setting, although there is a risk of hemolysis. This study evaluated the impact on hemolytic markers following the transfusion of 4 or more units of uncrossmatched LTOWB.

METHODS

Civilian adult trauma patients who received four or more units of leukoreduced group O+, low-titer (<50 anti-A and anti-B), platelet-replete uncrossmatched whole blood during their initial resuscitation and who survived for more than 24 hours after the transfusion were included in this retrospective study. Lactate dehydrogenase (LDH), total bilirubin, haptoglobin, potassium, and creatinine were evaluated on the day of LTOWB transfusion (Day 0) and the next 3 days. Blood product administration over the first 24 hours of admission was recorded.

RESULTS

There were 54 non-group O and 23 group O recipients of four or more LTOWB units. The median (interquartile range [IQR]) number of transfused LTOWB units was 4 (4-5) and 4 (4-4), respectively, the maximum number in both groups was eight. The non-group O patients received a median (IQR) volume of 1470 mL (1368-2052) of ABO-incompatible plasma. Comparing the non-group O to the group O recipients, there were no significant differences in the haptoglobin, LDH, total bilirubin, potassium, or creatinine concentrations at any of the time points. There were no reported transfusion reactions.

CONCLUSION

Receiving at least four LTOWB units was not associated with biochemical or clinical evidence of hemolysis.

Whole blood for postpartum hemorrhage: early experience at two institutions

BACKGROUND

Death from postpartum hemorrhage (PPH) remains a significant preventable problem worldwide. Cold-stored, low-titer, type-O whole blood (LTOWB) is increasingly being used for resuscitation of injured patients, but it is uncommon in PPH patients, and it is unclear what its role may be in this population.

STUDY DESIGN AND METHODS

Brief report of the early experience of WB use for PPH in two institutions, one university hospital and one private hospital.

RESULTS

Different approaches have been implemented at the two institutions, one designed for emergency release, uncrossmatched transfusion of LTOWB as part of a massive transfusion protocol (MTP) and one for high-risk obstetric patients with known placental abnormalities. A total of 7 PPH patients have received a total of 17 units of LTOWB between the two institutions. No severe adverse transfusion reactions were observed clinically in either institution and the clinical outcomes were favorable in all cases.

CONCLUSION

In our early experience, LTOWB can be implemented for two different PPH clinical scenarios. Larger studies are needed to compare outcomes between LTOWB and traditional component resuscitation strategies.