Novel method for determining when a field-collected donor unit is sufficiently full.

BACKGROUND: Whole blood (WB) collections can occur downrange for immediate administration. An important aspect of these collections is determining when the unit is sufficiently full. This project tested a novel method for determining when a field collection is complete. METHODS: The amount of empty space at the top of WB units, destined to become LTOWB or separated into components, that were collected at blood centers or hospitals was measured by holding a WB unit off the ground and placing the top of a piece of string where the donor tubing entered the bag. The string was marked where it intersected the top of the column of blood in the bag and measured from the top. The WB units were also weighed. RESULTS: A total of 15 different bags, two of which were measured in two different filling volumes, from 15 hospitals or blood centers were measured and weighed. The most commonly used blood bag, Terumo Imuflex SP, had a median string length of 9 mm (range: 2-24 mm) and weighed a median of 565.1 g (range: 524.8-636.7 g). CONCLUSION: Pieces of string can be precut to the appropriate length depending on the type of bag before a mission where field WB collections might be required and a mark placed on the bag before the collection commences to indicate when the unit is full.

Rate of D-alloimmunization in trauma does not depend on the number of RhD-positive units transfused: The BEST collaborative study.

BACKGROUND: Evidence indicates the life-saving benefits of early blood product transfusion in severe trauma resuscitation. Many of these products will be RhD-positive, so understanding the D-alloimmunization rate is important. METHODS: This was a multicenter, retrospective study whereby injured RhD-negative patients between 18-50 years of age who received at least one unit of RhD-positive red blood cells (RBC) or low titer group O whole blood (LTOWB) during their resuscitation between 1 January, 2010 through 31 December, 2019 were identified. If an antibody detection test was performed ≥14 days after the index RhD-positive transfusion then basic demographic information was collected, including whether the patient became D-alloimmunized. The overall D-alloimmunization rate, and the rate stratified by the number of units transfused, were calculated. RESULTS: Data were collected from nine institutions. Five institutions reported fewer than 10 eligible patients each and were excluded. From the remaining four institutions, all from the USA, there were 235 eligible patients; 77 (random effects estimate: 32.7%; 95% CI: 19.1-50.1%) became D-alloimmunized. Three of the institutions reported D-alloimmunization rates ≥38.6%, while the remaining institution's rate was 12.2%. In both random and fixed-effects models, the rate of D-alloimmunization was not significantly different between those who received one RhD-positive unit and those who received multiple RhD-positive units. CONCLUSION: In this large, multicenter study of injured patients, the overall rate of D-alloimmunization fell within the range previously reported. The rate of D-alloimmunization did not increase as the number of transfused RhD-positive units increased. These data can help to inform RhD type selection decisions.

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.

Prehospital Plasma Transfusion: What Does the Literature Show?

BACKGROUND: Early initiation of blood products transfusion after injury has been associated with improved patient outcomes following traumatic injury. The ability to transfuse patients' plasma in the prehospital setting provides a prime opportunity to begin resuscitation with blood products earlier and with a more balanced plasma: RBC ratio than what has traditionally been done. Published studies on the use of prehospital plasma show a complex relationship between its use and improved survival. SUMMARY: Examination of the literature shows that there may be a mortality benefit from the use of prehospital plasma, but that it may be limited to certain subgroups of trauma patients. The likelihood of realizing these survival benefits appears to be predicted by several factors including the type of injury, length of transport time, presence of traumatic brain injury, and total number of blood products transfused, whether the patient required only a few products or a massive transfusion. When taken as a whole the evidence appears to show that prehospital plasma may have a mortality benefit that is most clearly demonstrated in patients with blunt injuries, moderate transfusion requirements, traumatic brain injury, and/or transport time greater than 20 min, as well as those who demonstrate a certain cytokine expression profile. KEY MESSAGES: The evidence suggests that a targeted use of prehospital plasma will most likely maximize the benefits from the use of this limited resource. It is also possible that prehospital plasma may best be provided through whole blood as survival benefits were greatest in patients who received both prehospital plasma and RBCs.

Single Plasma Unit Transfusions in Adults Are Either Unnecessary or Underdosed.

OBJECTIVES: Previous studies of blood product use have shown higher inappropriate use of plasma compared with other products. Given typical weight-based dosing of plasma, we hypothesized that single plasma transfusions in adults would either be a nontherapeutic dose or outside clinical guidelines. METHODS: A single-center, retrospective review of nonoperative, nonapheresis plasma use was conducted from January 2020 to April 2020. Plasma transfusions were reviewed for compliance with clinical guidelines formulated at our institution as well as national and society guidelines. RESULTS: During the study period, 313 units of plasma were transfused. Of these, 152 (48.6%) were given against institutional or national guidelines, 126 plasma units (40.3%) were transfused as single units, and 187 (59.7%) were given as part of multiple-unit transfusions. All single-unit plasma transfusions during the study period were either underdosed or outside clinical guidelines. Units transfused with an indication of "Other" were significantly more likely to be outside clinical guidelines. CONCLUSIONS: Nonoperative, nonapheresis plasma use is often outside clinical guidelines. Single-unit plasma transfusions in adults are a potential target for patient blood management programs seeking to minimize unnecessary plasma use.

Echocardiography in patients with symptomatic intracranial stenosis.

BACKGROUND: Echocardiography is often performed in patients with stroke, even when alternative stroke causes are identified. We evaluated the use of echocardiography in patients with transient ischemic attack (TIA) or stroke caused by stenosis of a major intracranial artery. METHODS: The Warfarin Versus Aspirin for Symptomatic Intracranial Disease (WASID) trial was a National Institutes of Health-funded, randomized, double-blind, multicenter clinical trial in which 569 patients with TIA or ischemic stroke attributed to angiographically proven 50% to 99% stenosis of a major intracranial artery were randomly assigned to warfarin or aspirin. Patients with unequivocal cardiac sources of embolism were excluded. The risk of ischemic stroke, myocardial infarction, and vascular death was compared among patients who had or did not have echocardiography performed before enrollment, and Cox proportional hazards models were used to determine whether echocardiographic abnormalities present in greater than 5% of patients were associated with these outcomes. RESULTS: In all, 264 of 569 patients in WASID had echocardiograms; 37% were transesophageal. Of these 264 patients, 69 had subsequent ischemic stroke, myocardial infarction, or vascular death. Patients who underwent echocardiography had similar event rates to those who did not (P = .18). Common abnormalities identified on echocardiography were not associated with subsequent risk in this population. CONCLUSIONS: Among patients with TIA or stroke caused by intracranial arterial stenosis, echocardiography appears to offer limited diagnostic and prognostic value.

Predicted effects of proposed tightened acceptance criterion for Pb proficiency testing (PT) on PT sample pass rates for Pb point-of-care testing.

BACKGROUND: There is current advocacy for change in Pb proficiency testing (PT) acceptance criterion from ± 4 µg/dl ([Pb] <40 µg/dl; criterion a) to ± 2 µg/dl ([Pb] <20 µg/dl, criterion b). We examined the effect of this proposed change on PT sample pass rates for point-of-care testing (POCT) as predicted by imprecision of POCT PT sample results. METHODS: Inter-site standard deviations (s) of POCT PT results were tabulated as a function of [Pb] and characterized as a linear function of [Pb] (r(2)>0.8). Given s, predicted minimum, random-error-only PT failure rates (Fp) as a function of [Pb] were computed as the fraction of a normal distribution of results ([Pb]± s) that would fall outside of boundaries of acceptance criterion a or b. RESULTS: For [Pb]=2-20 µg/dl, current observed PT sample failure rates using criterion a range from 3 to 6%, which are greater than the predicted minimum failure rates based on s alone (Fp(a)=0-6%). In contrast, predicted minimum failure rates based on s using criterion b are greatly increased (Fp(b)=5-35%). CONCLUSIONS: Given the degree of inter-site imprecision among POCT Pb PT results, adoption of criterion b for PT acceptance will dramatically increase Pb PT sample failure rates for POCT due to random-error alone.