Spikes in demand for hospital transfusion services.

INTRODUCTION: Spikes in the demand for blood components represent a substantial challenge to transfusion services. Simple metrics for characterizing volatility in blood components within the hospital transfusion service have not been established. METHODS: We measured the volatility of demand for blood services at a large academic urban general hospital over a 6-month period from July 2019 to December 2019 prior to the SARS-CoV2 pandemic. RESULTS: Among 4416 consecutive hours assessed, there were 693 h (16%) with spikes in demand for blood components with a mean (sd) of 3.8 (2.7) spikes/day. Spikes in demand were frequently clustered. The median number of hours between spikes differed by shift (6 h for days; 3 h for evenings; 3 h for nights). The percentage of shift hours with demand spikes also differed (9% day; 19% evening; 18% night). During the study, 32,447 components were distributed to 19,431 patients. Of these, 11,819 components (36%) were distributed during hours of peak demand. Hours with a simultaneous spike in both component demand and patient demand occurred in 5% of hours or approximately once each day. CONCLUSION: Demand for transfusion services was highly volatile in an unpredictable fashion. We provide an approach that could be used to benchmark spikes in demand for blood services at hospitals. Consideration of the frequency, unpredictability, and magnitude of spikes in demand may be relevant for hemovigilance programs and for strategies to determine the laboratory staffing needed for good patient care.

International Survey of Trials of Convalescent Plasma to Treat COVID-19 Infection.

The collection and clinical use of COVID-19 convalescent plasma (CCP) as a therapy for COVID-19 infection is under development and early use in many centers worldwide. We conducted an international survey of centers undertaking studies of CCP to provide understanding of the common themes and differences between them. Sixty-four studies in 22 countries were identified from clinical trial registries and personal contacts of the authors. Twenty of the 64 centers (31%) from 12 of 22 countries (55%) responded to the survey. Of the 20 studies, 11 were randomized controlled trials (RCTs), and 9 were case series. Only 4 of the RCTs plan to recruit 400 patients or more, and only 3 RCTs were blinded. The majority of studies will study the effect of CCP on sick patients requiring hospitalization and those requiring critical care, and none is examining the role of CCP in non-infected at-risk individuals. A wide variety of primary and secondary outcomes are being used. The donor eligibility criteria among the studies are very similar, and the use of plasmapheresis for the collection of CCP is almost universal. The planned dose of CCP ranges from as little as 200 mL to well over 1 L, but is 400 to 800 mL or 4 mL/kg or greater in all the RCTs. There is considerable variability in donor antibody testing with no consistency regarding the cut-off for antibody titer for acceptance as CCP or the use of pathogen-inactivation. Our survey provides an understanding of the similarities and differences among the studies of CCP, and that by virtue of their design some studies may be more informative than others.

Complement and Coagulation: Cross Talk Through Time.

Two complex protein defense systems-complement and coagulation-are based on amplifying enzyme cascades triggered by specific local stimuli. Excess systemic activation of either system is pathologic and is normally prevented by a family of regulatory proteins. The 2 systems are ancient biological processes which share a common origin that predates vertebrate evolution. Recent research has uncovered multiple opportunities for cross talk between complement and coagulation including proteins traditionally viewed as coagulation factors that activate and regulate complement, and proteins traditionally seen as part of the complement system that participate in coagulation. Ten examples of cross talk between the 2 systems are described. The mutual engagement of both systems is increasingly recognized to occur in human diseases. Three conditions-paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, and the antiphospholipid syndrome-provide examples of the importance of interactions between complement and coagulation in human biology. A better understanding of the mutual engagement of these 2 ancient defense systems is expected to result in improved diagnostics and new treatments for systemic diseases.

James Blundell, Obstetrical Hemorrhage, and the Origins of Transfusion Medicine.

Although James Blundell is rightly acknowledged as the father of modern transfusion therapy, a review of the events surrounding the initial human-to-human transfusions in the first decades of the 19th century reveals substantial contributions by Blundell's collaborators. Bundell's uncle John Haighton provided substantial support for animal experimentation in the growing field of physiology studies. John Leacock of Barbados provided the essential original experiments that focused the path of investigation on within-species transfusions. London instrument makers such as Laundy and Lloyd provided precision-made syringes without risk of air embolism. Fellow obstetricians Charles Waller and Edward Doubleday became ardent supporters of the new therapy and brought case referrals to Blundell's attention and care. British medical journals, such as The Lancet, provided much needed dissemination of early successes to curious medical practitioners. This 200th anniversary year of the first successful attempts at human-to-human transfusion presents an opportunity to review the failures and successes which occurred during the first days of what would ultimately become a life-saving treatment for millions worldwide.

A touch of TRALI.

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated morbidity and mortality. The National Heart, Lung, and Blood Institute (NHLBI) and Canadian Consensus Conference definitions of TRALI exclude cases of mild TRALI. As a result, many cases of mild TRALI are likely to be missed. Three cases are reported in which patients experienced the acute onset of breathlessness in association with transfusion of blood components containing human leukocyte antigen (HLA) antibodies reactive with recipient HLA antigens. Despite the sudden onset of a pulmonary syndrome in association with transfusion, clinicians caring for these patients did not consider TRALI, and no case would meet recent consensus definitions. Nevertheless, supporting clinical and serologic evidence for TRALI was found in each case. Benefits in recognizing mild cases of TRALI include quantifying the true incidence of TRALI, understanding the physiology of mild versus severe TRALI, and preventing subsequent cases of TRALI due to donors found to have HLA antibodies.