Trial Of Pathogen-reduced Cryoprecipitate vs. Cryoprecipitated AHF to Lower Operative Transfusions (TOP-CLOT): study protocol for a single center, prospective, cluster randomized trial.

BACKGROUND: Intraoperative hemorrhage in cardiac surgery increases risk of morbidity and mortality. Low pre-operative and perioperative levels of fibrinogen, a key clotting factor, are associated with severity of hemorrhage and increased transfusion of blood components. The ability to supplement fibrinogen during hemorrhagic resuscitation is delayed 45-60 min because cryoprecipitated antihemophilic factor (cryo AHF) is stored frozen, due to a short post-thaw shelf life. Pathogen Reduced Cryoprecipitated Fibrinogen Complex (INTERCEPT Fibrinogen Complex, IFC) can be kept thawed, at room temperature, for up to 5 days, making it possible to be immediately available for hemorrhaging patients. This trial will investigate if earlier correction of acquired hypofibrinogenemia with IFC in hemorrhaging cardiac surgery patients reduces the total number of perioperatively transfused allogeneic blood products (red blood cells, plasma, and platelets) as compared to cryo AHF. METHODS: This is a single center, prospective, cluster randomized trial with an adaptive design. Acquired hypofibrinogenemia will be assessed by rotational thromboelastometry (ROTEM) and the threshold for cryo AHF/IFC transfusion defined as FIBTEM A10 ≤ 10 mm in bleeding patients. IFC/cryo AHF will be randomized by 1-month blocks. Cardiac surgery patients will be enrolled in the study if they have an eligible procedure and at least one dose of a cryo AHF/IFC product (approximately 2 g fibrinogen) is transfused. Data from the electronic health record, including the blood bank and lab information systems, will be prospectively collected from the health system's data warehouse. DISCUSSION: This trial aims to provide evidence of the clinical efficacy of utilizing readily available thawed IFC during acute bleeding in the cardiac surgery setting compared to traditional cryo AHF. TRIAL REGISTRATION: ClinicalTrials.gov NCT05711524. Feb 3, 2023.

Dissociable neuronal substrates of visual feature attention and working memory.

Attention and working memory (WM) are distinct cognitive functions, yet given their close interactions, it is often assumed that they share the same neuronal mechanisms. We show that in macaques performing a WM-guided feature attention task, the activity of most neurons in areas middle temporal (MT), medial superior temporal (MST), lateral intraparietal (LIP), and posterior lateral prefrontal cortex (LPFC-p) displays attentional modulation or WM coding and not both. One area thought to play a role in both functions is LPFC-p. To test this, we optogenetically inactivated LPFC-p bilaterally during different task periods. Attention period inactivation reduced attentional modulation in LPFC-p, MST, and LIP neurons and impaired task performance. In contrast, WM period inactivation did not affect attentional modulation or performance and minimally affected WM coding. Our results suggest that feature attention and WM have dissociable neuronal substrates and that LPFC-p plays a critical role in feature attention, but not in WM.

A ubiquitous spectrolaminar motif of local field potential power across the primate cortex.

The mammalian cerebral cortex is anatomically organized into a six-layer motif. It is currently unknown whether a corresponding laminar motif of neuronal activity patterns exists across the cortex. Here we report such a motif in the power of local field potentials (LFPs). Using laminar probes, we recorded LFPs from 14 cortical areas across the cortical hierarchy in five macaque monkeys. The laminar locations of recordings were histologically identified by electrolytic lesions. Across all areas, we found a ubiquitous spectrolaminar pattern characterized by an increasing deep-to-superficial layer gradient of high-frequency power peaking in layers 2/3 and an increasing superficial-to-deep gradient of alpha-beta power peaking in layers 5/6. Laminar recordings from additional species showed that the spectrolaminar pattern is highly preserved among primates-macaque, marmoset and human-but more dissimilar in mouse. Our results suggest the existence of a canonical layer-based and frequency-based mechanism for cortical computation.

A Cross-Sectional Evaluation of Publication Bias in the Plastic Surgery Literature.

BACKGROUND: Publication bias (PB) is the preferential publishing of studies with statistically significant results. PB can skew findings of systematic reviews (SR) and meta-analyses (MA), with potential consequences for patient care and health policy. This study aims to determine the extent by which SRs and MAs in the plastic surgery literature evaluate and report PB. METHODS: This cross-sectional study assessed PB reporting and analysis from plastic surgery studies published between January 1, 2015 and June 19, 2020. Full-texts of SRs and MAs were assessed by two reviewers for PB assessment methodology and analysis. Post-hoc assessment of studies that did not originally analyze PB was performed using Egger's regression, Duval and Tweedie's trim-and-fill, and Copas selection models. RESULTS: There were 549 studies evaluated, of which 531 full-texts were included. PB was discussed by 183 (34.5%) studies, and formally assessed by 97 (18.3%) studies. Among SR and MAs that formally assessed PB, PB was present in 24 (10.7%), not present in 52 (23.1%), and inconclusive in 8 (3.6%) studies; 141 (62.7%) studies did not report the results of their PB assessment. Funnel plots were the most common assessment method (n=88, 39.1%), and 60 (68.2%) studies published funnel plots. The post-hoc assessment revealed PB in 17/20 (85.0%) studies. CONCLUSION: PB is inadequately reported and analyzed amongst studies in the plastic surgery literature. Most studies that assessed PB found PB, as did post-hoc analysis of non-reporting studies. Increased assessment and reporting of PB amongst SRs and MAs would improve quality of evidence in plastic surgery.

Associations of donor, component, and recipient factors on hemoglobin increments following red blood cell transfusion in very low birth weight infants.

BACKGROUND: Anemia in very low birth weight (VLBW) infants is common and frequently managed with red blood cell (RBC) transfusions. We utilized a linked vein-to-vein database to assess the role of blood donors and component factors on measures of RBC transfusion effectiveness in VLBW infants. STUDY DESIGN AND METHODS: We linked blood donor and component manufacturing data with VLBW infants transfused RBCs between January 1, 2013 and December 31, 2016 in the Recipient Epidemiology Donor Evaluation Study-III (REDS III) database. Using multivariable regression, hemoglobin increments and subsequent transfusion events following single-unit RBC transfusion episodes were examined with consideration of donor, component, and recipient factors. RESULTS: Data on VLBW infants (n = 254) who received one or more single-unit RBC transfusions (n = 567 units) were linked to donor demographic and component manufacturing characteristics for analysis. Reduced post-transfusion hemoglobin increments were associated with RBC units donated by female donors (-0.24 g/dL [95% confidence interval (CI) -0.57, -0.02]; p = .04) and donors <25 years old (-0.57 g/dL [95% CI -1.02, -0.11]; p = .02). For RBC units donated by male donors, reduced donor hemoglobin levels were associated with an increased need for subsequent recipient RBC transfusion (odds ratio 3.0 [95% CI 1.3, 6.7]; p < .01). In contrast, component characteristics, storage duration, and time from irradiation to transfusion were not associated with post-transfusion hemoglobin increments. CONCLUSION: Donor sex, age, and hemoglobin levels were associated with measures of RBC transfusion effectiveness in VLBW infants. Mechanistic studies are needed to better understand the role of these potential donor factors on other clinical outcomes in VLBW infants.

Stimulus representations in visual cortex shaped by spatial attention and microsaccades.

Microsaccades (MSs) are commonly associated with spatially directed attention, but how they affect visual processing is still not clear. We studied MSs in a task in which the animal was randomly cued to attend to a target stimulus and ignore distractors, and it was rewarded for detecting a color change in the target. We found that the enhancement of firing rates normally found with attention to a cued stimulus was delayed until the first MS directed towards that stimulus. Once that MS occurred, attention to the target was engaged and there were persistent effects of attention on firing rates for the remainder of the trial. These effects were found in the superficial and deep layers of V4 as well as the lateral pulvinar and IT cortex. Although the tuning curves of V4 cells do not change depending on the locus of spatial attention, we found pronounced effects of MS direction on stimulus representations that persisted for the length of the trial in V4. In intervals following a MS towards the target in the RF, stimulus decoding from population activity was substantially better than in intervals following a MS away from the target. Likewise, turning curves of cells were substantially sharper following a MS towards the target in the RF. This sharpening appeared to result from both a "refreshing" of the initial transient sensory response to stimulus onset, and a magnification of the effects of attention in this condition. MSs to the target also enhanced the neuronal response to the behaviorally relevant target color change and led to faster reaction times. These results thus reveal a major link between spatial attention, object processing and its coordination with eye movements.

Dissociable neuronal substrates of visual feature attention and working memory.

Attention and working memory (WM) are distinct cognitive functions, yet given their close interactions, it has been proposed that they share the same neuronal mechanisms. Here we show that in macaques performing a WM-guided feature attention task, the activity of most neurons in areas middle temporal (MT), medial superior temporal (MST), lateral intraparietal (LIP), and posterior lateral prefrontal cortex (LPFC-p) displays either WM coding or attentional modulation, but not both. One area thought to play a role in both functions is LPFC-p. To test this, we optogenetically inactivated LPFC-p bilaterally during the attention or WM periods of the task. Attention period inactivation reduced attentional modulation in LPFC-p, MST, and LIP neurons, and impaired task performance. WM period inactivation did not affect attentional modulation nor performance, and minimally reduced WM coding. Our results suggest that feature attention and WM have dissociable neuronal substrates, and that LPFC-p plays a critical role in attention but not WM.

Epidemiology of Platelet Transfusions in Hospitalized Children: A Pediatric Hospital Information System Database Study.

OBJECTIVES: To describe the epidemiology and complications of platelet transfusions among hospitalized pediatric patients during 2010 to 2019. METHODS: We performed a retrospective cohort study of hospitalized children within the Pediatric Health Information System database. Pediatric encounters receiving at least one platelet transfusion during hospitalization from 2010 to 2019 were identified. Data regarding demographics, diagnoses, procedures required during hospitalization, complications, and outcomes were extracted for eligible encounters. RESULTS: Within the Pediatric Health Information System database, 6 284 264 hospitalizations occurred from 2010 to 2019. A total of 244 464 hospitalizations required at least one platelet transfusion, yielding a prevalence of 3.89% (95% confidence interval [CI], 3.87%-3.91%). Transfusion prevalence did not change significantly across the decade (P value = .152). Two-thirds of children receiving platelet transfusions were in their first 6 years of life, and the majority identified as male (55%). Recipients most commonly had diseases of the circulatory system (21%, 52 008 of 244 979), perinatal disorders (16%, 38 054 of 244 979), or diseases of the hematologic/immune systems (15%, 37 466 of 244 979). When adjusted for age, support by extracorporeal membrane oxygenation, mechanical ventilation, surgical intervention, and diagnostic category, the odds of thrombosis, infection, and mortality increased by 2% (odds ratio [OR], 1.02; 95% CI, 1.016-1.020), 3% (OR, 1.03; 95% CI, 1.028-1.033), and 7% (OR, 1.07; 95% CI, 1.067-1.071), respectively, with each additional transfusion. CONCLUSIONS: The prevalence of platelet transfusions among pediatric inpatients remained consistent across the decade. Our finding that increasing numbers of transfusions may be associated with elevated morbidity and mortality is consistent with other observation and experimental studies, highlighting the need to be thoughtful in weighing risks and benefits when prescribing repeated platelet transfusions to hospitalized children.

Antibody Titers in Transfusion Medicine: A Critical Reevaluation of Testing Accuracy, Reliability, and Clinical Use.

CONTEXT.­: Substantial variability between different antibody titration methods has been identified since the development and introduction of the uniform procedure in 2008. OBJECTIVE.­: To determine whether more recent methods or techniques decrease interlaboratory and intralaboratory variation measured using proficiency testing. DESIGN.­: Proficiency test data for antibody titration between 2014 and 2018 were obtained from the College of American Pathologists. Interlaboratory and intralaboratory variations were compared by analyzing the distribution of titer results by method and phase, comparing the results against the supplier's quality control titer, and by evaluating the distribution of paired titer results when each laboratory received a sample with the same titer twice. RESULTS.­: A total of 1337 laboratories participated in the antibody titer proficiency test during the study period. Only 54.1% (5874 of 10 852) of anti-D and 63.4% (3603 of 5680) of anti-A reported responses were within 1 titer of the supplier's intended result. Review of the agreement between laboratories of the same methodology found that 78.4% (3139 of 4004) for anti-A and 89.0% (9655 of 10 852) of laboratory responses for anti-D fell within 1 titer of the mode response. When provided with 2 consecutive samples of the same titer (anti-D titer: 16), 85% (367 of 434) of laboratories using the uniform procedure and 80% (458 of 576) using the other method reported a titer difference of 1 or less. CONCLUSIONS.­: Despite advances, interlaboratory and intralaboratory variance for this assay remains high in comparison with the strong reliance on titer results in clinical practice. There needs to be a reevaluation of the role of this test in clinical decision-making.

Blood utilization in liver transplantation (BUILT): A multidisciplinary survey of transfusion practices.

BACKGROUND: The purpose of this study was to survey liver transplant centers in the United States to assess baseline practices in blood utilization and identify opportunities for standardization to optimize blood use in these complex cases. STUDY DESIGN AND METHODS: Two surveys, one for transfusion medicine physicians and the other for anesthesiologists, were distributed to high-volume liver transplant centers. RESULTS: The response rate was 52% for both surveys. The majority of respondents (90%) indicated they issue a standardized number of blood products to start surgeries. The most common number of products issued before the start of cases were 10 red blood cells (RBC) and 10 plasma units with no platelets or cryoprecipitate. On average, fewer RBC (7.5) and plasma (7) units were transfused than issued. Decisions to transfuse RhD+ RBCs to RhD- patients and use antigen untested units in alloimmunized patients were mainly handled on a case-by-case basis. Many centers reported utilizing viscoelastic testing (97%) and cell salvage (97%). Most centers reported standardized, laboratory-based intraoperative transfusion goals for RBCs (65%) and fibrinogen replacement (52%) but lacked a standardized approach for plasma (55%) and platelets (58%). DISCUSSION: More blood products are issued during surgery than are transfused. Responses from anesthesiology providers suggest a broad consensus on practice. Almost all respondents use viscoelastic testing in the management of intraoperative coagulopathy, either alone or in combination with classical coagulation tests. The majority of programs do not transfuse clotting factor concentrates, including fibrinogen concentrate, prothrombin complex concentrates, and recombinant activated FVII, and do not use antifibrinolytics prophylactically.

Therapeutic plasma exchange practices in immune thrombocytopenia related hospitalizations: Results from a nationally representative sample.

Per the American Society for Apheresis, therapeutic plasma exchange (TPE) is a Category III indication in the management of immune thrombocytopenia (ITP). This nationally representative study evaluates TPE utilization in hospitalized adults with a primary admission diagnosis of ITP. Hospitalizations with ITP as the primary admitting diagnosis were analyzed from the 2010 to 2014 National Inpatient Sample, the largest all-payer inpatient database in the United States. Univariate and multivariable logistic regressions were used to determine clinical outcomes in ITP patients undergoing TPE. Sampling weights were applied to generate nationally representative estimates. From 2010 to 2014, there were a total of 56,149 admissions with a primary admitting diagnosis of ITP, of which 0.66% admissions (n = 372) also coded TPE. Most subjects undergoing TPE were the highest disease severity class: major (34.6%) and extreme severity (31.0%), by all-patients refined diagnoses-related groups severity of illness subclass. After multivariable analysis, underlying severity of illness remained the most significant predictor of TPE (P < .001). ITP admissions with TPE had a high rate of comorbidities (50%) and significantly longer mean length of hospital stay than those without (P < .001). TPE was reported in ~0.6% of hospitalizations with ITP as the primary diagnosis in this nationally representative sample from 2010 to 2014. TPE was performed in patients with the highest severity of underlying illness, and higher rates of comorbidities.

The cortical connectome of primate lateral prefrontal cortex.

The lateral prefrontal cortex (LPFC) of primates plays an important role in executive control, but how it interacts with the rest of the cortex remains unclear. To address this, we densely mapped the cortical connectome of LPFC, using electrical microstimulation combined with functional MRI (EM-fMRI). We found isomorphic mappings between LPFC and five major processing domains composing most of the cerebral cortex except early sensory and motor areas. An LPFC grid of ∼200 stimulation sites topographically mapped to separate grids of activation sites in the five domains, coarsely resembling how the visual cortex maps the retina. The temporal and parietal maps largely overlapped in LPFC, suggesting topographically organized convergence of the ventral and dorsal streams, and the other maps overlapped at least partially. Thus, the LPFC contains overlapping, millimeter-scale maps that mirror the organization of major cortical processing domains, supporting LPFC's role in coordinating activity within and across these domains.

High-throughput mapping of a whole rhesus monkey brain at micrometer resolution.

Whole-brain mesoscale mapping in primates has been hindered by large brain sizes and the relatively low throughput of available microscopy methods. Here, we present an approach that combines primate-optimized tissue sectioning and clearing with ultrahigh-speed fluorescence microscopy implementing improved volumetric imaging with synchronized on-the-fly-scan and readout technique, and is capable of completing whole-brain imaging of a rhesus monkey at 1 × 1 × 2.5 µm3 voxel resolution within 100 h. We also developed a highly efficient method for long-range tracing of sparse axonal fibers in datasets numbering hundreds of terabytes. This pipeline, which we call serial sectioning and clearing, three-dimensional microscopy with semiautomated reconstruction and tracing (SMART), enables effective connectome-scale mapping of large primate brains. With SMART, we were able to construct a cortical projection map of the mediodorsal nucleus of the thalamus and identify distinct turning and routing patterns of individual axons in the cortical folds while approaching their arborization destinations.

Overcoming Drug Interference in Transfusion Testing: A Spotlight on Daratumumab.

Daratumumab, a monoclonal antibody therapeutic, is highly efficacious and widely used in all stages of multiple myeloma and amyloidosis and has promising activity in other hematologic disorders. Daratumumab interacts with red blood cells, interfering with pre-transfusion testing. This interference can lead to compromising transfusion safety, extensive blood bank work ups and delays in provision of compatible units. Several methods have been developed to negate daratumumab interference with indirect antiglobulin testing. They are based on i) standard blood bank techniques including dithiothreitol and enzymatic treatment of reagent cells, using reagent red blood cells negative for CD38, ii) blocking CD38 antigens on reagent or donor cells, iii) neutralization of anti-CD38 antibody in patient plasma prior to testing, and iv) extended antigen typing of patient red blood cells in conjunction with provision of phenotypically matched units for transfusion. Implementation of those methods by the blood bank should be a planned effort coordinated with the patient's clinical team. Timely involvement of blood bank and transfusion services and educational efforts by both blood banks and clinical providers can improve the overall daratumumab safety profile in regard to blood transfusion.

Heterogeneity in Approaches for Switching From Universal to Patient ABO Type-Specific Blood Components During Massive Hemorrhage.

CONTEXT.­: ABO mistransfusions are rare and potentially fatal events. Protocols are required by regulatory agencies to minimize this risk to patients, but how these are applied in the context of massive transfusion protocols (MTPs) is not specifically defined. OBJECTIVE.­: To evaluate the approaches used by transfusion services for switching from universally compatible to patient ABO type-specific blood components during massive hemorrhage. DESIGN.­: We added 1 supplemental multiple-choice question to address the study objective to the 2019 College of American Pathologists proficiency test J-survey (J-A 2019). We also reviewed the available literature regarding this topic. RESULTS.­: A total of 881 laboratories responded to the supplemental question. Approximately 80% (704 of 881) reported a policy for ABO-type switching during an MTP. Policies varied considerably between responding laboratories, but most (384 of 704, 55%) required 2 ABO types to match before switching from universal to recipient-specific blood components. Additional safety measures used in a minority of these protocols included reaction strength criteria (103 of 704, 15%), on-call medical director approval (41 0f 704, 5.8%), universal red cell unit number limits (12 of 704, 1.7%), or the presence of a mixed field (3 of 704, 0.4%). CONCLUSIONS.­: This survey reveals that significant heterogeneity exists regarding the available approaches for ABO-type switching during an MTP. Specific expert guidance regarding this issue is very limited, and best practices have not yet been established or rigorously investigated.

Profiling of immune dysfunction in COVID-19 patients allows early prediction of disease progression.

With a rising incidence of COVID-19-associated morbidity and mortality worldwide, it is critical to elucidate the innate and adaptive immune responses that drive disease severity. We performed longitudinal immune profiling of peripheral blood mononuclear cells from 45 patients and healthy donors. We observed a dynamic immune landscape of innate and adaptive immune cells in disease progression and absolute changes of lymphocyte and myeloid cells in severe versus mild cases or healthy controls. Intubation and death were coupled with selected natural killer cell KIR receptor usage and IgM+ B cells and associated with profound CD4 and CD8 T-cell exhaustion. Pseudo-temporal reconstruction of the hierarchy of disease progression revealed dynamic time changes in the global population recapitulating individual patients and the development of an eight-marker classifier of disease severity. Estimating the effect of clinical progression on the immune response and early assessment of disease progression risks may allow implementation of tailored therapies.

Blood component utilization in COVID-19 patients in New York City: Transfusions do not follow the curve.

BACKGROUND: Blood suppliers and transfusion services have worked diligently to maintain an adequate blood supply during the COVID-19 pandemic. Our experience has shown that some COVID-19 inpatients require transfusion support; understanding this need is critical to blood product inventory management. STUDY DESIGN AND METHODS: Hospital-wide and COVID-19 specific inpatient blood product utilization data were collected retrospectively for our network's two tertiary academic medical centers over a 9-week period (March 1, 2020-May 2, 2020), when most inpatients had COVID-19. Utilization data were merged with a COVID-19 patient database to investigate clinical demographic characteristics of transfused COVID-19 inpatients relative to non-transfused ones. RESULTS: Overall, 11 041 COVID-19 patients were admitted and 364 received blood product transfusions for an overall transfusion rate of 3.3%. COVID-19 patients received 1746 blood components in total, the majority of which were red blood cells. COVID-19 patients' weekly transfusion rate increased as the pandemic progressed, possibly reflecting their increased severity of illness. Transfusion was significantly associated with several indicators of severe disease, including mortality, intubation, thrombosis, longer hospital admission, lower hemoglobin and platelet nadirs, and longer prothrombin and activated partial thromboplastin times. As the pandemic progressed, institutional adherence to transfusion guidelines improved for RBC transfusions compared to prior year trends but did not improve for platelets or plasma. CONCLUSION: There is a need to closely monitor the blood product inventory and demand throughout the COVID-19 pandemic as patients' transfusion needs may increase over time. Daily or weekly trending of patients' clinical status and laboratory values may assist blood banks in inventory management.