ABSTRACT
Background. The VA Million Veteran Program (MVP) studies what factors influence Veteran health. Current procedures involve collection of venous blood at MVP enrollment sites. To examine home specimen collection options, MVP performed a pilot study comparing two blood specimen collection devices and evaluated SARSCoV-2 antibody assays to determine known COVID-19 infection or vaccination. Methods. A sub-sample of MVP Veteran participants were asked to self-collect a capillary blood specimen using the Neoteryx Mitra Clamshell (up to 120uL dried blood) or Tasso-SST (up to 200uL liquid blood) per the vendor instructions. Veterans were randomly assigned to a device prior to consent. Eligibility included 30% of Veterans with known COVID-19 diagnosis or vaccination and sampling time was variable from these events. Veterans rated their device experience and shipped collected specimens directly to an MVP laboratory. Mitra tip (4) blood was eluted in 1 mL of 0.9% normal saline for 1 hour at room temperature shaking at 300 rpm. Tasso tubes were centrifuged per vendor instructions. All samples were stored at -80°C until tested with SARS-Cov-2 antibody (Ab) assays (InBios Spike IgG, BioRad Nucleocapsid (NC) Total Ab, Abbott NC IgG, and Abbott Spike IgG II) per vendor instructions. Results. 312 MVP participants consented to the pilot (52%) of which 136 (43.6%) were sent Mitra and 176 (56.4%) were sent Tasso-SST (Table 1). Participants rated the Mitra Tasso-SST equally on average as 4.4 on a 0-5 usability scale. The Abbott IgG II assay had the highest sensitivity across both devices (87% Mitra and 98% Tasso-SST) for detecting known COVID infection and/or vaccination. The InBios IgG assay with the Tasso-SST had the best sensitivity (97%) and specificity (80%) for detecting known COVID-19 infection and/or vaccination (Table 2). Conclusion. Veterans successfully collected their own specimens and had no strong preference for either device. The Tasso-SST combined with the InBios Spike IgG assay provided the highest combination of sensitivity and specificity. Limitations included one collection device per subject, varied timing of testing, unknown infection or vaccination status among some, and Tasso collection volume and Mitra whole blood dilution may have affected comparison across assays or performance.
ABSTRACT
[Formula presented] Background: Adult sickle cell patients on chronic transfusion therapy (CTT) garnered special concern during the COVID-19 pandemic, when mass cancellation of blood drives threatened the national blood supply. In response, the American Society of Hematology proposed several strategies to decrease blood utilization, while maintaining adequate disease control for sickle cell patients on CTT. These included targeting a higher end hemoglobin S%, switching patients to simple transfusions when appropriate, and transitioning to alternative disease modifying therapies. There is little evidence to support the safety of altering exchange therapy regimens. Accordingly, at the Johns Hopkins Sickle Cell Center for Adults, a multidisciplinary team of clinicians and transfusion medicine specialists evaluated patients on a case by case basis to determine how their exchanges could be modified to accommodate for anticipated blood supply shortages. We describe our blood conservation efforts during the COVID-19 pandemic and resulting clinical outcomes for adult patients with sickle cell anemia (SCA). Methods: For inclusion in this IRB-approved retrospective study, patients received at least 7 monthly exchange transfusions between March 2019 and February 2020 and continued care through March 2021. Decisions regarding CTT were made prior to data collection. Modifications to chronic exchanges included increasing the fraction of cells remaining (FCR), decreasing the end hematocrit, or switching to a hemodilution method. Additionally, select patients transitioned to monthly simple transfusions if they were clinically stable, had a hemoglobin ≤ 7 g/dL, and had a persistently suppressed hemoglobin S% (≤ 30). We collected basic demographics, pre-exchange laboratory studies, and exchange parameters before and after each transfusion encounter in the year before (March 2019 - February 2020) and during (March 2020 - February 2021) the COVID-19 pandemic. Lastly, we recorded presentations to urgent care and the emergency department;and hospital admissions during each time period. We reported descriptive statistics for the cohort and compared outcomes using the Wilcoxon signed-rank test and Mann Whitney U test. We analyzed data using Stata/SE Version 16.1. Results: We identified 58 patients with SCA who qualified for inclusion (Table 1). Fifty-three patients remained on chronic exchange transfusions during the pandemic, and five were switched to simple transfusions. For patients who remained on chronic exchanges, most received conventional automated red cell exchange (RCE) prior to (85%) and during the pandemic (77%). Use of hemodilution increased (15% to 23% of patients). Forty-three patients experienced an increase in mean FCR (33.6 (SD 11.6) vs 37.7 (4.7), p =.00). Of those, 22 patients saw a concomitant decrease in mean end hematocrit (30.8 (1.7) vs 29.6 (1.1), p =.00). These changes resulted in a decline in the average number of units per procedure (8.6 (1.9) vs 7.3 (1.7), p =.00), which corresponded to 890 units conserved. Mean pre-transfusion hemoglobin values declined (9.4 (1.3) vs 9.2 (1.3), p = 0.01), but hemoglobin S%, reticulocyte count, and ferritin values were unchanged (p > 0.05). Acute care presentations and hospital admissions declined, which were likely spurred by concerns about COVID-19 infection (Table 2, p < 0.05). During the pandemic, three patients died, one of whom had been switched to simple transfusions. This patient experienced a consistent rise in hemoglobin S% until death. Two of the remaining patients on simple transfusions were switched back to automated RCE due to an increase in hemoglobin S% above goal (Figure 1). Conclusions: During the COVID-19 pandemic, we conserved red blood cell units through expanded use of hemodilution, higher FCR values, and switching some patients to simple transfusions. Patients who remained on exchanges maintained hemoglobin S% values near a goal of 30% without increasing iron burden. In contrast, the majority of patients who were switched to simple transfusions were unable to maintain goal hematologic parameters, and one patient died. Our data suggest that in a blood shortage crisis, changing the exchange procedure itself may be the safest means of conserving blood in a population of adult sickle cell patients;however longer follow-up is needed to ensure that these changes are safe. [Formula presented] Disclosures: Lanzkron: GBT: Research Funding;Shire: Research Funding;Novo Nordisk: Consultancy;CSL Behring: Research Funding;Pfizer: Current holder of individual stocks in a privately-held company;Teva: Current holder of individual stocks in a privately-held company;Novartis: Research Funding;Imara: Research Funding;Bluebird Bio: Consultancy.
ABSTRACT
BACKGROUND: The occurrence of coronavirus disease 2019 (COVID-19) has overwhelmed the blood supply chain worldwide and severely influenced clinical procedures with potential massive blood loss, such as clipping surgery for aneurysmal subarachnoid hemorrhage (aSAH). Whether acute normovolemic hemodilution (ANH) is safe and effective in aneurysm clipping remains largely unknown. METHODS: Patients with aSAH who underwent clipping surgery within 72 hours from bleeding were included. The patients in the ANH group received 400 mL autologous blood collection, and the blood was returned as needed during surgery. The relationships between ANH and perioperative allogeneic blood transfusion, postoperative outcome, and complications were analyzed. RESULTS: Sixty-two patients with aSAH were included between December 2019 and June 2020 (20 in the ANH group and 42 in the non-ANH group). ANH did not reduce the need of perioperative blood transfusion (3 [15%] vs. 5 [11.9%]; P = 0.734). However, ANH significantly increased serum hemoglobin levels on postoperative day 1 (11.5 ± 2.5 g/dL vs. 10.3 ± 2.0 g/dL; P = 0.045) and day 3 (12.1 ± 2.0 g/dL vs. 10.7 ± 1.3 g/dL; P = 0.002). Multivariable analysis indicated that serum hemoglobin level on postoperative day 1 (odds ratio, 0.895; 95% confidence interval, 0.822-0.973; P = 0.010) was an independent risk factor for unfavorable outcome, and receiver operating characteristic curve analysis showed that it had a comparable predictive power to World Federation of Neurosurgical Societies grade (Z = 0.275; P > 0.05). CONCLUSIONS: ANH significantly increased postoperative hemoglobin levels, and it may hold the potential to improve patients' outcomes. Routine use of ANH should be considered in aneurysm clipping surgery.