Modifications to therapeutic plasma exchange to achieve rapid exchange on cardiopulmonary bypass prior to pediatric cardiac transplant.

BACKGROUND: Cardiac transplants increasingly occur following placement of ventricular assist devices (VADs). A strong association exists between human leukocyte antigen (HLA) sensitization and VAD placement; however, desensitization protocols that utilize therapeutic plasma exchange (TPE) are fraught with technical challenges and are at increased risk of adverse events. In response to increased VAD utilization in our pre-transplant population, we developed a new institutional standard for TPE in the operating room. METHODS: Through a multidisciplinary effort, we developed an institutional protocol for intraoperative TPE immediately prior to cardiac transplantation after cannulation onto cardiopulmonary bypass (CPB). All procedures used the standard TPE protocol on the Terumo Optia (Terumo BCT, Lakewood, CO, USA), but incorporated multiple modifications to limit patients' bypass times, and to coordinate with the surgical teams. These modifications included deliberate misidentification of replacement fluid and maximization of the citrate infusion rate. RESULTS: These adjustments allowed the machine to run at maximal inlet speeds, minimizing duration of TPE. To date, 11 patients have been treated with this protocol. All survived their cardiac transplantation operation. Hypocalcemia and hypotension were noted; however, none of these adverse events appeared to have clinical impact. Technical complications included unexpected fibrin deposition in the TPE circuit and air in the inlet line due to surgical manipulation of the CPB cannula. No thromboembolic complications occurred in any patient. CONCLUSION: We feel that this procedure can be rapidly and safely performed in HLA sensitized pediatric patients on CPB to limit the risk of antibody mediated rejection of their heart transplant.

Using trends and outliers in managing delayed transfusions.

OBJECTIVES: To investigate if time to initiate a blood transfusion after an informative laboratory test could feasibly be used by the transfusion medicine service as a metric to monitor for transfusion delays. BACKGROUND: Delayed transfusions may result in patient morbidity and mortality, but no standards for timely transfusion have been developed. Information technology tools could be implemented to identify gaps in provision of blood and to recognise areas of improvement. MATERIALS AND METHODS: Data obtained from a children's hospital's data science platform and time from the release of laboratory results to the initiation of transfusions were calculated and weekly medians were used for trend analyses. Outlier events were obtained using locally estimated scatterplot smoothing and generalised extreme studentized deviate test. RESULTS: Overall, the number of outlier events on the timing of transfusions based on patients' haemoglobin level and platelet count were small (n = 1 and n = 0 for 139 weeks, respectively). Investigation of these events for adverse clinical outcomes was non-significant. CONCLUSIONS: Herein, we propose that the trends and outlier events could be further investigated and used to make decisions and implement protocols to improve patient care.

Measuring the Impact of a Blood Supply Shortage Using Data Science.

BACKGROUND: Transfusion medicine is the only section of the clinical laboratory that performs diagnostic testing and dispenses a drug (blood) on the basis of those results. However, not all of the testing that informs the clinical decision to prescribe a blood transfusion is performed in the blood bank. To form a holistic assessment of blood bank responsiveness to clinical needs, it is important to be able to merge blood bank data with datapoints from the hematology laboratory and the electronic medical record. METHODS: We built an interactive visualization of the time from hemoglobin result availability to initiation of red blood cell (RBC) transfusion and monitored the result over a 2-year period that coincided with several severe blood shortages. The visualization runs entirely on free software and was designed to be feasibly deployed on a variety of hospital information technology platforms without the need for significant data science expertise. RESULTS: Patient factors, such as hemoglobin concentration, blood type, and presence of minor blood group antibodies influenced the time to initiation of transfusion. Time to transfusion initiation did not appear to be significantly affected by periods of blood shortage. CONCLUSION: Overall, we demonstrate a proof of concept that complex, but clinically important, blood bank quality metrics can be generated with the support of a free, user-friendly system that aggregates data from multiple sources.

Erythrocyte T-antigen activation in children: Patient characteristics and the hemolytic risk of transfusion.

BACKGROUND: T-antigen activation usually occurs upon red blood cell (RBC) membrane cryptantigen exposure due to bacterial enzymes. Although uncommon, the condition is probably underrecognized. There is concern about hemolysis after plasma and plasma-containing platelet transfusions due to naturally occurring anti-T antibody in healthy blood donors. However, experts have debated the extent and severity of clinical hemolysis due to anti-T. PROCEDURE: We retrospectively identified patients who tested positive for polyagglutination with Arachis hypogea and Glycine max lectins from 2008 to 2019. The records of the patients were reviewed to determine clinical symptoms, laboratory evidence of hemolysis, need for transfusion, and clinical outcomes. RESULTS: Ten patients were identified. At diagnosis, all were anemic and four had thrombocytopenia. Severe Streptococcus pneumoniae infection affected seven patients; one died. Seven of 10 patients (70%) had laboratory evidence of hemolysis. Peripheral blood smear findings in six patients included RBC agglutination and changes suggesting hemolysis (spherocytes and schistocytes), but three had unremarkable RBC morphology. Four patients required plasma or platelet transfusions; all survived to discharge. CONCLUSIONS: T-antigen activation is a rare entity. Most patients diagnosed at our hospital had hemolytic anemia and severe pneumococcal infection. Hemoglobin decreased after plasma and platelet transfusions in all patients assessed, but these transfusions were necessary to support treatment. RBCs were given to maintain appropriate hemoglobin levels.

Kinetics of Viral Clearance and Antibody Production Across Age Groups in Children with Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

OBJECTIVES: To improve understanding of transition from viral infection to viral clearance, and antibody response in pediatric patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. STUDY DESIGN: This retrospective analysis of children tested for SARS-CoV-2 by reverse transcription (RT) polymerase chain reaction (PCR) and immunoglobulin G antibody at a quaternary-care, free-standing pediatric hospital between March 13, 2020, and June 21, 2020, included 6369 patients who underwent PCR testing and 215 patients who underwent antibody testing. During the initial study period, testing focused primarily on symptomatic children; the later study period included asymptomatic patients who underwent testing as preadmission or preprocedural screening. We report the proportion of positive and negative tests, time to viral clearance, and time to seropositivity. RESULTS: The rate of positivity varied over time due to viral circulation in the community and transition from targeted testing of symptomatic patients to more universal screening of hospitalized patients. Median duration of viral shedding (RT-PCR positivity) was 19.5 days and time from RT-PCR positivity to negativity was 25 days. Of note, patients aged 6 through 15 years demonstrated a longer time of RT-PCR positivity to negativity, compared with patients aged 16 through 22 years (median 32 vs 18 days, P = .015). Median time to seropositivity, by chemiluminescent testing, from RT-PCR positivity was 18 days, whereas median time to reach adequate levels of neutralizing antibodies (defined as comparable with 160 titer by plaque reduction neutralization testing) was 36 days. CONCLUSIONS: The majority of patients demonstrated a prolonged period of viral shedding after infection with SARS CoV-2. It is unknown whether this correlates with persistent infectivity. Only 17 of 33 patients demonstrated adequate neutralizing antibodies during the time frame of specimen collection. It remains unknown whether immunoglobulin G antibody against spike structured proteins correlates with immunity, and how long antibodies and potential protection persist.