Therapeutic plasma exchange in patients with severe obesity (BMI >40): A survey of practices in the United States

BACKGROUND

The prevalence of obesity in the United States is estimated at 42.4% and expected to increase over the next decade. Therefore, understanding how to best perform certain medical procedures on severely obese (SO) patients is a necessity. This study presents results on the current methods of performing therapeutic plasma exchange (TPE) on SO patients. This paper aims to contribute to the existing literature by providing new insights into calculating plasma volume (PV) for TPE in SO patients.

METHODS

Blood Bank/Apheresis Directors at all institutions with pathology residency and/or blood banking/transfusion medicine fellowship programs were asked to complete a 5-question online survey about their institutional policies regarding TPE in SO patients. Survey data were analyzed to determine if institutions have policies in place to calculate PV in SO patients.

RESULTS

Out of the 144 institutions contacted, 45 (31%) completed the survey. Nine (20%) institutions had a policy to calculate PV differently for SO patients, 7 (16%) reported a specific body mass index (BMI) above which they alter PV calculation, and 7 (16%) reported a maximum volume exchanged in SO patients.

CONCLUSION

A minority of responding institutions had specific policies in place to calculate PV for TPE in SO patients. Practice patterns for calculating PV for TPE in SO patients varied, with some institutions adjusting PV calculations and others setting a maximum volume to be exchanged regardless of BMI. These findings highlight the need for establishing a clear method of calculating PV in SO patients.

Optimizing blood product utilization: A whole lot to gain and nothing to lose!

e18669

Background: Transfusion stewardship is a vital part of managing patients with hematologic malignancies (HM). Blood products are limited resources and blood product transfusion (txn) is costly and poses complications. Randomized trials in different clinical settings have shown that a conservative txn strategy is not inferior to more liberal txn strategy. As a result, the AABB and ASCO have recommended following a conservative txn strategy in patients with cancer (hemoglobin (hg) <7-8g/dL and platelets (plt) <10K in stable non-bleeding patients). Here we report our early outpatient institution’s experience implementing a contemporary txn approach in patients with HM. Methods: We formed a multi-disciplinary team to analyze blood product utilization. Overutilization was defined as orders for multi-units, packed red blood cells (pRBC) for hg >8 or plt for plt >10K in stable non-bleeding patients. Patients’ charts were audited during the baseline period to understand practice patterns. Data were collected using Qlik database. The baseline period (May 1, 2019-Feb 29, 2020) was compared to the intervention period (March 1 – December 31, 2020). A root cause analysis was performed. When possible 2-sided paired T-test was performed. If not possible, descriptive statistics were performed. Three interventions were developed and implemented sequentially: March 2020 – Blood bank began real-time review of blood products overutilization. May 2020 – Electronic Medical Record txn order set was revised to reflect recommended best practices. October 2020 –Txn guidelines revised for patients with HM. Results: During the study period, there were 3,227 pRBC and 2,817 plt transfused units in the outpatient setting. Monthly pRBC txn decreased from (mean(SD)) 168.5 (16.6) to 154.2(16.4) (p value: 0.14). Monthly plt txn decreased from 166.5 (26.5) to 115.2 (26.2) (p value: 0.001). Rates of multi-unit orders decreased significantly. Average monthly multi-unit orders decreased for pRBC (pre-48.6(5.9);post-24.3(7.6);p value 0.00007) and plts (pre-67.4(11.8);post-21.3(23.3);p value: 0.0002). Average hb at time of txn in the pre- and post-intervention period was 7.47 and 7.22. The percentage of txn in which the indication for txn was hb <7, 7-8, >8 changed from 34.6% to 56.3%, 52.6% to 32.8%, and 12.8% to 10.9% respectively. There was no significant increase in admissions for bleeding or increase in number of outpatient visits during the study period. Conclusions: Over 10-months, we significantly reduced outpatient blood product. Robust quality improvement methodology, engaging key stakeholders, and changing the culture of outpatient management were keys to success. To date, we have not seen any unintended consequences of these changes. These results are encouraging, as outpatient transfusion stewardship is thought to be harder given concerns about patients not being monitored as closely as in the inpatient setting.

TVGN-489: A novel approach for the production of SARS-CoV-2-specific cytotoxic T lymphocytes to treat COVID-19

SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to decrease mortality, there remains a need for curative therapies for active infections. Uncertainties regarding the duration of post-vaccination immunity and the rapidity of mutational evolution by this virus suggest that it is unwise to rely on preventative measures alone. Dysregulation of endogenous cellular immunity has been implicated in the failure to control COVID-19 infections suggesting that allogeneic T cell therapy using nature’s curative approach to viral infections could successfully be applied to vulnerable patients. Allogeneic virus-specific cytotoxic T lymphocytes (CTLs) have a long track record of safety and efficacy in treating viral infections occurring after allogeneic stem cell transplantation. We hypothesize that this approach can be applied to the treatment of Covid-19. Covid-19 specific CTLs were produced by priming and enriching T cells from convalescent patients using COVID-19 peptides predicted or demonstrated to bind to specific HLA alleles. Utilizing the globally common HLA-A*02:01 allele as the restriction element, 7 peptides from 4 COVID-19 gene/ORF products were identified and used as a pool for serial restimulation and enrichment on a peptide pulsed, HLA-A*02:01 antigen presenting cell monolayer. This preclinical effort produced CTLs of high purity (&gt;95% CD3+/CD8+, &gt;60% positive by tetramer staining) and potency (60% lysis of peptide pulsed targets at an effector to target ratio of 3:1) in sufficient quantities for clinical application. Trials using these TVGN-489 CTLs and those produced with other SARS-COV-2 peptides and HLA restriction elements will hopefully be launched shortly.

Point-of-care versus central testing of hemoglobin during large volume blood transfusion

Background

Point-of-care (POC) hemoglobin testing has the potential to revolutionize massive transfusion strategies. No prior studies have compared POC and central laboratory testing of hemoglobin in patients undergoing massive transfusions.

Methods

We retrospectively compared the results of our point-of-care hemoglobin test (EPOC®) to our core laboratory complete blood count (CBC) hemoglobin test (Sysmex XE-5000™) in patients undergoing massive transfusion protocols (MTP) for hemorrhage. One hundred seventy paired samples from 90 patients for whom MTP was activated were collected at a single, tertiary care hospital between 10/2011 and 10/2017. Patients had both an EPOC® and CBC hemoglobin performed within 30 min of each other during the MTP. We assessed the accuracy of EPOC® hemoglobin testing using two variables: interchangeability and clinically significant differences from the CBC. The Clinical Laboratory Improvement Amendments (CLIA) proficiency testing criteria defined interchangeability for measurements. Clinically significant differences between the tests were defined by an expert panel. We examined whether these relationships changed as a function of the hemoglobin measured by the EPOC® and specific patient characteristics.

Results

Fifty one percent (86 of 170) of paired samples’ hemoglobin results had an absolute difference of ≤7 and 73% (124 of 170) fell within ±1 g/dL of each other. The mean difference between EPOC® and CBC hemoglobin had a bias of − 0.268 g/dL (p = 0.002). When the EPOC® hemoglobin was < 7 g/dL, 30% of the hemoglobin values were within ±7, and 57% were within ±1 g/dL. When the measured EPOC® hemoglobin was ≥7 g/dL, 55% of the EPOC® and CBC hemoglobin values were within ±7, and 76% were within ±1 g/dL. EPOC® and CBC hemoglobin values that were within ±1 g/dL varied by patient population: 77% for cardiac surgery, 58% for general surgery, and 72% for non-surgical patients.

Conclusions

The EPOC® device had minor negative bias, was not interchangeable with the CBC hemoglobin, and was less reliable when the EPOC® value was < 7 g/dL. Clinicians must consider speed versus accuracy, and should check a CBC within 30 min as confirmation when the EPOC® hemoglobin is < 7 g/dL until further prospective trials are performed in this population.