In vivo and in vitro characteristics of double units of RBCs collected by apheresis with a single in-line WBC-reduction filter

Describing water treatment process performance: Why average log-reduction can be a misleading statistic

The degree to which a technology used for drinking water treatment physically removes or inactivates pathogenic microorganisms is commonly expressed as a log-reduction (or log-removal) and is of central importance to the provision of microbiologically safe drinking water. Many evaluations of water treatment process performance generate or compile multiple values of microorganism log-reduction, and it is common to report the average of these log-reduction values as a summary statistic. This work provides a cautionary note against misinterpretation and misuse of averaged log-reduction values by mathematically proving that the average of a set of log-reduction values characteristically overstates the average performance of which the set of log-reduction values is believed to be representative. This has two important consequences for drinking water and food safety as well as other applications of log-reduction: 1) a technology with higher average log-reduction does not necessarily have higher average performance, and 2) risk analyses using averaged log-reduction values as point estimates of treatment efficiency will underestimate average risk-sometimes by well over an order of magnitude. When analyzing a set of log-reduction values, a summary statistic called the effective log-reduction (which averages reduction or passage rates and expresses this as a log-reduction) provides a better representation of average performance of a treatment technology.

Red cell apheresis with automated in-line filtration

BACKGROUND

The aim of this study was to provide data on concurrent red blood cell (RBC) and platelet (PLT) apheresis with RBC in-line leukoreduction and automated addition of saline-adenine-glucose-mannitol (SAGM) using the new version (V6.0) of Trima Accel®.

METHODS

In this two-center paired study, each subject completed a test and a control procedure with an interval of 9 weeks between procedures. In the test arm, single RBC and PLT units were collected on the Trima Accel V6.0 (in-line leukofiltration and automated addition of SAGM). In the control arm, they were collected on Trima Accel V5.1/V5.2 (post-collection leukoreduction, manual SAGM addition). RBC percent hemolysis, potassium concentration and adenosine triphosphate over storage, hemoglobin (Hb) yield, and residual white blood cells (WBC) were determined.

RESULTS

34 subjects successfully completed both test and control procedures. Post-storage hemolysis was similar in both groups, and all values were less than 0.8% for both arms. Residual WBC counts in all RBC units were less than 1 × 10(6)/unit. In-line processed RBC units (V6.0) have a significantly higher volume and more Hb/unit due to filtration recovery improvements. All procedures were well tolerated by the subjects.

CONCLUSION

In-line filtration and automated addition of storage solution on Trima Accel V6.0 allows collection of ready-to-use RBC units that meet EU requirements.

In vitro quality of red blood cells (RBCs) collected by multicomponent apheresis compared to manually collected RBCs during 49 days of storage

BACKGROUND

New technologic developments enable automated collection and preparation of red blood cells (RBCs). This study's aim was to evaluate quality of apheresis-derived RBCs (ARBCs) collected as single units along with platelets (RBC-Ps) or double units (2-RBCs) with four different apheresis systems.

STUDY DESIGN AND METHODS

Sixty-six donors with similar baseline variables underwent RBC apheresis collection with various machines (Amicus [15 RBC-Ps] and Alyx [15 2-RBCs], Baxter; the Trima Accel [9 RBC-Ps, 8 2-RBCs], Gambro, and the MCS+[9 RBC-Ps, 10 2-RBCs], Haemonetics Corp.). In vitro properties were analyzed during 49 days of storage and compared to manual RBCs (MRBCs, n = 14).

RESULTS

All units but one, Alyx, demonstrated white blood cell counts of less than 1 x 10(6). ARBCs showed lower variability in volume compared to MRBCs. All units met international requirements (European, AABB) for hematocrit (50%-70%), hemoglobin (>40 g/unit), and RBC mass (>or=153 mL). pH values remained similar between study groups without reaching critical limits in any unit. MRBCs had slight advantages for hemolysis at the end of storage and were significantly superior in energy maintenance as indicated by less ATP degradation and potassium leak most likely due to more pronounced anoxidative glycolysis particularly during the first half of storage. Owing to more declining oxidative glucose metabolism, ARBCs demonstrated higher methemoglobin formation and subsequent oxygen release until the end of storage.

CONCLUSION

ARBCs exhibited better predictability in volume and absolute RBC mass than MRBCs and demonstrated sufficient in vitro quality throughout storage, even though lower ATP preservation and higher methemoglobin formation were observed compared to MRBCs probably due to differences in glucose metabolism.

Successful in vivo recovery and extended storage of additive solution (AS)-5 red blood cells after deglycerolization and resuspension in AS-3 for 15 days with an automated closed system

BACKGROUND

Previously, cryopreserved red blood cell (RBC) units derived from CPD/AS-5 whole-blood (WB) collections have been limited to 24 hours postthaw storage (1-6 degrees C).

STUDY DESIGN AND METHODS

Sixty-four leukoreduced (LR) and 54 nonleukoreduced (NLR) AS-5 (n = 118) RBC units from 500-mL WB collections were stored for 6 days, glycerolized, frozen (-70 +/- 5 degrees C) for at least 14 days, thawed, deglycerolized, and stored (1-6 degrees C) for 15 days resuspended in AS-3, using an automated closed-system cell processor (ACP 215, Haemonetics). Frozen units were stored in either ethylene vinyl acetate (EVA) or polyvinylchloride (PVC) bags. In vitro parameters were tested in all units 15 days after deglycerolization. In vivo 24-hour recovery was measured in 77 of 118 donors.

RESULTS

Postdeglycerolization in vitro RBC mass recoveries (mean +/- SD) were 96.8 +/- 5.7 and 94.7 +/- 5.6% for EVA LR and NLR units, respectively, and 97.3 +/- 6.2 and 94.7 +/- 6.2% for PVC LR and NLR units, based on unit weight and hematocrit after sampling for in vitro testing, immediately before glycerolization. Hemoglobin content (g/unit, mean +/- SD) after deglycerolization was 40.4 +/- 5.6 and 42.6 +/- 6.0 for EVA LR and NLR units, respectively, and 40.7 +/- 4.8 and 43.0 +/- 7.7 for PVC LR and NLR units. Hemolysis was 0.61 +/- 0.23 and 0.54 +/- 0.16% for EVA LR and NLR units, and 0.47 +/- 0.14 and 0.43 +/- 0.12% for PVC LR and NLR units. In vivo 24-hour recoveries on Day 15 were 83.0 +/- 6.7% (PVC NLR) up to 86.2 +/- 5.7% (EVA NLR).

CONCLUSION

With processing on the ACP 215 system, CPD/AS-5 LR and NLR thawed RBC units can be stored for up to 14 days after frozen storage at -65 degrees C or colder in EVA or PVC bags with acceptable in vivo and in vitro RBC quality.

Automated red cell collection--quality and value

Automated red cell collection was initially used largely for therapeutic purposes. New technology has rendered the procedure safer for donors and easier for machine operators. Optimal additive solution can be automatically added and the red cells filtered to provide a leucodepleted product. Two units of red cells may be collected during a single procedure from individuals who have a high enough red cell mass, whilst a single unit of red cells plus platelets or plasma can be collected from smaller donors. In vitro studies suggested that red cells collected by automated methods would be of better quality than those collected by gravity. This was not confirmed in vivo, but red cells collected by automated methods have the major advantage of consistency in terms of haemoglobin content, volume and haematocrit, compared with red cells collected by gravity. This standardised product is of particular value for transfusion dependent patients as the patient's haemoglobin can be maintained within narrow limits. The use of a double dose red cell product for transfusion to a single patient also confers benefit in terms of reduction in donor exposure.

Chronic red blood cell exchange to prevent clinical complications in sickle cell disease

We tracked the results of 394 manual or automatic red blood cell exchanges done with a cell separator in 20 sickle cell patients at high risk for recurrent complications. Over an average of 6 years, none of the patients developed complications related to the procedure or to the increased blood use. It was safe and effective in preventing complications of sickle cell disease, and if done automatically, reduced iron overload. Ferritin levels also decreased in patients treated with automatic red blood cell exchange. Furthermore, using Single Donor Red Blood Cell units (SDRC) we reduced the potential exposure to transfusion transmitted infectious diseases (TTI).

Extended storage of AS-1 and AS-3 leukoreduced red blood cells for 15 days after deglycerolization and resuspension in AS-3 using an automated closed system

BACKGROUND

The utilization of cryopreserved red blood cell (RBC) units had been limited by a maximum postdeglycerolization storage of 24 hours at 1 to 6 degrees C until the recent development of a closed system for the glycerolization and deglycerolization process.

STUDY DESIGN AND METHODS

Sixty leukoreduced additive solution (AS), AS-1 (n = 30) and AS-3 (n = 30) RBC units from 500-mL whole blood (WB) collections were stored for 6 days, glycerolized, frozen at -70 +/- 5 degrees C for at least 14 days, thawed, deglycerolized, and stored for 15 days at 1 to 6 degrees C. Glycerolization and deglycerolization were performed with the ACP 215. In-vitro variables were tested before glycerolization, on Day 0, and Day 15 after deglycerolization storage. Forty donors were assessed for double-label 24-hour percent recovery, and T1/2 survival time was measured for 20 donors.

RESULTS

Postdeglycerolization mean +/- standard deviation in-vitro RBC mass recoveries were 93 +/- 5 percent for AS-1 and 95 +/- 4 percent for AS-3. Mean hemoglobin +/- standard deviation after deglycerolization was 50.5 +/- 5.5g for AS-1 and 50.1 +/- 3.5g for AS-3. Mean hemolysis (Day 15) was 0.36 +/- 0.11 percent for AS-1 and 0.38 +/- 0.13 percent for AS-3. Double-label 24-hour in-vivo recoveries were 82.5 +/- 7.8 percent for AS-1 and 81.4 +/- 7.1 percent for AS-3. The 51Cr T1/2 value was 41.8 +/- 3.97 for AS-1 and 40.6 +/- 7.11 for AS-3. Other in-vitro variables were as expected.

CONCLUSION

Leukoreduced AS-1 and AS-3 RBCs after frozen storage at -70 +/- 5 degrees C can be stored for up to 14 days when processing is performed with the ACP 215 system with resuspension of deglycerolized RBCs in AS-3.