Rebecca Cardigan

BLOOD COMPONENTS: Red blood cell hemolysis during blood bank storage: using national quality management data to answer basic scientific questions

BACKGROUND: Hemolysis of red blood cells (RBCs) during blood bank storage is the most obvious manifestation of RBC storage system failure. However, its analysis is made difficult because the largest source of interunit difference is donor specific. Availability of data from national blood systems on large numbers of RBC units used for internal quality control (QC) purposes and stored and processed in uniform ways permits statistical analysis.

The quality of fresh-frozen plasma produced from whole blood stored at 4°C overnight

BACKGROUND: The aim of this study was to assess whether the quality of FFP produced from whole blood stored at 4°C overnight is adequate for its intended purpose.

Continuous venovenous haemofiltration using polyacrylonitrile filters does not activate contact system and intrinsic coagulation pathways

AbstractObjectives: To investigate whether continuous venovenous haemofiltration using polyacrylonitrile filters causes activation of the contact system and intrinsic coagulation pathways and if this, and/or low plasma levels of endogenous anticoagulants, influences filter lifespan.nn Design: Observational study.nn Setting: University Teaching Hospital Intensive Care Unit.nn Patients: Twelve critically ill patients with acute renal failure receiving continuous venovenous haemofiltration.nn Interventions: Blood samples were taken before starting haemofiltration, at 15u2009min, 1u2009h, 3–4u2009h, 8–12u2009h, 24u2009h and at 24-h intervals thereafter until filter blockage occurred. Measurement was made of the contact and intrinsic coagulation system proteins factor XII, activated factor XII and prekallikrein and the protease inhibitors antithrombin III, heparin co-factor II, alpha2-macroglobulin and C1-esterase inhibitor. Thrombin-antithrombin complex levels were measured to provide evidence of thrombin generation.nn Results: (i) Factor XII, prekallikrein and contact system inhibitors were subnormal in 10/12 and activated factor XII raised in 11/12 patients at baseline, implying pre-existing contact pathway activation. (ii) No change occurred during haemofiltration in the intrinsic coagulation pathway factor or inhibitor levels. (iii) Clotting of the filter circuit within the first 24u2009h occurred in 5/12 and was associated with low baseline levels of antithrombin III and heparin co-factor II. Only in these patients did thrombin-antithrombin complex levels rise significantly.nn Conclusions: The contact system was not activated further by continuous venovenous haemofiltration using polyacrylonitrile filters in critically ill patients. Premature clotting of the haemofilter circuit was more common in patients with very low levels of antithrombin III and heparin co-factor II; although this was related to thrombin generation, the intrinsic coagulation pathway does not appear to be implicated.

Thrombin generation and clot formation in methylene blue–treated plasma and cryoprecipitate

BACKGROUND: Methylene blue (MB) treatment of plasma is known to reduce the activity of clotting factors, but its effect on thrombin generation and clot formation is not well documented.

What Is the Maximum Time That a Unit of Red Blood Cells Can Be Safely Left Out of Controlled Temperature Storage

The objective of this systematic review was to identify and analyze the evidence base supporting the 30-minute and 4-hour rules in transfusion medicine. The 30-minute rule states that red blood cell (RBC) units left out of controlled temperature storage for more than 30 minutes should not be returned to storage for reissue; the 4-hour rule states that transfusion of RBC units should be completed within 4 hours of their removal from controlled temperature storage. Eligible studies were identified from searches (to October 2010) of a range of electronic databases (including The Cochrane Library, MEDLINE, EMBASE, and the National Health Service Blood and Transplants Transfusion Evidence Library) and contact with transfusion medicine and blood bank experts. Twenty-three studies were identified that measured the quality of the RBC unit (n = 19), bacterial contamination in the RBC unit (n = 4), or both (n = 2) after exposure to greater than 4 °C ± 2 °C from between 20 minutes to 42 days. The overall finding was that temperature exposure did not adversely affect the quality of the RBC units or result in significant bacterial contamination. However, the variation in the temperature of exposure, its duration, the amount of data reported by the individual studies, and the age of the studies (and thus their comparability to current clinical practice) make it difficult to draw significant conclusions. To reliably determine whether these time rules could be extended without an adverse risk to the RBC unit requires robust, modern studies using multiple combinations of blood, anticoagulant, and additive solutions with defined temperatures and times of exposure.

Pathogen inactivation of platelets using ultraviolet C light: effect on in vitro function and recovery and survival of platelets

BACKGROUND: We evaluated the effect of treating platelets (PLTs) using ultraviolet (UV)C light without the addition of any photosensitizing chemicals on PLT function in vitro and PLT recovery and survival in an autologous radiolabeled volunteer study.

Is perioperative plasma aprotinin concentration more predictable and constant after a weight-related dose regimen?

To determine whether a weight-related dose had advantages over a fixed, large-dose regimen, we measured plasma concentrations of aprotinin by using an enzyme-linked immunosorbent assay method at set time points in 30 patients having heart surgery with cardiopulmonary bypass. A weight-related dose comprising a preincision bolus injection of 40,000 kallikrein-inhibiting units (KIU)/kg (5.6 mg/kg) with the same amount given in the oxygenator prime was compared with a large-dose regimen of 2 × 106 KIU (280 mg) preincision bolus and addition to prime, together with an infusion of 500,000 KIU/h (70 mg/h). Peak plasma concentration in the Weight-Related group was less variable than with the fixed-dose regimen. Forty percent of patients allocated to the fixed-dose regimen had an aprotinin concentration of more than 400 KIU/mL, compared with none in the Weight-Related group; this suggests a relative overdosing in the early surgical period in the Fixed-Dose group. There was great individual variability between patients in the time-concentration curves for aprotinin, with no difference between the two regimens. The weight-related dose regimen benefited by not requiring an intraoperative infusion while achieving the same plasma concentrations of aprotinin.

Blood components produced from whole blood using the Atreus processing system.

BACKGROUND: The Atreus 2C+ system (Gambro BCT) automates whole blood (WB) processing into a single device. This study compared the quality of red blood cells (RBCs), fresh‐frozen plasma (FFP), and buffy coats (BCs) made from WB held with or without active cooling.

In vitro quality of single-donor platelets treated with riboflavin and ultraviolet light and stored in platelet storage medium for up to 8 days.

BACKGROUND: The Mirasol pathogen reduction technology system is known to increase the activation and metabolic rate of platelets (PLTs). Storage of Mirasol PLTs in PLT storage medium (PSM) has the potential to slow this accelerated PLT storage lesion. We investigated the quality of Mirasol‐treated PLTs stored in either 50% SSP+ or 50% Composol for 8u2003days.

Prion reduction of red blood cells: impact on component quality

BACKGROUND: A filter has been developed (P‐Capt, MacoPharma) to remove infectious prions from red blood cells (RBCs). We sought to assess 1) its operational use, 2) the quality of filtered components, and 3) whether filtration resulted in any significant changes to blood group antigens.