Use of Cellular and Plasma Apheresis in the Critically Ill Patient: Part 1: Technical and Physiological Considerations

Apheresis is the process of separating the blood and removing or manipulating a cellular or plasma component for therapeutic benefit. An apheresis procedure, or series of procedures, may be indicated in the critical care setting as primary or adjunctive therapy for certain hematologic, neurologic, renal, and autoimmune/ rheumatologic disorders. Optimal management of severely ill patients undergoing apheresis requires a working knowledge of the technical, methodological, and therapeutic considerations. These considerations include instrument hardware and separation methods, vascular access requirements, hemodynamic and hemostatic effects of the procedures, exposure to anticoagulants and homologous blood products, physiological variables affecting blood/plasma processing efficiency, and therapeutic endpoints for specific indications. Part 1 of this review will discuss each of those technological considerations and the basic physiological principles that guide this form of therapy. Part 2 of this series will deal with the clinical indications and applications for specific disorders that are most likely to affect patients in the intensive care unit.

Continuous plasma perfusion of dual cartridges in series: rationale and early clinical experience

To improve the efficiency of plasma perfusion on eliminating plasma paraquat (PQ), we designed continuous plasma perfusion of dual cartridges in series (CPPDCS) on Diapact Braun CRRT machine. The goals of this study were to evaluate the effective of CPPDCS on paraquat removal in patients with acute paraquat intoxication. Our results show that the PQ clearance rate of dual cartridges was significantly higher than that of single cartridge at 1st, 2nd, 3^rd, and 4th plasma perfusion. Compared with single-cartridge plasma perfusion, CPPDCS significantly reduced the frequency of cartridge replacement, shorten the time of perfusion. These results indicate that CPPDCS is effective than plasma perfusion of single cartridge on PQ clearance rate and may provide an effective treatment for PQ poisoning.

Characteristics of canine platelet-rich plasma prepared with five commercially available systems

OBJECTIVE

To characterize platelet-rich plasma (PRP) products obtained from canine blood by use of a variety of commercially available devices.

SAMPLE

Blood samples from 15 dogs between 18 months and 9 years of age with no concurrent disease, except for osteoarthritis in some dogs.

PROCEDURES

PRP products were produced from blood obtained from each of the 15 dogs by use of each of 5 commercially available PRP-concentrating systems. Complete blood counts were performed on each whole blood sample and PRP product. The degree of platelet, leukocyte, and erythrocyte concentration or reduction for PRP, compared with results for the whole blood sample, was quantified for each dog and summarized for each concentrating system.

RESULTS

The various PRP-concentrating systems differed substantially in the amount of blood processed, method of PRP preparation, amount of PRP produced, and platelet, leukocyte, and erythrocyte concentrations or reductions for PRP relative to results for whole blood.

CONCLUSIONS AND CLINICAL RELEVANCE

The characteristics of PRP products differed considerably. Investigators evaluating the efficacy of PRPs need to specify the characteristics of the product they are assessing. Clinicians should be aware of the data (or lack of data) supporting use of a particular PRP for a specific medical condition.

An Anti-Adhesion Technique in Microfluidic Channel Using Dielectrophoresis for Particle Processing Microfluidic Chip Applications

Particle adhesion to the walls of microfluidic channels is a prominent cause of deteriorating performance and reliability in miniaturized analytical devices; it can also cause unexpected changes in their structures and operating conditions. Therefore, the demand of anti-adhesion for wall loss reduction on particle processing chips is high. This paper demonstrates an anti-adhesion technique using dielectrophoresis. The proposed technique is applied to a distribution microchannel for a feasibility test and is then applied to a blood plasma filter, which is a human blood cell and plasma separation device. In the distribution microchannel, the application of electric potentials of 0-20 V(pp) at 3 MHz caused the wall loss of polystyrene latex (PSL) particles to decrease with decreasing particle diameter. When an electric potential of 20 V(pp) was applied in a distribution microchannel experiment using PSL particles, the wall loss decreased by 52.7 ± 3% for 10-μm-diameter particles. On the other hand, when a 20 V(pp) electric potential was applied in a distribution microchannel experiment using human blood cells, the wall loss decreased by 66.4 ± 6%. In the blood plasma filter, the wall loss decreased by 54.89 ± 5% at 20 V(pp) and 1 MHz. The purity efficiency of the blood plasma filter was 69.56% without the wall loss reduction technique and 95.14% when the applied electric potential was 20 V(pp).

[TERMINOLOGY OF THE PROCEDURES OF DRAWING BLOOD AND RECEIVING IT COMPONENTS]

The paper discusses the appropriate use of terminology denoting different types and different ways of blood sampling those of its components with the semantic, phonetic and technological point of view.

Hemolysis-free blood plasma separation

Hemolysis, involving the rupture of red blood cells (RBCs) and release of their contents into blood plasma, is a major issue of concern in clinical fields. Hemolysis in vitro can occur as a result of errors in clinical trials; in vivo, hemolysis can be caused by a variety of medical conditions. Blood plasma separation is often the first step in blood-based clinical diagnostic procedures. However, inhibitors released from RBCs due to hemolysis during plasma separation can lead to problems in diagnostic tests such as low sensitivity, selectivity and inaccurate results. In particular, a general lack of simple and reliable blood plasma separation methods has been a major obstacle for microfluidic-based point-of-care (POC) diagnostic devices. Here we present a hemolysis-free microfluidic blood plasma separation platform. A membrane filter was positioned on top of a vertical up-flow channel (filter-in-top configuration) to reduce clogging of RBCs by gravity-assisted cells sedimentation. With this device, separated plasma volume was increased approximately 4-fold (2.4 μL plasma after 20 min with 38% hematocrit human whole blood), and hemoglobin concentration in separated plasma was decreased approximately 90% due to the prevention of RBCs hemolysis, when compared to conventional filter-in-bottom configuration blood plasma separation platforms. On-chip plasma contained ~90% of protein and ~100% of nucleic acids found in off-chip centrifuged plasma, confirming comparable target molecule recovery efficiency. This simple and robust on-chip blood plasma separation device integrates with downstream detection modules to ultimately create sample-to-answer microfluidic POC diagnostics devices.

Microfluidic chip for plasma separation from undiluted human whole blood samples using low voltage contactless dielectrophoresis and capillary force

A plasma separating biochip is demonstrated using a capillary-driven contactless dielectrophoresis method with low voltage (~1 V) and high frequency induced electrostatics between red blood cells. The polarized red blood cells were aggregated and separated from plasma with a 69.8% volume separation and an 89.4% removal rate of red blood cells.

Platelet concentrates for topical use: bedside device and blood transfusion technology. Quality and versatility

More or less after a decade of experimental and pioneering manual procedures to prepare platelet-rich plasma (PRP) for topical use, several portable and bedside devices were made available to prepare the PRP at the point-of-care. This technical opportunity increased the number of patients who got access to the treatment with autologous PRP and PRP-gel. Since topical treatment of tissue with PRP and PRP-gel was restricted to autologous preparation, blood transfusion centers that professionally prepare donor-derived platelet concentrates were not able to cover the overwhelming request for autologous PRP supply. Principally for logistic and organization reasons blood transfusion centers usually fail the challenge of prompt delivery of PRP to the physician over large territory. Nevertheless the blood bank production of platelet concentrates is associated with high standardization and quality controls not achievable from bedside and portable devices. Furthermore it easy to demonstrate that high-volume blood bank-produced platelet concentrates are less expensive than low-volume PRP produced by portable and bedside devices. Taking also in consideration the ever-increasing safety of the blood components, the relationship between bedside device-produced and blood-bank-produced PRP might be reconsidered. Here we discuss this topic concluding that the variety of sources of PRP production is an opportunity for versatility and that, ultimately, versatility is an opportunity for the patient's care.

[Determination of cyclohexanone concentration in the plasma separator by gas chromatography]

This essay is to determine the cyclohexanone concentration of the plasma separator. The compound was introduced into the GC analytical system by the carrier gas. The determination was performed by the measurement of their peak area and by the external standard method.

Plasmapheresis in hyperviscosity syndrome

Three patients with Waldenström's macroglobulinaemia developed circulatory complications due to increased plasma viscosity, i.e. relative viscosity value above 4. Plasmapheresis was performed either in a Haemonetics 30 S cell separator, by plasma filtration through a CPS 10 TM filter or by a double-double pack Fenwal system. All three methods reduced the plasma viscosity and abolished the clinical symptoms. In cases of acute hyperviscosity syndrome, apheresis of small amounts of plasma by the double-double pack system may serve as an alternative to the more advanced techniques.

[Double filtration plasmapheresis in treatment of hyperlipidemic acute pancreatitis]

OBJECTIVE

To investigate the therapeutic effects of double filtration plasmapheresis(DFPP) in treatment of hyperlipidemic acute pancreatitis.

METHODS

Nine patients with acute hyperlipidemic pancreatitis were treated with DFPP in addition to the conventional therapeutic measures. The clinical symptoms,serum levels of triglyceride (TG) and APACHE II scores were observed before and after DFPP.

RESULT

After DFPP the clinical symptoms of patients were improved greatly; serum levels of TG decreased from (83.48 +/-2.54)mmol/L to (4.09 +/-0.65)mmol/L(P<0.01) and APACHE II scores decreased from 12.2 +/- 2.3 to 6.2 +/- 1.3(P <0.05). There were no significant side effects during and after DFPP.

CONCLUSION

DFPP can be effectively and safely applied in patients with acute hyperlipidemic pancreatitis.

Major coagulation disturbances during fractionated plasma separation and adsorption

Fractionated Plasma Separation and Adsorption (FPSA) is a novel nonbiologic detoxification system for the removal of protein-bound solutes. FPSA is used to bridge patients during fulminant liver failure, either to functional recovery or to liver transplantation. Besides liver failure associated protein bound solutes, several important uremic retention solutes share important protein binding. We observed repeated occlusive thrombosis of the arterio-venous conduit during FPSA in hemodialysis (HD) patients, resulting in acute loss of function. A major reduction of several coagulation factors was demonstrated, exceeding 50% for factor II, factor X and protein C. Broad disturbances of the coagulation system were confirmed in FPSA treated liver failure patients. An ex vivo recirculation model demonstrated nonspecific adsorption of coagulation factors protein S and protein C on the anion exchange cartridge. Direct contact between fractionated plasma and the Prometh02 anion exchanger causes significant adsorption of procoagulant and anti-coagulant factors, associated with clinically relevant adverse events.

[Apparatus-free membrane plasmapheresis in the complex therapy of victims with crush syndrome during evacuation under the conditions of an aeromobile hospital of the Russian MChS Ministry]

The paper analyzes the results of treatment in victims with the crush syndrome under the conditions maximally close to those of emergency situations. It is concluded that plasma exchange procedures should be performed within the next few hours after taking the victims from the obstructions, which reduces the risk of acute lung damage and death rates in this group of patients to a considerable extent.

Plasmapheresis in the treatment of acute vascular rejection: an experience on a dialysis unit

Despite numerous the advances made in transplantation, acute rejection remains a major complication. Recent studies have shown that the use of plasmapheresis in the treatment of acute vascular rejection improves the chances of graft survival. In 1997 the plasmapheresis was transferred to the management of the renal unit, because we could offer a 24-hour service for all acute cases in our hospital. The number of cases has steadily increased, incorporating not only plasmapheresis, but also stemcellpheresis and red blood cell exchanges. Since July 2003, we have started using plasmapheresis in the treatment of acute vascular rejection in renal transplants. When a biopsy shows acute vascular rejection (A.V.R), combined with a decreased urine production, the patient commences therapy. Treatment consists of consecutive sessions, alternating between two sessions using saline/ albumin followed by one session using fresh frozen plasma. Depending on the lymphocyte count, therapy is carried out in conjunction with a course of Antithymocyte globulin (A.T.G.) between July 2003 and October 2004, 124 transplants were carried out, 15 suffered from acute rejection. Six were diagnosed with A.V.R, of these six; five were successfully treated with plasmapheresis and A.T.G. One patient only needed plasmapheresis to ensure a reversal of acute vascular rejection. We encountered no problem with the technique itself and although plasmapheresis seems to improve the outcome of graft survival, we need to ask ourselves, as demand increases: "Do we have the capacity to treat these patients on our unit in the future and is it our domain?"

Microfluidic Devices for Continuous Blood Plasma Separation and Analysis During Pediatric Cardiopulmonary Bypass Procedures

As an extension of previous work, a microfluidic device, which can separate blood plasma in a continuous, real-time fashion from a whole blood, is successfully integrated with a mock cardiopulmonary bypass circuit. The functionality of the device is demonstrated with the use of freshly harvested bovine blood. The plasma selectivities were 100% and 99.4% and the plasma separation volume percents were 18.7% and 24.5% for 26% and 37% inlet hematocrit levels, respectively. As an advanced stage of this research, a microfluidic device, which can measure the concentration of clinically relevant blood plasma protein in a continuous fashion, is being developed on the basis of fluid handling circuits coupled to fluorescent cytometric bead assays. The functionality of the device is demonstrated with the use of a biotinylated FITC solution and a streptavidin-coated, 8-mum-diameter bead. The binding event between biotinylated FITC and the streptavidin bead is continuously detected within a detection window at the outlet of the device. For a known concentration (1 microg/ml) of biotinylated FITC solution, the measured fluorescent intensity is fairly constant and shows a stable gaussian distribution of the bead fluorescence intensity. It is expected that the proposed device can be used for continuous measurement of clinically relevant proteins during cardiac surgery with the cardiopulmonary bypass procedure.

Repeated automated plasmapheresis in goats (Capra hircus): a clinically safe and long-term refinement to current antibody recovery techniques

Automated plasmapheresis is an optimal method of plasma collection because the donor is a part of a closed loop where whole blood is withdrawn and separated and packed cells are returned in a serial fashion until the desired amount of plasma is obtained. The typical approach to collection of antibody-rich plasma involves withdrawal of whole blood from vaccinated animals, yielding approximately 1000 ml plasma from each animal, which is euthanized after this process. In the present study, 32 goats (Capra hircus) were vaccinated and conditioned for restraint in a modified Panepinto sling. Each animal was monitored clinically, including complete and differential blood counts and serum chemistries 24 h before and 24 to 48 h after each procedure. A jugular vein was surgically prepped, a 16-gauge needle catheter was placed, and the animal was attached to an automated plasmapheresis machine. After plasma removal, return of the resuspended packed blood cells, and infusion of 500 ml 0.9% NaCl, the animal was disconnected from the machine, the catheter removed, and the animal returned to the barn. There were no clinically significant changes in either the complete blood counts or the clinical chemistries during the course of this study. These 32 animals produced 240,000 ml of immunoglobulin-rich plasma over the course of this project and more than 949,000 ml of plasma to date. This study identifies a refinement in current antibody-recovery techniques and potentially reduces the number of animals necessary to produce bioreagents on a long-term and continual basis.

Platelet-rich plasma preparation using three devices: implications for platelet activation and platelet growth factor release

BACKGROUND

In this study, three commercial systems for the preparation of platelet-rich plasma (PRP) were compared and platelet growth factors release was measured.

METHODS

Ten healthy volunteers donated whole blood that was fractionated by a blood cell separator, and a table-top centrifuge to prepare PRP. Furthermore, an autologous growth factor filter was used to concentrate PRP fractionated by the blood cell separator. PRP was subsequently activated with autologously produced thrombin to degranulate the platelets to measure platelet-derived growth factor-AB (PDGF-AB), transforming growth factor-beta (TGF-beta), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF).

RESULTS

PRP contained significantly higher platelet counts compared with baseline values (p < 0.001). PDGF-AB concentrations were increased more than 18-fold in the platelet gel supernatant when the cell-separator and GPS were used, whereas only a 3-fold increase was seen with the AGF.

CONCLUSION

The three PRP devices enable the preparation of PRP for the release of high concentrations of platelet growth factor, but showed different harvesting capacities for the collection of concentrated platelets. The administration of thrombin for PRP activation resulted in the release of high concentrations of PDGF-AB and TGF-beta but only when PRP had not been activated during the preparation process in vitro.

Immunoadsorption Plasmapheresis Using a Phenylalanine Column as an Effective Treatment for Lupus Nephritis

Immunoadsorption plasmapheresis (IAPP) is effective for eliminating pathogenic molecules such as anti-DNA antibody (anti-DNA Ab) and immune complexes from the serum of patients with systemic autoimmune diseases. The purpose of this study was to assess patients with lupus nephritis (LN) treated by IAPP using a phenylalanine column and determine its efficacy with respect to conventional therapies. Six patients (M = 1, F = 5) with histologically proven LN associated with proteinuria and abnormal sedimentation on urinalysis were the subjects for this study. All were treated with oral corticosteroid (prednisolone 1 mg/kg/day) and IAPP (Immusorba PH - 350; 2 L of plasma twice weekly for 2 weeks). Serum anti-DNA Ab and complement, urinary protein, and creatinine clearance were measured over 6 weeks (pretreatment, before and after each of 2 IAPP sessions, and 1 and 4 weeks after the second IAPP session). Clinical efficacy of IAPP was compared with conventional pharmacotherapy regimes by conducting a retrospective review of 23 LN patients treated at our hospital using corticosteroid pulse therapy (CSPT, N = 7, intravenous methylprednisolone 500 mg/day for 3 days), intravenous cyclophosphamide pulse therapy (IVCY, N = 7), or corticosteroid monotherapy (CSMT, N = 9, oral prednisone 1 mg/kg body weight daily, for 4 weeks). Immunosuppressants and anticoagulants were not used. With IAPP, mean urinary protein excretion decreased from 2.2 +/- 1.7 g/day pretreatment to 0.4 +/- 0.6 g/day post-treatment (P < 0.001). Mean serum anti-DNA Ab also decreased from 84.0 +/- 88.1 U/mL pretreatment to 5.8 +/- 5.5 U/mL post-treatment (P < 0.05). In combination with corticosteroid therapy, IAPP would appear to be an effective and safe treatment for LN.

Two red blood cell units collected in SAG-M additive solution with the ALYX component collection system

The first protocol available for the new ALYX component system (Baxter Healthcare Inc.) allows automated collection of two Red Blood Cell (RBC) units from one donor. The primary objective of our evaluation was to assess donor safety, comfort and to check the quality of blood products collected. 30 procedures were performed on eligible donors according to French best donation practices. Eligibility criteria were defined in order to ensure a post donation hemoglobin concentration of 11 g/dL minimum. Pre donation ferritin level was also checked. 360 ml of absolute RBC were collected from each donor. Donors physiological parameters and haematological profile were measured immediately before and after donation. Adverse events and donors were observed during the procedure and followed daily during 5 days after donation. Hemolysis in RBC was followed until of shelf life (<0.8% on 42 days storage). The evaluation of different parameters during storage show no difference if we compare with the manual technique. The concentration of hemoglobin is good and all ou concentrates are conform. No serious adverse effects were reported during and after donation. All donors confirmed they would agree to donate 2 RBC units again with this system. We have seen a good quality of RBC products. This evaluation indicates that 2 RBC donation is feasible on the ALYX system, comfortable and safe for eligible donors.

Efficacy of double-filtration plasmapheretic cross-circulation with a high-permeability membrane using canine harvested liver in porcine fulminant hepatic failure model

INTRODUCTION

The use of bioartificial liver devices requires. A sufficient liver cell mass to provide adequate metabolic support, reduction of xenogeneic immune reactions, and avoidance of viral transmission. We have developed a plasmapheresis system using a semipermeable membrane combined with canine whole liver perfusion (PMCWLP). In this study, we investigated the efficacy of our system in a porcine fulminant hepatic failure (FHF) model.

METHODS

The porcine FHF model was established by intraportal administration of alpha-amanitin (0.1 mg/kg) and lipopolysaccharide (1 microg/kg). Nine hours after drug injection, xenogenic perfusion treatment was performed twice within 6 hours (n = 5). As the plasmapheresis device, we used a hollow-fiber module with cellulose diacetate porous fibers (pore size, 0.05 microm, surface area, 2 m2). The canine whole liver was perfused with modified Krebs solution, which is commonly used in many laboratories, containing albumin (2 g/dL) and glucose (300 mg/dL). Control pigs (n = 10), had the circuit not connected to the whole canine liver.

RESULTS

The survival of FHF pigs was significantly increased by the treatment (58.9 +/- 21.8 hour) compared with the controls (22.3 +/- 8.1 hour). Mean blood ammonia levels and intracranial pressure during treatment were significantly lower compared with control groups.

CONCLUSION

Treatment of FHF pigs with the system significantly increased survival time, suggesting that this method may have applications as a clinical liver assist device.

[Extracorporeal detoxication in patients with destructive pancreatitis]

Criteria of severity of endogenous intoxication in patients with destructive pancreatitis in enzymatic toxemia are discussed. It is demonstrated that the level of middle mass molecules and integral index of affection of the pancreas, abdominal cavity and retroperitoneal space are objective criteria of endogenous intoxication and can be used for determination of indications for extracorporeal detoxication and for assessment of treatment efficacy. Prescription of extracorporeal detoxication according to these criteria in an early period of the disease before multiple organ failure development promotes faster management of endotoxemia, prophylaxis of septic complications, decreases lethality and period of treatment of patients with destructive pancreatitis.

Evaluation of the Hemobag: a novel ultrafiltration system for circuit salvage

Following termination of bypass, the CPB circuit contains a significant volume of diluted blood. Various methods have been used to salvage this blood, including direct transfusion or centrifugation /washing of the circuit volume. These techniques produce a reinfusion product that is either dilute or free of plasma proteins. The purpose of this study is to evaluate the Hemobag ultrafiltration system, which may overcome these limitations. Yorkshire pigs (n = 4, approximately 40 kg) were placed on CPB (prime volume 1.5 L) for 60 min. Following CPB, control blood samples (Pre) were collected from the circuit. The circuit contents were then transferred into a Hemobag and processed. Blood samples (post) were then collected from the Hemobag. Pre- and post-samples were analyzed and compared using a Student's t-test. Parameters that were significantly different (p < .05) pre-Hemobag versus post-Hemobag were as follows: hematocrit 20.4+/-3.4% vs. 54.1+/-11.6%, total protein 2.4+/-0.4 vs. 8.2+/-2.9 gms/DL, fibrinogen 92.0+/-0.3 vs. 305.8+/-37.2 mg/DL. Parameters that were not significantly different but trended toward an increase post-Hemobag were platelet counts, heparin levels, white cell count, and plasma free hemoglobin. Parameters that showed no differences or trends included sodium, potassium, chloride, bicarbonate, and osmolarity. Processing times were measured at approximately 10 minutes. This device effectively concentrates post-bypass circuit volume, providing a product that is high in red blood cells and plasma proteins and may provide an alternative to current techniques for circuit volume salvage.

Artificial in vivo biofiltration: slow continuous intravenous plasmafiltration (SCIP) and artificial organ support

An intravenous plasmafiltration (SCIP) catheter has been developed and is proposed for clinical investigation into the alleviation of acute fluid overload by SCUF of the extracted plasma. The system utilizes a unique backflushing technique, high intravenous shear flow rates and biocompatible polymers to minimize protein and platelet aggregation along the filter surfaces. The absence of platelets from the extracted plasma promotes the longevity of ultrafiltration cartridges, thus theoretically minimizing attendant labor associated with continuous renal replacement therapies. Clinical studies are currently being planned for the near future. Plasma SCUF is envisioned as a predecessor technology to future applications in therapeutic apheresis, tissue engineering, therapeutic sorbent technologies. Further, with improved longevity profiles, intravenous SCUF or dialysis and implantable or wearable artificial organs based upon artificial in vivo biofiltration are possible.

Slow continuous intracorporeal plasmapheresis for acute fluid overload

Intermittent dialysis is still the predominant treatment for acute or chronic renal insufficiency in the USA despite increasing evidence that slower and longer fluid management therapies are more beneficial to the patient. We have investigated the use of slow continuous intracorporeal plasmapheresis (SCIP) as a more efficient and hemodynamically stable alternative means of treating acute fluid overload. In this paper we discuss preliminary observations on the safety of SCIP catheter insertion, fluid removal, extraction and pathology in Yorkshire pigs. SCIP catheters removed plasma for extracorporeal plasma water removal without significant gross or histopathological changes. Blood chemistry and cell counts remained stable during therapy. Toxicological studies indicated no pyrogenicity, hemolysis, cytotoxicity, acute systemic toxicity, delayed-type hypersensitivity, or blood recalcification coagulation inhibition. Intracutaneous extracts caused only mild irritation. SCIP therapy appears to be safe for use in the removal of plasma and plasma water from experimental animals.

Maximal flow rates and sieving coefficients in different plasmafilters: effects of increased membrane surfaces and effective length under standardized in vitro conditions

In Europe, capillary membrane filters are the favored method for plasmapheresis and detoxification systems including a plasma separation unit. Using capillary membrane filters clearance depends on the filtration rate and the sieving coefficient (Qs) for the plasma substrates. We investigated whether the increase of the effective membrane surface of plasmafilters enables higher clearance rates than a small plasmafilter. Heparinized porcine blood (5 I.U./l) of healthy pigs was used for an in vitro circuit. Filter types used were from GAMBRO: n = 5 PF1000N (effective membrane surface: 0.15 m(2)), n = 4 PF2000N (0.35) and from ASAHI: n = 4 PLASMAFLO OP-05W (L) (0.5). Spontaneous hemolysis was chosen to indicate the individual threshold limit for maximal flow rates. Sieving coefficient was determined for ten parameters at lowest and highest blood flow (Qb) and filtration rates (Qf). PF1000N enabled maximal flow rates as high as PF2000N and PLASMAFLO (Qb/Qf in ml/min: 200/40). Qs for most substrates were similar between the filter types and the flow rates. Compared to PLASMAFLO, the filter type with the largest membrane surface, the PF1000N provided significantly better Qs for triglycerides and albumin and a trend for a better elimination of cholesterol, GGT, and LDH. The sieving properties of the PF2000N ranged between PF1000N and PLASMAFLO. Under standardized in vitro conditions, the larger plasmafilters tested did not improve the overall performance of the plasmapheresis procedure. Thus, enlargement of the membrane surface such as provided by two commercially available and clinically well-established plasmafilters could not be proven to enable higher clearance rates.

Influence of different heparin concentrations on the results of in vitro investigations in plasmaseparation technology using capillary membrane filters

Capillary membrane filters are devices commonly used for plasmapheresis and recirculating detoxification systems, including plasmaseparation units. Besides clinical trials and case reports, research on plasmafiltration techniques is carried out using in vitro systems. Notably, such hemoperfused in vitro systems require anticoagulation protocols suitable for investigating the clearance performance and hemocompatibility of a plasmafilter. This study analyzes how different heparin concentrations affect filtration performance and the hemocompatibility under conditions typically employed during in vitro experiments. Porcine blood from healthy slaughtered animals was used in an in vitro circuit. The blood collecting system was primed with heparin. Depending on the study group, blood was anticoagulated with either 2.5 IU/ml or 5 IU/ml heparin. The filters were n=10 PF1000N (effective membrane surface: 0.15 m2). For each experiment, the maximal permissible flow rate was established by determining the point where spontaneous hemolysis occurred and/or pressure values exceeded the highest limit of the pressure units on the apheresis monitor. Sieving coefficients of ten parameters, platelet counts, and coagulation patterns were determined at the lowest and highest blood flow (Qb) and filtration rates (Qf). Except for the activated clotting time (ACT), both anticoagulation protocols caused the blood to respond to its exposition to the plasmafilters concerning the activation and inhibition of the coagulation system. A significant decrease in platelet counts did not occur. There were sporadic differences in sieving properties between the groups. However, heparinization with 2.5 IU/ml resulted in unreproducible flow rate profiles, and pressure levels were higher than in the group with 5 IU/ml heparin. Compared to heparinization at 2.5 IU/ml, higher levels of heparinization stabilize rheological properties of the blood, and thereby increase the reliability of data obtained from plasmafiltration experiments carried out in vitro.

Automated plasmapheresis compared with other plasma collection methods in the horse

The purpose of this study was to evaluate plasmapheresis as a method for plasma extraction in comparison with centrifugation or gravity sedimentation. The study was designed as a cross over trial with six Freiberger horses undergoing plasma donation by plasmapheresis followed by whole-blood donation and subsequent plasma production 4 weeks later. Automated plasmapheresis and whole-blood donation were well tolerated in all horses. The plasmapheresis method achieved an almost complete removal of erythrocytes and leucocytes from plasma at all flow rates. After blood bag centrifugation, significantly more erythrocytes (P < 0.01) and leucocytes (P < 0.01) were present in the prepared plasma compared with plasmapheresis plasma. Plasma prepared by gravity sedimentation contained significantly more erythrocytes and leucocytes than plasma prepared with the other techniques (P < 0.01), and platelet aggregation was observed. The coagulation proteins and the total protein content of plasma prepared after plasmapheresis and blood bag centrifugation did not differ significantly from values measured prior to collection (P > 0.05). However, the activity of factor VIII was significantly lower 24 h after gravity sedimentation of blood than activity prior to blood collection (P < 0.01). In conclusion, automated plasmapheresis is the method of choice for the production of high quality equine plasma.

Medical Devices; hematology and pathology devices; reclassification of automated blood cell separator device operating by filtration principle from class III to class II. Final rule

The Food and Drug Administration (FDA) is reclassifying the automated blood cell separator (ABCS) device operating by filtration principle, intended for routine collection of blood and blood components, from class III to class II (special controls). The special control requirement for this device is an annual report with emphasis on adverse reactions to be filed by the manufacturer for a minimum of 3 years. The agency is taking this action in response to a petition submitted under the Federal Food, Drug, and Cosmetic Act (the act) as amended by the Medical Device Amendments of 1976 (the 1976 amendments), the Safe Medical Devices Act of 1990 (the SMDA), and the Food and Drug Administration Modernization Act of 1997 (FDAMA). The agency is reclassifying the automated blood cell separator devices operating by filtration principle into class II (special controls) because special controls, in addition to general controls, are capable of providing a reasonable assurance of safety and effectiveness of the device.

Superlite Plasma Collection System

The Japanese Ministry of Health, Labor and Welfare launched a national initiative to become plasma self-sufficient by reducing reliance on imported plasma products and increasing plasma collections to enable plasma-derived pharmaceuticals, including albumin, globulin, and Factor VIII products to use plasma collected within Japan. In order to realize this goal, plasma collections from volunteer donors must increase to about 1.5 million litres of plasma per year (1) or about 50% more than what the Japan Red Cross currently collects. A mobile device, such as the Superlite system, will make it easier and more efficient for Japan's sole blood collection agency, the Japan Red Cross, to add plasma collection to mobile blood drives. Haemonetics Corporation (Braintree, MA, USA) has combined many years of apheresis experience with up-to-date technology to create the Superlite Plasma Collection System (PCS) for the Japan Red Cross. This new device, which is expected to greatly contribute to the Red Cross's national source plasma collection program, is even smaller than the Ultralite PCS and offers several advanced features and benefits. Light, compact, and very portable, the Superlite has a Japanese language friendly user interface that continually displays collection status, including time remaining in the collection procedure. The device features a protocol that limits extra-corporeal blood volume for low-weight donors; a program used in conjunction with a reduced volume disposable bowl. Superlite, designed for use in both fixed-site and mobile applications, combines the portable ease-of-use of the Ultralite with the collection process calculation abilities of the CCS to provide a state-of-the-art collection device that will help define the future of Japan plasma collection.

Plasma separator Plasmaflo OP

In recent years, polyethylene and polysulfone membranes have been used for plasma separation in Japan. The polyethylene membrane, manufactured by melt spinning method, has a sponge-like symmetric structure. The plasma separator Plasmaflo OP (Asahi Medical, Tokyo, Japan) with a polyethylene membrane shows excellent performance and safety for plasma separation. More than 20 indications for therapeutic plasmapheresis are reimbursed in Japan. Future development is expected in new membrane designs for new indications or advanced plasmapheresis methodologies.

Blood purification therapies using dextran sulfate cellulose columns Liposorber and Selesorb

Liposorber is a column used for plasma purification that adsorbs low-density lipoproteins with high selectivity, while Selesorb is a column that selectively adsorbs anti-DNA antibodies, anticardiolipin antibodies, and immune complexes. Both columns are packed with carriers, where a dextran sulfate ligand is bound to porous cellulose beads. Liposorber is used to treat familial hypercholesterolemia (FH), peripheral arterial disease (PAD), and focal segmental glomerulosclerosis (FGS): Selesorb is used to treat systemic lupus erythematosus (SLE). Treatment utilizing both columns is being used effectively in patients with refractory disease that is resistant to pharmacotherapy.

The structure and characteristics of polypropylene hollow fiber membrane plasma separator

Propylex is a membrane type plasma separator using a polypropylene hollow fiber membrane with regular and orderly rectangular pores, which has been developed and manufactured by Ube Industries, Ltd. This product is of its polypropylene membrane; (ii) little damage to blood cells even under high transmembrane pressure due to its characteristic pore structure; and (iii) slight fluctuations in the sieving coefficients for substances with high and low molecular weights even with increased throughput, which allows stable clinical use.

State of the art treatment of the most difficult low density lipoprotein (LDL) cholesterol problems: LDL apheresis

The patient benefit from reduction of an excessively elevated low density lipoprotein (LDL) cholesterol is now well established, especially when there is proven coronary atherosclerosis. Dietary adherence can lower LDL cholesterol by a maximum of 10% to 15%. The addition of a cholesterol-lowering medication frequently can achieve a major LDL cholesterol reduction. However, a small group of patients with a very high LDL cholesterol respond poorly to diet and pharmaceutical treatments. These same patients have the highest incidence for very premature coronary atherosclerosis and associated cardiac events. A few medical centers, including the University of Kentucky, have established a new program to benefit these difficult high-risk patients. The technique is known as LDL apheresis, an effective process for removal of LDL cholesterol. The procedure is highly effective but very costly and third-party approval barriers are preventing access to this essential treatment for some very high-risk coronary atherosclerosis patients.

Separation of IgG and IgM from albumin in citrated human plasma using electrodialysis and metal ion affinity precipitation

Plasmapheresis is the process by which plasma is separated from whole blood for therapeutic purposes. The primary reason to perform plasmapheresis is to remove immunoglobulins and not to necessarily remove the remainder of the plasma proteins. Nevertheless, most plasmapheresis is performed by centrifugal separation to remove bulk plasma. We have investigated whether electrodialysis and metal ion affinity precipitation can be used to selectively remove immunoglobulins from citrated plasma and potentially serve as an adjunctive technique to centrifugal plasmapheresis. Using a commercial electrodialysis device, we have desalted citrated plasma to separate immunoglobulins from albumin, and have determined the effects of pH adjustment and addition of zinc acetate for concomitant metal ion affinity precipitation. With desalted pH adjusted citrated plasma containing 1.5 mM zinc acetate, we achieved more than 80% recovery of albumin with removal of almost 60% of the immunoglobulin (Ig)G. Almost 80% of polyclonal IgM and 90% of monoclonal IgM was also removed. IgA was not effectively removed under any of the conditions tested. Selective precipitation with electrodialysis and zinc acetate precipitation appears to be an effective technique for the separation of IgG and IgM from albumin in citrated plasma.

[Plasma technologies in surgery of pulmonary echinococcosis]

178 patients were operated over 18 years for pulmonary echinococcosis, 100 of them with standard methods, 78--with plasma technologies (surgical device SUPR-2M). Close echinococcectomy was performed in 22.5% patients, open--in 69.1%, combination of these operations--in 8.4% patients. Plasma technologies were used at pneumolysis, cysts section, antiparasitic treatment of residual cavities, fibrous capsule resection (pericystectomy) or cystpericystectomy, marginal resection of the lung with cyst, bronchotomy, sanation of pleural cavity, zone of operation and margins of operative wound. It is demonstrated that postoperative complications were seen in 34% patients operated by standard methods and in 8.9% patients operated with plasma technologies, lethal outcomes were in 2 (2%) and 1 (1.3%) patients, respectively. Plasma technologies permitted to reduce postoperative complications rate 3.8 times and postoperative treatment by 9.8 bed days or by 45.8%. Long-term results were studied in 61 (78.2%) operated patients followed from 1 month to 7 years, there were no recurrence of echinococcosis.