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2.
Ther Apher ; 5(4): 270-82, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11724512

ABSTRACT

The use of membranes in blood processing range from the use of large-pore structures for filtration of blood for the removal of large particles (>20 microm transfusion filters) to membranes for the dialysis of blood for the removal of low molecular weight solutes in the treatment of renal failure. Within the past 20 years, membranes have been applied in the separation of plasma from whole blood. Compared to centrifugal plasma separation membrane, plasma separation is preferred when used with online plasma fractionation since the plasma is free of cells. In addition, membranes have also been applied in the online treatment of plasma for the selective removal of macromolecules in selected disease states obviating the need for plasma replacement products. The membranes used for plasma separation and fractionation may be distinguished from conventional dialysis membranes and high-flux membranes used in hemofiltration by their very high or select passage of plasma proteins. Membrane techniques are simple and safe to apply and can be competitive to other plasma separation and treatment technologies.


Subject(s)
Blood Component Removal , Membranes, Artificial , Cell Fractionation , Hemofiltration , Hemorheology , Humans
3.
Ther Apher ; 5(3): 193-206, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11467756

ABSTRACT

The developments in apheresis technologies and techniques and their clinical applications worldwide are technologically, sociologically, and economically driven. In the past, apheresis survey statistics have highlighted both the differences by geographical region in clinical practices and in the types of technologies utilized. While a national view of apheresis is critically important, an international view of apheresis may be more representative overall of this therapeutic modality than national results that are highly dependent on the local economics and the available technologies. These regional differences have provided a basis for the scientific and clinical assessments of these apheresis technologies and their clinical outcomes and have impacted the marketing and business developments of new technologies worldwide. The results of the International Apheresis Registry for 2000 reporting on 39 centers on 4 continents are presented. This survey collected data on 1,080 patients for a total of 15,257 treatments. Information gathered included patient demographics, medical history, treatment diagnoses, treatment specifics (type, methodology, access type, anticoagulants, drugs, equipment usage), side effects, clinical response, and payment provider. As in the prior International Apheresis Registry for 1983, the survey results highlighted the regional differences in apheresis usage and treatment specifics, indicating that an international overview of apheresis may be more representative of the impact of this therapeutic modality.


Subject(s)
Blood Component Removal/statistics & numerical data , Registries/statistics & numerical data , Technology Assessment, Biomedical/statistics & numerical data , Adult , Asia , Blood Component Removal/instrumentation , Blood Component Removal/methods , Central America , Data Collection/statistics & numerical data , Europe , Female , Humans , Male , Middle Aged , North America , South America
4.
Artif Organs ; 25(2): 75-88, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11251473

ABSTRACT

With the first clinical use of the artificial kidney over 5 decades ago, we entered into a new era of medicine-that of substitutive and replacement therapy. Yet it took nearly another 15 years until chronic treatment was possible and nearly another 15 years until widespread treatment was possible due to government support. The history of development and clinical use of other artificial organ technologies such as the artificial heart and heart valves, the artificial lung, artificial blood, joint replacements, the artificial liver, the artificial pancreas, immunologic, metabolic, and neurologic support, neurocontrol, and tissue substitutes have followed similar long development paths. Despite their relatively long time to be put into clinical use, the contributions of artificial organ technologies to the betterment of mankind have been unquestionably a major success. For example, modern day surgery would not be possible without heart-lung support, and the technologies for heart support have led to the development of various minimally invasive technologies. The powerful impact that artificial organ technologies presently has on our lives is seen through the statistic that in the U.S.A. nearly 1 in 10 persons is living with an implanted medical device. With the aging of our population and the improvements in technologies, these numbers will only increase.


Subject(s)
Artificial Organs/trends , Biomedical Technology , Animals , Artificial Organs/economics , Artificial Organs/standards , Cost-Benefit Analysis , Genomics , Heart, Artificial/economics , Heart, Artificial/standards , Humans , Kidneys, Artificial/economics , Kidneys, Artificial/standards , Liver, Artificial/economics , Liver, Artificial/standards , Robotics , Survival Analysis , Treatment Outcome , United States , User-Computer Interface
5.
Artif Organs ; 25(12): 945, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11843760
6.
ASAIO J ; 46(6): S69-72, 2000.
Article in English | MEDLINE | ID: mdl-11110297

ABSTRACT

Prions are novel proteinaceous-infectious agents that have been implicated in transmissible spongiform encephalopathies. It is now generally accepted that noninfectious prion proteins are normally produced by the host and may undergo a conformational change to an abnormal, pathologic form, which appears to be responsible for disease symptoms. Many methods of decontamination and sterilization are claimed to be ineffective against prion proteins. Incidences of iatrogenic transmission of prions due to medical devices have been reported, and the recommended clinical practices when handling suspected cases are reviewed. Recent results with a peracetic acid based sterilant indicate that it may be a safe and effective means of prion inactivation on medical devices.


Subject(s)
Equipment and Supplies/adverse effects , Prion Diseases/transmission , Animals , Disinfection/methods , Humans , Peracetic Acid , Prion Diseases/etiology , Prion Diseases/prevention & control , Safety , Sterilization/methods
8.
J AOAC Int ; 83(2): 269-75, 2000.
Article in English | MEDLINE | ID: mdl-10772163

ABSTRACT

The AOAC sporicidal method (966.04) recommends the use of porcelain penicylinders and black waxed silk sutures as carriers for demonstrating the sporicidal activity of sterilants. However, the silk carriers are not suitable for evaluating the sporicidal efficacy of oxidizing agents, and an inert polyester material (Dacron) is recommended as an alternative. Dacron provides an equivalent microbial and physical challenge to silk. Microbiologically, both materials demonstrated similar HCI resistance, which is required by the AOAC test, as well as equivalent spore loading and spore wash-off. Electron microscopy showed that both materials present the same braided microstructure, providing an equivalent physical challenge to the test sterilant. Dacron was more consistent than silk, and did not require extraction prior to spore loading. The extraction method for black waxed silk was variable and incomplete, which may compromise the activity of oxidizing sterilants and add to method variability. Silk was also structurally altered in the presence of oxidizing sterilants and increased sterilant degradation. Dacron did not affect the sterilant and was inert in the presence of oxidizing agents. Dacron sutures are proposed as inert alternatives to silk for evaluating the sporicidal efficacy of oxidizing agents.


Subject(s)
Oxidants/pharmacology , Polyethylene Terephthalates , Spores, Bacterial/drug effects , Sterilization , Hydrochloric Acid/pharmacology , Insect Proteins , Kinetics , Microscopy, Electron , Microscopy, Electron, Scanning , Peracetic Acid/chemistry , Polyethylene Terephthalates/chemistry , Silk , Tensile Strength
17.
Med Eng Phys ; 20(5): 383-92, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9773691

ABSTRACT

A model describing the sieving and transmembrane pressure behavior of plasma filtration is developed and numerically simulated. The model assumes a mechanistic criteria for particle passage through a membrane with cylindrical pores. The initial pore diameter distribution and porosity are assumed to be known. Model inputs include the particle diameter distribution, concentration and total flow rate of the permeate plasma solution. Outputs of the model include transmembrane pressure, the time-averaged sieving coefficients, and size distributions of the deposited particles and accumulated filtrate particles. Optimal filtration is characterized by high, stable sieving coefficients for desired particles, high retention of larger particles and relatively small increases in transmembrane pressure. These characteristics are realized for membranes with mean pore diameters equal to or slightly larger than mean permeate particle diameters. Simulations demonstrate that the incorporation of membrane properties into models of plasma filtration is both significant and readily possible.


Subject(s)
Hemofiltration , Models, Biological , Plasma/physiology , Biophysical Phenomena , Biophysics , Blood Proteins/isolation & purification , Hemofiltration/statistics & numerical data , Humans , Mechanics , Membranes, Artificial , Porosity
18.
J Thorac Cardiovasc Surg ; 114(3): 448-60, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9305199

ABSTRACT

OBJECTIVE(S): The reuse of disposable devices is a potential source of significant cost savings to hospitals. Venous and arterial perfusion cannulas under new and reused conditions were selected to identify the clinical, safety, technical, logistic, and economic issues that must be addressed to realize these savings. METHODS: Single- and dual-stage venous and arterial cannulas from two manufacturers were tested when new, after initial clinical use, and after a single clinical use plus up to nine simulated reuses. Reuse was simulated by end-to-end bending, coupling and uncoupling of the connectors, and by two 1-hour soaks in plasma at 4 degrees and 40 degrees C, respectively. Cannulas were decontaminated and then processed by a peracetic acid-based liquid chemical sterilization system after each use/reuse. Sterilization was validated by eliminating Bacillus subtilis spores from the cannulas on each of five consecutive cycles. Cannulas were tested for physical changes, functional integrity, biocompatibility, and in vivo performance in sheep. A cost analysis was also performed. RESULTS: Sterilization was successfully achieved. Mechanical changes were less than 20% on all variables studied and were undetectable by experienced cardiac surgeons in selective evaluation. No clinically important differences were found between new and reused cannulas, even after nine simulated reuses. Reusing cannulas four times would reduce the cost per procedure from $53 to $19 (64%). CONCLUSIONS: Preliminary data suggest that the perfusion cannulas tested can be safely and efficaciously used five times. Limited reuse of these disposable cannulas is technically feasible and cost-effective. Cannula reuse would result in a small incremental savings; however, with more expensive devices and higher-volume sterilization procedures, the savings could be considerably greater. This program provides a model for evaluation of other single-use medical devices for reuse.


Subject(s)
Catheterization, Peripheral/instrumentation , Disposable Equipment , Animals , Bacillus subtilis , Biocompatible Materials , Catheterization, Peripheral/economics , Cost-Benefit Analysis , Costs and Cost Analysis , Disposable Equipment/economics , Equipment Contamination , Equipment Reuse/economics , Feasibility Studies , Humans , Materials Testing , Perfusion/instrumentation , Sheep , Sterilization , Tensile Strength , Torsion Abnormality
19.
Biomed Instrum Technol ; 31(3): 248-9, 1997.
Article in English | MEDLINE | ID: mdl-9181243

ABSTRACT

The reuse of disposable devices is a potential source of significant cost savings to hospitals. Venous and arterial perfusion cannulae under new and reused conditions were selected to identify the clinical, safety, technical, logistic, and economic issues that must be addressed to realize these savings. Single- and dual-stage venous and arterial cannulae from two manufacturers were tested when new, after initial clinical use, and after a single clinical use plus up to nine simulated reuses. Reuse was simulated by end-to-end bending, coupling and uncoupling the connectors, and by two 1-hour soaks in plasma at 4 degrees C and 40 degrees C, respectively. Cannulae were decontaminated and then sterilized by a peracetic acid based liquid chemical sterilization system following each use/reuse. Sterilization was validated by eliminating Bacillus subtilis spores from the cannulae on each of five consecutive cycles. Cannulae were tested for physical changes, functional integrity, biocompatibility, and in vivo performance in sheep. A cost minimization analysis was also performed. No clinically important differences were found between new and reused cannulae, even after nine simulated reuses. Mechanical changes were less than 20% on all variables studied and were undetectable by experienced cardiac surgeons in selective evaluation. Sterilization was successfully achieved. Reusing cannulae for times would reduce the cost per procedure from $53 to $19 (64%). Perfusion cannulae tested can be safely and efficaciously used five times. This study suggests that reuse would result in a small incremental savings; however, with more expensive devices and higher-volume sterilization procedures, the savings could be exponentially greater. Although this study demonstrates that it may be technically feasible and cost-effective to reuse disposable cannulae, the U.S. Food and Drug Administration does not sanction the reuse of disposable cannulae.


Subject(s)
Catheterization/instrumentation , Disposable Equipment , Perfusion/instrumentation , Animals , Bacillus subtilis/drug effects , Biocompatible Materials , Cardiac Surgical Procedures/instrumentation , Catheterization/economics , Cold Temperature , Cost Savings , Cost-Benefit Analysis , Disinfectants/therapeutic use , Disposable Equipment/economics , Elasticity , Equipment Design , Equipment Reuse/economics , Equipment Safety , Feasibility Studies , Hospital Costs , Hot Temperature , Humans , Peracetic Acid/therapeutic use , Perfusion/economics , Plasma , Sheep , Spores, Bacterial/drug effects , Sterilization/methods , Surface Properties , United States , United States Food and Drug Administration
20.
Artif Organs ; 20(4): 346-54, 1996 Apr.
Article in English | MEDLINE | ID: mdl-9139623

ABSTRACT

Since the application by Thompson et al. in 1975 of plasma exchange for the treatment of 2 patients with familial hyperlipidemia, plasma purification techniques for selective low-density lipoprotein (LDL) removal (i.e., LDL apheresis) have been developed and adopted for the management of this disease. Thermofiltration is one of the LDL apheresis systems that utilizes membrane techniques developed by Nose and Malchesky's group in 1985. This article reviews its rationale, in vitro studies, animal studies, and clinical investigation. Thermofiltration effectively and selectively removes LDL cholesterol while retaining in the plasma physiologically important macromolecules such as albumin and high-density lipoprotein (HDL) cholesterol. Based on the global view of the treatment of atherosclerosis by LDL apheresis, membrane techniques are as effective, safe, and simpler to apply than other methods. Additionally, these methods are effective for the removal of lipoprotein (a) and fibrinogen; thus, they can address the needs in these application areas.


Subject(s)
Arteriosclerosis/therapy , Cholesterol, LDL/isolation & purification , Membranes, Artificial , Plasmapheresis/trends , Animals , Chemical Precipitation , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Cholesterol, VLDL/blood , Clinical Trials as Topic , Dextran Sulfate/chemistry , Dextran Sulfate/metabolism , Filtration , Heparin/pharmacology , Hot Temperature , Humans , Immunosorbents/chemistry , Immunosorbents/metabolism , Molecular Weight , Particle Size , Plasmapheresis/standards , Risk Factors
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