Surgery – Blood drawn and replaced or treated and returned to body – Constituent removed from blood and remainder returned to body
Patent
1988-11-15
1991-02-05
Pellegrino, Stephen C.
Surgery
Blood drawn and replaced or treated and returned to body
Constituent removed from blood and remainder returned to body
494 17, A61M 3700, B04B 500
Patent
active
049901320
DESCRIPTION:
BRIEF SUMMARY
METHOD AND APPARATUS FOR PLASMAPHERESIS
This invention relates to a method and an apparatus for carrying out plasmapheresis.
Half of the blood is so-called plasma, a yellowish liquid containing various proteins. The other half of the blood contains cellular material, such as red blood cells, white blood cells and platelets. Plasma is used in transfusions and as raw material for the pharmaceutical industry in connection with the production of pharmaceuticals, such as albumin, gamma globulin and Factor VIII (haemophilia medicament).
Plasma may be obtained in pure form by centrifugation, about 200 ml of red blood cells and about 250 ml of plasma being obtainable from a donated blood unit of about 500 ml, including anticoagulant. The plasma fraction can also be obtained by plasmapheresis, in which the blood of the blood donor is withdrawn and centrifuged whereupon the red blood cells are returned to the donor. Plasmapheresis is advantageous because it is a cheaper method of obtaining plasma in the case where red blood cells are not needed, because each withdrawal yields more plasma (in total 600 ml in the case of two-cycle plasmapheresis), and because plasmapheresis can be carried out more frequently than blood donation.
Relatively expensive automated equipment for plasmapheresis is known, such as the Haemonetic or Haemoscience machines which are made in the United States.
Apart from the high cost for the plasma production, these machines are only suitable for withdrawal in large blood banks, and for that reason plasmapheresis has to be carried out manually in most cases, especially when withdrawal is carried out in mobile units.
When plasmapheresis is carried out manually, blood is withdrawn from a blood donor (BG) and conveyed through a flexible tube to a bag positioned on a combined weighing scale and rocker. The scale discontinues the blood withdrawal and gives a warning when a sufficient amount of blood (about 450 ml) has been withdrawn, and the rocker mixes the blood with the anticoagulant. Thereupon the flexible tube is cut off under the action of heat so that the ends of the flexible tube are sealed, and the bag is carried to a centrifuge in which separation takes place. In the next step the bag is transferred to a squeezing device in which the plasma collected in the upper portion of the bag is expelled into a different bag. Saline is then added to the original bag containing the blood cells which are retransfused to the blood donor. Normally, this procedure is repeated with one and the same blood donor, that is, so-called two-cycle plasmapheresis is carried out, yielding 500-600 ml of plasma, including the originally added anticoagulant.
This system has many disadvantages: flexible tubes are required; the fractions held separated only under the action of the normal gravity, which means that high qualitY is not achieved, that is, that cellular material is left in the plasma. In order that high quality may be achieved, it is necessary to carry out repeated centrifugations and to transfer the plasma to a further secondary bag, which means added costs; separated from the blood donor; recruit persons for donating blood, which takes about 15 minutes, but it is more difficult to find persons who can sacrifice one hour.
The object of the present invention is to provide a method and an apparatus permitting small-scale semi-automated utilization of plasmapheresis e.g. in mobile units, such as blood buses, and having the following advantages over manual plasmapheresis:
This object is achieved by a method and an apparatus as defined in the claims.
When carrying out the method according to the invention, a centrifuge of the type described in Swedish patent application No. 8602242-3 may be used. This patent application discloses a centrifuge in which the processing space of the rotor includes an annular separation compartment and a central compartment. The volume of the separation compartment can be reduced during the centrifugation to displace a centrifugally separated component into the central compartment. An
REFERENCES:
patent: 4268393 (1981-05-01), Persidsky
patent: 4421503 (1983-12-01), Latham, Jr. et al.
patent: 4482342 (1984-11-01), Lueptow et al.
Unger Peter
Westberg Eric
Omega Medicinteknik AB
Pellegrino Stephen C.
LandOfFree
Method and apparatus for plasmapheresis does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for plasmapheresis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for plasmapheresis will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-8221