Chemistry: molecular biology and microbiology – Maintaining blood or sperm in a physiologically active state...
Patent
1996-05-20
1998-01-20
Saucier, Sandra E.
Chemistry: molecular biology and microbiology
Maintaining blood or sperm in a physiologically active state...
514 56, 514574, 514822, 210646, 210645, A61M 114
Patent
active
057099936
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention is from the field of medicine and relates to a process for preventing activation of enzyme systems in haemodialysis and in similar procedures with extracorporeal blood circulation by means of sequential anticoagulation.
TECHNICAL PROBLEM
There was a need for a simple and effective way of preventing the activation of enzyme systems in extracorporeal blood circulation in haemodialysis and in similar procedures.
PRIOR ART
Haemodialysis partly replaces the kidney function in patients with renal failure. A scheme of haemodialysis is shown in FIG. 1. The blood stream 7 of the patient flows along the arterial blood line by means of a blood pump 1. An anticoagulant 2 is added to the line, then blood passes into an arterial bubble trap 3 (preventing the invasion of air into the dialyser 4) and into a dialyser 4. From the dialyser 4 blood passes through a venous bubble trap 6 (preventing the entry of air into the patient) along the venous blood line into the patient's body. From the other side of the membrane of the dialyser 4 the flow of dialyse solution 5 flows into the dialyser 4. Solutes and water pass the semipermeable membrane of the dialyser 4 from the plasma into the dialyse solution 5 and vice versa.
At the contact of blood with artificial surfaces such as dialyser membranes or surfaces of blood tubing, different enzyme systems in blood are activated. Most important is the activation of thrombocytes and of the coagulation system, which leads to total blood coagulation in the extracorporeal blood circulation. For the prevention thereof anticoagulants and anticoagulating processes must be applied during haemodialysis or procedures similar thereto. A standard routine anticoagulation during haemodialysis or similar procedures with extracorporeal blood circulation is anticoagulation with heparin.
Other anticoagulants are also used such as prostacyclin, sodium citrate, nafamostat mesylate, heparin-free haemodialysis etc. These methods, however, are either technically much more sophisticated, e.g. the one with citrate which is not appropriate for chronic use either, or quite expensive and thus their use is limited only to patients with the risk of bleeding, for whom heparin is not suitable.
On the other hand the extent of activation also depends upon the dialyser membranes used. Now two main groups of membranes are used i.e. biocompatible (synthetic) membranes and bioincompatible (cellulose) membranes. Cellulose membranes which are much cheaper, are used in more than 80% dialysis patients, but for the said membranes complement activation is characteristic which is most pronounced in the 15th minute of haemodialysis. The complement activation is essentially smaller when synthetic membranes are used. The complement activation has adverse effects in haemodialysis of the patients having acute and chronic renal failure, but because of rather high costs less than 20% of dialysis patients are dialysed using synthetic membranes which do not activate a complement.
An ideal solution would be the use of wholly inert membranes which however do not exist so far.
SUMMARY OF INVENTION
The object of the invention is a process for preventing the activation of enzyme systems in extracorporeal blood circulation in haemodialysis and in similar procedures such as coagulation and activation of complement system or bradykinin system, by means of sequential coagulation, wherein in the first 15 to 30 minutes of haemodialysis or of a similar procedure, sodium citrate or nafamostat mesylate, preferaly sodium citrate, is given into the dialysis line as the anticoagulant, then the adding of the heparin-free anticoagulant is stopped and there is started with the addition of heparin in a conventional total dose, this addition being carried out till the end of the dialysis.
The inventive process is universal for routine work.
BRIEF DESCRIPTION OF DRAWING
FIG. 1 illustrates a haemodialysis scheme wherein numeral 1 represents the blood pump, 2 the anticoagulant, 3 and arterial bubble trap, 4 a dia
REFERENCES:
patent: 5032615 (1991-07-01), Ward et al.
patent: 5407581 (1995-04-01), Onodera et al.
Wallmark A. et al., Artificial Organs 8(1): 72-81 (1984).
Akizawa T. et al., Nephron 64(3): 376-81 (1993).
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