DE3243523A1 - Device for the removal of toxic substances from blood - Google Patents

Abstract

In a device for the removal of toxic substances from blood in which blood is continuously removed from the body, plasma is filtered out by splitting of the bloodstream into a filtration residue stream and a filtrate stream, the plasma is purified and, after replacement of the volume lost on purification by a replacement solution and addition of banked plasma, is combined again with the filtration residue stream and the combined stream is passed back into the body, the molecular fraction containing the toxic substances is filtered out of the filtrate stream for purification of the plasma. In this way, a considerable part of the autologous plasma is retained with a comparatively small expenditure. <IMAGE>

Description

Device for removing toxins from the blood.

The invention relates to a device for removing toxins from the blood with a plasma filter to continuously filter plasma out of a blood stream taken from the body with splitting of the blood stream into a filter residue stream and a filtrate stream, a means for removing the toxins from the Filtratstrom, a device for replacing the toxins when excreted lost volume by a substitution solution and a device for combining of the filtrate stream with the filter residue stream for the subsequent reintroduction in the body.

The toxins under consideration here are particularly circulatory Immune complexes, antigen-antibody complexes, toxins with high protein binding and Cell decay products.

The molecular sizes of these poisonous bodies are approximately between 0.5 and 3 Million daltons.

The plasma filters designed for the purpose of such devices have permeability curves such that they are below 3 million Daltons The smaller the molecule size, the larger the proportions. The plasma divides in one stream of filtrate and one the blood cells that completely are retained, containing filter residue stream.

Adsorption is used to remove toxins from the filtrate stream by means of activated carbon or other adsorbents and precipitation of the poisonous bodies (cryofiltration) and removal of precipitation.

However, the outlay on equipment required for this is very large.

Otherwise, the process is still at the experimental stage.

In practice, the filtrate is often simply completely discarded and replaced by substitution solution.

The invention is based on the object, the toxins with simpler Eliminate funds from the filtrate.

To this end, the invention envisages a device for excretion of the toxins one of the molecular fractions from the filtrate stream containing the toxins filtering off filter.

The invention thus dispenses with physico-chemical and chemical Methods of separation and separates only mechanically, taking advantage of the fact that the poisonous bodies collect in a certain, limited grain size range. This means that the plasma components falling into this area are also lost. But these are precisely those that are particularly light and fairly can be replaced entirely from canned food.

Incidentally, also arise according to the known methods, only differently than according to the grain size, losses of plasma substance.

The effort for this solution is not much greater than for the plasma exchange devices, in which no toxins are removed from the filtrate, but the filtrate, as mentioned, completely discarded and replaced by substitution solution replaced will. The result, however, is that the patient is 1/2 to 2/3 or even more of his gets its own plasma back from the filtrate.

A filter for all use cases could have a permeability limit from 60,000 to 100,000 daltons.

Almost all poisonous bodies are larger. Essential plasma components, such as numerous hormones, coagulation factors, low molecular weight protein fractions, e.g. B. albumin, are smaller and are retained in the blood, as are those dissolved in the serum Substances.

With regard to the latter, efforts will be made to control the plasma flow to divide on the filter so that no more serum flows off with the residue than is necessary for its transport.

Filters of the specified permeability also hold the Immunoglobulins in the blood, which are gladly excreted in the event of poisoning.

In principle, however, it is also possible for various types of poisoning use different, the respective poisonous body size adapted filters to the to obtain the greatest possible preservation of one's own blood plasma.

The said means for replacing the lost volume is preferably downstream of the filter in the filtrate stream.

In the following the invention is based on a drawn example further clarified.

A blood line 1 connected to a vein leads to a plasma filter 2, in which the bloodstream is divided and from which he passes through a filtrate line 3 and a filter residue line 4 continues to flow.

The plasma filter 2 is z. B. from the under the name "Hemaplex BT 900 "(company DIDECO s.p.a., I-41037 Mirandola) known type. The plasma filter lets through molecules below 3 million daltons, and the more the smaller the molecule it is.

The blood cells are retained and flow with part of the Blood plasma in the filter residue line 4 further.

The filter residue line 4 opens into a droplet chamber 5.

This is also of a known type. By adding air-free from below The liquid, which will be described in more detail, becomes a body-compatible concentration therein restored. A return line 6 then leads from the drop chamber 5 again into a vein in the body.

The filtrate line 3 leads via an expansion chamber, again known 7 to a filter 8. The filter 8 is e.g.

from the under the name "Amicon Diafilter 20-40" (Amicon Corporation, Lexington / Mass., USA) known species, but with greater permeability; the permeability limit should be, for example, 70,000 to 80,000 daltons.

The residue of the filter 8 containing the poisonous bodies passes over a discharge line 10 provided with a hose pump 9 into a vessel 11. It is discarded.

The filtrate of the filter 8 is through one with an expansion chamber 12 and a hose pump 13 provided line 14 to a further drop chamber 15 funded. In this, 16 substitution solution, if necessary

with canned plasma added in the same amount as she is discarded as filter residue in the vessel 11. The same amount is set by means of one in a connecting line 17 between the two gob chambers 15 and 5 arranged peristaltic pump 18, the mechanical part of which is the same as that of the peristaltic pump 9: the hose of the discharge line 10 and the hose of the Connecting line 17, both of which have the same diameter, are over the same Out pump segment of a roller pump.

The device delimits the molecular size fractions in which the poisonous bodies are to be found, with the plasma filter 2 in principle from above and with the filter 8 as closely as possible from below and eliminates them. The plasma filter 2 in the filtrate line 3 leaving the filtrate stream settles behind the filter 8, reduced by the part excreted there as the filtrate stream of the filter 8 continues in the line 14 and is after replacement of the eliminated part by the Substitution solution in the drop chamber 15 via the connecting line 17 in the Droplet chamber 5 reunited with the filter residue flow of the plasma filter 2, so that through the return line 6 finally largely endogenous blood in can be returned to the patient's bloodstream. Those in the excreted Molecular fractions contained and thus lost plasma components can essential parts from plasma reserves on the way via the substitution solution be replaced.

Claims (3)

Claims: Device for removing toxins from the Blood with a plasma filter (2) for the continuous filtering of plasma from one of the Blood stream taken from the body (1), splitting the blood stream into a filter residue stream (4) and a filtrate stream (3,14,17), a device (8) for separating the Toxins from the filtrate stream (3,14,17), a device (15,16) for replacement the volume lost in the elimination of toxins through a substitution solution and means (5) for combining the filtrate stream (3,14,17) with the filter residue stream (4) for the subsequent reintroduction (6) into the body, characterized in that that the device (8) for eliminating the toxins a containing the toxins Filter (8) filtering off molecular fractions from the filtrate stream (3,14,17). 2. Apparatus according to claim 1, characterized in that the filter (8) has a permeability limit of 60,000-100,000 Daltons. 3. Apparatus according to claim 1 or 2, characterized in that said means (15,16) for replacing the lost volume in the filtrate stream (3,14,17) is connected downstream of the filter (8).