JPS6061006A - Process for constructing mass transfer apparatus using hollow yarn - Google Patents

Abstract

PURPOSE:To construct a mass transfer apparatus for medical use having satisfactory sealing performance using hollow yarn by forming fluid passage forming members by at least one continuous annular protruded line formed to one body to an internal periphery of the fluid passage forming members, pressing the members to partition wall of the passage to establish sealing. CONSTITUTION:Both ends of a hollow yarn membrane 5 for exchanging gas are supported liquid-tightly by partition walls 5a, 5b in attaching covers 8, 9. A sealing mechanism is formed by fitting the fluid passage forming members 1a, 1b formed by the annular protruded lines 21, 22 to one body simultaneously or separately to the partition walls 5a, 5b respectively by screw fitting wherein the partition walls 5a, 5b are heated by allowing fluid e.g. air, N2, gaseous CO2, methane, etc. heated at 90-110 deg.C to contact for 10-300sec with the partition wall, or the partition wall is heated at 45-60 deg.C by infrared rays or by other method. The screw rings 19, 20 are fastened and the annular protruded line 21 bites into the partition walls 5a, 5b to establish sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION 10. Technical Field of the Invention The present invention relates to a hollow fiber type mass transfer device A3 and a method for manufacturing the same. To explain in detail, artificial kidney,
This invention relates to a method of manufacturing a medical hollow fiber mass transfer device such as an artificial lung.

Prior Art Conventionally, a hollow fiber mass transfer device, for example, an oxygenator, has a hollow fiber bundle consisting of a cylindrical housing, a large number of hollow fiber membranes for gas exchange inserted into the housing, and the hollow fiber membranes. an oxygen chamber formed by the outer surface of the housing and the inner surface of the housing, an oxygen supply port and an outlet communicating with the oxygen chamber, and an oxygen chamber that supports each end of the hollow fiber membrane, respectively. A hollow fiber oxygenator is known, which is comprised of a partition wall that isolates the membrane from the membrane, and a blood inlet and outlet that communicate with the internal space of each of the hollow fiber membranes.
38.947, JP-A No. 58-86.171 and JP-A No. 58-86.172). Further, the artificial kidney is formed by a cylindrical housing, a hollow fiber bundle consisting of a large number of hollow fiber membranes for dialysis inserted into the housing, an outer surface of the hollow fiber membranes, and an inner surface of the housing. A dialysis chamber, a dialysate supply port and a discharge port communicating with the dialysis chamber, a partition wall supporting each end of the hollow fiber membrane and separating it from the dialysis chamber, and communicating with the internal space of the hollow fiber membrane. A hollow-fiber artificial kidney consisting of an inlet and an outlet for blood is known (Chemistry Review Vol. 21, "Medical I-sized Chemistry")
pp. 144-146, published by Gakkai Publishing Center Co., Ltd. on November 25, 1978).

Thus, the inlet and outlet for the liquid to be treated in these hollow fiber mass transfer devices are formed by headers (eg, blood distribution members) fixed to both ends of the cylindrical housing. As shown in FIG. 1, the header 1 normally has a seal between the side surface of the blood outflow (input) chamber 2 and the partition wall 3 by means of a series installed in the annular groove 3 to prevent fluid leakage.
An O-ring 4 made of rubber or the like was used to connect the partition wall 5 to the IB.

However, with such a sealing method, [J1 silicone rubber is not only expensive, but also the work to fit the O-ring 4 well into the annular groove 3 is complicated, and moreover, the O-ring 4 may be damaged during assembly work. There was a risk that the seal would come off the annular groove 3, resulting in poor sealing.

(6) Purpose of the Invention Therefore, the purpose of the present invention is to provide a novel method for manufacturing a hollow fiber type mass transfer device.

Another object of the present invention is to provide a method for manufacturing medical hollow fiber mass transfer devices such as artificial kidneys and artificial lungs that have good sealing properties.

The above objects include a cylindrical housing, a hollow fiber bundle consisting of a large number of hollow fiber membranes for mass transfer inserted into the housing, and a material formed by the outer surface of the hollow fiber membrane and the inner surface of the housing. a transfer chamber and a first chamber communicating with the mass transfer chamber;
a fluid supply inlet for mass transfer and a JJI outlet; a compartment that respectively supports each end of the hollow fiber membrane and isolates it from the mass transfer chamber; In a method for manufacturing a hollow fiber mass transfer device comprising a second mass transfer fluid inlet and an outlet formed by a flow path forming member and communicating with the internal space of the hollow fiber membrane, the inner peripheral edge of the flow path forming member A flow path forming member in which at least one continuous annular protrusion is integrally formed on the part is 30 to 7.
This is achieved by a method for manufacturing a hollow fiber type mass transfer device, characterized in that annular grooves corresponding to the annular protrusions are formed and sealed in the partition wall by pressing against the partition wall heated to a temperature of 0°C. .

Further, in the present invention, the annular protrusion of the flow path forming member has a length of 1 mm.
This is a method for manufacturing a hollow fiber type mass transfer device having the above height. Further, the present invention is a method for manufacturing a hollow fiber type mass transfer device in which the partition wall is made of polyurethane. Furthermore, the present invention provides a curing agent in which the polyurethane is a mixture of a prepolymer of 4,4'-diphenylmethane diisocyanate and 11 difunctional castor oils, a polyfunctional polypropylene glycol with a Ninomiya castor oil derivative, and an amino alcohol. The claim is a method for manufacturing a hollow fiber mass transfer device, which is a mixture of The present invention is a method for manufacturing a hollow fiber type mass transfer device in which the mass transfer device is an artificial lung or an artificial kidney. Further, the method of manufacturing a hollow fiber type mass transfer device is disclosed by Kimi YC Ming, in which heating is performed by contact with a heated inert gas body.

(3) Specific structure of the invention A specific example of the invention will be described below with reference to the drawings in Appendix A.

FIG. 2 shows a hollow fiber oxygenator as an example of a mass transfer device according to the present invention. In other words, people's lungs are
The housing 6 is attached to the housing 6 by inserting the fittings 1nj1 into 4, and the housing 6 is provided with ring-shaped male screws 8 and 9 at both ends of the cylindrical body 7. , a large number of hollow fiber membranes for mass transfer (hollow fiber membranes for gas exchange), for example 10,000 to 60,000 wood, are spread throughout the housing 6.
are spaced parallel to each other along the longitudinal direction of the phase H. Then, both ends of the hollow fiber membrane 5 for gas exchange are separated from the partition walls 5a, 5 with the respective openings 1 in the covers 8, 9 not being closed.

b is supported in a liquid-tight manner. In addition, each of the partition walls 5
a and 5b constitute an oxygen chamber 11, which is a mass transfer chamber, together with the outer circumferential surface of the hollow fiber membrane 10 and the inner surface of the housing 6, close this, and connect the hollow fiber membrane 'I' for dregs exchange.
A second mass transfer fluid space C formed inside the oxygen chamber 11 separates the oxygen chamber 11 from a blood circulation space (not shown).

One side of the recovery 8 is provided with an inlet 12 for supplying oxygen, which is the first mass transfer fluid. An outlet 13 is provided to take out the other outlet (1112 m in the cover 9).

It is preferable that the inner surface of the cylindrical main body 7 of the housing 6 is provided with a restricting portion 14 for restricting the diaphragm and protruding from the center in the axial direction. However, the restraint part 14 is formed integrally with the cylindrical body on the inner surface of the metering body 7, and is made up of a large number of hollow fibers 11010... which are seeded inside the cylindrical body 7. The outer periphery of the yarn bundle 15 is tightened. In this way, the hollow fiber bundle 15 is narrowed at the center in the axial direction J3 to form a narrowed portion 16, as shown in FIG. Therefore, the filling rate of the hollow fiber membranes 10 differs in each part along the axial direction, and is highest in the central part. In addition, the filling rate of each part, which is difficult for reasons to be described later, is as follows. Mari", center aperture part 16
The filling rate is about 60 to 80%, and other cylindrical wood bodies 7
The filling rate at both ends of the hollow fiber bundle 15, that is, the outer periphery of the partition walls 5a, 51+, is about 2%.
It is 0-40%.

The hollow fiber membrane 10 is made of a porous polyolefin resin such as polypropylene or polyethylene for use in an artificial lung, and polypropylene is particularly preferred.Hereinafter, the medical substance transfer device of the present invention will be explained using an artificial lung as an example. . This hollow fiber membrane 10 for an artificial lung has a large number of pores communicating between the inside and outside of the wall. And its inner diameter is about 100~i, oooum 1 thickness is about 10~50um
1. The average pore diameter is about 200 to 2,000, and the porosity is about 20 to 80%. When a hollow fiber membrane made of this J:Ut1 polyolefin resin is used, gas movement is performed as a volumetric flow, so the membrane resistance during gas movement is small and the dregs exchange performance is significantly improved. However, a hollow fiber membrane C made of silicone can also be used.

Furthermore, the porous polypropylene and polyethylene ethylene as materials for the hollow fiber membrane 10 can be used as they are in the oxygenator.
IJ';c<, it is desirable to coat the surface that comes into contact with blood with an antithrombotic material. For example, materials with excellent gas permeability such as polyalkyl sulfone, ethyl cellulose, and polydimethylsilane (coxane) are treated to a thickness of about 1 to 20 μm. In this case, the gas permeability of the hollow fiber membrane 10 is not affected. If the membrane pores are covered to a certain extent, water vapor evaporation in the blood can be prevented. In such cases, microbubbles may flow into the blood, but as mentioned above, the membrane pores are coated with antithrombotic material. If it is, then this risk will not occur.Furthermore, needless to say, it is useful in preventing blood coagulation (occurrence of microtats).

Next, the above-mentioned partition walls 5a and 5b are formed by hoovering.

As mentioned above, the partition walls 5a and 5b perform the important function of forming a corner between the inside and outside of the hollow fiber membrane 1°.

Normally, the partition walls 5a and 5b are made by pouring a highly polar polymer botting agent, such as 311 polyurethane, onto the inner wall surface at both ends of the housing 10 using a centrifugal injection method, and allowing it to harden.Further details First, a large number of hollow fiber membranes 10 longer than the length of the housing 1...
After filling both open ends with a resin with high viscosity, they are placed side by side in the cylindrical main body 7 of the housing 6. After this, take out the covers 8, 9 (7 or more man-sized covers) and completely cover both ends of the hollow fiber membrane 10... While rotating the polymer cutting agent flows in from both ends.When the resin hardens after pouring, the mold cover is removed and the outer side of the resin is cut with a sharp knife to form the hollow fiber membrane 10.・Expose both open ends to the surface.

In this way, partition walls 5a and 5b are formed.

In the above embodiment, the center portion of the hollow fiber bundle 15 is the restraining portion 14.
Because it is narrowed down and expanded at both ends,
In the constricted portion 16, the filling rate of the hollow fiber membranes 10... increases, and inside the cylindrical body 7, the hollow fiber membranes 10...
is evenly distributed. Therefore, as compared to the case where the constriction part 16 is not formed, a stable flow in which oxygen gas is uniformly dispersed is formed, and as a result, the exchange efficiency of oxygen and carbon dioxide gas is increased. In addition, the area of both parts of the housing 6 is
6, the oxygen gas flow rate in this part changes rapidly, and as a result, the oxygen gas flow rate increases,
The effect of increasing the movement speed of carbon dioxide gas also occurs.

Note that the filling rate of the hollow fiber membranes 10 in the constricted portion 16 is preferably about 60 to 80%, and the reason for this is as follows. That is, if the filling rate is less than about 60%, there will be a portion where the restricting portion 14 cannot be narrowed down, and the distribution of the hollow fiber membranes 10 will become non-uniform, causing dill ringing, which will deteriorate the performance.

Furthermore, it is difficult to position the hollow fiber bundle 15 at the center of the upper part of the tube, which creates problems. On the other hand, when the filling rate exceeds about 80%, the hollow fiber membrane 10 in contact with the restraint part 14
. . . is pushed too hard and gets used to it, which stops the blood from flowing and causes a drop in efficiency (not only does it not work properly, but it also causes residual blood. Furthermore, when inserting the hollow fiber bundle 15 during processing, it is difficult to insert the bundle 15 tightly. It is difficult to work (because it becomes difficult).

In addition, the filling rate in the cylindrical body 2 was set to about 30-60%, but the reason for this is that if the filling rate is less than about 30%, the hollow fiber membrane 10... in the cylindrical body 2 (... As a result, the exchange efficiency decreases.It also becomes difficult to process.On the other hand, if the filling rate exceeds 60%, the hollow fiber membranes 10 will stick to each other, which is also bad for performance. This is because it has an impact.

Moreover, the filling rate C at the outer periphery of the partition walls 5a and 5b is approximately 20
~40%, but the reason for this is less than about 20%,
The distribution of the open ends of the hollow fiber membranes 10 tends to become non-uniform due to processing, resulting in problems such as non-uniform blood flow distribution and blood clots. On the other hand, when the filling rate exceeds 40%, the hollow system membrane 1
0... This is because close contact occurs between the partition walls 6 and 7, and a portion of the material of the partition wall 6.7 that is not filled with the botting agent appears, causing leakage.

In the above embodiment, only the restraining portion 14 partially protrudes from the inner surface of the housing 6, but the present invention is not limited to this, and a link-shaped member may be provided as a separate member, or a cylindrical body may be provided. An annular recess may be formed in the center, or the inner diameter of the medium heat section may be the smallest, and the inner diameter may be tapered to become larger at both ends.

The outer periphery of the partition walls 5a, 5b is 1 mm or more, preferably 1.0 to 2.0 mm, at the inner peripheral edge. The flow path forming portion +J1a, 1b having a height of Qmm and integrally formed with at least one continuous annular protrusion 21°22 is threaded with a screw ring 19.
An inflow chamber 2nJ3 and an outflow chamber 2b for blood, which is a second mass transfer fluid, are formed by screwing and fixing 20 to the covers 8 and 9, respectively.

In the flow path forming portions IJ1a and 1b, a population 25 i1'i of blood, which is a second mass transfer fluid, and an outlet 26 are formed, respectively, and air handling holes 27 and 28 are provided. There is. In addition, in Fig. 2, on each day there are 33. '34. ．． 35.36 has been taken.

The sealing mechanism is thus formed as follows. That is, 40-120°C, preferably 90-110°C
a fluid heated to 'C;
Nitrogen, carbon dioxide, methane, etc. for at least 10 seconds, preferably 10
The partition wall 5a is heated by contacting the partition wall 5a for 30 to 70 C) seconds, or by infrared heating or other methods.
In a state heated to 0°C, preferably 45 to 60°C, flow path forming members 1a and ib each formed with seven annular protrusions 21 and 22 as described above are applied to the partition walls 5a and 5b, respectively, at the same time or By screwing them in separately, the screw rings 19 and 20 are tightened and the annular protrusion 21 is attached to the partition wall 5a.
Seal is performed by embedding/v. It goes without saying that the partition wall may be heated after the annular protrusion of the flow path forming member is brought into contact with the partition wall.

Polycarbonate 1- is preferred as the flow path forming member of the mass transfer device according to the present invention. Moreover, polyurethane is preferable as the material for the partition walls.

As the polyurethane, any of prepolymer polyurethane, polyisocyanate polyurethane, isocyanate-modified polyurethane, etc. can be used, but prepolymer polyurethane is usually preferably used. Prepolymer polyurethanes include, for example, 4,4'-Schiff1nylmethane diisocyanate and trifunctional castor oil derivatives (e.g. polypropylene glycol ester of ricinoleic acid, molecular
540) with prepolymer (NCO/'0H=1:
1 to 1.5), trifunctional castor oil derivative and polyfunctional polypropylene glycol (molecular ff 12,000 to 3°00
0> and amidial alcohol (weight ratio 50-70
: 15-25: 15-25) and a curing agent having almost the same number of functional groups as J: sea urchin, for example 65:35-59:
It has a weight ratio of 41 to 711, can be cured at room temperature, has appropriate elasticity, and has excellent adhesive properties.

The above is an example of an oxygenator; in this oxygenator, if a heat exchanger is coaxially connected to one end of the oxygenator, as described in Japanese Patent Application No. 115,868/1980, this heat exchanger It goes without saying that the flow path forming member used at the other end (the end opposite to the oxygenator) can also be firmly sealed in the same manner.
It is υ.

In addition, as hollow fiber membranes between medical material transfer stations with a structure similar to the above-mentioned oxygenator, regenerated cellulose membranes using the copper ammonia method, regenerated Rolulose II membranes using the cellulose acetate method, and polymethyl methacrylate membranes are used as hollow fiber membranes. An artificial kidney can be obtained by using hollow fiber membranes such as complex membranes, polyacrylic nitrile membranes, nitrogen-denyl alcohol composite membranes, etc.

FIG. 3 shows a hollow fiber artificial kidney as another example of the mass transfer 118II device 6 according to the present invention. That is, the artificial kidney is equipped with a housing 46, which is provided with male screw covers 48 and 49 at both ends of a cylindrical main body 4-/17, and inside the housing 46, , a large number of e.g. 5°OOOO to 10,000
Hollow fiber membrane for mass transfer (hollow fiber for hemodialysis Ia>5o
are spaced apart from each other in parallel along the longitudinal direction of the housing 46. Both ends of the hollow fiber membrane 50 are mounted in the covers 48 and 49 and supported in a liquid-tight manner by the partition walls 45a and 45b, respectively, with the openings not being closed. Moreover, each of the above-mentioned isolation walls 45a.

45b constitutes a dialysis chamber 51, which is a mass transfer chamber, between the outer circumferential surface of the hollow fiber membrane i 50 and the inner surface of the housing 46, closes this chamber, and connects the hollow fiber membrane i 50 to the inner surface of the housing 46. A partition wall is used to separate the blood circulation space, which is a second mass transfer fluid space formed inside the dialysis chamber 51, from the dialysis chamber 51.

On one side, the cover 48 has an IJ and an inlet 52 for supplying dialysate, which is the first mass transfer fluid.The other side has an outlet II 53 on the cover 49 for discharging the dialysate. The installation is done.

The outer surface of the partition walls 4.5a, 45b is 1 m along the inner peripheral edge.
m or more, preferably 1.0 to 2. A flow path forming member 418, 4 lb having a height of On+m and integrally formed with at least one continuous annular protrusion 51.52 is brought into contact with the partition walls 45a, 45b, and a threaded ring 59. 6
By screwing and fixing 0 to covers/l-8 and 49, an inflow chamber 42a and an outflow chamber 42b for blood, which is the second mass transfer fluid, are respectively formed. An inlet 65 and an outlet 66 for blood, which is the second mass transfer fluid, are formed in the flow path forming members 41a' and 41b, respectively.

Such a sealing mechanism is formed in the same manner as in the case of an oxygenator, as described above. In addition, the material that forms the partition walls is
The same is true for artificial lungs.

The medical mass transfer device of the present invention having the above configuration is used by being incorporated into an extracorporeal circulation circuit for a second mass transfer fluid, such as blood. For example, in the case of an artificial lung, blood is introduced from the blood inlet 25 by a blood pump (not shown) and passes through each hollow fiber membrane 10 through the blood inlet chamber 2a, while the inlet 12 The element introduced into the first mass transfer chamber 16 is applied, carbon dioxide gas is discharged, and then the blood passes through the blood outflow chamber 2b and flows out [-,!
It is discharged from 26. 4 Jl of oxygen in the first mass transfer material 16 is discharged to the outlet 13 together with carbon dioxide gas.

In the case of an artificial kidney, the principle is almost the same, and dialysate is used instead of oxygen.

Note that blood is introduced from the inlet 12 in the opposite direction, and the blood is introduced into the mass transfer chamber 1.
6 is led out through the outlet port 13, while a mass transfer fluid such as oxygen is allowed to flow in from the blood inflow chamber 2a,
It may be passed through the hollow fiber membrane 10 and discharged from the outflow chamber 2b.

Next, the present invention will be explained in more detail with reference to Examples.

Examples 1-8 a3 J, and Comparative Examples 1-2 about io, oo
Hollow fiber membrane 50 of o copper ammonia cellulose regenerated fibers
Using this method, a hollow fiber type artificial kidney as shown in FIG. 3 was manufactured. In this case, the partition wall is a prepolymer (NCo101-1=1
:1-1.5), trifunctional castor oil derivative and polyfunctional polypropylene glycol (molecular ff12.000-3.0
00) and amino alcohol (mffi ratio 50)
~70: 15~25: 15□-25) and a hardening agent of 65~5 so that the number of functional groups almost matches.
A mixture of 9:35:41 by weight was used.

In addition, the sealing mechanism uses a continuous annular protrusion having an acute angle in cross section and a height of 1 mm integrally formed in the flow path forming members 41a and 41b, and air heated to 110'C is applied to the partition wall 45a at 30°C. The outer corner wall 45a was heated to a predetermined temperature and the screw ring 59 was tightened. The other end was also sealed in the same manner.

When a liquid tightness test was conducted on the artificial kidney obtained by the above method, the results shown in Table 1 were obtained.

(Left below) ■1 Specific Effects of the Invention As described above, the method for manufacturing a mass transfer device according to the present invention provides at least one
A flow path forming part (4) in which continuous annular protrusions are integrally formed, and a partition wall (11) that is pressed into a partition wall heated to a temperature of 30 to 70°C.
Since an annular groove corresponding to the annular convex strip is formed and sealed in the partition wall by twisting, there is no need to use an O-ring as in the conventional material transfer 1PIl mounting. There is no need to fit the O-ring, making it extremely simple! ) A perfect seal can be achieved in one method, which not only simplifies the assembly process, but also eliminates the occurrence of defective products due to O-ring misalignment.

Further, when the annular protrusion formed on the inner peripheral edge of the flow path forming member has a height of 1 mm or more, the IJI, particularly the sealing effect, is low. Further, when the partition wall is a mixture of polyurethane, particularly a prepolymer such as 4,4'-diphenylmethane diisocyanate and a trifunctional castor oil derivative, and a curing agent consisting of a mixture of trifunctional polypropylene glycol and an amino alcohol, By heating, the annular protrusions become easier to bite into the partition wall, further increasing the sealing effect. In addition, workability is improved by using a heated inert gas as the heating method.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a sealing mechanism of a conventional medical substance transfer device, FIG. 2 is a sectional view showing an example of an artificial lung according to the present invention, and FIG. 3 is an example of an artificial kidney according to the present invention. FIG. Ia, 1b, -41a, , 4 lb -=-
Channel forming member, 2a, 2b, 42a, 42b・
...first fluid inlet/outlet, 6,46...housing, 7.47...cylindrical body, 10.50...hollow fiber membrane,
5a, 5b, 45a, 45b --- partition wall, 12
．． 13; 52, 53... first mass transfer fluid inlet/outlet, 21, 22, 51.52... annular protrusion, 29
．． 30,59.60... annular groove, 25.26,65.
66...Second fluid power inlet/outlet. Figure 3

Claims (1)

[Scope of Claims] (1) A cylindrical housing, a hollow fiber bundle formed from a large number of mass transfer hollow fiber membranes inserted into the housing, and an outer surface of the hollow fiber membrane and an inner surface of the housing. a mass transfer chamber formed by J: a first mass transfer fluid supply port and a first mass transfer fluid outlet communicating with the mass transfer chamber; 1fi away from the material transfer room
A hollow space formed by a partition wall and a second mass transfer fluid inlet and outlet formed by a flow path forming member attached to the end of the housing and communicating with the inner space of the hollow fiber membrane is used for mass transfer. In the method for manufacturing a device, the partition wall is heated to a temperature of 30 to 70° C., the flow path forming member having at least one continuous annular protrusion integrally formed on the inner peripheral edge of the flow path forming member. A method for producing a hollow fiber type mass transfer device, characterized in that an annular groove corresponding to and covering the annular protrusion is formed in the partition wall by pressing the partition wall to seal the partition wall. (2) The method for manufacturing a hollow fiber material 88 charge according to claim 1, wherein the annular protrusion of the flow path forming member has a height of 111t11 or more. (3) The method for manufacturing a hollow fiber mass transfer device according to claim 1, wherein the partition wall is made of polyurethane. (4) Polyurethane is a mixture of a prepolymer of 4,4'-diphenylmethane diisocyanate-1 and a trifunctional castor oil derivative, a curing agent consisting of a mixture of trifunctional polypropylene glycol, and an amino alcohol. A method for manufacturing a hollow fiber mass transfer device according to claim 3. (5) Claims 1 to 4, wherein the heating is performed by contacting with a heated inert gas body. A method for manufacturing a hollow fiber mass transfer device according to any one of (6) Claim 1, wherein the mass transfer device is an artificial lung.
5. A method for manufacturing a hollow fiber mass transfer device according to any one of Items 5 to 5. (7) The method for manufacturing a hollow fiber type mass transfer device according to any one of claims 1 to 6 of the 11th edition, wherein the mass transfer device is an artificial kidney.