Liquid purification or separation – Casing divided by membrane into sections having inlet – Dialyzer with dialysate proportioning means
Reexamination Certificate
2002-07-16
2004-11-23
Kim, John (Department: 1723)
Liquid purification or separation
Casing divided by membrane into sections having inlet
Dialyzer with dialysate proportioning means
C210S097000, C210S232000, C210S254000, C210S258000
Reexamination Certificate
active
06821421
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a hemodialyzing unit that removes waste products on the blood from a patient suffering from renal insufficiency or the like, employing a hemodialysis membrane, and more particularly, to the hemodialyzing unit that is applied to a case where dialysis is difficult to perform at a general flow rate of dialytic fluid, and a dialytic fluid circuit for the same.
BACKGROUND OF THE INVENTION
When hemodialysis is conducted employing an artificial dialyzer, a blood pump and a dialytic fluid pump are controlled in a hemodialyzing unit as follows. The blood pump is controlled so that the flow rate of blood circulating in a blood circuit is constant. The dialytic fluid pump is controlled so that the flow rate of dialytic fluid in contact with the blood through a hemodialysis membrane is constant similarly (by a single-path method). According to the hemodialysis, substances are transferred between the dialytic fluid and the blood, thereby removing moisture or waste products in the blood. The removed quantity is closely related to the blood flow rate and the flow rate of dialytic fluid. According to the general hemodialysis treatment (hemodialyzing unit), the flow rate of dialytic fluid is 500 ml/min, and can be decreased so far as to reach a level of 300 ml/min.
However, the general hemodialysis cannot be applied to types of patients and cases such as a patient who tends to be in disequilibrium syndrome, a case of a renal disease having a complication of a circulatory system or a case of a multiple organ failure. For these patients and cases, the application of a Continuous Hemo Dialysis (CHD), a Continuous Hemo Filtration (CHF), and a Continuous Hemo Dia-Filtration (CHDF) has been studied and exhibits some effects. The CHD and CHDF are characterized by continuously and slowly conducting water removal or fluid supply. However, according to these methods, it is difficult to adjust the flow rate in a low flow rate range in the general hemodialyzing unit or a dialytic fluid supply unit. Therefore, the CHD or CHDF requires a device for the exclusive use, and further, supplemental fluid for a filtering-type artificial kidney to be given.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is an object of the present invention to provide a hemodialyzing unit that can be used at a low flow rate of dialytic fluid, by which a wide range of treatments of the CHD (or CHDF), SHD (or SHDF), and HD (or HDF) can be conducted without employing a special device for the exclusive use required for conducting the CHD or CHDF. Moreover, it is an object of the present invention to provide a hemodialyzing unit for conducting these treatments at low cost, and a dialytic fluid circuit for the same.
It should be noted that the SHD designates Slow Hemo Dialysis and the SHDF designates Slow Hemo Dia-Filtration in the specification, which are conducted at a low flow rate of dialytic fluid. More specifically, the SHD and the SHDF refer to the dialysis in which a dialytic fluid has a decreased flow rate, so as to be flowed slowly, whereby the water removal or the substance transfer is performed slowly.
The above-mentioned treatment is applied to a linking (intermediate) treatment for a patient having serious renal insufficiency when the treatment is shifted from the CHD (or CHDF) to the HD (or HDF). According to the treatment, the flow rate of dialytic fluid is in a range of about 10 to 250 ml/min (not exceeding 300 ml/min to be the lowest flow rate for the general dialyzing unit). One dialysis period (treatment period) is about 4 or 5 hours to 8 hours, similarly to the case of the general dialysis. It does not take as long as the case of the CHD, which takes 12 to 24 hours.
It is another object of the present invention to provide a hemodialyzing unit that can be applied to both cases of the general hemodialysis and the hemodialysis at a low flow rate of dialytic fluid. To be specific, the present invention aims to provide a hemodialyzing unit that can be used for the general hemodialysis in a usual mode, and, if required, can be used for conducting a wide range of treatments, such as CHD (or CHDF), SHD (or SHDF), and HD (or HDF) by a minor change in the device configuration.
The hemodialyzing unit of the present invention includes a dialytic fluid supply line for feeding a dialytic fluid from a dialytic fluid supply/discharge unit to a dialyzer, a dialytic fluid discharge line for feeding a dialytic fluid discharged from the dialyzer to the dialytic fluid supply/discharge unit, and a bypass line for connecting both the lines at the respective intermediate portions. Accordingly, the dialytic fluid supply line includes an upstream supply line extending from the dialytic fluid supply/discharge unit to a coupling portion to the bypass line and a downstream supply line extending from the coupling portion to the bypass line to the dialyzer. Further, the dialytic fluid discharge line includes an upstream discharge line extending from the dialyzer to the coupling portion to the bypass line and a downstream discharge line extending from the coupling portion to the bypass line to the dialytic fluid supply/discharge unit. The downstream supply line is provided with a flow rate adjusting member.
As described above, the downstream supply line is provided with the flow rate adjusting member, thereby controlling the flow rate of the dialytic fluid flowing into the dialyzer. Since the general dialytic fluid supply/discharge unit cannot adjust the dialytic fluid to be fed to the dialytic fluid supply line at a low flow rate, the normal flow rate of dialytic fluid flows into the upstream supply line. In contrast, the downstream supply line is additionally provided with the flow rate adjusting member, whereby the flow rate of dialytic fluid is controlled to be low, and consequently, the dialytic fluid can be fed to the dialyzer at a low flow rate. The dialytic fluid that passes through the upstream supply line, not to be fed to the dialyzer, becomes a redundant dialytic fluid. The redundant dialytic fluid passes through the bypass line, and then the downstream discharge line, to be discharged from the dialytic fluid supply/discharge unit.
Any flow rate adjusting member may be used as long as it suitably adjusts the flow rate of dialytic fluid of the downstream supply line, preferably having a simple structure. For instance, the flow rate adjusting member can be composed of a dialytic fluid feed pump, or a dialytic fluid feed pump and a pump tube attached thereto. Moreover, it is preferable that the flow rate adjusting member can adjust the flow rate of dialytic fluid in a lower flow rate range than the dialytic fluid supply/discharge unit. There is no particular limit to the dialytic fluid feed pump; however, in general, a roller pump or a peristaltic pump, or the like is employed, for instance.
Moreover, in the hemodialyzing unit having the above-mentioned configuration, it is more preferable to control the dialytic fluid feeding rate through the upstream supply line to be larger than that through the downstream supply line.
Therefore, it is preferable for the hemodialyzing unit of the present invention to employ a dialytic fluid feed pump capable of adjusting the flow rate to be 150 ml/hr. In view of the upper limit of the flow rate of dialytic fluid, it is preferable to adjust the flow rate of dialytic fluid in a range of the lowest dialytic fluid feeding rate of 150 ml/hr to the highest dialytic fluid feeding rate of 30,000 ml/hr. If it is desired to accurately control the dialytic fluid feeding rate in a low flow rate range, it is preferable to use the pump having a controllable range in the lowest flow rate of dialytic fluid of 150 ml/hr to the highest flow rate of dialytic fluid of 9,000 ml/hr. Moreover, the use of the dialytic fluid feed pump, to which pump tubes having different diameters can be attached, allows the flow rate setting range to be varied by exchanging the pump tube. The general dialysis can be conducted sufficiently at the lowest flow rate of d
JMS Co. Ltd.
Kim John
Merchant & Gould P.C.
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