CA1119971A

CA1119971A - Hemodialysis system with modular dialysate manifold assembly

Info

Publication number: CA1119971A
Application number: CA000285084A
Authority: CA
Inventors: James T. Hutchisson
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1976-09-07
Filing date: 1977-08-19
Publication date: 1982-03-16
Also published as: DE2740062C3; BR7705935A; DE2740062B2; JPS5334396A; IN147809B; FR2363333B1; GB1591205A; DE2740062A1; FR2363333A1; IT1219981B

Abstract

HEMODIALYSIS SYSTEM WITH MODULAR
DIALYSATE MANIFOLD ASSEMBLY

ABSTRACT OF THE DISCLOSURE

A hemodialysis system comprising a modularized dialysate flow circuit manifold assembly. The manifold assembly is detachably secured in the hemodialysis system for ready replacement, whereby cross-contamination problems associated with multiple patient use of the system may be simply eliminated by the dedication of a manifold assembly to each patient.

S P E C I F I C A T I O N

Description

~ 7 BACXGROUND OF THE INVENTION:
Field o~ the Invention This invention relates generally to hemodialysis or arti~icial kid~ey systems ~or treatment o~ blood to remove waste impurities and undesirable components therefrom, and more ~pecifically, to an i~proved hemodialysis system which overcomes cross-contamination problems associated with multiple p~tient use of the system.
Description of the Prior Art EIemodialysis systems have been in general use for a n~ber of years in the treatment o~ renal disease and disability, and h~ve proven highly e~ective in providing artificial kidney ~unctions for persons whose own natural kidneys are ~unctionally impaired. In operation of the he~odialysis ~ystem, blood containing waste substances, such as ~or example urea, creatinine, excess electrol~tic salts and water, is withdrawn ~rom the body and ~lowed through a dialyzer in indirect ~ass trans~er relationship with an a~ueous dialysate solution. m e dialyzer may be o~ various co m entional types including a mass trans~er ~ember such as an extended sur~ace elastomeric membrane or a hollow fiber bundle across which the waste substances are transferred by coneentration gradient (solute impurities) or osmotic pressure (water) ~rom the blsod to the dlalysate solu~ion. From the dialyzer the blood which has thus been depleted in impurities is returned to the patient's body. The impurity-enriched dialysate rolution from the dialyzer is either disposed of to waste or else is regenerated as by sorbent means to remove the ~ste impurities there~rom prior t~ being recirculated to the dialyzer ~or re.newed mass trans~er ~rom the blood to the solution~
Altho~gh arti~icial kidney hemodialysis systems have demonstrated widespread acceptance and e~ectiveness in use, the majority o~ such systems which have been developed to date are costly, large in size and hea~y in weight. Accordingly, these systems have heretofore been primarily employed in hospital renal treatment facilities and "satellite"
dialysis centers. The geog~aphically fixed locations of these hemodialysis

-2-lln2s f~cilities tends to signi~icantly restrict the mobility of persons requiring dialysis treatment and involves inherent problems of accessi-bility and expense of travel for persons living in sparsely populated areas or otherwise at great distance from the treatment center. Due to the widespread character o-~ renal disease and disability, the aforementioned problems af~ect substantial nu~bers of the population;
at present, ~or example, maintenance hemodialysis is e~ployed to prese~e and protect the lives of approximately 24,000 persons in the ~Jnited States alone. One of the greatest limitations o~ the dialytic regimen of treatment imposed on these patients is a ~orced alteration in li~e style as associated with the need for physical attachment to a hemodialysis system two or three times each week.
In an ef*ort to ease the problems oP geographical confinement o~ individu~l hemodialysis patients, patient travel in groups to areas served by dialysis centers within and outside of the United States has been organized by patient associations such as the National Association o~ Patients on Hemodialysis and Transplantation (NAPHT). Despite such ef~orts, however, medical and scheduling problems continue to imoede free travel by the dialysis patient. For example, domestic dialysis centers may be filled to capacity and thus unable to accept guest patients. Foreign dialysis centers may be prohibitively expensive or absolutely closed to tourists or visiting patients.
Under the foregoing considerations, a particular problem is ~aced by patients who are hepatitus carrier~, i.e., whose blood is Australian antigen po~itive, since they are generally excluded from all centers and thus are denied travel opportunities. Such e~clusion results ~rom the potential for cross-contamination of other patients from viral residues in the dialysate ~low circuit of the hemodialysis system after use of the system by a hepatitus carrying patient. In convention~l practice, the patient is ~oined to the dialy~er means in a closed ~low loop by means o~ connecting lengths of flexible elastic tubing joined in turn to an arteriovenous shunt or ~istula attached to the patient. Is~smuch as the dialyzer means, shunt and connective blood flow tubing are generally disposable or susceptible to sterilization for re-use without undue di~ficulty, the treatment o~ blood cont~ining viral hepatitus by such equipment poses no particular difficulty.
Nosietheless, during dial~sis, such viral contaminants are able to dif-~usionally pass through the mass trans~er sur~ace, i.e., dialyæer membrane~
~rom the in~ected blood to the dialysate solution ~lowed through the dialyæer~
The a~oYe described entry o* contaminant species into the dialysat~ solution flow circuit during treatment results in a potential health hazard not associated with the blood flow circuit. m is is because the dialysate solution ~low circuit, unli~e the blood flow circuit, is neither disposable in its entirety or readily adaptable to complete sterilization. Various physical characteristics of the dialysate solution in the dialysis system during treatment are extremely critical and, accordingly, a number of processin~ moslitoring, adjustment and control steps are typically employed in the dialysate solution ~low circuit to insure effectiveness of the dialyzing operation and con-comitant protection o~ the patient. For example, heatin~ and tempe~ature control means are generally utilized in the dialysate solution flow circuit to maintain the temperature oP the dialysate solution therein at a proper level, e.g. 98-100F, to prevent undue heating or cooling of the blood by heat exchange with the dialysate solution and to prevent hemolysis. In addition, conductivity o~ the dialysate solution is characteristically monitored to insure that the solution has the proper level o~ salini-ty and electrolytic characteristics. Such provision is made so that vital components of the blood are not lost to the dialysate solution by ion diffusion across the mass transfer surfaces in the dialyzer. ~inally blood leak detection means are generally coupled to the dialysate solution flow circuit to insure that only indirec-t mass transfer-i.e., diffusional and osmotic -transfer of species across the dialyzer membrane-is occurring, without direct cross-leakage be-tween the respective fluids in the dialyzer.
Due to the necessity of utilizing the above-mentioned monitoring and equipment means in the dialysate solu-tion flow circuit, such flow cir-cuits are not disposable in the manner of the previously-described blood flow circuits. Furthermore, such dialysate solution flow circuits are diffi-cult to effectively sterilize due -to the likelihood of damage to the sensit-ive monitoring and control components coupled into the circuit by chemical steriliæing agents or elevated temperature sterilizing techniques. Thus, the problems associated with potential cross-contamination in~dialysis treatment due to multiple patient use of' the hemodialysis system are sub-stantial and have not been satisfactorily overcome by the prior art.
The present invention seeks to provide an impxoved hemodialysis system for the treatment of blood to remove waste impurities therefrom.
The invention further seeks to provide a hemodialysis system in which cross-contamination problems associated with multiple patient use of the system are readily overcome.
~ dditionally, -the present invention seeks to provide a hemodialysis system of` the above type which is compac-t, lightweight and readily portable.

SUM~RY OF THE I~VENTION:
This invention relates to a hemodialysis appa~Ltus ~or treatment o~ blood to remove ~raste impurities therefrom. The apparatus includes dialyzer means through ~hich waste impurity-containing blood and a dialysate solution are passed in indirect mass t m ns~er dialyæing relation-ship ~or transfer of the waste impurities from the blood to the dialysate solution. ~eans are provided ~or supplying ~aste impurity-containing blood ~rom a patient to the dialyzer means, and for returning ~aste impurity-depleted blood to the patient. Means are also provided ~or suppl~ing dialysate solution to the dialyzer means along with means ~or discharging ~aste ir~purity-enriched dialysate solution from the dialyzer means ~orming a dialysate ~low circuit.
In the i~provement o~ the invention~ the dialysate ~low circuit includes a modularized dialysate solution manifold assembLy. The assembly comprises a base support member, with dialysate solution flow passage means mounted on the base support member having an inlet and an outlet detachabl~ coupled to the dialysate solution ~low circuit ~or ~low o~ Qialysate through the ~low passage means ~rom the inlet to the outlet thereof. Means are included ~or heating the dialysate solution in the ~low passage means to forra warm dialysate solution. The apparatus incLudes means ~or sensing the temperature o~ the warm dialysate solution positioned downstream ~rom the heating means and for ad~usting the rate o~ heatir~lg o~ the dialysate solution by the heating means in response to the temperature sensing to maintain a predetermined dialysate solution teraperature level. Monitor sensing means are positioned in the ~low passage means including: means ~or detecting blood leakage into the dialysate solution, means ~or sensing the electrolytic conductivity o~ the dialysate solution, and means ~or sensing the dialysate solution temperature.

Thus, this invention provides in a hemodialysis apparatus ~or treatment of blood to remove ~aste impurities therefrom, including:
dialyzer means through which waste-impuri-ty containing blood and a dialysate solution are passed in indirect mass transfer dial~zi.ng relationship for transfer of said waste impurities from said blood to said dialysate solu-tion; means ~or supplying waste impurity~con-taining blood ~rorn a pa-tient to said dialyzer means; means for returning waste impurity-depleted blood to said patient; and means for supplying dialysate solution to saicl aial-yzer means and means for discharging waste impuri-ty-enriched dialysate sol-ution from said dialyzer means ~orming a dialysate flow circuit, the imp-rovemen-t wherein said dialysate flow circuit includes a modularized dial-ysate solution manifold assembly and tubing segments for flowing dialysate solution to and discharging di.al~sate solu-tion from said mani~old assembly, said manifold assembly comprising:
(a) a base support plate member with mai.n flat top and bottom surfaces having spaced-apart dialysate solution inlet and outlet openings therein, with coupling means associated with said inlet and outlet openings on the main top surface of said base support plate member for detachably joining the manifold assembly with said dialysate solution tubing segments;
~b) means positioned on the main bottom surface of said base support plate member comprising a tubular passage having an inlet end communicating with said dialysate solution inlet opening for flow of dialysate soLution therethrougll to an outlet encl of said tub-llar passage and means for heatirlg said dialysate solution in said tubular l~assage to form warm dialysatc so1ution;
(c) mc~ns for scnsillg thc tcmpcraturc of saicl w~lrm clialysate solution positioned downstream from said hcating means and for aclj~lsting the rate of heating of snid dialysatc solutioll by saicl heatirlg mcans irl response to saidtemperaturc sensing to maintLlin a prc~ctcrmincd dialysate solution tcmperature level;

~ _ 6a 7~1 ~ d) a flow enclosurc means positioncd on tllc main bottom surface of said base support plate mcmbcr containill~ a dialysate solution flow passage having an inlet joined to the outlet end of said tubular passage of ~b) and having an outlet communicating with said dialysate solution outlet opening for flow of d.ialysate solution therethrougll, with monitor sensing means positioned in said dialysate solution flow passage including:
means for detecting blood leakage into said dialysate solution, means for sensing the electrolytic conductivity of said dialysate solution, and means for sensing said dialysate solution temperature, the apparatus being constructed such that said manifold assembly may readily be detached from said dialysate solution tubing segments and separ-ably removed from the remainder of said hemodialysis apparatus.

..

' ~ - 6b 7:31 Brief Description of the Drawings Figure 1 is a generalized schematic block diagram of a hemodialysis system according to the present invention.
Figure 2 is a plan view of a compact portable hemodialysis system according to the present invention, as contained in a unitary suitcase-type enclosure.
Figure 3 is a perspective view of the peristaltic blood pump employ-ed in the Figure 2 hemodialysis system.
Figure 4 is a plan view of the peristaltic blood pump, flexible 1~ resiliant tubing pumping section and anchor bloc~ assembly employed in the Figure 2 hemodialysis system, showing the dimensional characteristics thereof.
Figure 5 is a bottom view of the modularized dialysate flow circuit manifold assembly for the Figure 2 hemodialysis system, showing the details of construction thereof.
Figure 6 is a partially assembled view of a section o the tubular heating means employed in the Figure 5 manifold assembly, showing the construc-tion thereof.
Figure 7 appearing on the same sheet of drawings as Figures 3 and 4 is a side elevational view of a hemodialysis system of a type as shown in Figure 2, showing the details of construction of the dialysate manifold assembly.
Figure 8 appearing on the same sheet of drawings as Figure 1 is a schematic wiring diagram for the dialysate manifold assembly o:E Figures 5 and 7.

,~, ',.,1 ~. .

7~

Re~erring now to the drawings, Fig. l shows A generalized schematic block diagram of a hemodialysis system such as is suitably employed in the practice o~ the present lnvention. In this illustrative system, the patient or hemodialysis subJect lO is joined in a closed loop blood ~lo~ circuit ~ormed by blood ~low tubing segments ll, 13 and 15 with dialyzer means 14, which may be o~ Pny suitable conventional type, as ~or example a parallel plate or hollow fiber bundle type.
Waste impurity-containing blood is withdrawn ~rom the patient a5 by means of an arterial fistula, cannula or shunt (not shown) and trans-~erred by tubing segment ll to peristaltic pump means 12, described more *ully hereinafter, located upstream o* the dialyzer means 14. ~y means of the pump means 12, the withdr&wn waste impurity-containing blood is persitalticall~ pumped to advance blood through the above-described blood ~low circuit. The speed of the peristaltic pump means is sui~Lbly con~rolled by ~otor speed control 35 coupled there~ith, to obtain the necessary flow rate o~ blood through the blood ~low circuit, as for example about 200 milliliters per minute.
A~ter pumping by the peristaltic pump means 12, the ~Lste impurity-containing blood is passed via line 13 through the dialyzer means l4 in indirect mass trans~er dialyzing relationship with the dialyzing solution enterln~ the dialyzer in line 21. A9 mentioned, the dialyzer means may suitably be o~ the parallel ~low hollow Yiber type comprising a bundled array o~ hollow fibers through which the wQste impurity-containing blood is passed in countercurrent ~low relationship with the dialysate solution flowing through the bundled array along the exterior surfaces o~ the hollow fibers. Waste impurity-depleted blood is returned from the dialy~er means to the patient by blood return line 15. The blood return line has pressure monitoring means 16, e.g. an anaeroid manometer, associated therewith to indicate the return blood pxessure level, so as to permit the patient or other attendant to ad~ust the speed o~ the blood pump means or shut the apparatus do~m ~hen the venous blood pressure le~el in the blood flow circuit increases ~r decreases to ~alues outside o~ acceptable lirnits.
The waste impurity-enriched dialysate solution is discharged ~rom the dialyzer means in line 23~ passed to the peristaltic pump ~eans 24 and peristaltically pumped therein to advance the dialysate solu~ion through the dialysate solution ~low circuit at suf~icient rate ~or efficient trans~er o~ waste impurities from the blood to the dialysate ~olution in the dialyzer means, as for example at a flow rate of about 500 milliliters/minute. The peris~altically pumped dialysate solution i~ discharged into line 25, in which it ~lows to adsorbent ~ilter means 26. Adsorbent ~ilter rrleans 26 mQy in practice comprise a cannister o~
20~-300 grams o~ granular activated charcoal disposed in the dialysate ~olution ~low circuit QS shown downstream from the dialy~er means for removal o~ waste impurities ~rom the waste impurity-enriched dialys~te solution discharged ~ro~ the dialyzer means. In this manner, by passa~e through the adsorbent ~ilter means 26, the dialysate solution is partially sorptively regenerated before being passed in line 27 to dialysate solution supply container 16. The dialysate solution supply container 16 contains a suitable volurne o~ solution ~or all or a portion o~ the dlalyzing operation; ~or example, in accordance with the present invention, whereby the hemodialysis system may be provided in a srnall, compact, lightweight enclosure ~or ease o~ portability, as hereina~ter described, the dialysate solution supply container may suitably be ~or~ed o~ a ~lexible, colLapsible rr~terial such as polyethylene with a volume o~
between 10 and 30 liters From the supply container 16, the dialysate solution is with-drawn in line 17 and passed to heating means 18 wherein the dialysate solution is heated if necessary to approximately 98-100 F. Such heating is carried out to yield a proper dialysate solution temperature _g_ to prevent undue heating or cooling of the blood by heat exchange with the dialysate solution and to prevent hemolysis. Warm dialy-sate solution is flowecl from the heating means 18 in line 19 to the dialysate solution sensing assembly 20.
In the sensing asse~bly, means are provided for sensing the tem~era-ture of the dialysate solution together wi-th rreans for converting the dialysate solution temperature sensing into a trans-mittable signal. This tem~erature sensing signal is transmitted by signal wires 38a and 40 to the temperature control circuit 28, which oompares the temperature sensing signal with a set point value and generates a resultant control signal which is transmitted by control signal transmitting means 49 to the heating means 18 to provide the requisite level of heating for maintaining the set point value. In this manner, the rate of heating of the dialysa-te solution by the heating means is adjusted in response to the temperature sensing in the assembly 20 to mL~intain a predeterm~ned dialysate solution ternperature level.
Another temperature sensing signal from wire 38 is passed to amplifier 29 wherein the signal is amplified. The amplified temperature sensing signal is then passed in signal transmitting lina 41 to the visual temperature display means coupled with the ternperature sensing means by the aforerr.entioned signal transmitt:Lng rneans for indication of the sensed dialysate solution temperatu~.
Such visual display represents a safet.~ rreans which permits the user or other attendant to take proper steps, i.e., shut dcwn the dialysis system in the event oE malfunctlon or failure of the temperature oontrol circuit 28 or hea-ting means 18.
Also in the sensing assembly 20, means are provided for sensing the electrolytic conductivity of the dialysate solution, to-gether with rr,eans for converting the dialysate solution electrolytic oonductivity sensing in-to a transmittable signal. The conductivity sensing signal is transmltted by signal wire 42 to amplifier 33, and the resulting Rmplified conductiv.ity sensing signal is transmitted by signal wire 43 to visual display means 34 ~or indication o~ the sensed dialysate solution electrolytic conductivity. Such ~onitoring o~ conductivity is desired to insure that the dialysate solution has the proper level o~ salinity and electrolytic characteristics, so that vital components o~ the blood are not lost to the dialysate solution by ion di~fusion across the mass transfer sur~aces in the dialyzer.
As shown, an audio alarm means 31 is coupled with the tempera-ture sensing signal transmitti~g wire 41 and with the conductivity sensine ~ignal transmitting wire 43 by th~ further respective signal transmitting wires 44 and 45. In this rnanne~ alarm means 31 is arranged for emitting an audible alarm when the sensed dialysate solutio~ temperature or conductivity exceeds a predetermined value, thus noti~ying the user or attendant that one or both of these dialysate solution characteristics is outside of` the desired limits by an extent which can then be readily determined by visual inspection of the display means 30 and 34 as an aid in determining the corrective action to be taken. As a ~urther sa~eky ~a-$ure the audio alarm means may be coupled by signal wire 46 with motor speed control 35 which in turn is joined by signa.l wire ~3 with the peristaltic blood pump 12 drive means, arranged so that the motor speed control means 35 is shut down by the transmitted audio alarm sign~l, thereby deackivating the peristaltic pump means in the blood ~low circuit upon the emission of the audio alarm from the alarm means 31.
Finally, the dialysate solution sensing assembly 20 comprises means for detecting blood leakage into the dialysate solution Mow stream together with means for converting the blood ].eakage detection into a transmittable signal. This signal is transmitted by signal wire 47 to blood leakage detection output means 37, which ~ay suitsbly comprise visual display or audio alarm means. ~lese blood leak detection means are provided tc insure that only indirect mass transfer -- i.e., diffusional and osmotic transfer of species across the dialyzer membrane -- is occurring, without direct cross-leakage between the respective fluids in the dialyzer.
From the dialysate solu~ion sensing assembly 20, the dialysate solution is flowed through lino 21, having negative pressure adjustment means 22 and negative pressure monitoring means 36 disposed therein, to the dialyzer means 14, Negative pressure is employed on the dialysate solution side of the lo membrane in the dialyzer means to effect water removal from the blood by ultrafiltration. The negative pressure on the dialysate side of the dialyzer means is adjusted by adjustment means 22 such as an eliptical flow valve and monitored by monitoring means 36 such as an anaeroid manometer.
In the Fig. 1 system, the dialysate solution supply and discharge means comprise a closed loop dialysate flow circuit made up o~ flow line segments 17, 19, 21, 23, 25 and 27 which join the dialyzer means 14 with the dialysate solution 9upply container 16, for batch recirculation of the dialysate 801ution through the dialyzer means. Alternatively, it is to be recognized that closed loop recirculation of dialysate could r~adily be eliminated in the illustrative system by deletion of the adsorbent filter means and dialysate solution return line 27. Such modification would provide a single pass, open loop dialysate solution flow circuit, wherein dialysate solution is withdrawn from the dialysate supply container 16, flowed through the dialysate solution heating means 18 and sensing ~ , .

1102~

assembly 20 to dialyzer 14, from which it is discharged to dialysate solution pump means 24 and finally passed out of the treatment s~stem in line 25 7 to drain on other end use means.
Fig~ 2 is a plan view o a compact portable hemodialysis system according to the present invention~ as contained in a unitary suitcase-type enclosure 50. The enclosure comprises lower section 51 with a lower facing panel 53 and upper section 52 with upper facing panel 54. As shown, the upper and lower sections are hingedly joined together and are fitted and retained lo toge~her with the aid o~ complimentary locking numbers 74 and 75. ~hen so fitted together, the enclosure is highly compact, measuring 21 inches in length by 12 inches in width by 6 inches in height. In practive, the enclosure casing may be formed of lightweight material such as aluminum so that the weight of the entire enclosure assembly is maintained sufficiently low for portabillty, as for example on the order of 24 pounds.
The system is designed to operate on conventional 120/
2~0 volt alternating current, as provided to the system by the power line 55 entering the enclosure lower section 51 beneath facing panel 53. From the enclosure lower section, the power required ~or operation of the various monitoring and output display means on the right hand side of the upper section facing panel 54 as provided by paneL connector line 56 linked with the power supply line 55 by a ~ 12 volt direct current, 240 milliamp power supply beneath lower panel 53. Power is supplied to the s~ystem circuitry by means of the power switch 57 located below fuse holder 58 on the lower panel 53 and joined to the power supply line 5S.

7~1. 11028 The blood flow circuit ~or the Fig. 2 system comprises tubing segments 11, 13 and 15 which may be of a conventional type ~or~ned of transparan~ polyvinylchloride or silicor~e elastomer. Waste impurity containing blood in accessed from ~he pa~ient as for ~xample by an arterio-venous fistula and is passed in the arterial feed line 11 to the peristaltic blood pump 12, as described more ully hereinafter, and the peristaltically pumped blood there-from is passed through line 13 ~o the dialyzer 15. The dialyæer is of the p~rallel. flow hollow fiber type previously described lo having about 1.50 meters2 of membrane mass transfer exchange area for dialysis. In the dialyzer, the waste impurity consti-tuents o the blood such as urea, uric acid and creatinine di~fuses from the blood across the membrane into the dialysis solution.
Wat~r removal ~rom the blood is carried out b~ ultra~iltration e~ected by using ~p ~o 350 mm Hg negative pressure on the dial~æate solution side of the memb~a~e and up to 500 mm ~ overall trans-mem~rane negative pre~sure. Typically one to two liters o~ water is re~oved during the dialysis treatment.

From the dialyzer 14, which is supportively positioned adiacent the enclosure unit by means of a clamp and stand asseMbLy joined to the exterior side wall of the enclosure lower section, the waste impurity-depletecl blood is returned in line 15 to the patient. Line 15a is joined to blood return line 15 and communicates with venous pressure manometer 16 which monitors the return blood pressure over the pressure range of from 0 to 350 mm Hg.
The dialys~te solution -flow circuit for the Fig. 2 syste~
comprises tubing segments 17, 21a, 21b, 23 and 25, which also ~ 7 ~ .

may be o~ a conventional type ~ormed o~ polyvinyLchloride or silicone rubber.
From the dialysate solution supply means, which may ~or ex~mple com-prise a 21 li~er collapsible polyethylene contalner holding dialysate solution which is changed t-.~ice to fresh solution during the course of a four to five hour dialysis treatment, the dialy-~ate solution is passed in line 17 into the dialysate manifold asse~bly as hereinafter described in greater detail7 through the inlPt opening 76 in base support plate member 59. Ihe base support plate me~ber 59 is detachably secured to the lower panel lo 53 in enclosure 50 by suitable screw or bolt fastener means.
In the dialysate manifold assembly the dialysate solution is heated to the extent necessary to maintain temperature of the solution at about 98F and temperature, conductivity and blood leak are monitored. The dialysate solution heating means associated with the dialysate manifold assembly are activated by power switch 62. An adjustment dial 60 is provided on the top side "of base support plate member 59 for manual adjustment of the set point control temperature for the dialysate heating means, and indication lamp 61 above adjustment dial 60 indicates when the heating means have been activa~ed by the dialysat~
solution temperature control circuit.

From the dialysate soLution m~ni~oLd as~embly, warm diaLys~te solution passes through the outlet opening 77 in base suppor-t pl~te member 59 into line 21a. Line 21 a is ~oupled via line 36a with the negative pressure manometer 36, for visual monitoring of the dialysate solution negative pressure in the range of 0 to 37~l ~.1028 35O mm Hg. From line 21a the dial~sate solution flo~s through ellip-tical control valve 229 which is manually adjustable for varying the negative pressure of the dialysate solution, depending on the water content of the waste impurity-containing blood bein~
dialyzed and the desired degree of removal of water therefrom.
The elliptical valve 22 is connected on its downs~ream side with line 216 through which the dialysate solution flows to the dialyzer 14 for mass transfer of waste impurities from the blood to the dialysate solution. Waste impurity-enriched lo dialysate solution is discharged from the dialyzer 14 in line 23 a~d passed to the peristaltic dialysate solution pump 24.
The dialysate solution is advanced by the peristaltic pump 24 thxough line 25 for recirculation to the aforementioned dialysate ~upply container.

me power ~or all sensors in the dialy~ate manifoLa assembl~, as well as the temper~ture controL circuit is provided by the same DC power supply means positioned beneath lower section panel 53 as supplies power to the el,ectronics monitoring module on the upper right ~ hand corner o-upper section panel 54 through connecting line 56. All sensors in the dialysate solut~.on manifold asse~bly are monitored and read out on the upper section panel monitorin~
module. Panel calibration controls 64, 65 and 66 are respect-ively provLded for the conductivity, temperature and blood leak detection parameters monitored in the dialysate solution mani-fold assembly, together with upper section panel test points 78 to facilitate calibration. Alarm iimits are fixed for tem-~Le~ 110 2 8 peraturQ and conductivity~ and are adjus~able for blood leak detection, by varying the blood leak detection calibration setting of adjustment dial means 65. A blood leak detection warning light 70 is provided which is responsively coupled with blood leak sensing means in the dialysate solution mani-fold assembly, together with an audio blood leak detection alarm 71 likewise coupled to the blood leak sensing means.
m e visual displays 67 and 68 for dialysate solution temperature and conductivity conditions, respectively, are provided by red light emitting diodes (LEDs) indicating high (HI) or low (LO) conditions, i.e., val~s outside of the predetermined range limits. A green LED (N) indicates normal operating conditions.
The audio alarm 71, also coupled to the dialysate solution mani-fold assembly temperature and conductivity sensing means as described in connection with Fig. 1 hereinabove, provides a 2.2 KHz 80 decibel signal. For convenience, a switch 69 permits disconnection of the audio alarm 71 while retaining the respect-ive visual alarm~. The dialysate solution electrolytic conduc-~ivity alarm limits are at ~ 1% o~ the calibration point, corre-~ponding to 13.5 millimhos nominally. Dialysate solution tem-perature alarm limits are a~ -~ 2, of the calibration point, corresponding to 98~F nominally.
The peristaltic blood pump 12 and peristaltic dialysate solution pump 24 in the Fig. 2 system are identically dimen-sionally sized. The pump heads of these pumps are separately driven by double gear reduction shunt ~ound D.C. motor drive means.
Blood flow rate from the pump is controlled by variable motor 1lo2~
~ 7 ~

sp~ed control ~m2ans 639 by which the drive means are coupled with the blood pump head assembly for rotation thereof at a speed in the range of from 50 to 400 rpm~ to induce pulsatile flow in the blood being advanced by the pump through the blood flow ~rcuit. Preferably, the blood flow rate is maintained at a value of about 200 milliliters/minute cluring dialysis. The dialysate solution peristaLtic pump 24 is identical in design to the peristaltic blood pump 12, but has associated drive means eoupled to its pump head assembly for rota~ion thereof at a speed in the range of from 200 to 600 rpm, to provide a dialy-~ate solution low rate of about 500 milliliters/minute and induce pulsatile 10w in the dialysate solution being advanced throu~h the dialysate solution flow circuit and passed through ~he dialyzer Means.
Fîg. 3 is a perspective view of the peristaltic blood pump 12 employed in the Fig. 2 hemodialysis system. As shown the pump head assembly 79 includes ~he pump head base member 80 inset with set screws 81 for rigidly attaohing the pump head assembly to a rotatable shaft coupled with the motor drive means thereor~ In this ~ashion the pump head base member is positioned for rotation about a fixed axis. Mounted on the pump head base member by bolt or screw fastener means for inde-pendent rotation about respective axes parallel to the base member fixed axis are three circumferentially spaced apart rollers 83 disposed between the lower and upper tubing guide members 82 and 84, respectively~

~ 1102~

Fig. 4 is a plan view of the peristaltic blood pump, flexible resiliant tubing pumping sec~ion and anchor block - assembly employed in the Fig. 2 hemodialysis system, showing the dimensional characteristics thereof. As shown, the blood flow cirruit comprises tubular segments 11 and 13 joined to a flexible resiliant tubing pumping section 86 through which blood is pumped. An anchor block 87 is provided for anchoring the end segments of the flexible resili~nt tubing pumping section 86 such that the tubing Eorming the pumping section is tensionally lo extended around the pump head assembly 79. In this arrangement the tubing is simultaneously engaged and compressed by at least ~wo of the circumferentially spaced apart roller~ 83 with at least partial closure of the tubing at the points of compression, as shown. The rollers 83 are mounted for longitudinal movement of the points of compression along the tubing during rotation o the pump head assembly to advance blood through the tubing.
As illustrated th~ pumping sectîon o flexible resiliant tubing is anchored at the ace 88 of the anchor block 87, opposite the side on which the pump head assembly is positioned, by means o~
the ~langed connector means 89 attached to the end segments o the flexible resiliant tubing pumping section and to the ends o~ the blood ~low lines 11 and 13.

In the pre~erred practice o~ the present inven-tion, high frequency pulsatile ~lows o~ blood are passed through the dialyæer means of the hemodialysis s~stem to reduce blood ~ilm mass trans~er resistances in the dialyæer means. For such purpose, the peristaltic blood pump means comprises three rollers mounted on the base : member, each roller having a diameter R, as shown in Fig.f4 of between 0.25 and 0.75 inch and circumferentially spaced apart a~ an angle of 120 from the other rollers with a radial distance P between the roller axis and pump head assembly member 80 fixed axis of from 0.50 to 1.25 inches. The pre~erred practice also employs a flexible resiliant tubing pumping section length, as measured longitudinally along the tubing between the anchored end segments thereof, of from 6.0 to 6.75 inches, a lo wall thickness of from o.o3 to 0.10 inch and an internal diameter of from 0.18 to 0.25 inch, with drive means coupled to the pump head assembly for rotation thereof at a speed in the range of from 50 to 400 rpm.
Although peristaltic pump means have been employed by the prior art for pumping blood in hemodialysis system blood flow circuits, the prior art has not been able to achieve the intensity of pulsatile flow which is realized in the abo~e ar~ngement. This is a consequence of the striking difference in physical dimensions and operating rotational speeds between th~ peristaltlc blood pump mean~s of the above arrRngement and the pump means of the prior art. As compared with conventiona.l blood pumps o~ the type generally used in hemodialysis systems, the peristaltic blood pump meanQ o~ the above arrangement are only about 1/10 of the size of conventional pumps and operate at about 10 times the rotational speed o~ conventional pumps.
The reason that the prior art has not attempted to u.se pumps having such small size and high rotational speeds is due to the -2~

expected occurrence of excessive levels o~ hemolysis under such dimensional charac~eristics and operating conditions. For this reason and in an effort to minimize hemolysis effects, the prior art has utilized massive peristaltic pump means and slow rotatio-c pump speeds to pump blood through the hemodialysis system. This in turn has severely impeded the development of small, light and inexpensive portable hemodialysis ~ys~ems such as suitably employed in the instant invention.

Unexpectedly, the peristaltic blood pu~p means described above have be~n ~ound to ba remar~ably ~ree ~rom hemolysis and related cell damage e~ects in use. The reason for such beneficial and wholly unexpected behavior is not fully understood. It ~ay be that the intensely pulsatile cha~acter of the blood ~low associated ~ith the high rotational pump speeds together with the short pumping volume segment length (length along the tubing section between the points of compression o~ successive rollers against the tubing section) in some manner act anomalously to "cushion" the blood being pumped so as to minimize adverse pumping compression e~ects. NonetheLess, ~1e do not wish to be bound by any particuLar theory by way of e~planation of the reT~rkably low incidence o~ 3uch adverse pumping compression e~fects, subject only to speci~ic essential system ~eatures and elements herein described.

~28 ~119971 Under the above ar~ngement, the peristaltic pumping section of tubing must be both flexible and resiliant so that the tubing,even though under continuously varying tensional and compressive load conditions, does not tend to fatigue and crack in use and so that the tubing quickly reacquires its undeformed shape and dimensions after the direct bearing of roller compres-sion on the tubing is released as the roller moves along the length of the tubing. Tubing pumping sections formed of sili-cone elastomers have been found to satisfy the foregoing requiremerlts and to be particularly useful in the practice of this invention.
As mentioned, the rollers mounted on the pump head assembly must have a diameter of between 0.25 and 0.75 inch. At diameter values below 0.25 inch, the roller tends to be too small, impart-ing insufficient thrust to the blood as the roller engages the tubing pumping section, ~ith resulting loss of efficiency in the pu~nping operation. If the roller diameter exceeds about 0. 75 inch an excessive amount of tubing is occluded when the roller engages the tubing pumping section9 thereby undesirably lower-ing the instantaneous volumetric pumping capability of the pu p means and hence the pumping eficiency of the pump means. The peri~taltic pumps en~ploy three rollers circumferentially spaced apart at an angle o~ 120 from the other rollers. I less than three rollers were employed, the pulsatile wave frequency produced by thepump means would be reduced by at least half since the wave or pulsation frequency is proportional to the number of rollers in the pump head assembly. As a result, the pump means would have to operate at correspondingly, unaccept-37~

ably high rotation~l ~peeds to achie~e the same pulsatiie flow c~lar3cteristics ~s are desirably realized ~ith three pump head assembly r~llers. If more than three pump head assembly rollers are employed, fabrication of the pump head assembly becomes increasingly complex due to the use of additional component parts and the requirement of close dimen-sional tolerances therefor; in addition, with more than three rollers, the frequency of the pulsatile flow output o~ the pump is increased to such a level that undesirable aberrant flow efects, as for example pulsatile wave interference and short-circuiting, become significant. The three rollers employed in the pump head assembl~ are most efficientl~ uni~ormly clrcumferentially spaced ~part -- i.eO, circum~erentially spaced apart by an angle o~ 120 --in order to provide an e~ective regular and uniform outpu-t pulsatile ~low o~ blood from the pump means.
The peristaltic pump also desirably employs a radial distance, as measured between a given roller axis and the pump head assembly base member fixed axis, of from 0.50 to 1.25 inches.
The reasons for such limits are co.nplimentary to the reasons discussed above for the roller diameter l:Lmits. If the radial distance is less than about 0.50, an excessive amount of tubing is occluded when the roller engages the tubing pumping section, thereby undesirably lowering the instantaneous volumetric pumping capability of the pump means and hence the pumping ef~iciency o~ the pump means.

~ 3 ~ ~ ~

On the other hand, if the radial distance is greater than about 1.25 inches, the unsupported lengths of tubing between adjacent rollers tend to be too long relative to the size of the rollers contacting the tubing, so tha~ the roller tends to impart insuf-ficient thrust to the blood as the roller engages the tubing p~mping section, with resulting loss of efficiency in the pump-ing operation. The flexible resiliant tubing pumping section under the present invention must have a length as measured longitudinally along the tubing between the anchored end segments lo thereof, of from 6.0 to 6.75 inches, a wall thickness o~ from 0.03 to 0.10 inch, and an internal diameter of from 0.18 to ~25 inch. As the pumping section tubing length, e.g., measured longitudinally along the tube between the coupling members 89 in the illustrative Fig. 4 embodiment, decreases below about 6.0 inches, a point is reached where it is not physically possible to extend the tubing around the pump head assembly with adequately low tension. At length values above about 6.75 inches, the length o~ the tubing tends to overmatch the dimensions of the pump head assembly, with the result that i~ the tubing is anchored with the proper tension for at le~st partial closure at the points o~ compression of the rollers against the tubing, such tensioning also tends to at least partially close significant lengths of the tubing between the adjacent rollers. ~ tubing wall thickness of at least 0.03 inch is necessary to insure the leak-tight integrity of the pumping section, which is subjected to continuous and rapid swings of tensional extens:ion and relax-ation such as tend to undul~ fatigue and rupture tubings of ~ 7 ~

lesser thickness. At tubing thicknesses above 0.40 inch, the pumping section tends to become too rigid for adequate and proper compression by the rollers. If the internal diameter of ~he tubing pumping section decreases below about 0.18 inchg there tends to be an improper match between the tube size and the roller size requirements, with the result that an excessive volume of tubing is occluded with corresponding reduction in ~lood pumping efficiency for the system. On the other hand, at tubing internal diameter values above 0.25 inch, an excessive o amount of tension is required for at least partial ~losure of the tubing a~ the ponts of compression by the rollers, beyond the tensile strength properties of most otherwise suitable flex-ible resiliant tubing materials o~ construction.
Finally, the peristaltic blood pump means desirably er~plo~ drive means cou~:led to the p~u~p head assembly o the blood pump for rotation thereof at a speed in the range of from 50to 400 rpm, to induce pulsatile flow in the blood being advanced through the flexible resiliant tubing pumping section. As the rotational speed of the pump head assembly decreases to values below about 50 rpm, the flow regime changes from turbulent to laminar, with a disproportionate reduction in mas~s transfer eficiency for the dialysis system; at such low rpm values, the intensity o the pulsatile flow from the peris-taltic pump is relatively low and does not compensate for the transition from the turbulent to the laminar flow regime. At rotational speeds above 400 rpm, the intensity of the peristaltic pumps pulsatile flow output is increased to such extent that ~ 7 ~

hemolysis effects finally become significantly large. Pre~erably, the drive means are coupled to the pump head assem~ly of the peristaltic blood pump ~or rotation thereof at a speed in the range o~ from 180 to ~0 rpm.
In a preferred me-thod aspect under the ~oregoing, the previously described peristaltic blood pump and broad operational pump head assembly rotational speed range o~ 50 to 400 rpm correspond to the production of a pulsatile ~low in the waste impurity-containin~ blood with-drawn from a patient by the peristaltic pumping having a ~requency oi between 100 and 800 cycles/minute whereby the pulsatile flo~ o~ blood is passed through the dialyzer means to reduce blood film m~ss trans~er resistance therein, in accordance with the formula ~ = S x (~ - 1) wherein = peristaltic pumping pulsatile flow frequency, cycles/minute, S = pump head assembly rotational speed, rpm, and N = number o~ pump head assembly rollers (= 3~.
Accordingly, in pre~erred prsctice, the pulsatile blood ~low has a ~re~uency o~ between 200 and 400 cycles/minute.
In accordance with the present invention, the dialysate solution ~lo~ circuit Joined to the dialyzer means may suitably include a ~lexible resiliant tubing pumping section through which dialysate solution is pumped, with ~urther peristaltic pump means coupled to the ~lexible resiliant tubing section in the dialysate solutlon ~lo~ circuit in the same manner as the peristaltic pump in the blood ~low circuit, as ~or example is shown in the Fig. 2 embodiment of the invention. In one arrangement under khis embodiment, the further peristaltic p~p means and the flexible resiliant tubing section in the dialysate solution flow circuit are dimensionally si~ed identically with the peristaltic pump means and the ~lexible resiliant tubing section in the blood flow circuit. Drive means are coupled to the pump head assembly of the further peristaltic pump means for rotation thereo~ at a speed in the range o~
from 200 to 600 rpm, to induce pulsatile ~low in the dialysate solution being advanced through the f`lexible resiliant tubing pumping section of the dialysate solution ~low circuit and passed through the dialyzer ~eans. The reason ~or such higher range of rotational speed ~alues ~or the peristaltic dialysate solution pump relative to the speed range ~or the peristaltic blood pump is that in the dialysate solution ~low circuit a substantially higher ~luid flow rate, e.g. about 450 500 milliliters dialysate solution/minute, is required, as opposecl to a ~low rate of approx~mately 200 ~illiliters blood/minute ~or the blood flow circuit. Accord~ngly, i~ the f~rther peristaltic pump means and the ~lexible resiliant tubing section in the dialysate solution ~low circuit are dimensionally si2ed identically with the peristaltic pump means and the ~lexible resiliant tubing section in the blood flow circuit~ the rotational speed of' the dialysate solutlon pump head assembly will be determined soLely b~ the volumetric flow rate requirements of the dialysate solution flow circuit, and will not depend on laminar to turbulent flow transition condikions or ~luid darnage considerations as in the case of the blood flow circuit. Nonetheless, the above-mentioned dialysate solution pump head assembly rotational speed range o~ 200 to 600 rpm provides an intense pulsatile flow in the dialysate ~low circuit which reduces the dialysate film mass trans~er resistance in the dialyzer and thus additionally enhances the dialyzing ef~iciency o~ the hemo-~ialysis system. In accordance with the previously stated rormula, the method aspect associated with the above-described dialysate solution ~low circuit relates to peristaltically pumping dialysate solution in the dialysate flow circuit to produce a pulsatile flow of the dialysate solution therein havin~ a f`requency of between 4UO Rnd 12uO cycies;
minute. In pre~erred practice~ drive meang are coupled to the pump . .... , _ ... , ., .. ~ .

head assembL~ o~ the dialysate solution peristaltic pump mezns for rotation thereof at a speed of ~ro~ 450 to 500 rpm. Of course, it will be a~preciated that it may be desirable or necessary to deploy pump means other than peristaltic pump means in the aial~sate solution flow circuit to circulate ~luid therein, as for example, eccentric ring type pumps or gear ~pumps. ~onetheless, the use o~ peristaltic pump means, of the type described above in connection with the blood ~10~J circuit, in the dialysate solution ~low circuit permits a significant reduction in dialysate fluid film m~ss tr~ns~er resistance in the dialyæer to be reali~ed, with con-comitant increase in overall system dialyæing e~iciency.

Fig. 5 is a bottom view of the modularized dialysate ~low ~ircuit manifold assembly for the F~g. 2 hemodialysis system, sh~wing the details of construction thereof. From the dialysate solution supply container, as shown in Fig. l, the dial~sate solution flows through a connecting tubing segment and passes into the inlet opeDing 76 in base ~upport me~ber 59 of the ~anifold assembly to the heater 90.
Heater 90 comprises a thermally conducti~e tubular passage ~hrough which the dialysate solution ~lows for heating therein by insulated resistance heating strip means spirally wound around tne tubul~r passage. The wound heating strip is energized by current carrying èlectrical wires 104 and 105 joined thereto from the electronics en-closure 99. In the heater 90, the dialysate solution is ~armed i~ necessary to a temperature in the vicinity o~ 98F and then flo-~ed ~nto the manifold sensor block 911 which is a flow enclosure means con-taining an extended dialysate solution flow passage 93, along which are positioned temperature control sensing means 94 and photocell blood leak detection means adjacent the flow passage inlet 92.
Along the main length o~ the dialysate solution flow passa~e 93 are positioned a pair of spaced apart electrodes 96 as di~lysate solution electrolytic conductivity sensing means. At the outlet end -2~-11~28 o~ the manifold sensor block 91, adjacent to the outlet opening 77 in the base support member 59, are disposed a thermistor temperature monitoring sensor 97 and a photocell blood leak detector light source 98.
The dialysate solution discharged from the ~anifold sensor block 91 'through outlet opening 77 flows into a connecting tubing segment attached on the top side of the base support member 59 to negative pressure monitoring and adjustment means before passage to the dialyzer means.
In the illustrative manifold assembly, the temperature control sensing means 94 may suitably be joined with a conventional integrated circuit temperature transducer 103 mounted in socket 102 on the electronics enclosure 99. Transaucer circuit 103 is optically coupled with a silicon rectifier gate ~.eans in the electronics enclosure 9~ which controls the current signal transmitted in wires 104 and 105 to the heating strip for heat exchanger 9~. In this manner, the thermo-control circuit is arranged to mQintain the temperature o~ the dialysate solution to within ~0.5F about an adjustable control set point. All sensing means in the manifold sensor bLock 91--blood leak sensor 95, electrolytic conductivity sensors 96, and temperature sensor 97--are monitored and read out on the electronics display section of the upper secti.on panel 54, as shown and described in connection with the Fig. 2 embocliment of the invention.
In the illustrated manifold assem~ly, the sensor block 91 may suitably be formed o~ nylon, as a unitary block structure which is easily removed for cleaning and repair. The manifold Qssembly ~urther includes heater indicator lamp 61 suitably coupled to the silicon recti~ier gate means in the electronics enclosure 99~ to visually indicate when the heating means have been activated, and temperature calibration potentiometer 60 for adjustment of the set point dialysate solution temperature. The electronics enclosure 99 proYides power and signal readout connection means including low voltage sensor signal connector lO0 which is joined to the aforementioned upper section panel display module and 120 volt AC connector lOl to supply po~ler to the heating means associated with the ~anifold assembly.
Fig. 6 ~s a partially assernbled view of a section of the tubular heating means employed in the Fig. 5 r~anifold assembl~r, showing the construction thereo~. As illustrated, the dialysate solution heating means 90 comprises a tube 108 the wall of which is helioally ribbed ~Tith corrugated ribs lO9. The tube 108 may be formed of 316 Stainless Steel, with a nomir.al outer diarneter ~ 2 inch and a length o~ 2~ inchesO
e helical ribbing oP the tubing walls creates a vortex ~low o~ dialysate solution through the tubing which in turn fl~cilitates e~icient heat trans~er to the dialy~ate solution from the heating tape 110 spirally wound around the tubing 108. The tape llO suitAbly comprises an insulated 28~ watt heating tape. Alwninum foil lll is spirally w~apped around the heating tape llO to improve the heat transfer efficiency of the ~ape b~y reducing radiative heat losses there~rom and to mechanically protect the he~ting tape.
Fig. 7 is a side elevational view of a hemodialysis system as shown in Fig. 2, sho~Ting the details of construction of the dialysate manifold assembly. As sho m, the base support member 59 is provided in the ~orm of a plate or planar sheet. In this form, the rnanifold assembly may be detachably secured in the hemodialysis systern ~or ready replacement, with the inlet and the outlet of the dialysate solution flo~T
passage means of the mani~old assembly clet,achably coupLed to the dialysate solution ~low circuit as by coupling means 76 and 77 ~Jhereby cross-contamination problems associated with multiple patient use of the system ~y be si~ly eliminated by the dedication of a manifold assembly to each patient.
Fig. 8 is a schematic wiring diagram for the dialysate manifold assembly of Figs. 5 and 7. The connections of the electrolytic con-ductivity sensing elect~odes 96, blood leak sensing means 95, blood leak light source 93, strip heater 90~ pilot lamp 61, dialysate solution temperature control sensor 94, temperature control ad~ustment potentiometer -3o-~ 11028 means 60 and the dialysate solution temperature sensing means 97 with the electronics enclosure circuit connector 99, low voltage signal connector lO0 and 120 volt A.C. connector lO1 are clearly shown.
Although preferred embodiments of the invention haYe been described in detail it will be appreciated that other embodiments are contemplated only with modi~ications of the disclosed features, as being within the scope o~ the invention.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a hemodialysis apparatus for treatment of blood to remove waste impurities therefrom, including: dialyzer means through which waste-impurity containing blood and a dialysate solution are passed in indirect mass transfer dialyzing relationship for transfer of said waste impurities from said blood to said dialysate solution; means for supplying waste impurity-containing blood from a patient to said dialyzer means; means for returning waste impurity-depleted blood to said patient; and means for supplying dialysate solution to said dialyzer means and means for discharg-ing waste impurity-enriched dialysate solution from said dialyzer means forming a dialysate flow circuit, the improvement wherein said dialysate flow circuit includes a modularized dialysate solution manifold assembly and tubing segments for flowing dialysate solution to and discharging dialysate solution from said manifold assembly, said manifold assembly comprising:
(a) a base support plate member with main flat top and bottom surfaces having spaced-apart dialysate solution inlet and outlet openings therein, with coupling means associated with said inlet and outlet openings on the main top surface of said base support plate member for detachably joining the manifold assembly with said dialysate solution tubing segments;
(b) means positioned on the main bottom surface of said base support plate member comprising a tubular passage having an inlet end communicating with said dialysate solution inlet opening for flow of dialysate solution therethrough to an outlet end of said tubular passage and means for heating said dialysate solution in said tubular passage to form warm dialysate solution;
(c) means for sensing the temperature of said warm dialysate solution positioned downstream from said heating means and for adjusting the rate of heating of said dialysate solution by said heating means in response to said temperature sensing to maintain a predetermined dialysate solution temperature level;
(d) a flow enclosure means positioned on the main bottom surface of said base support plate member containing a dialysate solution flow passage having an inlet joined to the outlet end of said tubular passage of (b) and having an outlet communicating with said dialysate solution outlet opening for flow of dialysate solution therethrough, with monitor sensing means positioned in said dialysate solution flow passage including:
means for detecting blood leakage into said dialysate solution, means for sensing the electrolytic conductivity of said dialysate solution, and means for sensing said dialysate solution temperature, the apparatus being constructed such that said manifold assembly may readily be detached from said dialysate solution tubing segments and separ-ably removed from the remainder of said hemodialysis apparatus.

2. Apparatus according to claim 1 wherein said dialysate solution temperature sensing means of (c) is positioned in said dialysate solution flow passage of (d).

3. Apparatus according to claim 1 wherein said means for heating said dialysate solution comprise an insulated resistance heating strip means wound around said tubular passage.

4, Apparatus according to claim 1 further comprising: means for converting said temperature sensing of means (d) into a transmittable signal; means for transmitting said temperature sensing signal; visual display means coupled with said temperature sensing means by said signal transmitting means for indication of said sensed dialysate solution temperature; means for converting sensed dialysate solution electrolytic conductivity into a transmittal signal; means for transmitting said electrolytic conductivity sensing signal; and visual display means coupled with said electrolytic conductivity sensing means by said conductivity signal transmitting means for indication of said sensed dialysate solution electrolytic conductivity.

5. Apparatus according to claim 3 further comprising: audio alarm means coupled with said temperature sensing signal transmitting means and with said conductivity sensing signal transmitting an audible alarm when the sensed dialysate solution temperature or conductivity exceeds a pre-determined value.

6. Apparatus according to claim 1 wherein said means for supplying waste impurity-containing blood from a patient to said dialyzer means include a flexible resiliant tubing pumping section through which blood is pumped, with said blood supplying means and said means for returning waste impurity-depleted blood to said patient forming a blood flow circuit, further comprising: peristaltic pump means with a rotatable pump head assembly including a base member positioned for rotation about a fixed axis with a plurality of circumferentially spaced apart rollers mounted thereon for independent rotation about respective axes parallel to the base member fixed axis; means for anchoring the end segments of the flexible resiliant tubing pumping section such that the tubing is tensionally extended around the pump head assembly, being simultaneously engaged and compressed by at least two of said circumferentially spaced apart rollers with at least partial closure of the tubing at the points of compression, said rollers being mounted for longitudinal movement of the points of compression along the tubing during rotation of said pump head assembly to advance blood through said tubing.

7. In a hemodialysis apparatus for treatment of blood to remove waste impurities therefrom, including: dialyzer means through which waste-impurity containing blood and a dialysate solution are passed in indirect mass transfer dialyzing relationship for transfer of said waste impurities from said blood to said dialysate solution; means for transferring waste impurity-containing blood from a patient to said dialyzer means including a flexible resiliant tubing pumping section through which blood is pumped and means for returning waste impurity-depleted blood to said patient forming a blood flow circuit; means for transferring dialysate solution to said dialyzer means and means for discharging waste impurity-enriched dialysate solution from said dialyzer means forming a dialysate solution flow circuit including a flexible resiliant tubing pumping section through which dialysate solution is pumped; dual peristaltic pump means each with a rotatable pump head assembly including a base member positioned for rotation about a fixed axis with a plurality of circumferentially spaced apart rollers mounted thereon for independent rotation about respective axes parallel to the base member fixed axis; means for anchoring the end segments of the flexible resiliant tubing pumping sections in said blood flow circuit and said dialysate solution flow circuit such that the tubing in each circuit is tensionally extended around the pump head assembly of one of said peristal-tic pump means and is simultaneously engaged and compressed by at least two of said circumferentially spaced apart rollers of the peristaltic pump means for said circuit with at least partial closure of the tubing at the points of compression, the rollers of each peristaltic pump means being mounted for longitudinal movement of the points of compression along the associated tubing during rotation of said pump assembly to advance fluid through said tubing; the improvement wherein said dialysate flow circuit includes a modularized dialysate solution manifold assembly and tubing segments of said dialysate solution flow circuit for flowing dialysate solution to and discharging dialysate solution from said manifold assembly, said manifold assembly comprising;
(a) a base support plate member with main flat top and bottom surfaces having spaced-apart dialysate solution inlet and outlet openings therein, with coupling means associated with said inlet and outlet openings on the main top surface of said base support plate number for detachably joining the manifold assembly with said dialysate solution tubing segments;
(b) means positioned on the main bottom surface of said base support plate member comprising a tubular passage having an inlet end communicating with said dialysate solution inlet opening for flow of dialysate solution therethrough to an outlet end of said tubular passage and means for heating said dialysate solution in said tubular passage to form warm dialysate solution;
(c) means for sensing the temperature of said warm dialysate solution positioned downstream from said heating means and for adjusting the rate of heating of said dialysate solution by said heating means in response to said temperature sensing to maintain a predetermined dialysate solution temperature level;
(d) a flow enclosure means positioned on the main bottom surface of said base support plate member containing a dialysate solution flow passage having an inlet joined to the outlet end of said tubular passage of (b) and having an outlet communicating with said dialysate solution outlet opening for flow of dialysate solution therethrough, with monitor sensing means position in said dialysate solution flow passage including: means for detecting blood leakage into said dialysate solution, means for sens-ing the electrolytic conductivity of said dialysate solution, and means for sensing said dialysate solution temperature, wherein said dual peristaltic pump means, anchoring means, pump drive means, and said modularized dialysate solution manifold assembly are mounted for service in a unitary enclosure, and said modularized dialysate solution manifold assembly is detachably mounted in said unitary enclosure, whereby said manifold assembly may readily be detached from said dialysate solution tubing segments and separably removed from the remainder of said hemodialysis apparatus in said unitary enclosure.