Apparatus and method for monitoring and controlling a peritoneal dialysis therapy

Abstract

An apparatus for performing peritoneal dialysis includes a housing; a peritoneal dialysis supply bag supported by and/or located above the housing; a first valve for controlling gravity flow of fresh peritoneal dialysis fluid from the supply bag to a patient; a second valve for controlling gravity flow of used peritoneal dialysis fluid from the patient to a drain; and a pressure sensor positioned and arranged with respect to the gravity flow of fresh peritoneal dialysis fluid or the gravity flow of used peritoneal dialysis fluid to provide a reading used to evaluate a head height pressure.

Claims

1. An apparatus for performing peritoneal dialysis comprising: a housing; a peritoneal dialysis supply bag supported by the housing, such that in use the peritoneal dialysis supply bag is located elevationally above a patient; a first valve for controlling gravity flow of fresh peritoneal dialysis fluid from the peritoneal dialysis supply bag to the patient; a second valve for controlling gravity flow of used peritoneal dialysis fluid from the patient to a drain, wherein the drain in use is located elevationally below the patient; a first pressure sensor positioned and arranged with respect to the gravity flow of fresh peritoneal dialysis fluid to provide a first reading used to evaluate a first gravity head pressure; a second pressure sensor positioned and arranged with respect to the gravity flow of used peritoneal dialysis fluid to provide a second reading used to evaluate a second gravity head pressure; and a controller configured to establish the first and second gravity head pressures due to a location of the peritoneal dialysis supply bag and a location of the drain using the first and second readings.

2. The apparatus of claim 1, wherein the drain includes a drain container located below the housing for collecting the used peritoneal dialysis fluid.

3. The apparatus of claim 1, wherein the peritoneal dialysis supply bag is placed on the housing.

4. The apparatus of claim 1, wherein the drain is elevationally disposed below a peritoneal cavity of the patient.

5. The apparatus of claim 1, wherein at least one of (i) the first pressure sensor is integrated with the first valve, or (ii) the second pressure sensor is integrated with the second valve.

6. The apparatus of claim 1, wherein the first and second valves are operable respectively with a fill line and a drain line.

7. The apparatus of claim 1, wherein the first pressure sensor is placed in mechanical communication with a line carrying the gravity flow of fresh peritoneal dialysis fluid.

8. The apparatus of claim 1, wherein the second pressure sensor is placed in mechanical communication with a line carrying the gravity flow of used peritoneal dialysis fluid.

9. An apparatus for performing peritoneal dialysis comprising: a housing; a peritoneal dialysis supply bag located above the housing, such that in use the peritoneal dialysis supply bag is located elevationally above a patient; a first valve for controlling gravity flow of fresh peritoneal dialysis fluid from the peritoneal dialysis supply bag to the patient; a second valve for controlling gravity flow of used peritoneal dialysis fluid from the patient to a drain, wherein the drain in use is located elevationally below the patient; a first pressure sensor positioned and arranged with respect to the gravity flow of fresh peritoneal dialysis fluid to provide a first reading used to evaluate a first gravity head pressure; a second pressure sensor positioned and arranged with respect to the gravity flow of used peritoneal dialysis fluid to provide a second reading used to evaluate a second gravity head pressure; and a controller configured to establish the first and second gravity head pressures due to a location of the peritoneal dialysis supply bag and a location of the drain using the first and second readings, respectively.

10. The apparatus of claim 9, wherein the drain includes a drain container located below the housing for collecting the used peritoneal dialysis fluid.

11. The apparatus of claim 10, wherein the drain container hangs from the housing.

12. The apparatus of claim 9, wherein the peritoneal dialysis supply bag is placed on the housing.

13. The apparatus of claim 9, wherein at least one of (i) the first pressure sensor is integrated with the first valve, or (ii) the second pressure sensor is integrated with the second valve.

14. The apparatus of claim 12, wherein the first pressure sensor is placed in mechanical communication with a line carrying the gravity flow of fresh peritoneal dialysis fluid.

15. The apparatus of claim 9, wherein the second pressure sensor is placed in mechanical communication with a line carrying the gravity flow of used peritoneal dialysis fluid.

16. A method for performing peritoneal dialysis comprising: enabling gravity flow of fresh peritoneal dialysis fluid to a patient; enabling gravity flow of used peritoneal dialysis fluid from the patient; sensing a first pressure of the fresh peritoneal dialysis fluid prior to flowing to the patient and a second pressure of the used peritoneal dialysis fluid prior to flowing from the patient; and programming a controller to evaluate (i) a first gravity head pressure from the first sensed pressure prior to a flow of the fresh peritoneal dialysis fluid into a peritoneal cavity of the patient and (ii) a second gravity head pressure from the second sensed pressure prior to a flow of the used peritoneal dialysis fluid from the patient's peritoneal cavity.

17. The method of claim 16, which includes sequencing plural valves to gravity flow the fresh and used peritoneal dialysis fluids to and from the patient.

18. A method for performing peritoneal dialysis comprising: enabling gravity flow of fresh peritoneal dialysis fluid from a source to a patient; enabling gravity flow of used peritoneal dialysis fluid from the patient to a drain; sensing a first pressure of the fresh peritoneal dialysis fluid prior to flowing from the source and a second pressure of the used peritoneal dialysis fluid prior to flowing to the drain; and programming a controller to evaluate (i) a first gravity head pressure from the first sensed pressure prior to a flow of fresh peritoneal dialysis fluid into a peritoneal cavity of the patient and (ii) a second gravity head pressure from the second sensed pressure prior to a flow of used peritoneal dialysis fluid to the drain.

19. The method of claim 18, which includes sequencing plural valves to gravity flow the fresh and used peritoneal dialysis fluids from the source and to the drain, respectively.

20. The method of claim 19, which includes integrating at least one of (i) the first pressure sensor with a first valve of the plural valves, or (ii) the second pressure sensor with a second valve of the plural valves.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 illustrates, schematically, a prior art automated peritoneal dialysis system;

(2) FIG. 2 illustrates, schematically, a prior art automated peritoneal dialysis system;

(3) FIG. 3 illustrates, schematically, a prior art automated peritoneal dialysis system;

(4) FIG. 4 illustrates, schematically, an automated peritoneal dialysis system made in accordance with the present invention;

(5) FIG. 5 illustrates, schematically, a second embodiment of an automated peritoneal dialysis system made in accordance with the present invention;

(6) FIG. 6 illustrates, schematically, a third embodiment of an automated peritoneal dialysis system made in accordance with the present invention;

(7) FIG. 7 illustrates, schematically, a fourth embodiment of an automated peritoneal dialysis system made in accordance with the present invention;

(8) FIG. 8 illustrates a pressure sensor made in accordance with the present invention;

(9) FIG. 9 illustrates a fifth embodiment incorporating dual pumping chambers and pressure sensors made in accordance with the present invention;

(10) FIG. 10 illustrates, schematically, a dual lumen catheter that can be utilized with the present invention;

(11) FIG. 11 is a sectional view taken substantially along line 11-11 of FIG. 10;

(12) FIG. 12 illustrates, graphically, the urea concentration in blood and the urea concentration in a dialysate during a multiple dwell dialysis session;

(13) FIG. 13 illustrates, graphically, the concentration of urea in a patient's bloodstream versus the concentration of urea in a dialysate solution for an automated peritoneal dialysis solution practiced in accordance with the prior art; and

(14) FIG. 14 illustrates, graphically, the concentration of urea in a patient's bloodstream versus the concentration of urea in a dialysate for an automated peritoneal dialysis therapy session carried out in accordance with the present invention.

(15) It should be understood that the drawings are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

(16) Turning to FIG. 4, a cycler 30 includes a dialysate container 11 connected to a pump 31. The pump 31 is connected to a pressure sensor 32. The pump 31 and pressure sensor 32 are disposed in-line in a lumen 33 that connects the dialysate container 11 to a catheter 34. Control valves are provided at 35, 36. A drain container 13 is also connected to a pump 36 which is connected to a sensor 37. The pump 36 and sensor 37 are also connected in-line to a lumen 38 which connects the drain container 13 to the catheter 34. Control valves are again provided at 41, 42. During the fill, the pump 31 pumps dialysate from the container 11 through the lumen 33 and catheter 34 into the peritoneum (not shown) of the patient 12. During this time, the sensor 37 monitors and measures the intraperitoneal pressure. A signal is sent to the controller of the cycler 30 shown schematically at 43. A control panel is indicated generally at 44.

(17) During the drain, the sensor 31 can accurately monitor and measure the intraperitoneal pressure of the patient 12. In the embodiment illustrated in FIG. 4, no pumps or control valves are disposed between the sensor 32 and the patient 12.

(18) Turning to FIG. 5, a cycler 50 is illustrated which includes reversible pumping chambers 51, 52 with sensors 53, 54 disposed between the reversible pumping chambers 51, 52 and the patient 12 respectively. Control valves 55 and 56 are disposed on another side of the reversible pumping chamber 51 and the sensor 53 and control valves 57, 58 are provided on either side of the reversible pumping chamber 52 and sensor 54. The sensors 53, 54 actually measure the pressure on the diaphragms of the reversible pumping chambers 51, 52.

(19) Turning to FIG. 6, a cycler 60 is illustrated with a chamber 61 for accommodating the drain container 13 and a chamber 62 for accommodating the dialysate container 11. Each chamber 61, 62 is equipped with an integrated valve assembly and pressure sensor shown at 63, 64. In the embodiment 60 shown in FIG. 6, the chamber 61 must be capable of being evacuated. Dialysate may flow from the dialysate container 11 by way of gravity or pressure fill. Again, the sensors of the valve assembly/sensor combinations 63, 64 monitor the intraperitoneal pressure of the patient 12 as discussed above.

(20) In the embodiment 70 illustrated in FIG. 7, the dialysate container 11 and drain container 13 are both connected to integrated control valves and pressure sensors 71, 72. Each of the integrated control valves and pressure sensors 71, 72 are connected to lumens 73, 74 respectively which are connected to the catheter 75a by way of a Y-connection. The details of all the Y-connections and clamps are not shown but are known to those skilled in the art. Flow from the dialysate container 11 to the patient is carried out under the gravitational head shown at 75 while flow from the patient to the drain container 13 is carried out under the gravitational head shown at 76.

(21) FIG. 8 illustrates one in-line pressure sensor 80 that is suitable for use with the present invention. Redundant load cells 81, 82 are connected to the flexible pressure sensing membrane 83 by a vacuum connected by the line 84, 85. A lumen connecting the cycler to the patient is shown at 86.

(22) FIG. 9 illustrates a dual-pumping chamber cassette 87 which includes an output line 88 which connects the cassette 87 to the patient and an input line 89 connecting the patient to the cassette 87. The line 90 connects the cassette 87 to the dialysate container (not shown). Each pumping chamber 91, 92 is in communication with all three lines 88, 89 and 90. Thus, every line can be connected to either pumping chamber 91, 92. The pumping chambers 91, 92 are bound on one side by a common diaphragm shown at 93. Flow is controlled by the use of diaphragm valves shown at 94, 95, 96 and 97. Pressure sensors are shown at 120, 121, 122, 123, 124 and 125. However, pressure sensors 123 and 120 are the sensors used to measure intraperitoneal pressure in accordance with the present invention. The remaining sensors 121, 122, 124, 125 are used to monitor the operation of the pumps 126, 127.

(23) When the left diaphragm pump 126 is pushing dialysate to the patient, the sensor 123 can measure the intraperitoneal pressure through the line 89. When the left diaphragm pump 126 is draining fluid from the patient through the line 89, the sensor 120 can measure intraperitoneal pressure through the line 88 and while the right pump 127 is pumping fluid to the drain container (not shown) through the drain line shown schematically at 128. When the right diaphragm pump 127 is being used to drain fluid from the patient, the sensor 120 can measure intraperitoneal pressure while the left diaphragm pump 126 is pumping fluid to the drain container (not shown) through the drain line shown schematically at 129.

(24) FIGS. 10 and 11 illustrate a dual-lumen catheter 100 which includes separate passageways 101, 102. The employment of a dual lumen catheter 100 as compared to a dual lumen patient line can move the point at which the pressure is measured to within the peritoneum itself by way of communication through the separate flowpaths 101, 102. The dual lumen catheter 100 installs like a single lumen catheter, yet will function either as a flow through or a standard catheter. Both fluid pathways 101, 102 are used to withdraw and deliver fluid during the drain and fill. While one pathway delivers fluid, the other pathway drains. The end section, shown generally at 103, is perforated.

(25) A comparison of an APD therapy for a prior art APD cyclers and one manufactured in accordance with the present invention are summarized as follows:

(26) TABLE-US-00001 Current APD Cycler Using Therapy Parameter Cycler Invention Total Therapy Volume 15 liters 15 liters Fill Volume 2.2 liters 2.5 liters max Fill Pressure Limit not applicable 14 mm Hg max Total Therapy Time 8 hours 8 hours Last (Day) Fill Volume 1,500 ml 1,500 ml Last Fill Dextrose Same Same Initial Drain Alarm 1,200 ml 1,200 ml Drain X of N Alarm 80% 80%

(27) TABLE-US-00002 TABLE 1 Comparison of Therapies for Current Cyclers versus Cycler using Invention Method Therapy Phase Therapy Parameter Prior Art Cycler I Prior Art Cycler 2 Invention Cycler 3 Initial Drain Drain Volume 1,200 ml 1,200 ml 1,200 ml Patient Volume 300 ml 300 ml 300 ml Fill I of 5 Fill Volume 2,200 ml 2,200 ml 2,500 ml Patient Volume 2,500 2,500 2,800 Fill Pressure not applicable not applicable 12 mm Hg Drain 1 of 5 Drain Volume 1,800 ml 2,200 ml 2,200 ml Patient Volume 700 ml 300 ml 600 ml Fill 2 of 5 Fill Volume 2,200 ml 2,200 ml 2,400 ml Patient Volume 2,900 ml 2,500 ml 3,000 ml Patient Pressure not applicable not applicable 14 mm Hg Drain 2 of 5 Drain Volume 1,800 ml 2,200 ml 2,200 ml Patient Volume 1,100 ml 300 ml 800 ml Fill 3 of 5 Fill Volume 2,200 ml 2,200 ml 2,200 ml Patient Volume 3,300 ml 2,500 ml 3,000 ml Patient Pressure not applicable not applicable 14 mm Hg Drain 3 of 5 Drain Volume 1,801 ml 2,200 ml 2,200 ml Patient Volume 1,499 ml 300 ml 800 ml Fill 4 of 5 Fill Volume 2,200 ml 2,200 ml 2,200 ml Patient Volume 3,699 ml 2,500 3.000 ml Patient Pressure not applicable not applicable 3,000 ml Drain 4 of 5 I Drain Volume 1,800 ml 2,200 ml. 2,200 ml Patient Volume 1,899 ml 300 ml 800 ml Fill 5 of 5 Fill Volume uF Alarm Bypass 2,200 ml 2,200 ml 2,200 ml Patient Volume 4,099 ml 2,500 ml 3,00 ml Patient Pressure Patient Wakes Overfull, not applicable 14 mm Hg Manually Drains 1,500 ml Drain 5 of 5 Drain Volume 1,800 ml 2,200 ml 2,200 ml Patient Volume 799 ml 300 ml 800 ml Final Fill Fill Volume 1,500 ml 1,500 ml 1,500 ml

(28) Inspection of Table 1 shows that cycler 1 woke the patient at around 4:30 in the morning with a negative uF alarm at the beginning of Fill 5. The patient bypassed the alarm because he did not feel overfull and immediately fell back asleep. He woke up about minutes later when he had difficulty breathing and felt extremely overfull. He manually drained about 1500 ml but was unable to go back to sleep. He filed a formal product complaint with the manufacturer.

(29) The data of Table 1 shows that cycler 2 ran a completely normal therapy but the total therapy clearance (calculated based upon the sum of the night patient volumes) was only 84.5% of that obtained by cycler 3, which was using the cycler that used the method of the current invention.

(30) The data of Table 1 shows that cycler 3 ran a completely normal therapy and that the fill volume was limited on one occasion by the maximum fill volume but on four occasions by the patient's intraperitoneal pressure. This patient never felt any discomfort and had no alarms during the night. The limit on the IPP prevented him from being overfilled even though he had successive drains that were not complete. The volume of fluid in his peritoneum never exceeded 3 liters.

(31) The patient on cycler 1 had an intraperitoneal pressure in excess of 14 mm Hg during dwells 3 and 4. His breathing may have been impaired and his heart may have had to work harder but the discomfort was not enough to wake him up from a sound sleep until it peaked at 4,099 ml during dwell 5.

(32) In conclusion, the method of the present invention provides for optimum fills and therefore more clearance while preventing overfills that bring discomfort and inhibit the function of vital body organs. A negative uF alarm would seldom occur because overfills of the required magnitude would be prevented by the IPP sensors.

(33) Calculation of Intraperitoneal Pressure (IPP)

(34) In order to calculate the IPP, one may first calculate the patient head height correction using conservation of energy:
(V.sup.2+Ppa.sub.gh)+Frictional Losses=0

(35) The velocity V of fluid through the patient line is the same at both ends of the line as is the fluid density, so this equation can be written as
(P.sub.2P.sub.1)pa.sub.g(h.sub.2h,)+Frictional Losses=0

(36) which can be rearranged as

(37) $h=\frac{\left(P_1-P_2\right)-\mathrm{Frictional}\mathrm{Losses}}{a_g}$

Example 1

(38)
P1=L25 psig=85060 (gram/cm)/(cm.sup.2-sec.sup.2)
P2=0.9 psig=61240 (gram/cm)/(cm.sup.2-sec.sup.2)
Frictional Losses=39130(gram/cm)/(cm.sup.2-sec.sup.2) with flow of 197 cm/min in a 4 mm ID line at a velocity of approximately 172 cm/sec, wherein
a.sub.g=981 cm/sec.sup.2
=1 gram/cm.sup.3

(39) $h=\frac{\left(\left(85060-30620\right)-39130\right)\left(\mathrm{gram}\text{/}\mathrm{cm}\right)/\left({\mathrm{cm}}^2-{\sec }^2\right)}{1\mathrm{gram}\text{/}{\mathrm{cm}}^3*981\mathrm{cm}\text{/}{\sec }^2}$
h=15.6 cm (The patient is 15.6 cm below the membrane)

Example 2

(40)
P1=1.25 psig=85060 (gram/cm)/(cm.sup.2-sec.sup.2)P2=0.45 psig=30620 (gram/cm)/(cm.sup.2-sec.sup.2)
Frictional Losses=39130 (gram/cm)/(cm.sup.2-sec.sup.2) with flow of 197 cmn/min in a 4 mm ID line at a velocity of approximately 172 cm/sec, wherein
a.sub.g=981 cm/sec.sup.2
=1 gram/cm.sup.3

(41) $h=\frac{\left(\left(85060-30620\right)-39130\right)\left(\mathrm{gram}\text{/}\mathrm{cm}\right)/\left({\mathrm{cm}}^2-{\sec }^2\right)}{1\mathrm{gram}\text{/}{\mathrm{cm}}^3*981\mathrm{cm}\text{/}{\sec }^2}$
h=+15.6 cm (The patient is 15.6 cm above the membrane)

(42) The patient head height can be established at the beginning of each fill. Any changes in the head height that occur during the fill can be attributed to an increase in intraperitoneal pressure (IPP) since the patient is asleep.

(43) Turning to FIG. 12, the concentration gradient between the urea concentration 110 in the patient's blood and the urea concentration 111 in the dialysate for typical APD cyclers is illustrated graphically. Comparing the results illustrated in FIGS. 13 and 14, it is evident that APD cyclers equipped with the sensors of the present invention provide superior results. Specifically, the data illustrated graphically in FIG. 13 was obtained using a prior art APD cycler. The data obtained in FIG. 14 was obtained using an APD cycler utilizing two sensors for monitoring intraperitoneal pressure. Note that the urea concentration 110 in the bloodstream is lower in FIG. 14 than in FIG. 13. Further note, the dialysate volume or fill volume is lower for the therapy illustrated in FIG. 14 than the therapy illustrated in FIG. 13. Thus, the present invention provides improved urea clearance with lower fill volumes.

(44) It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the appended claims.