US 12,447,250 B2
Peritoneal dialysis system using pressurized chamber and pumping bladder
John Zafiris, Hawthorn Woods, IL (US)
Assigned to Baxter International Inc., Deerfield, IL (US); and Baxter Healthcare SA, Glattpark (CH)
Filed by BAXTER INTERNATIONAL INC., Deerfield, IL (US); and BAXTER HEALTHCARE SA, Glattpark (CH)
Filed on Aug. 12, 2021, as Appl. No. 17/400,688.
Claims priority of provisional application 63/067,006, filed on Aug. 18, 2020.
Prior Publication US 2022/0054723 A1, Feb. 24, 2022
Int. Cl. A61M 1/28 (2006.01); A61M 1/16 (2006.01)
CPC A61M 1/28 (2013.01) [A61M 1/1601 (2014.02); A61M 1/1641 (2014.02); A61M 2205/3331 (2013.01); A61M 2205/3379 (2013.01); A61M 2210/1017 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A peritoneal dialysis system comprising:
a chamber;
a hydraulic pump;
an inflatable bladder located within the chamber and in hydraulic fluid communication with the hydraulic pump;
a pressure sensor positioned and arranged to sense pneumatic pressure within the chamber;
a flexible container or bag removably placed inside the chamber, the flexible container or bag fluidly coupled to at least one fluid line and configured to receive fresh or used dialysis fluid;
at least one valve fluidly located between the flexible container or bag and the at least one fluid line; and
a control unit configured to:
determine (i) a first amount of air within the flexible container or bag and/or the chamber before a discharge stroke of the hydraulic pump via a first ideal gas law calculation when the at least one valve is closed by:
(a) taking a first pressure reading via the pressure sensor,
(b) causing a first measurement amount of hydraulic fluid to be metered into the inflatable bladder, and
(c) taking a second pressure reading via the pressure sensor for use with the first ideal gas law calculation,
determine (ii) a second amount of air within the flexible container or bag and/or the chamber after the discharge stroke of the hydraulic pump via a second ideal gas law calculation when the at least one valve is closed by:
(a) taking a first pressure reading via the pressure sensor,
(b) causing a second measurement amount of the hydraulic fluid to be metered into the inflatable bladder, and
(c) taking a second pressure reading via the pressure sensor for use with the second ideal gas law calculation, and
determine (iii) a discharge volume of the fresh or used dialysis fluid from the flexible container or bag for the discharge stroke of the hydraulic pump by subtracting a difference between the first amount of air and the second amount of air from a known amount of the hydraulic fluid metered to the inflatable bladder for the discharge stroke.
 
20. A peritoneal dialysis system comprising:
a hydraulic pump;
a chamber;
an inflatable bladder located within the chamber and in hydraulic fluid communication with the hydraulic pump;
a pressure sensor positioned and arranged to sense pneumatic pressure within the chamber;
a flexible container or bag removably placed inside the chamber, the flexible container or bag fluidly coupled to at least one fluid line and configured to receive fresh or used dialysis fluid; and
a control unit configured to cause
(i) a draw stroke in which a measured amount of hydraulic fluid is removed from the inflatable bladder by the hydraulic pump to draw the fresh or used dialysis fluid into the flexible container or bag,
(ii) a first air amount determination to be made by taking pressure measurements using the pressure sensor before and after attempting to compress air within the chamber,
(iii) a discharge stroke in which a second measured amount of the hydraulic fluid is delivered to the inflatable bladder by the hydraulic pump to discharge the fresh or used dialysis fluid from the flexible container or bag,
(iv) a second air amount determination to be made by taking pressure measurements using the pressure sensor before and after attempting to compress the air within the chamber, and
(v) a discharge volume of the fresh or used dialysis fluid for the discharge stroke to be determined by subtracting a difference between the first air amount and the second air amount from the second measured amount of the hydraulic fluid delivered to the inflatable bladder for the discharge stroke.