Automated peritoneal dialysis cycler and methods of use

Abstract

Automated peritoneal dialysis (APD) cycler systems and methods are disclosed. The APD cycler can include a heater tray with load cells configured to measure the weight of fluid contained within a heater bag and/or a drain bag. The load cells can be toggleable between enabled and disabled configurations. The APD cycler can include a pressure-based volume measurement system, which can be used to confirm measurements made by the load cells. In some embodiments, the APD cycler can have algorithms for tracking an estimated patient volume to prevent overfilling the patient.

The following is claimed: 
     
         1 . A dialysis system comprising:
 a containment chamber containing a first volume of gas and configured to receive a fill bag and a drain bag therein;   a first pressure sensor configured to measure the pressure in the containment chamber;   a reference chamber containing a second volume of gas;   a second pressure sensor configured to measure the pressure in the reference chamber;   a valve configured to selectively open and close a pathway between the containment chamber and the reference chamber;   one or more pumps configured to apply pressure to the containment chamber and to the reference chamber; and   a controller configured to apply a first pressure to the containment chamber using the one or more pumps, to apply a second pressure to the reference chamber using the one or more pumps, to open the pathway between the containment chamber and the reference chamber with the valve, and to measure an equalized pressure in at least one of the containment chamber and the reference chamber after the pressures of the containment chamber and the reference chamber have substantially equalized.   
     
     
         2 . The dialysis system of  claim 1 , wherein the controller is configured to calculate the first volume of gas inside the containment chamber based at least in part on the measured equalized pressure. 
     
     
         3 . The dialysis system of  claim 2 , wherein the controller is configured to determine a volume of an amount of fluid in at least one of the fill bag and the drain bag based at least in part on the calculated first volume of gas inside the containment chamber. 
     
     
         4 . The dialysis system of  claim 3 , further comprising a weigh scale configured to measure the weight of an amount of fluid in at least one of the fill bag and the drain bag. 
     
     
         5 . The dialysis system of  claim 4 , wherein the controller is configured to compare the measurement of the weigh scale to the calculated volume of the amount of fluid in at least one of the fill bag and the drain bag, and to post an alarm if the calculated volume differs from the measurement of the weigh scale by more than a threshold amount. 
     
     
         6 . The dialysis system of  claim 4 , wherein the controller is configured to calculate the volume of the fluid in at least one of the fill bag and the drain bag based at least in part on the measured weight, to compare the volume calculated from the measured weight to the volume calculated from the equalized pressure, and to post an alarm if the volume calculated from the measured weight differs from the volume calculated from the equalized pressure by more than a threshold amount. 
     
     
         7 . The dialysis system of  claim 1 , wherein the first pressure applied to the containment chamber is a negative pressure, and wherein the second pressure applied to the reference chamber is a negative pressure. 
     
     
         8 . The dialysis system of  claim 7 , wherein the second pressure applied to the reference chamber is a higher negative pressure than the first pressure applied to the containment chamber. 
     
     
         9 . The dialysis system of  claim 1 , further comprising one or more heating elements configured to warm fluid in the fill bag. 
     
     
         10 . The dialysis system of  claim 1 , wherein the controller is configured to determine a volume of an amount of fluid in at least one of the fill bag and the drain bag based at least in part on the measured equalized pressure. 
     
     
         11 . A method of determining a volume in a dialysis system, comprising:
 providing a containment chamber containing a first volume of gas and configured to receive a fill bag and a drain bag therein;   providing a reference chamber containing a second volume of gas;   applying a first pressure to the containment chamber using one or more pumps;   applying a second pressure to the reference chamber using the one or more pumps;   opening a pathway between the containment chamber and the reference chamber;   allowing the pressures of the containment chamber and the reference chamber to substantially equalize;   measuring an equalized pressure in at least one of the containment chamber and the reference chamber; and   calculating, using one or more computing devices, the first volume of gas inside the containment chamber based at least in part on the measured equalized pressure.   
     
     
         12 . The method of  claim 11 , further comprising determining a volume of an amount of fluid in at least one of the fill bag and the drain bag based at least in part on the calculated first volume of gas inside the containment chamber. 
     
     
         13 . The method of  claim 12 , further comprising measuring the weight of an amount of fluid in at least one of the fill bag and the drain bag using a weigh scale. 
     
     
         14 . The method of  claim 13 , further comprising:
 comparing the measured weight to the calculated volume of the amount of fluid in at least one of the fill bag and the drain bag; and   posting an alarm if the calculated volume differs from the measurement of the weigh scale by more than a threshold amount.   
     
     
         15 . The method of  claim 13 , further comprising:
 calculating the volume of the fluid in at least one of the fill bag and the drain bag based at least in part on the measured weight;   comparing the volume calculated from the measured weight to the volume calculated from the equalized pressure; and   posting an alarm if the volume calculated from the measured weight differs from the volume calculated from the equalized pressure by more than a threshold amount.   
     
     
         16 . The method of  claim 11 , wherein the first pressure applied to the containment chamber is a negative pressure, and wherein the second pressure applied to the reference chamber is a negative pressure. 
     
     
         17 . The method of  claim 16 , wherein the second pressure applied to the reference chamber is a higher negative pressure than the first pressure applied to the containment chamber. 
     
     
         18 . The method of  claim 11 , further comprising warming fluid in the fill bag.