Simulation of patient drain phase in peritoneal dialysis

Abstract

A method of modeling a patient's peritoneal dialysis drain phase includes (a) modeling a first segment of a drain phase curve as having a constant flowrate, (b) modeling a second segment of the drain phase curve as having a decaying exponential flowrate, and (c) ensuring that a drain flowrate does not fall below a certain level during therapy by incorporating a switching component so that (i) at a first time the first segment is active while the second segment is inactive and (ii) at a second time the first segment is inactive while the second segment is active.

The invention is claimed as follows: 
     
         1 . A method of modeling a patient's peritoneal dialysis drain phase comprising:
 modeling a first segment of a drain phase curve as having a constant flowrate;   modeling a second segment of the drain phase curve as having a decaying exponential flowrate; and   ensuring that a drain flowrate does not fall below a certain level during therapy by incorporating a switching component so that (i) at a first time the first segment is active while the second segment is inactive and (ii) at a second time the first segment is inactive while the second segment is active.   
     
     
         2 . The method of  claim 1 , which includes setting a flow transition percentage at which the switching component transitions from the first segment to the second segment. 
     
     
         3 . The method of  claim 2 , wherein setting the flow transition percentage includes setting a volume at which the switching component transitions from the first segment to the second segment. 
     
     
         4 . The method of  claim 2 , wherein setting the flow transition percentage includes setting a percentage of time at which the first segment is active relative to the second segment. 
     
     
         5 . The method of  claim 1 , which includes setting a minimum drain volume or drain volume percentage that must be met during the drain phase. 
     
     
         6 . The method of  claim 1 , which further includes determining (i) a minimum drain percentage or minimum drain volume, (ii) a low flowrate level, and (iii) a drain phase time that is long enough for the minimum drain percentage or minimum drain volume to be met but not long enough for an actual drain flowrate to fall below the low flowrate level. 
     
     
         7 . The method of  claim 1 , which further includes modeling for the patient a dwell time for a peritoneal dialysis dwell phase. 
     
     
         8 . The method of  claim 1 , which further includes determining a low drain flowrate threshold below which therapy is stopped during the drain phase. 
     
     
         9 . The method of  claim 1 , which includes modeling the constant flowrate for a particular patient body position taken during the drain phase. 
     
     
         10 . A peritoneal dialysis method comprising:
 modeling a first segment of a drain phase curve for a peritoneal dialysis drain phase as having a constant flowrate;   modeling a second segment of the drain phase curve for the peritoneal dialysis drain phase as having a decaying exponential flowrate;   incorporating a switching component so that (i) at a first time during the drain phase the first segment is active while the second segment is inactive and (ii) at a second time during the drain phase the first segment is inactive while the second segment is active;   using the modeled first and second drain phase segments and the switching component to determine at least one of: (i) a drain time for the drain phase, (ii) a low flowrate setting, or (iii) a minimum drain volume percentage; and   entering at least one of the drain time, the low flowrate setting, or the minimum drain volume percentage into an automated peritoneal dialysis (“APD”) machine.   
     
     
         11 . The method of  claim 10 , wherein modeling the second drain phase segment includes empirically calculating a patient specific decaying exponential constant. 
     
     
         12 . The method of  claim 11 , wherein empirically calculating the patient specific decaying exponential constant is performed based upon a drain type, the drain type including (i) a pumped drain or (ii) a gravity fed drain. 
     
     
         13 . The method of  claim 11 , wherein empirically calculating the patient specific decaying exponential constant is performed based upon a pump type, the pump type including (i) a peristaltic pump or (ii) a membrane pump. 
     
     
         14 . A peritoneal dialysis method comprising:
 modeling a first segment of a drain phase curve as having a constant flowrate;   modeling a second segment of the drain phase curve as having a decaying exponential flowrate;   incorporating a switching component so that (i) at a first time the first segment is active while the second segment is inactive and (ii) at a second time the first segment is inactive while the second segment is active; and   using the modeled first and second drain phase segments and the switching component to set in an automated peritoneal dialysis (“APD”) machine at least one of: (i) a low flowrate level; or (ii) a minimum drain volume percentage.   
     
     
         15 . The method of  claim 14 , which further includes modeling an appropriate dwell time for the patient and setting the dwell time into the APD machine. 
     
     
         16 . The method of  claim 15 , which includes using the minimum drain volume percentage to determine the appropriate dwell time. 
     
     
         17 . A peritoneal dialysis method comprising:
 modeling a first drain phase curve including (i) a first segment having a constant flowrate, (ii) a second segment having a decaying exponential flowrate, and (iii) a switching component that causes the first segment to be active at a first time while the second segment is inactive, and the first segment to be inactive at a second time while the second segment is active;   modeling a second drain phase curve including (i) a first segment having a constant flowrate, (ii) a second segment having a decaying exponential flowrate, and (iii) a switching component that causes the first segment to be active at a first time while the second segment is inactive, and the first segment to be inactive at a second time while the second segment is active;   selecting one of the first or second drain phase curves for a peritoneal dialysis treatment; and   setting at least one parameter of the peritoneal dialysis treatment based upon the selected drain phase curve.   
     
     
         18 . The method of  claim 17 , wherein the at least one parameter includes at least one of a drain time, a drain volume or a drain flowrate. 
     
     
         19 . The method of  claim 17 , wherein modeling the first drain phase curve includes modeling the first drain curve for a first patient body position, and wherein modeling the second drain phase curve includes modeling the second drain curve for a second patient body position. 
     
     
         20 . The method of  claim 17 , wherein the body positions include standing, sitting or lying down.