Temperature compensation for pneumatic pumping system

A dialysis system having temperature compensation comprising:

• a pumping mechanism including
• a disposable cassette including least two pumping chambers, and
• a reference chamber;
• and
• a controller configured to (i) input a temperature measurement of one of the pumping chambers, (ii) select an offset temperature that is dependent on the measured temperature, (iii) apply the offset temperature to the measured temperature, and (iv) correct a volume of air pumped by the particular pumping chamber using the formula
• V
• d
• =
• V
• r
• *
• T
• do
• *
• Tr
• cal
• *
• (
• Pr
• 2
• -
• Pr
• 1
• )
• T
• r
• *
• Td
• cal
• *
• (
• Pd
• 1
• -
• Pd
• 2
• )
• ,
• wherein Vd is the corrected volume, Vr is a nominal chamber volume, Tdo is the temperature of the chamber with the offset applied, Tr is the temperature of the reference chamber, Trcal/Tdcal is a correction factor calibrated at 37° C., and (Pr2−Pr1/(Pd1−Pd2) is a ratio of the pressure differences of the reference chamber and the particular pumping chamber before and after equalization.

A peritoneal dialysis system including temperature compensation, the system comprising:

• a pumping system including
• a disposable chamber, and
• a reference chamber;
• and
• a controller configured to
• (i) calculate a volume of air delivered to the disposable chamber using the formula
• V
• d
• =
• V
• r
• *
• (
• Pr
• 2
• -
• Pr
• 1
• )
• (
• Pd
• 1
• -
• Pd
• 2
• )
• ,
• wherein Vd is the volume, Vr is a reference volume of the reference chamber, and (Pr2−Pr1) is a difference between a pressure in the reference chamber before and after equalization, and (Pd1−Pd2) is a difference between a pressure in the disposable chamber before and after equalization,
• (ii) calculate a corrected volume of air delivered to the disposable chamber by multiplying Vd by a ratio of a temperature of a membrane adjacent the disposable chamber to a temperature in the reference chamber, Tm/Tr, and by a ratio of Trcal/Tdcal, wherein Trcal is a previously measured temperature in the reference chamber, and Tdcal is previously measured temperature in the disposable chamber, and
• (iii) calculate a corrected volume of dialysate pumped by the dialysis system using the corrected volume of air delivered to the disposable chamber.

A peritoneal dialysis system comprising:

• a pumping system including
• a pumping mechanism,
• a disposable chamber, and
• a reference chamber;
• and
• a controller configured to:
• (i) measure a temperature of air pumped from the disposable chamber,
• (ii) calculate a volume of air delivered to the disposable chamber using the formula
• V
• d
• =
• V
• r
• *
• (
• Pr
• 2
• -
• Pr
• 1
• )
• (
• Pd
• 1
• -
• Pd
• 2
• )
• ,
• wherein Vd is the volume, V, is a reference volume of the reference chamber, and (Pr2−Pr1) is a difference between a pressure in the reference chamber before and after equalization, and (Pd1−Pd2) is a difference between a pressure in the disposable chamber before after equalization,
• (iii) calculate a corrected volume of air delivered to the disposable chamber by multiplying Vd by:
• (a) a ratio of an offset temperature to a temperature in the reference chamber, Tm/Tr, the offset temperature including the measured temperature of the air corrected by an offset, wherein the offset depends on the measured temperature and the disposable chamber, and
• (b) a ratio of Trcal/Tdcal, wherein Trcal is a previously measured temperature in the reference chamber, and Tdcal is a previously measured temperature in the disposable chamber, and
• (iii) calculate a corrected volume of dialysate pumped by the dialysis system using the corrected volume of air delivered to the disposable chamber.

A dialysis system comprising:

• a pneumatic distribution manifold including
• a heater, and
• a reference volume chamber;
• a disposable chamber;
• and
• a controller configured to (i) control a temperature of the first heater by monitoring a temperature of the manifold, (ii) monitor temperature of air in the disposable chamber, (iii) calculate a corrected volume of air delivered to the disposable chamber using a temperature of air in the reference volume chamber, and (iv) correct a volume of dialysate pumped by the dialysis system using the calculated corrected volume of air delivered to the disposable chamber.