Medical fluid pumping system having real time volume determination

A medical fluid pumping system comprising:

• a medical fluid pump;
• a first pressure chamber separate from and connected fluidly to the medical fluid pump;
• a second pressure chamber separate from and connected fluidly to the medical fluid pump;
• first and second pressure sensors connected operably to the first and second pressure chambers, respectively;
• at least one processor operable with the pressure sensors to calculate a volume of gas in the medical fluid pump prior to a pump-out stroke using a reading from the first pressure sensor after exposing the pump to gas pressure from the first pressure chamber and to use the calculated volume of gas in combination with a known volume of the second pressure chamber and a pressure decay reading taken via the second pressure sensor during the pump-out stroke to calculate at least one volume of fluid pumped during the pump-out stroke;
• wherein the at least one processor is further configured to:
• (a) calculate a volume of gas in the medical fluid pump after the pump-out stroke using a reading from the first pressure sensor after exposing the pump to gas pressure from the first chamber;
• and
• (b) calculate a total volume of fluid pumped via the pump-out stroke by subtracting the volume of gas in the medical fluid pump after the pump-out stroke from the volume of gas in the medical fluid pump prior to the pump-out stroke;
• and
• wherein the total volume of fluid pumped via the pump-out stroke is a first total volume, and which includes a second total volume of fluid pumped calculated by the processor using a final pressure decay reading taken via the second pressure senor, the at least one processor further configured to compare the first and second total fluid volumes pumped via the pump-out stroke.

A medical fluid pumping system comprising:

• a medical fluid pump;
• a pressure chamber connected fluidly to the medical fluid pump;
• a pressure sensor connected operably to the pressure chamber;
• and
• at least one processor operable with the pressure sensor to calculate at least one volume of fluid pumped during a pump-out stroke Vfluid,t according to an equation
• Vfluid,t=(Ppress, initial/Ppress,t−1)(Vpress+Vgas), wherein
• (i) Ppress,initial is an initial pressure of the pressure chamber prior to the pump-out stroke;
• (ii) Ppress,t is a pressure of the pressure chamber at a time t during the pump-out stroke;
• (iii) Vpress is a known volume of the pressure chamber;
• and
• (iv) Vgas is a volume of gas in the medical fluid pump prior to the pump-out stroke.

A medical fluid pumping system comprising:

• a medical fluid pump;
• a pressure chamber connected fluidly to the medical fluid pump;
• a pressure sensor connected operably to the pressure chamber;
• and
• at least one processor operable with the pressure sensor to calculate at least one volume of fluid pumped during a pump-fill stroke Vfluid,t according to an equation
• Vfluid,t=(Ppress, initial/Ppress,t−1)(Vpress+Vgas), wherein
• (i) Ppress,initial is an initial negative pressure of the pressure chamber prior to the pump-fill stroke;
• (ii) Ppress,t is a negative pressure of the pressure chamber at a time t during the pump-fill stroke;
• (iii) Vpress is a known volume of the pressure chamber;
• and
• (iv) Vgas is a volume of gas in the medical fluid pump under negative pressure prior to the pump-fill stroke.