Fluid conveyance monitoring system in an extracorporeal blood treatment device
A method for monitoring conveyance of fluid in a device for extracorporeal blood treatment, whereby fluid is conveyed by a peristaltic pump in a fluid system from a low-pressure side to a high-pressure side in that an elastically deformable fluid line positioned between the low-pressure side and the high-pressure side is deformed between a support surface and at least two squeeze elements of a rotor rotating opposite the support surface in such a way that a conveyance volume section is formed between the squeeze elements, whereby a fluid pressure value in the fluid system is detected for the conveyance volume section that is specific to the conveyance volume section, and whereby the detected conveyance-volume-specific fluid pressure value of a conveyance cycle n is compared with the detected conveyance-volume-specific fluid pressure value of a previous conveyance cycle n−x.
1. A method for monitoring a conveyance of fluid in a device for extracorporeal blood treatment, the method comprising the steps of:
conveying fluid in a fluid system with a peristaltic pump from a low-pressure side to a high-pressure side by deforming an elastically deformable fluid line positioned between the low-pressure side and the high-pressure side between a support surface and at least two squeeze elements of a rotor rotating opposite the support surface such that a conveyance volume section is formed between the squeeze elements and conveyed in each of a plurality of conveyance cycles;
detecting a fluid pressure value in the fluid system for the conveyance volume section in two or more conveyance cycles; and
comparing the detected conveyance volume fluid pressure value of one conveyance cycle n with the detected conveyance volume specific fluid pressure value of at least one preceding conveyance cycle n−x.
2. The method of claim 1 , wherein x is a value between 1 and 50.
3. The method of claim 2 , wherein the value is between 5 and 40.
4. The method of claim 3 , wherein the value is between 5 and 30.
5. The method of claim 4 , wherein the value is between 5 and 20.
6. The method of claim 1 , further comprising:
subjecting pressure progression of the detected fluid pressure value to digital signal analysis.
7. The method of claim 1 , further comprising:
determining a cross-correlation function of the fluid pressure value for the conveyance cycle n and the at least one preceding conveyance cycle n−x.
8. The method of claim 1 , wherein the detecting step comprises:
detecting venous pressure p V .
9. The method of claim 1 , wherein the detecting step comprises:
detecting fluid pressure value p BE before a dialyzer.
10. The method of claim 1 , wherein the detecting step comprises:
detecting arterial pressure p A .
11. The method of claim 1 , further comprising:
emitting an error signal when the detected fluid pressure exceeds a threshold value.
12. The method of claim 1 , further comprising:
determining a correlation with a predefined expectation function.