Method for ascertaining the vertical distance between a patient (level of surgical intervention) and a fluid delivery pump
Subject matter of the invention is a method for determining the difference in height level between a medical fluid pump and the body cavity of a patient for the correction of the measurement of the fluid pressure existing at the outlet end.
1. A method for determining a difference in height level h pat between a patient ( 10 ) and a fluid feed pump ( 5 ) with a current sensor ( 12 ) and with a bidirectional pressure sensor ( 6 ) in a second tube section ( 7 ) between fluid feed pump ( 5 ) and connection to a connector ( 8 ) or an instrument ( 9 ),
comprising a reservoir ( 1 ) of a medical device arranged above the fluid feed pump ( 5 ), fluidic connection paths that are initially unfilled, and a volume of the fluidic connection paths being known, characterized by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ) with a transport roller wheel ( 4 ) through a through-going fluidic connection of the reservoir ( 1 ),
b) stop fluid feeding as soon as the bidirectional pressure sensor ( 6 ) detects a change in pressure, which is caused by a fed water column,
c) backward rotation of the transport roller wheel ( 4 ) while measuring, by the current sensor ( 12 ), a motor current required for feeding from a first tube section ( 3 ) to the reservoir ( 1 ),
d) calculation of a pressure value P wat of a water column before the fluid feed pump from the required motor current,
e) continuation of fluid feeding until the second tube section ( 7 ) is completely filled,
f) detection of the fluid exiting from an open end of the second tube section ( 7 ) or the instrument ( 9 ) by evaluation of the pressure values at the bidirectional pressure sensor ( 6 ),
g) termination of fluid feeding,
h) evaluation of a pressure value P hyd of the bidirectional pressure sensor ( 6 ),
i) use of the pressure value P hyd for the determination of the difference in height level h pat between the fluid feed pump and the patient ( 10 ),
wherein when the pressure value P hyd is positive, this indicates that the fluid feed pump ( 5 ) is below the height level of the patient ( 10 ),
when the pressure value P hyd is negative, this indicates that the fluid feed pump ( 5 ) is above the height level of the patient ( 10 ),
when the pressure value P hyd is 0 (zero), this indicates that the fluid feed pump ( 5 ) is at a height level of the patient ( 10 ).
2. The method according to claim 1 , wherein the detection of a proper exit of the fluid through the second tube section ( 7 ) and the medical instrument ( 9 ) in a cavity of the patient ( 10 ) is performed by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ), until a pressure value different from zero is indicated at the bidirectional pressure sensor ( 6 ),
b) further fluid feeding, until a fed volume is larger than a volume of the tube, with the pressure measured at the bidirectional pressure sensor ( 6 ) remaining constant,
c) detection of a pressure increase at the bidirectional pressure sensor ( 6 ) after feeding a liquid volume, which is larger than the volume of the tube.
3. The method according to claim 1 , wherein detection of a faultily closed valve ( 8 ) is performed by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ), until a pressure value different from zero is indicated at the bidirectional pressure sensor ( 6 ),
b) further fluid feeding, wherein the pressure measured at the bidirectional pressure sensor ( 6 ) increases, before a fed volume corresponds to a volume of the tube.
4. The method according to claim 1 , wherein detection of the instrument faultily not being in a body cavity of the patient or of a non-closed connection between the second tube section ( 7 ) and the instrument ( 9 ) is performed by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ), until a pressure value different from zero is indicated at the bidirectional pressure sensor ( 6 )
b) further fluid feeding, until a fed volume is larger than a volume of the tube, with the pressure measured at the bidirectional pressure sensor ( 6 ) remaining constant,
c) detection that after feeding a liquid volume, which is larger than the volume of the tube, no pressure increase is measured at the bidirectional pressure sensor ( 6 ).
5. The method according to claim 1 , wherein the volume of the fluidic connection paths of the fluid feed is read out from an information carrier provided at a tube set prior to starting the fluid feeding.
6. The method according to claim 5 , characterized by that the information carrier is an RFID-Chip, a magnetic tape, a barcode or an EPROM.
7. A method for determining a difference in height level h pat between a patient ( 10 ) and a fluid feed pump ( 5 ) with a current sensor ( 12 ) and with a unidirectional pressure sensor ( 6 ) in a second tube section ( 7 ) between fluid feed pump ( 5 ) and connection to a connector ( 8 ) or an instrument ( 9 ),
comprising a reservoir ( 1 ) of a medical device arranged above the fluid feed pump ( 5 ), fluidic connection paths that are initially unfilled, and a volume of the fluidic connection paths being known, characterized by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ) with a transport roller wheel ( 4 ) through a through-going fluidic connection of the reservoir ( 1 ),
b) stop fluid feeding as soon as the unidirectional pressure sensor ( 6 ) detects a change in pressure, which is caused by a fed water column,
c) backward rotation of the transport roller wheel ( 4 ) while measuring, by the current sensor ( 12 ), a motor current required for feeding from a first tube section ( 3 ) to the reservoir ( 1 ),
d) calculation of a pressure value P wat of a water column before the fluid feed pump from the required motor current,
e) continuation of tube and instrument filling until the second tube section ( 7 ) is completely filled,
f) detection of the fluid exiting from an open end of the second tube section ( 7 ) or instrument ( 9 ) by evaluation of pressure values at the unidirectional pressure sensor ( 6 ),
g) termination of fluid feeding,
h) evaluation of a pressure value P hyd of the unidirectional pressure sensor ( 6 ),
i) use of a positive pressure value P hyd for the determination of the difference in height level h pat between the fluid feed pump and the patient ( 10 ),
wherein when the pressure value P hyd is positive, this indicates that the fluid feed pump ( 5 ) is below the height level of the patient ( 10 ),
when the pressure value P hyd is 0 (zero), this indicates that the fluid feed pump ( 5 ) is at the height level of the patient ( 10 ) or above the height level of the patient ( 10 ),
j) in case of a pressure value P hyd being 0 (zero), backward feeding of the fluid by backward rotation of the transport roller wheel ( 4 ),
k) determination of a motor current by evaluation of the current sensor ( 12 ) and calculation of the pressure for the determination of the difference in height level h pat between the patient ( 10 ) and the fluid feed pump ( 5 ).
8. A method for determining a difference in height level h pat between a patient ( 10 ) and a fluid feed pump ( 5 ) with a current sensor ( 12 ) and with a bidirectional pressure sensor ( 6 ) in a second tube section ( 7 ) between fluid feed pump ( 5 ) and connection to a connector ( 8 ) or instrument ( 9 ), and with a second pressure sensor ( 11 ) between a reservoir ( 1 ) and a transport roller wheel ( 4 ) with the reservoir ( 1 ) of a medical device being arranged above the fluid feed pump ( 5 ), wherein fluidic connection paths that are initially unfilled, and a volume of the fluidic connection paths being known, characterized by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ) with a transport roller wheel ( 4 ) through a through-going fluidic connection of the reservoir ( 1 ) to the transport roller wheel,
b) stop fluid feeding as soon as the bidirectional pressure sensor ( 6 ) detects a change in pressure, which is caused by a fed water column,
c) reading a pressure value P wat at the second pressure sensor ( 11 ),
d) continuation of tube and instrument filling until the second tube section ( 7 ) is completely filled,
e) detection of the fluid exiting from an open end of the second tube section ( 7 ) or instrument ( 9 ) by evaluation of the pressure values at the bidirectional pressure sensor ( 6 )
f) termination of fluid feeding,
g) evaluation of a pressure value P hyd of the bidirectional pressure sensor ( 6 ),
h) use of the pressure value P hyd for the determination of the difference in height level h pat between the fluid feed pump and the patient ( 10 ),
wherein when the pressure value P hyd is positive, this indicates that the fluid feed pump ( 5 ) is below the height level of the patient ( 10 ),
when the pressure value P hyd is negative, this indicates that the fluid feed pump ( 5 ) is above the height level of the patient ( 10 ),
when the pressure value P hyd is 0 (zero), this indicates that the fluid feed pump ( 5 ) is at the height level of the patient ( 10 ).
9. A method for the determination of a difference in height level h pat between a patient ( 10 ) and a fluid feed pump ( 5 ) with a current sensor ( 12 ) and with a unidirectional pressure sensor ( 6 ) in a second tube section ( 7 ) between fluid feed pump ( 5 ) and connection to a connector ( 8 ) or instrument ( 9 ), and with a second pressure sensor ( 11 ) between a reservoir ( 1 ) and a transport roller wheel ( 4 ), with the reservoir ( 1 ) of a medical device being arranged above the fluid feed pump ( 5 ), fluidic connection paths that are initially unfilled, and a volume of the fluidic connection paths being known, characterized by the following steps:
a) fluid feeding by the fluid feed pump ( 5 ) with a transport roller wheel ( 4 ) through a through-going fluidic connection of the reservoir ( 1 )
b) stop fluid feeding as soon as the unidirectional pressure sensor ( 6 ) detects a change in pressure, which is caused by a fed water column,
c) reading a pressure value P wat at the second pressure sensor ( 11 ),
d) continuation of tube and instrument filling until the second tube section ( 7 ) is completely filled,
e) detection of the fluid exiting from an open end of the second tube section ( 7 ) or instrument ( 9 ) by evaluation of the pressure values at the unidirectional pressure sensor ( 6 ),
f) termination of fluid feeding,
g) evaluation of a pressure value P hyd of the unidirectional pressure sensor ( 6 ),
h) use of a positive pressure value P hyd for the determination of the difference in height level h pat between the fluid feed pump and the patient ( 10 ),
wherein when the pressure value P hyd is positive, this indicates that the fluid feed pump ( 5 ) is below the height level of the patient ( 10 ),
when the pressure value P hyd is 0 (zero), this indicates that the fluid feed pump ( 5 ) is at the height level of the patient ( 10 ) or above the height level of the patient ( 10 ),
i) in a case of a pressure value P hyd 0 being (zero), backward feeding of the fluid by backward rotation of the transport roller wheel ( 4 ),
j) determination of a motor current by evaluation of the current sensor ( 12 ) and calculation of the pressure for the determination of the difference in height level h pat between the patient ( 10 ) and the fluid feed pump ( 5 ).