Method for detecting an occlusion in an infusion line
First Claim
1. A method for detecting an occlusion in an infusion line connected to an infusion device, comprising:
- measuring a force applied to a piston by a pusher device of an infusion device during an infusion operation performed by the infusion device for moving the piston along a movement direction into a cylindrical tube in order to deliver a medical fluid from the cylindrical tube towards an infusion line connected to the cylindrical tube,calculating, from the measured force, a value indicative of a pressure in the cylindrical tube, wherein for calculating said value indicative of said pressure a frictional force value indicative of a friction of the piston relative to the cylindrical tube is taken into account,comparing said value indicative of said pressure to a threshold value to determine whether an occlusion is present in the infusion line during the infusion operation performed by the infusion device,wherein the frictional force value is determined using a mathematical model modelling the friction of the piston relative to the cylindrical tube in dependence on a position of the piston relative to the cylindrical tube along the movement direction and in dependence on a velocity by which the piston is moved relative to the cylindrical tube.
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Accused Products
Abstract
A method for detecting an occlusion in an infusion line (3) connected to an infusion device (1) comprises: measuring a force (F) applied to a piston (21) by a pusher device (12) of an infusion device (1) for moving the piston (21) along a movement direction (X) into a cylindrical tube (20) in order to deliver a medical fluid from the cylindrical tube (21) towards an infusion line (3) connected to the cylindrical tube (20); calculating, from the measured force (F), a value indicative of a pressure (P) in the cylindrical tube (20), wherein for calculating said value indicative of said pressure (P) a frictional force value (F0) indicative of a friction of the piston (21) relative to the cylindrical tube (20) is taken into account; and comparing said value indicative of said pressure (P) to a threshold value to determine whether an occlusion is present in the infusion line (3). Herein, the frictional force value (F0) is determined using a mathematical model modelling the friction of the piston (21) relative to the cylindrical tube (20) in dependence on the position of the piston (21) relative to the cylindrical tube (20) along the movement direction (X) and in dependence on the velocity by which the piston (21) is moved relative to the cylindrical tube (3). In this way a method for reliably detecting an occlusion in an infusion line during an infusion process is provided.
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Citations
16 Claims
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1. A method for detecting an occlusion in an infusion line connected to an infusion device, comprising:
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measuring a force applied to a piston by a pusher device of an infusion device during an infusion operation performed by the infusion device for moving the piston along a movement direction into a cylindrical tube in order to deliver a medical fluid from the cylindrical tube towards an infusion line connected to the cylindrical tube, calculating, from the measured force, a value indicative of a pressure in the cylindrical tube, wherein for calculating said value indicative of said pressure a frictional force value indicative of a friction of the piston relative to the cylindrical tube is taken into account, comparing said value indicative of said pressure to a threshold value to determine whether an occlusion is present in the infusion line during the infusion operation performed by the infusion device, wherein the frictional force value is determined using a mathematical model modelling the friction of the piston relative to the cylindrical tube in dependence on a position of the piston relative to the cylindrical tube along the movement direction and in dependence on a velocity by which the piston is moved relative to the cylindrical tube. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detecting an occlusion in an infusion line connected to an infusion device, comprising:
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measuring a force applied to a piston by a pusher device of an infusion device during an infusion operation performed by the infusion device for moving the piston along a movement direction into a cylindrical tube in order to deliver a medical fluid from the cylindrical tube towards an infusion line connected to the cylindrical tube, calculating, from the measured force, a value indicative of a pressure in the cylindrical tube, wherein for calculating said value indicative of said pressure a frictional force value indicative of a friction of the piston within the cylindrical tube is taken into account, comparing said value indicative of said pressure to a threshold value to determine whether an occlusion is present in the infusion line during the infusion operation performed by the infusion device, determining, at a current position of the piston, a slope value associated with the measured force at the current position of the piston as the piston is moved along the movement direction, and if the slope value lies within a predetermined range, assuming that the frictional force value is equal to the measured force at a position prior to the current position for calculating said value indicative of said pressure. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method for detecting an occlusion in an infusion line connected to an infusion device, comprising
(a) measuring a force applied to a piston by a pusher device of an infusion device for moving the piston along a movement direction into a cylindrical tube in order to deliver a medical fluid from the cylindrical tube towards an infusion line connected to the cylindrical tube, calculating, from the measured force, a value indicative of a pressure in the cylindrical tube, wherein for calculating said value indicative of said pressure a frictional force value indicative of a friction of the piston relative to the cylindrical tube is taken into account, comparing said value indicative of said pressure to a threshold value to determine whether an occlusion is present in the infusion line, wherein the frictional force value is determined using a mathematical model modelling the friction of the piston relative to the cylindrical tube in dependence on a position of the piston relative to the cylindrical tube along the movement direction and in dependence on a velocity by which the piston is moved relative to the cylindrical tube; -
and (b) measuring a force applied to a piston by a pusher device of an infusion device for moving the piston along a movement direction into a cylindrical tube in order to deliver a medical fluid from the cylindrical tube towards an infusion line connected to the cylindrical tube, calculating, from the measured force, a value indicative of a pressure in the cylindrical tube, wherein for calculating said value indicative of said pressure a frictional force value indicative of a friction of the piston within the cylindrical tube is taken into account, comparing said value indicative of said pressure to a threshold value to determine whether an occlusion is present in the infusion line, determining, at a current position of the piston, a slope value associated with the measured force at the current position of the piston as the piston is moved along the movement direction, and if the slope value lies within a predetermined range, assuming that the frictional force value is equal to the measured force at a position prior to the current position for calculating said value indicative of said pressure, wherein the steps of (a) and (b) are carried out in parallel during an infusion operation performed by the infusion device. - View Dependent Claims (16)
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Specification