EP0341364A2
Expired / Lapsed
EP
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Container-side occlusion detection system for a medication infusion system
Assignee: Cessione ivac Corp
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Filing: 1988-11-30
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Granted: —
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Expires: 2008-11-30
Abstract
Abstract A system for detecting an occlusion in the upstream or container side fluid line of a disposable cassette for use in a medical infusion system. The cassette includes a piston-type pump with inlet and outlet valves, and is used with a main pump unit including motors for driving the pump and valves contained in each cassette. The system uses control circuitry to monitor the motor current during the intake stroke of the pump in the cassette. The value is compared with a set value in order to detect an upstream occlusion in the fluid line leading to the pump, and to provide an alarm in the event of a container-side occlusion.
Inventors
- 👤 John B. Slate
- 👤 James L. Henke
- 👤 Son Hoang Hong
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:50
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/36; A61M5/365; A61M5/14; A61M5/168; A61M5/16831; A61M2205/00; A61M2205/12; Y; Y10; Y10S; Y10S128/00; Y10S128/13
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
125 words
A container-side occlusion detection system for use in a medication infusion system having a disposable cassette mounted on a main pump unit characterised by:- a pump located in the cassette for delivering a fluid from a fluid source, a motor (804A) located in the main pump unit for driving the pump; means for monitoring (829) a parameter during the fill stroke of the pump, the parameter being indicative of the presence or absence of a container-side occlusion in the fluid line, the monitoring means providing as an output a CSOD value characteristic of the parameter; and means for comparing (836) the CSOD value to a preselected alarm threshold value, the comparing means (836) initiating an alarm when the CSOD value exceeds the preselected alarm value.
Claim 2
Dependent Claim
125 words
A container-side occlusion detection system for use in a medication infusion system having a disposable cassette mounted on a main pump unit characterised by:- a pump located in the cassette for delivering a fluid from a fluid source, a motor (804A) located in the main pump unit for driving the pump; means for monitoring (829) a parameter during the fill stroke of the pump, the parameter being indicative of the presence or absence of a container-side occlusion in the fluid line, the monitoring means providing as an output a CSOD value characteristic of the parameter; and means for comparing (836) the CSOD value to a preselected alarm threshold value, the comparing means (836) initiating an alarm when the CSOD value exceeds the preselected alarm value.
Claim 3
Dependent Claim
37 words
A system as claimed in Claim 1 characterised in that the parameter is motor current, and the monitoring means preferably comprises an integrator (830) taking the first integral of the motor current to produce the CSOD value.
Claim 4
Dependent Claim
36 words
A system as claimed in Claim 2, characterised in that the integrator (830) integrates motor current during the fill stroke, and optionlly also during a period following the fill stroke but prior to the deliver stroke.
Claim 5
Dependent Claim
45 words
A system as claimed in Claim 2 or Claim 3 characterised in that the integrator (830) holds the CSOD value during the deliver stroke to allow the CSOD value to be sampled, and the integrator (830) is optionally reset prior to the succeeding fill stroke.
Claim 6
Independent Claim
74 words
A system as claimed in any preceding claim, characterised in that the monitoring means additionally comprises, an analog-to-digital converter (832) for converting the CSOD value into a digital signal and optionally a shunt resistor (840) in series with the motor (804A), the input to the integrator (830) being provided across the shunt resistor, and optionally means for calibrating (834) the system, the calibration means (834) providing as an output the preselected alarm threshold value.
Claim 7
Independent Claim
40 words
A system as claimed in any preceding claim characterised in that the preselected threshold value is the measured CSOD value using a test cassette having no cassette friction, multiplied by a constant factor between 1.5 and 3.0, for example 2.
Claim 8
Dependent Claim
40 words
A system as claimed in Claim 5 or Claim 6 characterised in that the calibration means (834) provides minimum and maximum limits to the preselected threshold value, for example a minimum limit of 42 and a maximum limit of 80.
Claim 9
Independent Claim
54 words
A system as claimed in any preceding claim, characterised in that the motor is driven by periodic pulses, the pulses being either at a lower commanded drive voltage for example approximately 5 volts, or at a higher commanded drive voltage for example approximately 13 volts, the higher voltage being used at higher flow rates.
Claim 10
Dependent Claim
60 words
A system as claimed in Claim 8, characterised in that the CSOD value is monitored following each fill stroke when the motor is being driven at the lower commanded drive voltage, and is preferably monitored once during each time a predetermined number of periodic pulses, for example five, occurs when the motor is being driven at the commanded drive voltage.
Claim 11
Dependent Claim
28 words
A system as claimed in Claim 9 characterised in that in a start-up infusion at the higher voltage, the CSOD value is monitored during the second periodic pulse.
Claim 12
Dependent Claim
77 words
A system as claimed in Claim 9 or Claim 10, characterised in that when the CSOD value is to be monitored during a periodic pulse, the drive voltage is reduced to the lower value until the pump is driven through one complete fill stroke, after which the drive voltage is returned to the higher value, a periodic pulse including both the lower drive voltage and the higher drive voltage being referred to as a hybrid voltage pulse.
Claim 13
Dependent Claim
90 words
A system as claimed in Claim 11, characterised in that the width of a hybrid voltage pulse is calculated according to the formula: where Np is the calculated position in the delivery cycle (between 0 and 160 encoder counts, where 0 is the beginning of the delivery cycle and is the end), N c is the command to the rate control expressed as encoder counts (i.e. converted from M\Ml/h), U13 is the pulse width calculated by the closed loop controller at the present sampling period, and g is the gain.
Claim 14
Independent Claim
34 words
A system as claimed in any preceding claim characterised by means for generating an alarm (838) in response to the comparing means (836) determining that the CSOD value exceeds the preselected alarm threshold value.
Claim 15
Independent Claim
108 words
A method of detecting a container-side occlusion in a medication infusion system having a disposable cassette mounted on a main pump unit, the cassette including a pump for delivering a fluid from a fluid source to a patient and including a motor (804a) driving the pump characterised by: monitoring a parameter during the fill stroke of the pump, the parameter being indicative of the presence or absence of a container-side occlusion in the fluid line; providing a CSOD value output characteristic of the parameter; comparing the CSOD value to a preselected alarm threshold value; and initiating an alarm when the CSOD value exceeds the preselected alarm threshold value.
Claim 16
Independent Claim
108 words
A method of detecting a container-side occlusion in a medication infusion system having a disposable cassette mounted on a main pump unit, the cassette including a pump for delivering a fluid from a fluid source to a patient and including a motor (804a) driving the pump characterised by: monitoring a parameter during the fill stroke of the pump, the parameter being indicative of the presence or absence of a container-side occlusion in the fluid line; providing a CSOD value output characteristic of the parameter; comparing the CSOD value to a preselected alarm threshold value; and initiating an alarm when the CSOD value exceeds the preselected alarm threshold value.
References Cited (Backward Citations)
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