Capacitive priming sensor for a medical fluid delivery system
Inventors
Assignees
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Publication Number
US-12447252-B2
Publication Date
2025-10-21
Expiration Date
Abstract
A capacitive priming sensor for a medical fluid delivery system is disclosed. In an example embodiment, a priming sensor includes a housing including a recessed section configured to accept a portion of a patient tube. The housing includes a first electrode located adjacent to a portion of the patient tube when the portion of the patient tube is inserted into the housing and a second electrode located above the first electrode. The priming sensor also includes a capacitive sensor that measures a capacitance between the first electrode and the second electrode. A processor operates with the capacitive sensor and is configured to use the measured capacitance to determine a transition between a dry tube state and a wet tube state. The processor then causes a pump to stop pumping dialysis fluid through the patient tube for the priming sequence after the wet tube state is determined.
Core Innovation
The invention relates to a capacitive priming sensor for a peritoneal dialysis apparatus, including automated peritoneal dialysis (APD). A recessed housing section accepts a portion of a patient tube and includes a first electrode adjacent to the patient tube portion, a second electrode above the first electrode separated by a first gap, and a third electrode below the first electrode separated by a second gap. The electrodes are arranged to form capacitors, and the processor measures capacitance to determine whether the patient tube is in a dry tube state, a wet tube state, or a no-tube state.
The processor uses capacitance measured between the first electrode and the second electrode to determine a first transition between the dry tube state and the wet tube state when dialysis fluid rises to a level at least the first electrode. The processor uses capacitance measured between the first electrode and the third electrode to determine a second transition between the dry tube state and the wet tube state when the dialysis fluid rises to a level at least the second electrode. The claims also refer to threshold- and time-qualified transition criteria for determining the first and second transitions.
The processor operates with at least one pump to control the priming sequence based on the transitions. After the first transition is determined, the processor causes the at least one pump to reduce a pumping speed of the dialysis fluid through the patient tube for the priming sequence, and after the second transition is determined, the processor causes the at least one pump to stop pumping for the priming sequence. The user interface can display messages and alarms for missing tubes, failed priming, external electrical interference, and interference or no-transition conditions.
Claims Coverage
The document contains at least one independent claim, with additional dependent claims refining the inventive features. Across the claims, the inventive features center on using two capacitive measurements between three electrodes to detect first and second dry-to-wet transitions and adjusting pump behavior during priming accordingly.
Recessed housing electrodes forming capacitors for priming detection
A peritoneal dialysis apparatus having a housing with a recessed section accepting a portion of the patient tube, including a first electrode adjacent to the patient tube portion, a second electrode above the first electrode separated by a first gap, and a third electrode below the first electrode separated from the first electrode by a second gap.
Dual capacitive sensors measuring different electrode capacitances
A first capacitive sensor measuring first capacitance values between the first electrode and the second electrode, and a second capacitive sensor measuring second capacitance values between the first electrode and the third electrode.
Dry-to-wet transitions determined from measured capacitance values
A processor configured to determine a first transition between a dry tube state and a wet tube state using the measured second capacitance values when the dialysis fluid rises within the tube portion to a level at least the first electrode, and to determine a second transition between the dry tube state and the wet tube state using the measured first capacitance values when the dialysis fluid rises within the tube portion to a level at least the second electrode.
Pump speed reduction and priming stop based on first and second transitions
The processor configured to cause the at least one pump to reduce a pumping speed after determining the first transition, and to cause the at least one pump to stop pumping after determining the second transition.
Threshold- and time-qualified transition criteria
Determining the first and second transitions by comparing changes in measured capacitance values to respective first and second transition thresholds, including refinements that specify threshold behavior and timing constraints.
Electrode gap size constraint
The first gap is defined with a size between 0.5 millimeters and 2 centimeters.
Electrode conductive construction options
The first and second electrodes include one of specified conductive components or coatings.
No-transition alert for possible leak or patient line occlusion via user interface
Using measured capacitance values to determine whether there has been no transition between dry and wet tube states and displaying an alert via a user interface for a possible leak or patient line occlusion.
Overall, the claims cover a peritoneal dialysis apparatus that detects a first and a second dry-to-wet transition using capacitance measurements between electrodes in a recessed housing section, and that adjusts priming pump behavior by reducing pump speed after the first transition and stopping pump pumping after the second transition. Dependent claims further constrain transition determination, electrode geometry, electrode conductive construction, and add user-interface alerting for no-transition conditions.
Stated Advantages
Insensitive to ambient light and tube/fluid properties.
Provides reliable detection of tube presence (no-tube vs dry) and fluid level (dry vs wet) during priming.
Controls priming sequence by reducing pump speed after a first dry-to-wet transition and stopping pumping after a second dry-to-wet transition.
Issues user-interface messages and alarms for missing tubes, failed priming, external electrical interference, and interference or no-transition conditions, including alerts for possible leak or patient line occlusion.
Enables or disables dialysis treatment based on wet detection.
Documented Applications
Automated peritoneal dialysis (APD) priming using capacitive sensing of dry-to-wet transitions in a patient tube and pump control during a priming sequence.
User interface alerting during the priming sequence for missing tubes, failed priming, external electrical interference, and interference or no-transition conditions including possible leak or patient line occlusion.
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