Automated Peritoneal Dialysis Load Cell Calibration for Fluid Tracking
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Solution Overview
Problem
Existing automated peritoneal dialysis (APD) systems face issues with pneumatic cassette systems causing delays and acoustic noise, leading to user dissatisfaction and inefficiencies in treatment.
Innovation Solution
A streamlined APD system utilizing a peristaltic pump and disposable cassette that organizes tubing, allowing for two-directional pumping, and incorporates a user-friendly interface and bag shelf enclosure to manage fluid containers efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If pneumatic cassette systems are used in automated peritoneal dialysis, then fluid management can be automated, but acoustic noise increases and treatment delays occur
Solution Approach 1:
The patent replaces the pneumatic system with a peristaltic pump mechanism that uses mechanical compression of a flexible tubing to move fluid. This substitution eliminates the acoustic noise associated with pneumatic components while maintaining automated fluid management capability through the motor-driven roller compression system.
Solution Approach 2:
The patent extracts and removes the pneumatic cassette system components that generate acoustic noise and treatment delays. By eliminating the pneumatic reservoir, valves, and associated tubing from the system, the invention resolves the noise and delay issues while preserving the essential fluid delivery function through the peristaltic pump.
2Extent of automation
If pneumatic cassette systems are used in automated peritoneal dialysis, then fluid management can be automated, but treatment delays occur
Solution Approach 1:
The peristaltic pump provides continuous, reliable fluid delivery without the delays associated with pneumatic system priming, pressure equalization, and valve actuation. The direct mechanical compression of tubing ensures immediate fluid movement when required, eliminating treatment delays while maintaining automation.
Solution Approach 2:
The peristaltic pump system is self-regulating and requires no external pressure sources or complex valve timing sequences. The motor-driven rollers automatically advance and compress the tubing in a continuous cycle, providing seamless fluid delivery without the delays inherent in pneumatic system operation.
3Object-affected harmful factors
If peristaltic pump system is implemented, then acoustic noise is reduced, but pumping capability must be maintained
Solution Approach 1:
The peristaltic pump uses a motor-driven roller compression mechanism that generates sufficient pumping pressure and flow rate to replace pneumatic capability. The rhythmic compression and release of the flexible tubing creates peristaltic waves that propel fluid forward with adequate force for dialysis treatment requirements.
Solution Approach 2:
The peristaltic pump operates through periodic compression and relaxation cycles of the tubing by the rollers. This rhythmic action creates continuous fluid propulsion with sufficient power output, maintaining pumping capability while operating quietly compared to pneumatic systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces noise, eliminates delays associated with pneumatic systems, and enhances user experience by automating fluid management and treatment processes, while also reducing overall disposable costs.
Implementation Method 1
A peristaltic pump actuator under control of a control unit is located on the actuation surface of the cycler. The disposable cassette includes a peristaltic pump tube that the user guides over the peristaltic pump actuator when loading the cassette. In operation, the peristaltic pump actuator compresses the peristaltic pump tube at multiple points against a raceway.
Implementation Method 2
The cycler includes a weigh scale having multiple load cells to monitor the amount of fresh dialysis fluid delivered to the patient, the amount of used dialysis fluid removed from the patient
Implementation Method 3
Hemodialysis (HD), which in general uses diffusion to remove waste products from a patient's blood. A diffusive gradient occurs across the semi-permeable dialyzer between the blood and an electrolyte solution called dialysate or dialysis fluid to cause diffusion.
Implementation Method 4
Waste, toxins and excess water pass from the patient's bloodstream, through the capillaries in the peritoneal membrane, and into the dialysis fluid due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane.
Data Source
AI summary
A dialysis machine operable with a disposable set having at least one container, the dialysis machine including a pump actuator operable to pump dialysis fluid to and/or from the at least one container; a weigh plate positioned to support the at least one container; a plurality of operational load cells positioned to support the weigh plate; a linear actuator positioned to apply a force to the weigh plate; a calibration load cell positioned to measure the force applied by the linear actuator; and a control unit in operable communication with the operational load cells, the linear actuator and the calibration load cell, the control unit configured to cause the linear actuator to apply the force to the weigh plate, compare resulting outputs from the operational load cells and the calibration load cell, and determine a calibration factor from the comparison for offsetting future outputs from the operational load cells.