Dialysis Fluid Pressure Sensing for Residual Volume Control
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Solution Overview
Problem
Automated peritoneal dialysis machines lack the ability to accurately determine the residual volume of dialysis fluid in the patient's peritoneal cavity, leading to uncertainty in fluid management and potential overfilling, which can cause patient discomfort and adverse cardiopulmonary effects.
Innovation Solution
The system incorporates a pump interface with pneumatic pressure control and pressure sensors to monitor pressure changes during fluid delivery and removal, using a control unit to halt pumping when a pressure spike is detected, indicating the patient is full, and employing a pressure limit or slope analysis to ensure accurate fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automated peritoneal dialysis machines pump dialysis fluid into the patient's peritoneal cavity without pressure monitoring, then the fluid delivery process is simple and fast, but the machine cannot accurately determine residual volume leading to overfilling and patient discomfort
Solution Approach 1:
A pressure sensor is introduced as an intermediary device between the pump interface and the patient's peritoneal cavity. The sensor measures pressure changes in the dialysis fluid during infusion, providing indirect information about residual volume without requiring direct volume measurement. This resolves the contradiction by enabling accurate measurement through a simple pressure sensing mechanism rather than complex volumetric measurement systems.
Solution Approach 2:
The patent replaces complex mechanical volume measurement systems with a pressure-based sensing system. Instead of using mechanical displacement sensors or volumetric tracking mechanisms, the system uses pressure sensors to detect fluid accumulation in the peritoneal cavity. This substitution achieves accurate residual volume determination while maintaining system simplicity.
2Reliability
If the machine continues pumping based on predetermined fill volumes, then the pumping process is efficient and automated, but the patient may be overfilled causing adverse cardiopulmonary effects
Solution Approach 1:
The system implements feedback control by continuously monitoring pressure changes during fluid infusion and comparing them against predetermined pressure limits or rate-of-change thresholds. When the pressure signal indicates the patient is full (reaching a limit or exceeding the rate of change), the controller automatically stops pumping. This feedback mechanism ensures patient safety while maintaining efficient automated operation, resolving the contradiction between reliability and productivity.
3Measurement precision
If pressure sensors are integrated into the pump interface, then real-time pressure monitoring is achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The pressure sensor is integrated into the pump interface assembly, allowing the same component to serve multiple functions: fluid pumping, pressure monitoring, and communication with the controller. This multi-functional integration enables accurate pressure measurement while simplifying manufacturing by reducing the number of separate components and assembly steps, thereby resolving the contradiction between measurement precision and ease of manufacture.
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
This approach prevents overfilling and over-pressurization of the patient, enhancing the precision of fluid delivery and comfort during automated peritoneal dialysis treatments by accurately determining when the patient is full, thereby minimizing the risk of adverse effects.
Implementation Method 1
a pressure sensor positioned and arranged to measure pressure within the actuation area
Implementation Method 2
a valve positioned and arranged to selectively vent the actuation area to atmosphere
Implementation Method 3
a pump interface including an actuation area for delivering positive pressure or negative pressure to the medical fluid handling device to move medical fluid into or out of the device
Data Source
AI summary
Systems and methods are disclosed for incorporating patient pressure into medical fluid delivery. An example system includes a medical fluid delivery machine and a medical fluid handling device including a patient line for being placed in fluid communication with a patient. The medical fluid delivery machine includes a control unit, a pump actuator for actuating the medical fluid handling device to move medical fluid into or out of the device, and a pressure sensor configured to sense a pressure of the medical fluid. The control unit is programmed to perform a routine during pumping in which the control unit determines if at least a component of a signal reading from the pressure sensor is indicative of a pressure within the patient, and determines from the component of the signal reading indicative of the pressure in the patient whether to continue pumping or stop pumping.