Dialysis Blood Circuit Occlusion Detection via Pressure Trend Analysis
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Solution Overview
Problem
Existing dialysis systems face challenges in accurately detecting occlusions in blood circuits, leading to high false alarm rates and potential premature termination of dialysis treatments.
Innovation Solution
A dialysis system with a manifold, pressure sensor, non-transient memory, and controller that processes pressure values to generate an occlusion indicator value, determining whether to trigger an alarm based on a calculated difference between average and recent pressure values, with adjustable weights and thresholds to minimize false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensors are used to detect pressure changes in the blood circuit, then occlusion detection capability is improved, but false alarm rate increases
Solution Approach 1:
The system dynamically adjusts the alarm threshold based on baseline pressure values established during normal operation. The controller continuously monitors pressure changes and adapts the detection criteria to account for variations in patient physiology and treatment conditions, thereby reducing false alarms while maintaining reliable occlusion detection.
Solution Approach 2:
The patent changes the detection parameter from absolute pressure threshold to pressure change rate (dP/dt) and pressure differential across the dialyzer. By monitoring the rate of pressure change rather than fixed thresholds, the system can distinguish between normal pressure fluctuations and actual occlusions, significantly reducing false alarm rates.
2Measurement precision
If alarm thresholds are set to be sensitive for early occlusion detection, then detection accuracy is improved, but false positive alarms increase causing premature treatment termination
Solution Approach 1:
The system implements feedback by continuously monitoring pressure values and adjusting alarm thresholds based on established baseline patterns. The controller learns normal pressure variations during treatment and only triggers alarms when pressure changes deviate significantly from the learned pattern, reducing false positives while maintaining high detection accuracy.
Solution Approach 2:
The system performs preliminary action by establishing baseline pressure values and detection parameters during the initial phase of treatment before actual dialysis begins. This pre-calibration allows the system to adapt to each patient's specific physiology and treatment conditions, enabling accurate detection without false alarms during the actual treatment.
3Reliability
If multiple pressure measurement points are added to improve occlusion detection accuracy, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The pressure sensor serves multiple functions: it monitors pressure in the blood circuit, detects occlusions, establishes baseline values, and triggers alarms. By making the pressure sensor multi-functional rather than adding separate sensors for each function, the system achieves high detection reliability without increasing overall device complexity.
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 effectively detects occlusions with reduced false alarms, ensuring timely intervention and maintaining the integrity of dialysis treatments.
Implementation Method 1
a pressure sensor in physical communication with manifold at a position proximate said blood outlet port
Data Source
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AI summary
The present specification describes systems and methods for detecting an occlusion in a tubing carrying a patient's blood through a manifold and into a dialyzer in a dialysis system. A controller measures pressures value of the blood at a predetermined point after exiting the manifold and before entering the dialyzer, calculates a historical running average, calculates a weighted sum of the most recent pressure values, and determines whether to trigger an occlusion alarm based on a function of the historical running average and the weighted sum of the most recent pressure values.