Foley Catheter Oxygen Sampling to Minimize Diffusion Error
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Solution Overview
Problem
Existing Foley catheters face challenges in accurately monitoring kidney oxygenation status due to oxygen diffusion through the catheter walls, leading to skewed urine oxygen measurements, which can complicate the detection of acute kidney injury (AKI) and hinder timely clinical interventions.
Innovation Solution
A Foley catheter system with a pump and dissolved oxygen sensor configuration that actively moves urine from the bladder to the sensor, minimizing oxygen diffusion and enabling accurate oxygen content measurement by reducing transit time and using impermeable materials to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Foley catheter is used to remove urine from the bladder, then urine can be drained effectively, but oxygen diffusion through the catheter wall occurs at low flow rates, leading to inaccurate oxygen measurements
Solution Approach 1:
The patent extracts the harmful oxygen diffusion effect by removing the catheter wall barrier between the urine and external environment. By using a pump to actively withdraw urine through a dedicated sampling lumen, the system eliminates the stagnant low-flow conditions that allow oxygen diffusion through the catheter wall, thereby obtaining accurate oxygen measurements that reflect true bladder urine oxygenation.
Solution Approach 2:
The patent introduces an intermediary pump system that actively transports urine from the bladder through a sampling lumen to the oxygen sensor. This intermediary mechanism bypasses the problematic diffusion pathway through the catheter wall and creates a controlled high-flow sampling path that prevents oxygen diffusion while enabling accurate measurement.
2Measurement precision
If urine flow rate is low (typical for catheterized patients), then the catheter functions normally, but oxygen diffusion into the urine increases, skewing measurements
Solution Approach 1:
The patent applies dynamics by creating two distinct flow regimes: the main drainage lumen operates at low flow rates typical of catheterized patients, while the sampling lumen operates at high flow rates driven by the pump. This dynamic separation allows the system to maintain normal catheter function while achieving accurate oxygen measurements through the high-flow sampling path that minimizes diffusion.
Solution Approach 2:
The patent segments the catheter into multiple lumens with different functions: a drainage lumen for normal urine removal at low flow rates, and a dedicated sampling lumen for active high-flow urine transport to the oxygen sensor. This segmentation allows independent optimization of each function, resolving the contradiction between maintaining normal low-flow drainage and achieving accurate oxygen measurements.
3Reliability
If a dissolved oxygen sensor is placed in the bladder to monitor kidney oxygenation, then real-time monitoring is enabled, but oxygen diffusion through the catheter wall causes measurement errors
Solution Approach 1:
The patent introduces an intermediary active sampling system that transports urine directly from the bladder to the oxygen sensor through a dedicated sampling lumen. This intermediary high-flow path isolates the measurement from the harmful diffusion effect of the catheter wall, enabling reliable and precise kidney oxygenation monitoring without measurement errors.
Solution Approach 2:
The patent applies preliminary action by actively pumping urine through the sampling lumen before it can be affected by oxygen diffusion through the catheter wall. This preliminary high-flow transport ensures that the urine sample reaches the sensor quickly, minimizing exposure to diffusion and ensuring accurate baseline measurements of kidney oxygenation.
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 provides real-time, continuous monitoring of kidney oxygenation, reducing the risk and severity of AKI by allowing clinicians to intervene promptly, thereby improving patient outcomes and potentially avoiding complications such as chronic kidney disease.
Implementation Method 1
oxygen diffusion through a wall of the Foley catheter may occur at the relatively low flow rates that are typical for urine output for catheterized patients
Data Source
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AI summary
Example systems, catheters, and methods are disclosed for actively sampling a fluid. An example system includes a pump configured to pump fluid to direct the fluid a dissolved oxygen sensor and the dissolved oxygen sensor configured to output a signal indicative of an amount of dissolved oxygen in the fluid.