Dialysis System Cerebral Oxygen Saturation Control
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Solution Overview
Problem
Current hemodialysis systems cannot continuously measure blood pressure, leading to delayed adjustments in operating conditions, which may not timely prevent symptoms caused by cerebral blood flow reduction, and patients with diabetes can experience symptoms even with normal blood pressure readings.
Innovation Solution
A dialysis system that includes a measurement apparatus for continuous monitoring of regional oxygen saturation and a control apparatus that adjusts hemodialysis operating conditions, such as blood flow rate, dialysis fluid flow rate, and water removal amount, to prevent decreases in cerebral oxygen saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blood pressure is measured intermittently during hemodialysis, then the measurement system is simple, but the response time is delayed and cannot detect sudden changes in dialysis subject state
Solution Approach 1:
The patent implements continuous monitoring of regional oxygen saturation (rSO2) in the cerebral tissue using near-infrared spectroscopy (NIRS). Unlike intermittent blood pressure measurement, the rSO2 monitoring operates continuously throughout the hemodialysis session, ensuring no sudden changes in cerebral blood flow go undetected. This continuous measurement approach eliminates the time lag inherent in periodic measurements and provides real-time feedback on cerebral perfusion status.
2Ease of operation
If blood pressure measurement is used to monitor cerebral blood flow, then the measurement method is simple, but it fails to detect cerebral blood flow reduction in diabetic patients with normal blood pressure
Solution Approach 1:
The patent replaces the mechanical/physiological measurement of blood pressure with an optical measurement system (NIRS) that directly measures regional oxygen saturation in cerebral tissue. This substitution allows direct assessment of cerebral blood flow and oxygenation status without relying on blood pressure as an indirect proxy, thereby detecting cerebral hypoperfusion even when blood pressure remains within normal ranges, particularly in diabetic patients with autonomic neuropathy.
3Device complexity
If hemodialysis operating conditions are adjusted based on lowered blood pressure readings, then the control system is simple, but the adjustment timing is delayed and symptoms may already occur
Solution Approach 1:
The patent implements a feedback control system where continuous rSO2 measurements provide real-time information about cerebral oxygen saturation status. When rSO2 decreases below a predetermined threshold or shows a significant rate of change, the system immediately triggers adjustment of hemodialysis operating conditions (such as reducing ultrafiltration rate or blood flow rate). This closed-loop feedback mechanism ensures timely intervention before clinical symptoms of cerebral hypoperfusion manifest, overcoming the delayed response inherent in intermittent blood pressure monitoring.
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 allows for more reliable suppression of symptoms related to cerebral blood flow reduction during hemodialysis by enabling timely adjustments based on continuous monitoring of cerebral oxygen saturation, even in patients with diabetes.
Implementation Method 1
a measurement apparatus for measuring a regional oxygen saturation of the dialysis subject
Data Source
AI summary
A dialysis system includes a dialysis apparatus, a measurement apparatus, and a control apparatus. The dialysis apparatus performs hemodialysis on a dialysis subject. The measurement apparatus measures a cerebral regional oxygen saturation of the dialysis subject. The control apparatus adjusts a hemodialysis operating condition by the dialysis apparatus so as to suppress decrease in the cerebral rSO2 based on the cerebral rSO2 of the dialysis subject measured by the measurement apparatus during operation of the hemodialysis by the dialysis apparatus.