Brain Neuroprotection Using Rectangular Pulsatile Bypass Flow
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Solution Overview
Problem
Existing non-invasive cerebral autoregulation monitoring technologies lack real-time sub-minute temporal resolution and are prone to signal noise, failing to promptly identify the start of cerebral autoregulation impairment events during surgery, which can lead to postoperative cognitive dysfunction (POCD).
Innovation Solution
A system utilizing a heart-lung machine with periodic rectangular blood flow pulsation and non-invasive monitoring of transient cerebral autoregulation functions, enabling sub-minute temporal resolution and immediate alarm triggers for neuroprotection, adjusting blood flow and anesthesia parameters to minimize impairment duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moving time averaging is used to calculate CA index, then signal to noise ratio is improved, but temporal resolution is worsened (averaging time close to or more than five minutes)
Solution Approach 1:
The patent applies periodic action by using periodic arterial blood pressure pulses generated by the heart-lung machine to stimulate transient cerebral autoregulation functions. This periodic stimulation allows the system to achieve high signal-to-noise ratio measurements within sub-minute time frames, resolving the contradiction between measurement precision and temporal resolution that exists in conventional continuous monitoring methods.
Solution Approach 2:
The patent implements preliminary action by pre-establishing the heart-lung machine in periodic rectangular blood flow pulsation mode before surgery begins. This preliminary configuration enables the system to immediately provide high-resolution temporal monitoring of cerebral autoregulation without requiring lengthy averaging periods, thus achieving both high signal-to-noise ratio and sub-minute temporal resolution simultaneously.
2Ease of operation
If non-invasive monitoring of ABP slow waves is used, then monitoring is simplified, but signal noises and artifacts increase
Solution Approach 1:
The patent extracts the problematic slow wave ABP monitoring component from the system by replacing it with periodic rectangular blood flow pulsation generated by the heart-lung machine. This extraction eliminates the source of signal noises and artifacts while maintaining non-invasive monitoring simplicity, as the system no longer relies on correlating ABP slow waves with cerebral blood flow velocity or oxygenation.
Solution Approach 2:
The patent substitutes the mechanical/physiological slow wave ABP monitoring system with an engineered periodic pulsation system. By replacing the natural slow wave correlation method with artificial periodic rectangular pulses, the system achieves cleaner signals without the noise and artifacts inherent in non-invasive ABP slow wave monitoring, while maintaining ease of operation.
3Reliability
If conventional ABP and cerebral blood flow velocity correlation is used, then monitoring is available, but real-time sub-minute temporal resolution is not achieved
Solution Approach 1:
The patent uses periodic action through rectangular blood flow pulsation to achieve real-time sub-minute temporal resolution. The periodic stimulation creates clear transient responses that can be measured and analyzed within seconds, enabling the system to identify the start of CA impairment events with much faster temporal resolution than conventional correlation methods while maintaining reliable monitoring availability.
Solution Approach 2:
The patent applies dynamics by transitioning from static slow wave correlation to dynamic transient function monitoring. The periodic rectangular pulsation creates dynamic challenges to cerebral autoregulation that can be measured in real-time, enabling sub-minute temporal resolution while maintaining the reliability of continuous monitoring through the heart-lung machine's integrated system.
Data Source
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AI summary
The present invention is directed generally to a method and apparatus for human brain neuroprotection during surgery. The invention includes use of a heart-lung machine (20) to generate periodic rectangular pulsation of blood flow (25). The invention uses a non-invasive cerebrovascular blood flow autoregulation - CA - monitor (30) to continuously record transient functions such as dynamic autoregulation functions of a human brain cerebrovascular autoregulation system and process the data to generate an alarm (70) to indicate CA impairment and take steps to minimize the CA impairment event.