Closed-Loop Blood Pressure Control Using Pharmacokinetic Models
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Solution Overview
Problem
Current methods for managing blood pressure in the operating room lack the incorporation of mechanistic cardiovascular models, leading to suboptimal post-operative outcomes due to manual and non-mechanistic approaches.
Innovation Solution
A closed-loop system that includes sensors to measure blood pressure waveforms, pumps to administer vasopressors and vasodilators, and a processor to calculate infusion rates based on a circuit model of blood circulation, allowing for precise control of blood pressure through calculated infusion rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual blood pressure management methods are used, then the system complexity is low, but the blood pressure control precision is insufficient
Solution Approach 1:
The system implements a closed-loop feedback mechanism where the sensor continuously monitors blood pressure waveform and feeds this information back to the processor. The processor compares the measured waveform with the target waveform and automatically adjusts the infusion rates of vasopressors and vasodilators accordingly, achieving precise blood pressure control without manual intervention.
Solution Approach 2:
The system enables self-service control where the automated control system independently manages blood pressure regulation. The processor automatically calculates optimal infusion rates and the pump executes adjustments without requiring continuous manual input from anesthesiologists, allowing the system to self-regulate blood pressure based on real-time physiological data.
2Reliability
If non-mechanistic approaches are used, then the ease of operation is high, but the post-operative outcomes are poor
Solution Approach 1:
The system replaces manual mechanical control with an automated electronic control system based on mechanistic cardiovascular models. The processor uses physiological models to understand cardiovascular dynamics and automatically adjusts drug infusion rates, substituting human manual operation with an intelligent system that provides more reliable and consistent blood pressure management.
Solution Approach 2:
The system dynamically changes infusion rate parameters based on real-time blood pressure waveform analysis. The processor continuously adjusts the infusion rates of vasopressors and vasodilators by modifying these parameters according to the deviation from target blood pressure, enabling adaptive control that improves outcomes while maintaining ease of operation.
3Measurement precision
If automated control systems are implemented, then the blood pressure management precision is improved, but the device complexity increases
Solution Approach 1:
The system achieves multi-functionality by integrating sensor monitoring, waveform analysis, model-based calculation, and drug delivery control into a single unified platform. The processor performs multiple functions including measuring blood pressure, comparing with target values, calculating optimal infusion rates using cardiovascular models, and controlling the pump, thereby reducing the need for separate devices while maintaining high precision.
Data Source
AI summary
A closed-loop system for blood pressure control that accounts for various mechanisms of the cardiovascular system. In some example cases, a pharmacokinetic-pharmacodynamic model of the cardiovascular system's response to cardiovascular system actuators, such as vasoactive drugs, is generated. Two example actuators are employed in the example framework: phenylephrine, to raise blood pressure, and nicardipine, to lower blood pressure. The pharmacodynamic components employs a two-element Windkessel model. A model predictive control framework is built based on the pharmacokinetic-pharmacodynamic model.