Anesthetic Dosing Control via Exhaled Gas Feedback
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Solution Overview
Problem
Current methods for controlling anesthetic dosing in anesthesia are inaccurate due to the unpredictable redistribution and breakdown of anesthetics in the body, leading to variable blood concentrations and potential patient safety risks.
Innovation Solution
A method and system that measure the concentration of anesthetic in exhaled gas, perform simulation calculations to estimate blood concentration, adapt parameters based on comparisons between simulated and measured values, and generate control signals to optimize drug dosing, using a compartment model to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a three-compartment model is used to predict anesthetic blood concentration, then the control system can operate with available data, but the prediction accuracy is marked by very great relative errors on the order of magnitude of 30%
Solution Approach 1:
The patent implements a feedback mechanism where the simulated breathing gas concentration is continuously compared with the actually measured concentration. Based on this comparison, the model parameters (particularly k10 elimination rate) are adapted and optimized. This closed-loop feedback system resolves the contradiction by using measurement feedback to improve prediction accuracy while maintaining the computational efficiency of the three-compartment model.
Solution Approach 2:
The patent dynamically adjusts model parameters, specifically the elimination rate k10, based on the comparison between simulated and measured breathing gas concentrations. This parameter adaptation allows the system to compensate for inter-patient variability and improve blood concentration prediction accuracy without changing the fundamental three-compartment model structure.
2Reliability
If an excessively high quantity of anesthetic is administered to ensure sufficient anesthesia depth, then anesthesia coverage is improved, but patient safety is compromised due to potential injuries from overdose
Solution Approach 1:
The feedback mechanism continuously monitors breathing gas concentration and adapts the dosing model parameters accordingly. This allows for real-time optimization of the anesthetic dosage, ensuring sufficient anesthesia depth while preventing overdose by adjusting the elimination rate parameter k10 based on actual measured versus simulated concentrations.
Solution Approach 2:
The patent replaces direct blood concentration measurement (which would be invasive and complex) with a substituted approach: measuring breathing gas concentration and using it to infer blood concentration through the compartment model. This substitution enables safe, non-invasive monitoring with sufficient accuracy for clinical decision-making.
3Object-affected harmful factors
If an excessively low quantity of anesthetic is administered to avoid overdose, then patient safety is improved, but the patient may not be sufficiently anesthetized and may perceive the surgical procedure
Solution Approach 1:
The continuous feedback loop compares simulated and measured breathing gas concentrations, allowing the system to dynamically adjust the elimination rate parameter k10. This ensures that the lowest effective dose is administered to maintain adequate anesthesia depth while preventing both overdose and underdose conditions.
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 significantly enhances the accuracy of anesthetic blood concentration monitoring and control, reducing the risk of overdose or underdose by continuously adapting parameters and optimizing drug administration.
Implementation Method 1
the concentration of the drug administered by the drug dosing device is determined in the gas exhaled by the patient with a sensor
Data Source
AI summary
A method and a system control a drug dosing device (1) for administering a drug to a patient (19). The quantity (c0) of the drug administered from the drug dosing device (1) is determined or calculated. The concentration of the drug in the gas exhaled by the patient (19) is measured as a first patient value (c1M). A simulation calculation is carried out, in which a second patient value (cp) is calculated from the administered quantity of the drug (I), taking into account a parameter (k10). A simulated first patient value (c1′) is calculated in the simulation calculation, taking into account the parameter (k10). A comparison of the simulated first patient value (c1′) to the measured first patient value (c1M) is carried out. The parameter (k10) is adapted on the basis of the comparison. The calculated second patient value (cp) is used to generate a control signal (S).