Optical Sensor Ratiometric Correction for Glucose Measurement
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Solution Overview
Problem
Current methods for monitoring blood glucose levels in critically ill patients are inadequate for real-time, accurate measurements, particularly in ICU settings, where tight glycemic control is crucial to reduce mortality and complications.
Innovation Solution
An optical sensor system utilizing an optical fiber with a fluorescence chemistry and a selectively permeable membrane, coupled with a chemical indicator system and a temperature sensor, is designed for intravascular glucose monitoring, providing continuous and accurate glucose concentration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor system with fluorescence chemistry and selectively permeable membrane is used for intravascular glucose monitoring, then measurement accuracy and real-time monitoring capability are improved, but device complexity increases
Solution Approach 1:
The sensor system is divided into distinct functional components: an optical fiber for light transmission, a selectively permeable membrane for analyte separation, a chemical indicator system for fluorescence response, and a reference region for ratiometric correction. This segmentation allows each component to be optimized independently while maintaining overall system accuracy and reducing the complexity of individual parts.
Solution Approach 2:
A chemical indicator system acts as an intermediary between the glucose analyte and the optical detection system. The indicator converts chemical information (glucose concentration) into optical signals (fluorescence intensity), enabling indirect but accurate measurement while protecting the optical fiber from direct exposure to blood components.
Solution Approach 3:
The system utilizes changes in fluorescence emission intensity and wavelength as glucose concentration varies. By monitoring these optical parameter changes through ratiometric correction (comparing excited and emitted light intensities), the system achieves high measurement precision while using relatively simple detection electronics.
2Reliability
If continuous real-time glucose monitoring is implemented in ICU patients, then patient outcomes and mortality rates are improved, but healthcare costs and resource requirements increase
Solution Approach 1:
The optical sensor enables continuous real-time glucose monitoring without interruption, allowing clinicians to maintain tight glycemic control continuously rather than through intermittent measurements. This continuous action improves patient outcomes by preventing glucose excursions while using resources efficiently through automated monitoring.
Solution Approach 2:
The system provides real-time feedback on glucose levels, enabling closed-loop insulin therapy where insulin dosing is automatically adjusted based on continuous glucose measurements. This feedback mechanism improves patient outcomes while reducing healthcare resources by eliminating the need for frequent manual blood glucose checks and laboratory testing.
3Adaptability or versatility
If a chemical indicator system is disposed within the gap between optical fiber and atraumatic tip, then glucose sensing capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The sensor structure is segmented into distinct regions: the optical fiber, a gap region containing the chemical indicator system, and the atraumatic tip. This segmentation allows the indicator system to be positioned in the gap without requiring precise alignment with the optical fiber core, as the indicator's fluorescence response can be detected through the optical fiber even with some positional variation.
Solution Approach 2:
The gap region serves multiple functions: it houses the chemical indicator system, allows for light transmission from the optical fiber, and provides space for the indicator to interact with glucose through the selectively permeable membrane. This multi-functionality reduces the precision requirements for manufacturing compared to designs where the indicator must be precisely positioned at a single location.
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 enables real-time, accurate monitoring of blood glucose levels, improving patient outcomes and reducing healthcare costs by facilitating tight glycemic control, potentially saving lives and lowering costs.
Implementation Method 1
a chemical indicator system capable of generating an emission light signal in response to an excitation light signal, wherein the intensity of the emission light signal is related to the analyte concentration
Implementation Method 2
a selectively permeable membrane disposed over the gap
Data Source
AI summary
Embodiments of the invention are directed to an optical sensor for detecting glucose. The sensor comprises a chemical indicator system disposed within a gap between the distal end of an optical fiber and an atraumatic tip portion, wherein the optical fiber and atraumatic tip portion are coupled by a coupling member, such as a rod or hypotube or cage that traverses the gap. The sensor further comprises a means for generating and detecting an optical reference signal unrelated to the glucose, such that ratiometric correction of glucose measurements for artifacts in the optical system is enabled.