Fluorescent pH Indicator for Nasogastric Tube Placement
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Solution Overview
Problem
Current methods for determining gastric pH in critically ill patients are time-consuming, costly, and often inaccurate, particularly when using visual indicators that require manual comparison with reference colors, posing challenges in managing gastric ulcers and medication dosages effectively.
Innovation Solution
A nasogastric tube insertion system comprising a guide element and inserter element that facilitates the insertion of a nasogastric tube into the stomach, potentially incorporating a chemical-property indicating medium to provide immediate pH feedback, allowing for accurate and efficient measurement of gastric pH without the need for laboratory analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual indicators (litmus paper) are used to determine gastric pH, then the measurement can be performed at the bedside without laboratory equipment, but the color change is gradual and requires manual comparison with reference colors, reducing measurement precision
Solution Approach 1:
The patent applies color changes by incorporating pH-sensitive fluorescent dyes that change emission color or intensity in response to pH changes. The indicator composition contains multiple fluorescent compounds with different pKa values, each contributing to the overall color response. This allows precise pH determination through spectral analysis rather than subjective visual comparison, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent replaces the mechanical/visual comparison system with an optical detection system. Instead of manually comparing paper colors to reference charts, the system uses a light source to excite the fluorescent indicator and a detector to measure the emitted light spectrum. This substitution of mechanical visual assessment with optical measurement eliminates subjectivity and improves precision while maintaining bedside usability.
2Measurement precision
If laboratory analysis methods are used to determine gastric pH, then measurement precision is high, but the process is time-consuming and costly
Solution Approach 1:
The patent implements self-service by making the indicator system self-contained and autonomous. The pH measurement device requires minimal operator intervention - simply applying the indicator to the sample and obtaining an automated spectral reading. The system performs its own measurement and calculation without requiring laboratory equipment or personnel, providing rapid results at the bedside. This eliminates the time loss associated with transporting samples to laboratories while maintaining measurement precision through objective optical detection.
Solution Approach 2:
The patent extracts the essential measurement function from the complex laboratory environment. By removing the need for laboratory equipment, personnel, and processing steps, the system brings the pH determination capability directly to the patient bedside. The indicator composition and detection device are designed to function independently of laboratory infrastructure, extracting only the core measurement need while eliminating time-consuming transport and processing steps.
3Ease of operation
If aspirated stomach contents are placed in open test tubes for analysis, then the pH can be measured, but the practitioner must handle bodily fluids in the open, creating mess and potential contamination
Solution Approach 1:
The patent applies flexible shells and thin films by using a closed-tube design where the indicator is contained within a flexible membrane or thin-walled container. The aspirated stomach contents are introduced into this closed system, and the pH measurement occurs through the wall of the flexible container or by introducing the sample into a sealed reaction chamber. This eliminates the need for open test tubes, containing the bodily fluids throughout the procedure and eliminating mess and exposure hazards while maintaining ease of operation through simple tube-based handling.
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 system enables rapid, accurate, and cost-effective determination of gastric pH, improving patient management by reducing morbidity and mortality associated with gastric ulcers and optimizing medication dosages.
Implementation Method 1
Detection of the desired characteristic is typically shown using a visual indicator, such as a colorimetric medium that changes from a first color to a second color upon sufficient contact with the fluid
Data Source
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AI summary
An apparatus (5500) comprises a detection indicator and a housing. The detection indicator (5806) is configured to change from a first visual indication to a second visual indication upon contact with a fluid based on a characteristic of the fluid. The housing comprises an interior chamber configured to receive the fluid and to provide contact between the fluid and the detection indicator. The housing is configured to removably engage a lumen (5804) inserted into a patient to receive the fluid from the patient through the lumen.