Capillary Refill Time Measurement Using Dual-Wavelength Optical Detection

Solution Overview

Problem

Current methods for assessing dehydration in patients, particularly in pediatric settings, rely on manual and qualitative evaluations that are time-consuming and provide limited quantitative data, making it challenging to accurately determine dehydration severity and vascular function.

Innovation Solution

An automated device using dual radiation sources and detectors to measure capillary refill time, with one source emitting radiation equally absorbed by oxyhemoglobin and deoxyhemoglobin, and a second source providing a reference signal, allowing for quantitative assessment of dehydration and vascular function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual visual and manual tests are used to assess dehydration, then the method is simple and requires minimal equipment, but the measurement is time-consuming and provides only qualitative information

Engineering Contradiction:

Improvemeasurement precisionVSAvoidtime

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical testing with an automated optical measurement system. A probe applies controlled pressure to a measurement region and uses radiation sources and detectors to automatically measure capillary refill time, eliminating the need for manual observation and timing while providing quantitative results.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device performs self-measurement without requiring skilled clinician intervention. The automated probe applies pressure, detects radiation changes, and calculates capillary refill time independently, allowing rapid assessment without consuming valuable clinical time.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If manual capillary refill testing is performed, then the procedure is quick to perform, but it provides only qualitative information about dehydration severity

Engineering Contradiction:

Improvequantitative measurement capabilityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical testing with an automated optical measurement system. A probe applies controlled pressure to a measurement region and uses radiation sources and detectors to automatically measure capillary refill time, eliminating the need for manual observation and timing while providing quantitative results.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system measures changes in radiation absorption parameters to quantify capillary refill time. By monitoring absorption of radiation at different wavelengths during the refilling process, the device converts a qualitative observation into a measurable quantitative parameter.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If single-wavelength radiation source is used, then the device is simpler, but it cannot distinguish between oxyhemoglobin and deoxyhemoglobin absorption characteristics

Engineering Contradiction:

Improvehemoglobin differentiation capabilityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the radiation measurement into separate wavelength channels. Multiple radiation sources emit at different wavelengths, and detectors separately measure absorption at each wavelength, allowing differentiation between oxyhemoglobin and deoxyhemoglobin based on their distinct absorption spectra.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system measures changes in radiation absorption parameters to quantify capillary refill time. By monitoring absorption of radiation at different wavelengths during the refilling process, the device converts a qualitative observation into a measurable quantitative parameter.

Inventive Principle:

Principle #35Parameter changes

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 device enables rapid and reliable quantitative measurement of capillary refill time, effectively determining dehydration severity and vascular function, independent of skin pigmentation, and can monitor changes post-intervention.

Implementation Method 1

The first radiation may be selected to be absorbed substantially equally by an amount of oxyhemoglobin or the same amount of deoxyhemoglobin

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

at least one detector for detecting the first radiation and the second radiation

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS9603559B2Capillary refill time diagnostic apparatus and methods

Publication Date: 2017.03.28 CHILDRENS MEDICAL CENT CORP

AI summary

An apparatus for measuring capillary refill time has a measurement module containing at least two radiation sources and at least one detector configured to detect radiation from each source that interacts with and is received from a measurement region of a patient or subject. One radiation source may be characterized by a wavelength that is absorbed substantially equally by oxyhemoglobin and deoxyhemoglobin. The other radiation source may be substantially unaffected by the presence or absence of blood in the measurement region. The measurement module may be applied against a measurement region of a patient for a first time period, and the released from the measurement region for a second time period, and detected signals processed to quantitatively evaluate capillary refill time.