Infant Aortic Coarctation Detection via Photoplethysmography
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Solution Overview
Problem
Current methods for detecting aortic coarctation in newborns, such as pulse oximetry and physical examination, have low sensitivity and are often delayed, leading to increased morbidity and mortality due to the difficulty in reliably assessing blood pressure variations and pulse transmission in neonates.
Innovation Solution
The method involves obtaining photoplethysmographic signals from the right hand and foot of an infant, analyzing end-diastolic maxima and minima to determine time delay and pulse amplitude, calculating mean and standard deviation, and using ratios to detect the likelihood of aortic coarctation through a system with a photoplethysmograph and computing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse oximetry screening is performed to detect CCHD, then oxygen saturation can be quantified, but sensitivity for coarctation of the aorta remains low
Solution Approach 1:
The patent segments the pulse signal into distinct components (dicrotic notch, peak, foot) and analyzes each segment's temporal characteristics. By dividing the pulse waveform into measurable segments and comparing their timing relationships between upper and lower extremities, the system achieves more sensitive detection of coarctation while maintaining non-invasive measurement.
Solution Approach 2:
The patent transitions from traditional single-point pulse oximetry to multi-dimensional temporal analysis of pulse waveforms. By measuring the time differences between corresponding points (dicrotic notch to dicrotic notch, peak to peak, foot to foot) in upper and lower extremity pulses, the system adds a temporal dimension that reveals hemodynamic abnormalities missed by conventional saturation monitoring alone.
2Measurement precision
If upper and lower limb blood pressures are measured to assess CoA, then blood pressure variation can be detected, but the wide variation in healthy newborns makes reliable assessment difficult
Solution Approach 1:
The patent replaces mechanical blood pressure measurement with optical photoplethysmography. By using light transmission through tissue to detect pulse waveform characteristics, the system eliminates the need for invasive or complex mechanical BP cuffs, providing continuous, non-invasive temporal pulse analysis that is more reliable in neonates with wide normal variability.
Solution Approach 2:
The patent changes the measurement parameter from absolute blood pressure values to relative temporal pulse characteristics (time differences between upper and lower extremity pulse events). This parameter transformation normalizes the measurement across individuals with different baseline blood pressures, making detection reliable despite wide normal variations in healthy newborns.
3Measurement precision
If physical examination with pulse palpation is performed, then pulse transmission delay can be assessed, but the technique is challenging to perform in neonates
Solution Approach 1:
The patent replaces manual pulse palpation with automated optical pulse detection. By using photoplethysmographic sensors to electronically detect pulse waveforms, the system eliminates the skill-dependent manual examination, making the assessment easier to perform while maintaining precise measurement of pulse transmission characteristics in neonates.
Solution Approach 2:
The patent enables the pulse signal to self-analyze its own temporal characteristics. The system automatically identifies dicrotic notches, peaks, and feet in the pulse waveform and calculates time differences without requiring external manual measurement, allowing the pulse signal itself to provide the diagnostic information through automated processing.
4Measurement precision
If pulse oximetry is performed after ductus arteriosus closure, then oxygen saturation may appear normal, but lower body ischemia develops due to reduced aortic blood flow
Solution Approach 1:
The patent segments the pulse waveform into characteristic points (dicrotic notch, peak, foot) and analyzes the temporal relationships between upper and lower extremity pulses. This segmentation allows detection of pulse transmission delays and amplitude differences that indicate reduced aortic blood flow, enabling ischemia detection even when overall oxygen saturation appears normal due to ductus closure.
Solution Approach 2:
The patent adds temporal dimension analysis to traditional saturation measurement. By measuring the time difference between upper and lower extremity pulse events, the system detects hemodynamic abnormalities related to reduced aortic flow that are not captured by single-point oxygen saturation, revealing ischemia before it becomes clinically apparent.
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 improves the detection of aortic coarctation by quantifying pulse delay and amplitude differences, providing a reliable alternative to existing methods and reducing the risk of delayed diagnosis.
Implementation Method 1
Photoplethysmography (PPG) is the measurement of the systolic increase in tissue blood volume by light transmission through an extremity. The systolic increase in the arterial blood pressure is accompanied by an increase in arterial blood volume resulting in reduced light transmission.
Data Source
AI summary
Methods and systems are described for detecting the likelihood of an aortic coarctation in an infant using photoplethysmographic pulse signals obtained from the hand and foot of the infant.