Finger Cuff with LED-PD Sensor for Blood Pressure Accuracy
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Solution Overview
Problem
Finger cuff-based blood pressure monitoring devices face challenges in accuracy due to suboptimal cuff positioning, leading to unreliable measurements as a loose cuff requires additional energy and may read artificially high blood pressure.
Innovation Solution
A system with a finger cuff containing a bladder and an LED-PD pair, connected to a processor that applies pneumatic pressure and measures the plethysmogram to determine the cuff's fitness on the patient's finger, ensuring accurate blood pressure monitoring by maintaining constant arterial volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the finger cuff is attached loosely to the patient's finger, then the ease of operation is improved, but the measurement precision deteriorates due to additional energy consumption and artificially high blood pressure readings
Solution Approach 1:
The system performs preliminary diagnostic measurements (plethysmogram assessment, arterial volume verification) before confirming the cuff is ready for blood pressure measurement. This preliminary action detects improper cuff fit early, preventing inaccurate measurements while maintaining ease of attachment by allowing users to simply attach the cuff and let the system verify proper fit.
Solution Approach 2:
The system provides real-time feedback through the plethysmogram signal quality assessment and arterial volume monitoring. If the cuff is loose or improperly positioned, the system detects this through abnormal plethysmogram characteristics and provides feedback to the user to adjust the cuff, thereby maintaining measurement precision without complicating the attachment process.
2Measurement precision
If the finger cuff is attached tightly to the patient's finger, then the measurement precision is improved by preventing cuff movement, but the comfort and ease of operation deteriorate
Solution Approach 1:
The system performs preliminary diagnostic measurements including plethysmogram quality assessment and arterial volume verification to determine if the cuff is properly fitted. This allows the system to distinguish between intentionally tight proper-fit conditions and excessively tight uncomfortable conditions, ensuring measurement precision while protecting user comfort.
Solution Approach 2:
The system continuously monitors plethysmogram signal quality and arterial volume during measurement. If the cuff becomes too tight or shifts position, the system detects changes in signal characteristics and provides feedback to alert the user to adjust the cuff, maintaining measurement reliability without requiring excessive tightness that would reduce comfort.
3Ease of operation
If the cuff stretches to reach the finger in a loose fit, then the ease of operation is improved, but the energy consumption increases and measurement accuracy deteriorates
Solution Approach 1:
The system performs preliminary diagnostic measurements using the plethysmogram sensor and pressure sensor to assess cuff fit quality before initiating blood pressure measurement. This early detection prevents excessive energy consumption by identifying loose cuffs that would require the bladder to stretch excessively, allowing users to readjust the cuff to a proper fit.
Solution Approach 2:
The system monitors energy consumption patterns and plethysmogram signal quality during operation. When the bladder needs to stretch excessively to maintain measurement due to a loose cuff, the system detects this through abnormal energy consumption and signal characteristics, providing feedback to the user to tighten the cuff, thereby reducing energy consumption and improving accuracy.
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 provides precise blood pressure monitoring by assessing the cuff's fit and adjusting pressure accordingly, enhancing measurement reliability and accuracy.
Implementation Method 1
The infrared light may be sent through the finger in which a finger artery is present. The infrared sensor picks up the infrared light and the amount of infrared light registered by the sensor may be inversely proportional to the artery diameter
Implementation Method 2
by inflating the bladder in the finger cuff, a pressure is exerted on the finger artery. If the pressure is high enough, it will compress the artery
Data Source
AI summary
Disclosed is a system to monitor a finger cuff connectable to a patient's finger to be used in measuring the patient's blood pressure by a blood pressure measurement system utilizing the volume clamp method and to measure the plethysmogram of the finger cuff. The system comprises the finger cuff that includes an enclosing portion that encloses a patient's finger. The enclosing portion includes a bladder and a light emitting diode (LED) and photodiode (PD) pair. The system further comprises a processor to: command applying pneumatic pressure to the bladder of the finger cuff from a low pressure to a high pressure; measure the plethysmogram of the finger cuff as the pressure increases from the low pressure to the high pressure; and determine fitness of the finger cuff on the patient's finger based on the measured plethysmogram. When the finger cuff is placed around the patient's finger, the bladder and the LED-PD pair aid the processor in measuring the plethysmogram.