Dual-Mode NIBP Inflation Control for Small-Cuff Pulse Detection
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Solution Overview
Problem
Existing non-invasive blood pressure (NIBP) devices face challenges in maintaining a constant inflation rate and minimizing pump perturbation frequencies, especially for small cuff sizes, leading to unreliable measurements and interference with pulse signals.
Innovation Solution
A dual-mode NIBP system with adjustable valves and hoses of different diameters for adult/pediatric and neonatal cuffs, using a restricted flow path and adaptive control to ensure accurate pressure control and minimize noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a pump operates at low RPM to inflate small cuffs slowly, then patient comfort is improved and maximum cuff pressure is reduced, but pump perturbation frequencies approach the upper frequency range of interest for pulse identification, causing noise to obscure the pulse signal
Solution Approach 1:
The patent extracts the pump perturbation noise from the measurement signal by identifying and removing specific frequency components that correspond to pump operations. This allows the pulse signal to be detected without interference from the pump noise, resolving the contradiction between patient comfort (low RPM operation) and measurement precision (pulse signal detection).
Solution Approach 2:
The system uses feedback by monitoring the pressure signal for pump perturbation frequencies and adjusting the measurement process accordingly. The controller identifies when pump noise is present and takes corrective actions to eliminate its interference with pulse signal detection, maintaining measurement precision while operating at low RPM for patient comfort.
2Ease of operation
If the pump operates at low RPM to provide controlled inflation for small cuffs, then inflation rate control is improved, but the pump becomes unstable and perturbation frequencies interfere with pulse identification
Solution Approach 1:
The patent removes the harmful effect of pump instability by extracting and eliminating the perturbation frequencies from the pressure signal. This allows the system to maintain reliable measurements even when operating at low RPM with potentially unstable pump performance, preserving both ease of operation and measurement reliability.
Solution Approach 2:
The system converts the harmful pump perturbation frequencies into useful information by using them as markers to identify when pump noise is present. This allows the controller to distinguish between actual pulse signals and pump-induced artifacts, improving measurement reliability while maintaining low RPM operation for controlled inflation.
3Device complexity
If a single valve system is used for cuff deflation, then device complexity is reduced, but reliability is compromised if the valve fails
Solution Approach 1:
The patent applies beforehand cushioning by providing a backup valve that can take over if the primary valve fails. This redundancy ensures reliable cuff deflation while maintaining relatively simple device complexity, as the backup valve is integrated into the existing valve control architecture without requiring complex additional mechanisms.
4Productivity
If rapid inflation is used to achieve standard blood pressure measurements, then measurement speed is improved, but patient comfort deteriorates due to intense and prolonged cuff squeeze
Solution Approach 1:
The patent uses periodic action by implementing oscillometric measurements during the inflation process itself, allowing multiple blood pressure estimates to be obtained at different pressure points during a single inflation cycle. This enables faster measurements without requiring intense or prolonged cuff inflation, improving both measurement speed and patient comfort.
Solution Approach 2:
The system applies dynamics by continuously adjusting the inflation rate and pressure based on real-time measurement needs. The controller can accelerate inflation when measurements are obtained quickly or decelerate to maintain patient comfort, dynamically optimizing the balance between measurement speed and patient comfort throughout the measurement process.
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 reliable blood pressure measurements for various cuff sizes by distinguishing between adult/pediatric and neonatal cuffs, ensuring stable inflation rates and reducing pump noise interference, thereby enhancing measurement accuracy and comfort.
Implementation Method 1
The pump is configured to direct air into the cuff to inflate the cuff to a target pressure level
Implementation Method 2
the air pump is turned off, and the cuff is deflated in a controlled, step-down manner
Implementation Method 3
The housing 105 further comprises a measurement system that detects pressure oscillations emanating from the cuff 115 and generates a blood pressure measurement
Data Source
AI summary
The present specification describes methods and systems for on-inflate non-invasive blood pressure (NIBP) measurement suitable for cuffs of various sizes. In embodiments, an adapter hose connecting the cuff to the NIBP device is dynamically identified. Embodiments provide a restriction in at least one of the valves in the NIBP device to enable a controlled release of air from the device during the cuff inflation process.