Plethysmographic Setpoint Adjustment for Accurate Arterial Pressure

Solution Overview

Problem

Existing methods for determining plethysmographic setpoints in volume-clamped arterial pressure measurements often ignore the value of the previous setpoint, leading to persistent or repeated errors in setpoint determination and inaccurate arterial pressure waveform data.

Innovation Solution

A method and system that determine a setpoint based on a previously-used setpoint and a setpoint adjustment value, using waveform features of an arterial volume waveform measured at a constant applied pressure, to adjust the plethysmographic setpoint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If physical calibration (PHYSIOCAL) is used to identify the correct setpoint, then arterial pressure waveform data accuracy can be improved, but the complexity of the calibration process increases and requires additional time

Engineering Contradiction:

Improvearterial pressure waveform data accuracyVSAvoidcalibration process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing optimal setpoint adjustment values in a lookup table during device manufacturing or initialization. These adjustment values are determined in advance based on waveform feature analysis, eliminating the need for complex real-time calibration procedures during clinical use.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating a simplified model or representation of the calibration data in the form of a lookup table. Instead of performing complex physical calibration procedures, the system copies pre-computed adjustment values that can be quickly retrieved and applied, reducing both complexity and time requirements.

Inventive Principle:

Principle #26Copying

2Measurement precision

If physical calibration (PHYSIOCAL) is used to identify the correct setpoint, then arterial pressure waveform data accuracy can be improved, but the time required for calibration increases

Engineering Contradiction:

Improvearterial pressure waveform data accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing optimal setpoint adjustment values in a lookup table during device manufacturing or initialization. These adjustment values are determined in advance based on waveform feature analysis, eliminating the need for complex real-time calibration procedures during clinical use.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating a simplified model or representation of the calibration data in the form of a lookup table. Instead of performing complex physical calibration procedures, the system copies pre-computed adjustment values that can be quickly retrieved and applied, reducing both complexity and time requirements.

Inventive Principle:

Principle #26Copying

3Device complexity

If the previous setpoint value is ignored in setpoint determination, then the device complexity is reduced, but measurement precision deteriorates due to persistent or repeated errors

Engineering Contradiction:

Improvesetpoint determination complexityVSAvoidsetpoint determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by incorporating the previous setpoint value into the current setpoint determination process. The system uses waveform feature analysis to generate adjustment values that are applied to the previous setpoint, creating a feedback loop that continuously refines the setpoint value and eliminates persistent or repeated errors.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical or manual calibration systems with an electronic computational approach. By using waveform feature analysis and lookup tables, the system substitutes sophisticated electronics and algorithms for simpler but error-prone methods, improving precision without proportionally increasing complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Improves the accuracy of arterial pressure measurements by aligning the setpoint with the unstressed arterial volume, reducing errors and enhancing the amplitude of the measured arterial pressure waveform.

Implementation Method 1

A non-invasive sensor includes an air bladder and a photoplethysmographic sensor

Methodology Applied

Scientific EffectPhotoplethysmography: Absorption (EM radiation)

Data Source

PatentUS20260013743A1Setpoint adjustment for arterial pressure measurements

Publication Date: 2026.01.15 BECTON DICKINSON & CO

AI summary

A method of measuring arterial pressure includes receiving a first arterial volume setpoint, adjusting an air pressure of an air bladder to a first air pressure, receiving a first plethysmographic signal from a plethysmographic sensor, analyzing the first plethysmographic signal to determine a first waveform feature, generating a setpoint adjustment value based on the first waveform feature, and generating a second arterial volume setpoint. The first arterial volume setpoint is received by a processor and an air pressure of the air bladder is adjusted by a pressure controller operatively connected to the processor. The first plethysmographic signal is representative of a first arterial volume waveform and is received by the processor while the air pressure of the air bladder is at the first air pressure. The second arterial volume setpoint is generated by adjusting the first arterial volume setpoint based on the setpoint adjustment value.