Medical Device Power Optimization via Cardiac Cycle Modulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Photoplethysmography systems face challenges in optimizing power consumption while maintaining high-quality physiological parameter determination, particularly in battery-powered devices where light source power consumption is significant and can lead to heating effects.

Innovation Solution

The system modulates light drive signal parameters, such as intensity and duty cycle, in synchronization with cardiac cycles or other physiological changes to reduce power usage and heat generation, using techniques like cardiac cycle modulation and drive cycle modulation, and adjusts sampling rates based on physiological activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light source power consumption is increased to maintain high-quality physiological parameter determination, then measurement precision is improved, but use of energy worsens

Engineering Contradiction:

Improvephysiological parameter determination qualityVSAvoidlight source power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system employs cardiac cycle modulation to periodically vary light source operation, activating the light source only during specific phases of the cardiac cycle when physiological signals are most informative. This periodic activation maintains measurement precision by capturing critical signal portions while reducing overall power consumption by keeping the light source inactive during other phases

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts light source parameters including intensity, duty cycle, and activation timing based on real-time detection of cardiac cycle phase and physiological signal characteristics. This dynamic adaptation allows the system to optimize the balance between measurement quality and power consumption by varying light output according to instantaneous physiological conditions

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If light source power consumption is increased to maintain signal quality, then measurement precision is improved, but temperature increases

Engineering Contradiction:

Improvesignal qualityVSAvoidemitter heating

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

By implementing cardiac cycle modulation that periodically activates the light source only during diagnostically valuable phases of the cardiac cycle, the system maintains sufficient signal quality for accurate physiological parameter determination while significantly reducing cumulative heat generation from the light source through reduced duty cycle operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system applies different operational characteristics to light source activation during different cardiac cycle phases, concentrating light output during phases where physiological signals provide maximum diagnostic value while minimizing or eliminating light output during other phases, thereby localizing thermal effects to specific time windows rather than continuous operation

Inventive Principle:

Principle #3Local quality

3Duration of action of moving object

If battery capacity is increased to extend operation time, then duration of action is improved, but weight increases

Engineering Contradiction:

Improvebattery lifeVSAvoiddevice weight

Core Design Contradiction:

Duration of action of moving objectVSWeight of moving object

Solution Approach 1:

The system uses cardiac cycle modulation to periodically activate the light source only during phases when physiological signals are most informative, thereby extending battery life through reduced power consumption while maintaining the device's portability and weight characteristics without requiring oversized battery capacity

Inventive Principle:

Principle #19Periodic action

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 extends battery life, reduces heating, and maintains accurate physiological parameter measurement by optimizing power usage without compromising signal quality.

Implementation Method 1

generate a light drive signal for activating a light source to emit a photonic signal

Methodology Applied

Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

receive a light signal attenuated by the subject, wherein the signal comprises a component corresponding to the emitted photonic signal

Methodology Applied

Scientific EffectLight attenuation: Absorption (EM radiation)

Implementation Method 3

The generated signals may be used to determined physiological parameters such as blood oxygen saturation, hemoglobin, blood pressure, pulse rate

Methodology Applied

Scientific EffectPhotoplethysmography: Photoelectric Effect

Data Source

PatentUS9517018B2Methods and systems for power optimization in a medical device

Publication Date: 2016.12.13 COVIDIEN LP

AI summary

A physiological monitoring system may use photonic signals to determine physiological parameters. The system may vary parameters of a light drive signal used to generate the photonic signal from a light source such that power consumption is reduced or optimized. Parameters may include light intensity, firing rate, duty cycle, other suitable parameters, or any combination thereof. In some embodiments, the system may use information from a first light source to generate a light drive signal for a second light source. In some embodiments, the system may vary parameters in a way substantially synchronous with physiological pulses, for example, cardiac pulses. In some embodiments, the system may vary parameters in response to an external trigger.