Ventilatory Depression Detection System Using Motion-Filtered Capnography

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Solution Overview

Problem

Current patient monitoring systems fail to reliably detect ventilatory depression in postoperative patients, particularly in non-intubated individuals, leading to delayed interventions and increased mortality due to inadequate ventilation, with existing systems generating frequent false alarms and insufficient continuous monitoring in general wards.

Innovation Solution

A system combining capnography, motion sensors, and pulse oximetry to continuously monitor ventilation and oxygenation, which uses verbal and tactile stimuli to prompt patients to breathe when hypoventilation is detected, reducing false alarms and enabling early intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pulse oximetry is used to monitor patient breathing, then oxygen saturation can be measured, but false alarms occur frequently due to patient motion artifacts

Engineering Contradiction:
Improvebreathing detection accuracyVSAvoidfalse alarms
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system segments the breathing detection function into multiple independent sensor components: capnography sensor for CO2 detection, motion sensors for artifact detection, and pulse oximetry for oxygen saturation. Each sensor independently monitors a specific aspect, and their combined analysis improves reliability while filtering false alarms through cross-validation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces motion sensors as an intermediary to detect and filter motion artifacts before they trigger false alarms. The motion sensor data acts as a mediator that validates whether changes in respiratory parameters are genuine or artifacts of patient movement, thereby reducing false alarm generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If continuous monitoring is implemented in general wards, then early detection of hypoventilation is possible, but system complexity and cost increase

Engineering Contradiction:
Improveventilatory depression detectionVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system merges multiple existing monitoring functions into a single integrated platform: capnography for ventilation monitoring, pulse oximetry for oxygenation, and motion sensing for artifact detection. This consolidation achieves reliable continuous monitoring while managing complexity through unified signal processing and a single alarm system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The monitoring system is designed with multi-functionality to serve various clinical settings (general wards, post-anesthesia care, outpatient areas) using the same core technology platform. The system can adapt to different patient populations and monitoring needs without requiring separate specialized equipment, thereby controlling complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple sensors are combined for comprehensive monitoring, then detection accuracy improves, but device complexity increases

Engineering Contradiction:
Improverespiratory rate detectionVSAvoidsensor integration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system employs feedback mechanisms where each sensor continuously monitors and validates the readings of other sensors. The capnography sensor provides feedback on ventilation status, pulse oximetry feedback on oxygenation, and motion sensors provide feedback on artifact presence. This cross-validation feedback loop improves measurement precision while managing complexity through coordinated signal processing.

Inventive Principle:
Principle #23Feedback

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 effectively detects hypoventilation and prompts patients to breathe, reducing rescue events and emergency transfers, while minimizing false alarms and improving response times, thereby decreasing hospital mortality and ICU stays.

Implementation Method 1

ventilation of patients in general wards or outpatient settings may not be monitored

Methodology Applied
Scientific EffectCapnography:

Implementation Method 2

The pulse oximeter measures the blood oxygen saturation (SpO2)

Methodology Applied
Scientific EffectPulse oximetry:

Implementation Method 3

differences in the studied patient populations, reference signals, respiratory rate detection and the statistical models used in the studies make comparisons between such studies difficult

Methodology Applied
Scientific EffectMotion detection: Accelerometer

Data Source

PatentUS20230078892A1System and method for detecting ventilatory depression and for prompting a patient to breathe
Publication Date: 2023.03.16 RESPIRATION AI LLC
  • US20230078892A1 patent drawing
  • US20230078892A1 patent drawing
  • US20230078892A1 patent drawing

AI summary

A system and method for prompting a patient experiencing ventilatory depression to breathe includes at least one sensor for detecting ventilatory depression by detecting inadequate breathing or lack of breathing in the patient. The system also includes one or more sensors for determining the type of breathing problem experienced by the patient. A sensor for detecting motion of the patient is used to determine whether the patient is moving. If inadequate or a lack of breathing is detected and the patient is not moving, the system provides verbal prompts or tactile stimuli to prompt the patient to breathe to improve patient ventilation.