APRV Respirator Trigger Window for Spontaneous Expiratory Efforts

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Solution Overview

Problem

In the APRV respiration mode with the % PEF criterion, spontaneous patient inspirations can lead to prolonged application of low pressure, causing excessive air removal from the lungs due to unsynchronized pressure release with patient breathing, which is not effectively addressed by existing technologies.

Innovation Solution

A process that detects spontaneous expiratory efforts and initiates pressure release only within a predetermined trigger window, set to avoid synchronization with patient inspirations, allowing for improved synchronization with the % PEF criterion and maintaining constant inspiration time for better oxygenation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the APRV mode operates with the % PEF criterion without synchronization to patient respiratory activity, then the pressure release can be automatically adapted to lung changes, but spontaneous patient inspirations can cause prolonged low pressure application leading to excessive air removal from the lungs

Engineering Contradiction:

Improveautomatic adaptation of pressure release durationVSAvoidexcessive air removal from lungs

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors patient flow to detect spontaneous expiratory efforts and uses this feedback to determine whether to trigger a pressure release. The trigger window is dynamically adjusted based on detected patient respiratory activity, ensuring pressure release only occurs during appropriate phases of the patient's respiratory cycle.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The trigger window duration and timing are made dynamic rather than fixed, allowing the system to adapt to varying patient respiratory patterns. The window can be adjusted in real-time based on detected expiratory efforts, enabling the system to respond to changing respiratory conditions while preventing harmful effects.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the pressure release duration is extended to ensure complete breathing out, then CO2 elimination is improved, but alveoli may collapse and cannot participate in ventilation anymore

Engineering Contradiction:

ImproveCO2 eliminationVSAvoidalveoli stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The system uses % PEF criterion as a feedback mechanism to determine when to terminate pressure release, monitoring the patient's expiratory flow relative to peak expiratory flow. This ensures pressure release is terminated at the appropriate moment based on actual lung emptying status, preventing both incomplete CO2 elimination and alveolar collapse.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If the trigger window is set to detect spontaneous expiratory efforts, then pressure release can be synchronized with patient respiratory activity, but the device complexity increases

Engineering Contradiction:

Improvesynchronization with patient respiratory activityVSAvoiddetection and control mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The system uses the patient's own respiratory signals to trigger pressure release, eliminating the need for complex external synchronization mechanisms. The patient's expiratory efforts naturally provide the trigger signal, and the system simply needs to detect and respond to these self-generated signals within the defined trigger window.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8695597B2Process for operating a respirator and/or anesthesia device in the APRV mode with the %PEF criterion and a device operated correspondingly

Publication Date: 2014.04.15 DRAGERWERK AG

AI summary

A process for operating a respirator and/or anesthesia device in the APRV mode with the % PEF criterion which includes a detection of a spontaneous expiratory effort by the patient and initiation of a pressure release phase when the detected spontaneous expiratory effort by the patient falls within a predetermined trigger window (Tfreg). A device is provided that is operated correspondingly.