Respirator SpO2 Feedback Control for Adaptive Ventilation

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Solution Overview

Problem

Existing ventilators do not adequately address the risk of lung damage in patients, particularly premature infants, by failing to adapt ventilation settings in response to changes in oxygen saturation levels.

Innovation Solution

A ventilator system that monitors oxygen saturation (SpO2) and adjusts ventilation parameters such as PEEP and FiO2 to maintain optimal oxygen levels, using a PID controller to dynamically adjust ventilation based on patient-specific respiratory activity and SpO2 levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fixed ventilation settings are used, then device complexity is reduced, but oxygen saturation control deteriorates

Engineering Contradiction:
Improveventilation control systemVSAvoidoxygen saturation control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The ventilator incorporates an oximeter to continuously measure oxygen saturation (SpO2) and uses this feedback to automatically adjust ventilation parameters. The control system compares measured SpO2 values with target ranges and modifies PEEP, FiO2, or ventilation frequency accordingly, creating a closed-loop control system that maintains reliable oxygen saturation control without requiring complex manual adjustments.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If manual adjustment of ventilation parameters is used, then adaptability to patient conditions deteriorates, but device complexity is reduced

Engineering Contradiction:
Improveventilation adaptation to patient conditionsVSAvoidventilation control system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The ventilator system performs self-adjustment of ventilation parameters based on real-time SpO2 monitoring. The control algorithm automatically modifies PEEP levels, oxygen concentration (FiO2), and ventilation frequency according to the patient's current oxygen saturation status, enabling the system to adapt to changing patient conditions without requiring continuous manual intervention while maintaining manageable device complexity through automated decision-making algorithms.

Inventive Principle:
Principle #25Self-service

3Reliability

If SpO2 monitoring and automatic adjustment are implemented, then oxygen saturation control improves, but device complexity increases

Engineering Contradiction:
Improveoxygen saturation controlVSAvoidventilation control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ventilator integrates multiple functions into a unified control system: SpO2 monitoring via oximeter, automatic PEEP adjustment, FiO2 control, and ventilation frequency regulation all operate through a single control algorithm. This multi-functional integration improves oxygen saturation control reliability while managing device complexity by consolidating control logic rather than requiring separate independent systems for each function.

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

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 reduces the risk of lung damage by ensuring appropriate ventilation support, minimizing hyper- or hypoventilation, and maintaining optimal oxygen saturation, thus improving patient outcomes.

Implementation Method 1

the risk of lung damage in patients, particularly premature infants, by failing to adapt ventilation settings in response to changes in oxygen saturation levels

Methodology Applied
Scientific EffectOximetry: Absorption Spectroscopy

Data Source

PatentEP4140525B1Respirators
Publication Date: 2025.08.20 FRITZ STEPHAN
  • EP4140525B1 patent drawingFigure 1
  • EP4140525B1 patent drawingFigure 2
  • EP4140525B1 patent drawingFigure 3

AI summary

This invention relates to a ventilator with a breathing tube connection for attaching a breathing tube, an actuator pneumatically connected to the breathing tube connection for delivering air to a patient via the breathing tube connection, an oximeter connection electrically connected to the control unit for providing an oxygen saturation signal, and a digital, programmable control unit. The control unit is programmed to determine the oxygen saturation from the oxygen saturation signal. The end-of-expiration pressure and the respiratory rate are increased if the oxygen saturation falls below a lower limit. In a further embodiment, the device determines whether the oxygen saturation falls below a lower limit and, if so, initiates backup ventilation at a predetermined rate.The frequency of backup ventilation is reduced when the oxygen saturation exceeds the lower limit again. In a further embodiment, backup ventilation is terminated when the oxygen saturation exceeds a medium limit. The invention further relates to corresponding control methods.