Variable Oxygen Flow Control for Apnea Detection
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Solution Overview
Problem
Current breathing detection systems during procedural sedation are inadequate, as they fail to accurately differentiate between true apnea and oxygen delivery device displacement, and cannot accurately determine the fraction of inhaled oxygen, leading to potential delays in detecting inadequate respiration and wastage of supplemental oxygen.
Innovation Solution
A system and method that utilize a processor to analyze breathing pressure values and oxygen flow rates to determine if a patient is breathing, and if not, compares these values to ambient pressure to differentiate between apnea and oxygen delivery device displacement, while also calculating the volume of inhaled oxygen using a pressure sensor and oxygen flow analyzer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed flow rate oxygen is delivered continuously, then oxygen supply is ensured, but most oxygen is wasted as the patient exhales
Solution Approach 1:
The patent implements dynamic oxygen flow delivery by adjusting the flow rate in real-time based on detected breathing patterns. The system transitions from fixed continuous flow to variable flow that responds to patient inhalation events, delivering oxygen only when needed and at appropriate rates to match patient demand.
Solution Approach 2:
The system delivers oxygen in periodic pulses synchronized with patient breathing cycles. By detecting inhalation events and triggering oxygen delivery during these periodic inhalation phases, the system ensures oxygen is supplied during useful inhalation periods while avoiding waste during exhalation phases.
2Measurement precision
If capnometry is used to monitor respiration, then breath detection accuracy is improved, but the signal is degraded when high oxygen flow is given
Solution Approach 1:
The patent introduces pressure sensing as an intermediary measurement method that indirectly detects breathing events through pressure changes in the airway. This alternative measurement approach bypasses the limitation of capnometry signal degradation by using a different physical parameter (pressure) that is not affected by high oxygen flow dilution of carbon dioxide.
Solution Approach 2:
The system replaces the chemical measurement approach of capnometry (measuring CO2 concentration) with a mechanical measurement approach (measuring pressure changes). This substitution eliminates the signal degradation problem because pressure changes during inhalation are detectable regardless of oxygen flow rate, providing reliable breath detection even when CO2 signal is degraded.
3Reliability
If high oxygen flow is increased to treat hypoxia, then oxygenation is improved, but the exhaled carbon dioxide signal is diluted
Solution Approach 1:
The patent uses pressure sensing as an intermediary method to monitor breathing events independently of carbon dioxide signal quality. By detecting pressure changes during inhalation, the system can identify when a patient is breathing without relying on the CO2 signal, allowing clinicians to safely increase oxygen flow to treat hypoxia while maintaining reliable breathing monitoring through the pressure-based intermediary measurement.
4Ease of operation
If breathing detection systems are simplified, then ease of operation is improved, but the ability to differentiate apnea from device displacement is reduced
Solution Approach 1:
The patent implements a multi-functional pressure sensing system that performs multiple detection functions through a single sensor. The pressure sensor simultaneously detects breath attempts, distinguishes between apnea and device displacement, and provides information about patient breathing effort. This universal approach maintains system simplicity while achieving multiple detection objectives through clever use of pressure measurement physics.
Solution Approach 2:
The system uses feedback from pressure sensor readings to dynamically determine the appropriate alarm response. By continuously monitoring pressure patterns and comparing them against expected breathing patterns, the system can differentiate between true apnea (no pressure changes) and device displacement (pressure changes consistent with patient effort). This feedback mechanism enables accurate differentiation while maintaining operational simplicity through automated pattern recognition.
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 solution provides accurate detection of patient breathing and identification of oxygen delivery failures, reducing waste and ensuring timely intervention during sedation, by differentiating between apnea and device displacement and calculating the fraction of inhaled oxygen.
Implementation Method 1
detecting a patient's breathing pressure value to determine a plurality of breathing pressure values; measuring an ambient pressure to provide an ambient pressure value
Implementation Method 2
measuring an oxygen flow rate through an oxygen delivery device to provide an oxygen flow rate value
Data Source
AI summary
A method and apparatus deliver a variable flow of oxygen to a patient. The apparatus may include a flow control valve, a pressure sensor to detect a patient's breathing pressure and ambient pressure, an oxygen flow analyzer to measure oxygen flow to the patient, and a processor to analyze the breathing pressure values, ambient pressure value, and oxygen flow rate values and to determine when a patient is inhaling. When the processor determines the patient is inhaling, the processor calculates an optimal oxygen flow rate to deliver to a patient, which may depend on a pre-selected flow rate and an oxygen backlog, and the processor sends a signal to the flow control valve to deliver the optimal oxygen flow rate to the patient.