Selective Ramping of Therapeutic Pressure in Breathing Apparatus
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Solution Overview
Problem
Existing CPAP devices cause discomfort during the transition from a wakeful state to sleep due to the sudden application of airway pressure, leading to non-compliance in patients, despite advancements in pressure regulation and ramping mechanisms.
Innovation Solution
A method and system for selective ramping of therapeutic pressure in a patient breathing apparatus, which gradually increases the gas delivery pressure from an initial level to a prescription level over a defined ramp duration, using a ramp delay and derived delivery pressure increase rate, to minimize discomfort and facilitate smoother transition to therapeutic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full therapeutic pressure is applied immediately upon device activation, then the airway is effectively supported from the start, but patient discomfort increases due to the sudden pressure application during the transition to sleep
Solution Approach 1:
The device applies a preliminary low pressure level before transitioning to the full therapeutic pressure. This preliminary action allows the patient to acclimate to the presence of positive pressure without immediate discomfort, while still providing sufficient airway support to prevent collapse during the transition to sleep.
Solution Approach 2:
The device dynamically adjusts the pressure level over time, transitioning from an initial low pressure to the prescription pressure level. This dynamic pressure adjustment matches the patient's physiological transition from wakeful to sleep state, providing optimal airway support at each stage without causing discomfort.
2Object-affected harmful factors
If therapeutic pressure is reduced during the expiratory phase to minimize discomfort, then patient comfort improves, but the effectiveness of airway support may be compromised
Solution Approach 1:
The device applies periodic pressure reductions synchronized with the patient's breathing cycle. Pressure is reduced during the expiratory phase when airway collapse risk is lower, then restored during inspiration when support is most needed. This periodic modulation maintains airway effectiveness while minimizing discomfort during expiration.
Solution Approach 2:
The device uses feedback from flow sensors to detect the patient's breathing phase and adjust pressure accordingly. When expiration is detected, pressure is reduced; when inspiration is detected, pressure is restored to full therapeutic level. This feedback-based control ensures airway support effectiveness is maintained while reducing discomfort during appropriate phases.
3Measurement precision
If expensive flow sensors and control systems are used to achieve precise pressure regulation, then pressure accuracy improves, but device cost increases
Solution Approach 1:
The device uses pressure sensors as an intermediary measurement approach rather than direct flow sensing. By measuring pressure changes and inferring flow conditions from pressure gradients, the system achieves sufficient control accuracy for therapeutic pressure modulation without requiring expensive flow sensors, thereby reducing device complexity and cost.
Data Source
AI summary
A respiratory assistance device includes a patient interface for coupling to a patient respiratory passageway, and a selectively regulated therapeutic gas flow source in pneumatic communication with the patient over the patient interface. A ramping controller is connected to the therapeutic gas flow source and is receptive to inputs of a prescription pressure level, an initial pressure level, a total ramp duration, and a numeric value corresponding to a ramping duration. Therapeutic gas flow at an initial pressure level is regulated for a ramp delay duration reciprocal to the ramping duration relative to the total ramp duration. The ramping controller incrementally increases therapeutic gas flow to the prescription pressure level from a ramp start time to a ramp end time at a delivery pressure increase rate derived from the numeric value of the ramping duration and the total ramp duration.