How CPAP Machines Gradually Increase Air Pressure for Sleeping Patients
A 1993 patent describing a CPAP machine that lets patients choose how slowly the air pressure ramps up to their therapeutic level, making it easier to fall asleep.
Original patent title: “Device for monitoring breathing during sleep and control of CPAP treatment that is patient controlled”
A 1993 patent describing a CPAP machine that lets patients choose how slowly the air pressure ramps up to their therapeutic level, making it easier to fall asleep. Granted to Individual in 1993 with 10 claims and 231 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes a method and device for Continuous Positive Airway Pressure (CPAP) therapy. It allows a patient to set a 'ramp' period, where the machine starts at a low, comfortable air pressure and gradually increases to the required therapeutic level over a period of time selected by the user. The device uses a delay timer mechanism to automate this transition, ensuring the patient is not blasted with full therapeutic pressure while they are still trying to fall asleep. Once the timer expires, the machine maintains the preset therapeutic pressure to keep the airway open throughout the night.
The gap
What does this patent NOT cover?
- Does not cover automatic pressure adjustment based on real-time detection of snoring or breathing sounds.
- Does not cover systems that adjust pressure based on inhaled air flow volume or rate.
- Does not cover non-CPAP respiratory devices that do not use a sealed mask or nasal prongs.
- Does not cover methods that lack a user-selectable variable time period for the pressure ramp.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The innovation lies in shifting the control of the therapy's onset to the patient, recognizing that psychological comfort during the transition to sleep is just as critical to treatment success as the physical pressure itself.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Ramp feature on ResMed AirSense 10
SmartRamp settings on Philips DreamStation
Standard CPAP machines with user-defined ramp timers
Why it matters
The bigger picture
Before this invention, CPAP machines often delivered full pressure immediately, which many patients found uncomfortable or intolerable, leading to low compliance. By introducing the 'ramp' feature, this patent helped make CPAP therapy a viable, long-term treatment for obstructive sleep apnea. It is a foundational concept in modern sleep medicine that significantly improved patient adherence to treatment.
Filed
December 12, 1991
Granted
April 6, 1993
Market context
Who's building on this
Companies in this space
Major medical device manufacturers like ResMed and Philips Respironics have built their entire product lines around the principles of patient-controlled comfort settings. These companies continue to refine these ramp algorithms, integrating them with cloud-based monitoring and AI-driven pressure adjustments.
Market impact
This patent helped normalize CPAP therapy by addressing the critical 'barrier to entry' of initial discomfort. It transformed CPAP from a clinical, hospital-grade intervention into a standard home-care appliance, creating a multi-billion dollar market for sleep apnea treatment devices.
Claim 1 — Plain English
What this patent covers
This patent describes a method and device for Continuous Positive Airway Pressure (CPAP) therapy. It allows a patient to set a 'ramp' period, where the machine starts at a low, comfortable air pressure and gradually increases to the required therapeutic level over a period of time selected by the user. The device uses a delay timer mechanism to automate this transition, ensuring the patient is not blasted with full therapeutic pressure while they are still trying to fall asleep. Once the timer expires, the machine maintains the preset therapeutic pressure to keep the airway open throughout the night.
The clever bit
The innovation lies in shifting the control of the therapy's onset to the patient, recognizing that psychological comfort during the transition to sleep is just as critical to treatment success as the physical pressure itself.
What it does not cover
- Does not cover automatic pressure adjustment based on real-time detection of snoring or breathing sounds.
- Does not cover systems that adjust pressure based on inhaled air flow volume or rate.
- Does not cover non-CPAP respiratory devices that do not use a sealed mask or nasal prongs.
- Does not cover methods that lack a user-selectable variable time period for the pressure ramp.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Moderate
Citation count
40/40
Highly cited
Claim breadth
7/20
Moderate scope
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$99K – $317K
Midpoint $198K · expired or expiring · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
1 independent claim · 0 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
10 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Lynch, C., & Sullivan, C. E. (1993). How CPAP Machines Gradually Increase Air Pressure for Sleeping Patients (U.S. Patent No. 5,199,424). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/5199424/cpap-sleep-apnea-sullivan
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How CPAP Machines Gradually Increase Air Pressure for Sleeping Patients cover?
A 1993 patent describing a CPAP machine that lets patients choose how slowly the air pressure ramps up to their therapeutic level, making it easier to fall asleep.
Who owns patent US 5199424?
Individual owns this patent, granted in 1993.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 5199424 cited by?
This patent has been cited by 231 later patents that build on its ideas.
What problem does this patent solve?
Before this invention, CPAP machines often delivered full pressure immediately, which many patients found uncomfortable or intolerable, leading to low compliance. By introducing the 'ramp' feature, this patent helped make CPAP therapy a viable, long-term treatment for obstructive sleep apnea. It is a foundational concept in modern sleep medicine that significantly improved patient adherence to treatment.
What does this patent NOT cover?
Does not cover automatic pressure adjustment based on real-time detection of snoring or breathing sounds.
Same assignee
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