Method and apparatus for improving the comfort of CPAP

• US 7,128,069 B2
• Filed: 06/18/2004
• Issued: 10/31/2006
• Est. Priority Date: 06/20/2003
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Price, Andrew Martin, Farrugia, Steven Paul, Richard, Ron, Alder, Matthew
• Primary Examiner(s): Lewis, Aaron J.
• Application Number:
  US10/871,970
• Publication Number:
  US 20050005937A1
• Time in Patent Office: 865 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.23
• US Class Current: 128/204.18
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/417 the bone marrow
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 16/022 Control means therefor
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 2016/0018 electrical
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3365 Rotational speed
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2230/63 : Motion, e.g. physical activity

Abstract

A low-cost CPAP apparatus in which, upon detection of the transition from inhalation to exhalation, the blower motor is de-energized to allow it to freewheel. When the pressure in the patient mask (or whatever interface is utilized) reaches a minimum pressure level during exhalation, the motor is re-energized and its speed is controlled so to maintain the pressure at a level suitable for exhalation. Upon detection of the transition from exhalation to inhalation, the motor speed is increased to provide higher pressures in the patient mask suitable for inhalation.

Claims

1. In a CPAP apparatus having an electric motor, an impeller rotated by the motor, a patient interface, an air delivery conduit for delivering air from the impeller to the patient interface, a mechanism for determining the pressure in the patient interface, and a control mechanism that causes air to be delivered at a desired pressure to the patient interface, and that detects transitions between inhalation and exhalation of a respiratory cycle of a patient;

a method of controlling the motor operation during a sequence of respiratory cycles comprising the steps of;

(i) upon detection of the transition from inhalation to exhalation, de-energizing the motor to allow the motor to freewheel;

(ii) when the pressure in the patient interface reaches a minimum pressure level during exhalation, re-energizing the motor and controlling its speed so to maintain the pressure at a level suitable for exhalation; and

(iii) upon detection of the transition from exhalation to inhalation, increasing the motor speed to provide higher pressures in the patient interface suitable for inhalation,

wherein during a ramp phase the motor speed is controlled in step (iii) so as to increase the pressure over successive respiratory cycles and to provide a substantially constant pressure during any single respiratory cycle while increasing the substantially constant pressure over successive respiratory cycles.