Device and method for the treatment of sleep apnea syndrome

• US 5,645,054 A
• Filed: 10/27/1994
• Issued: 07/08/1997
• Est. Priority Date: 06/01/1992
• Status: Expired due to Term

• Current Assignee: SleepNet Corporation
• Original Assignee: SleepNet Corporation
• Inventors: Muller, Robert A., Sadrnoori, Bijan, Parise, Gerald J., Cotner, Ronald L., Asacker, Thomas E.
• Primary Examiner(s): Asher, Kimberly L.
• Application Number:
  US08/331,030
• Time in Patent Office: 985 Days
• Field of Search: 128/204.23, 128/204.26, 128/205.25, 128/207.18, 128/716, 128/719, 128/204.21
• US Class Current: 128/204.23
• CPC Class Codes: A61F 5/56 Devices for preventing snoring by influencing the respiratory system by gas treatment A61M16/00
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/022 Control means therefor
• 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 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A62B 7/00 Respiratory apparatus for medical purposes A61M16/00

Abstract

The present invention comprises a method and apparatus for the treatment of sleep apnea through the application of real-time, interactive positive airway pressure within the airway of a patient attached to the system. A single sensor is arranged in fluid communication with the airway of the air delivery conduit, and is designed to detect abnormal inspiratory flow to the patient'"'"'s airway on a single breath basis. Output air pressure from the air source to the airway of the patient is continuously increased, instantaneously stopped, and slowly decreased in response to real-time changes in the patient'"'"'s inspiratory flow curve detected and interpreted by this apparatus, thus providing the optimal pressure required to restore airway patency on each breath.

Claims

1. System for treating critical airflow limitation in a patient, the system comprising:

means for generating a pressurized gas flow;

a conduit in fluid communication with said generating means for delivering the gas flow to an airway of a patient;

a flow sensor in fluid communication with the gas flow for generating a breath signal having an amplitude representative of patient breathing; and

circuitry for regulating the gas flow responsive to said breath signal by controlling the generating means, said circuitry comprising;

a) means for providing a base level pressure of gas flow;

b) means for monitoring the breath signal to identify a normal breath attribute sensed by said flow sensor;

c) means for monitoring the breath signal to identify a critical airflow limitation;

d) means for continuously and non-incrementally increasing pressure of the gas flow to no greater than a preselected maximum system pressure upon detection of a critical airflow limitation indicated by absence of a normal breath attribute in a single breath in said breath signal within a predetermined period from detection of a normal breath attribute; and

e) means for decreasing pressure of the gas flow upon detection of restored breathing indicated by presence of said normal breath attribute in a single breath in said breath signal, said normal breath attribute corresponding to a time-based amplitude in a single breath.

2. The invention according to claim 1 wherein

the normal breath attribute comprises a minimum duration of peak inspiratory flow from initiation of inspiration.

3. The invention according to claim 2 wherein the circuitry comprises:

a reference circuit for creating a reference signal which lags the breath signal in amplitude and time; and

a detection circuit for detecting the initiation of inspiration at crossing of the breath signal with the reference signal.

4. The invention according to claim 3 wherein

the breath signal corresponds to gas flow pressure;

and

breath signal amplitude corresponding to the minimum duration of peak inspiratory flow is less than amplitude of the reference signal.

5. The invention according to claim 2 wherein the circuitry comprises;

a timing circuit for measuring said predetermined period; and

an antifalsing circuit for resetting the timing circuit upon detection of a breath having the normal breath attribute.

6. The invention according to claim 1 wherein the predetermined period is less than an apneic event duration of at least ten seconds.

7. The invention according to claim 1 wherein:

the generating means includes an output port;

the delivery conduit has a proximal end in fluid communication with the output port and a distal end in fluid communication with the patient airway; and

the flow sensor is disposed in a gas circuit disposed between the output port and the delivery conduit proximal end.

8. A method for treating critical airflow limitation in a patient comprising the steps of:

supplying a pressurized gas flow at a base level pressure to an airway of a patient;

sensing and generating a breath signal having an amplitude representative of patient breathing by sensing said gas flow;

providing circuitry for regulating the gas flow responsive to said breath signal by controlling the supplying of the pressurized gas flow, wherein said circuitry comprises;

a) means for providing a base level pressure of gas flow;

b) means for monitoring the breath signal to identify a normal breath attribute sensed by said flow sensor; and

c) means for monitoring the breath signal to identify a critical airflow limitation;

continuously and non-incrementally increasing pressure of the gas flow to no greater than a preselected maximum system pressure upon detection of critical airflow limitation indicated by absence of a normal breath attribute in a single breath in said breath signal within a predetermined period from detection of a normal breath attribute; and

decreasing pressure of the gas flow upon detection of restored breathing indicated by presence of said normal breath attribute in a single breath in said breath signal, said normal breath attribute corresponding to a time-based amplitude in a single breath.

9. The method according to claim 8 wherein:

the normal breath attribute comprises a minimum duration of peak inspiratory flow from initiation of inspiration.

10. The method according to claim 9 wherein initiation of inspiration is established by the circuitry:

creating a reference signal which lags the breath signal in amplitude and time; and

detecting crossing of the breath signal with the reference signal.

11. The method according to claim 9 further comprising the steps of:

measuring said predetermined period using a timing circuit; and

restarting said predetermined period upon detection of a breath having the normal breath attribute.