Method and apparatus for the intermittent delivery of oxygen therapy to a person

• US 5,558,086 A
• Filed: 11/23/1994
• Issued: 09/24/1996
• Est. Priority Date: 12/16/1992
• Status: Expired due to Fees

• Current Assignee: Freedom Air Services
• Original Assignee: Freedom Air Services
• Inventors: Smith, Donald M., Townley, Roderick M.
• Primary Examiner(s): Asher, Kimberly L.
• Application Number:
  US08/347,237
• Time in Patent Office: 671 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.23, 128/204.26, 128/204.29, 128/205.22, 128/205.24
• US Class Current: 128/204.26
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 16/0841 for sampling
• CPC Class Codes: A61M 2016/0024 with an on-off output signal, e.g. from a switch
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2202/0007 introduced into the body
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/03 Gases in liquid phase, e.g. cryogenic liquids

Abstract

A portable apparatus for supplying dosages of an oxygen-containing gas to the respiratory tract of a person in synchronization with the inhalation phase of the respiratory cycle of said person comprising: (a) a low voltage step control relay with an inlet port for connecting to a source of oxygen-containing gas having a gas proportion regulator; (b) a low voltage microbridge mass gas flow sensor connected to a gas outlet for connection to the respiratory tract of the person said gas flow sensor sensing the duration of oxygen containing gas flow during each inhalation phase of the respiratory cycle of the person and transmitting corresponding information to a microcontroller; (c) a programmed low voltage microcontroller for receiving electrical signals from the gas flow sensor upon detection by the gas flow sensor of the beginning or termination of inhalation by the person; (d) a portable low voltage electrical power supply for operating the low voltage gas flow sensor, the low voltage microcontroller, and the low voltage step control relay; (e) a display panel connected to the microcontroller and the gas flow sensor for displaying programmed data from said microcontroller, and data received from said gas flow sensor; and (f) a keyboard connected to said microcontroller for enabling manual commands to be conveyed to said microcontroller.

Claims

1. A portable apparatus for carrying by a person and supplying dosages of an oxygen-containing gas in synchronization with the inhalation phase of the respiratory cycle of a person, comprising:

(a) a low voltage step control relay having a gas inlet port on the apparatus adapted for connection to a source of oxygen-containing gas;

means for reciprocally moving said step control relay from a closed non-gas flow position to an open gas flow position responsive to an electrical signal from a microcontroller of sufficient length of time to open said step control relay, for maintaining said step control relay, after being opened, in an open gas flow position without drawing further electrical current, and for moving said step control relay from an open gas flow position to a closed non-gas flow position responsive to a subsequent electrical signal from a microcontroller of sufficient length of time to close said step control relay;

(b) a low voltage microbridge mass gas flow sensor connected to a gas outlet port on the apparatus, said gas flow sensor sensing the commencement of inhalation, the duration of oxygen containing gas flow, and the termination of inhalation during each inhalation phase of the respiratory cycle and transmitting corresponding commencement, duration and termination information to a microcontroller;

(c) a programmed low voltage microcontroller for receiving a first electrical signal from the gas flow sensor upon detection by the gas flow sensor of the commencement of inhalation, and for transmitting said first electric signal to the step control relay of sufficient duration to cause the step control relay to move to said open gas flow position; and

for receiving a second electrical signal from the gas flow sensor upon detection by the gas flow sensor of the termination of inhalation, and for transmitting said second electric signal to the step control relay of sufficient duration to cause the step control relay to move to said closed non-gas flow position;

(d) a portable low voltage electrical power supply for operating the low voltage step control relay, the low voltage gas flow sensor and the low voltage microcontroller;

(e) a display on the apparatus connected to the microcontroller and the gas flow sensor for displaying programmed data from said microcontroller, and data received from said gas flow sensor;

(f) a keyboard on the apparatus connected to said microcontroller for enabling manual control commands to be conveyed to said microcontroller; and

(g) said apparatus having a total mass capable of being carried by a single person.

2. An apparatus as claimed in claim 1 wherein the step control relay comprises an on-off reciprocating valve incorporating a step controlled latching solenoid.

3. An apparatus as claimed in claim 2 wherein the gas flow sensor is constructed of dual sensing elements flanking a central heating element, and by means of an unsupported thin film with low heat capacity, senses the commencement and the termination of gas flow inhalation.

4. An apparatus as claimed in claim 1 wherein the step control relay has an oxygen inlet port and an air inlet port, and is equipped with a regulator that blends the oxygen and the air according to a ratio determined by the microcontroller.

5. An apparatus as claimed in claim 1 wherein the microcontroller is electronically supported by a crystal which acts as a time base and time regulates the microcontroller.

6. An apparatus as claimed in claim 1 wherein the display is a low voltage liquid crystal display.

7. An apparatus as claimed in claim 6 including random access memory connected to said microcontroller and said liquid crystal display.

8. An apparatus as claimed in claim 7 including a data output port on the apparatus which is connected to said microcontroller and enables said apparatus to be connected to an exterior microprocessor.

9. An apparatus as claimed in claim 6 wherein the keyboard includes a manual control which enables a person to call up assorted programmed messages or data on the liquid crystal display.

10. An apparatus as claimed in claim 1 wherein said microcontroller is connected to a piezobuzzer on the apparatus, said microcontroller activating said piezobuzzer responsive to a predetermined condition programmed into the microcontroller occurring.

11. An apparatus as claimed in claim 1 including an oximeter sensor means adapted to be connected between a person and the microcontroller for monitoring the pulse rate of a person using the apparatus.

12. An apparatus as claimed in claim 10 wherein said keyboard includes a manual control which enables said microcontroller to operate in a programmed automatic mode.

13. An apparatus as claimed in claim 1 wherein said step control relay, said gas flow sensor, said microcontroller, and said electrical power supply are housed in a protective case, the display panel and keyboard are mounted on the exterior of said case, and the gas inlet port and the gas outlet port are mounted in the exterior walls of the case.

14. An apparatus as claimed in claim 13 wherein a cannula or mask is connected to said gas outlet port gas pressure changes in said cannula or mask being sensed by said gas flow sensor, which responds to gas pressure changes indicative of the commencement or termination of inhalation, and transmits corresponding electrical signals to the microcontroller.

15. An apparatus as claimed in claim 1 wherein the portable power supply is a rechargeable long-life battery.

16. An apparatus as claimed in claim 15 wherein the battery is a rechargeable lithium battery.

17. An apparatus as claimed in claim 15 including a light emitting diode on the apparatus which illuminates when the electrical current level of the battery drops below a predetermined level.

19. An apparatus as claimed in claim 1 wherein the microcontroller tallies the cumulative sum of oxygen consumed over a given length of time.

18. An apparatus for carrying by a person and supplying dosages of an oxygen-containing gas to the respiratory tract in synchronization with the inhalation phase of the respiratory cycle comprising:

(a) a low voltage step control relay with an on-off reciprocating valve with a step-controlled latching solenoid, and a gas inlet port on a surface of the apparatus adapted for connection to a source of oxygen-containing gas having a gas proportion regulator;

means for reciprocally moving said step control relay from a closed non-gas flow position to an open gas flow position responsive to an electrical signal from a microcontroller of sufficient length of time to open said step control relay, for maintaining said step control relay in an open gas flow position without drawing further electrical current, and for moving said step control relay from a gas flow open position to a closed non-gas flow position responsive to with a subsequent electrical signal from a microcontroller of sufficient length of time to close said step control relay;

(b) a low voltage microbridge mass gas flow sensor constructed of dual sensing elements flanking a central heating element, and said gas flow sensor by means of unsupported thin film with low heat capacity, sensing gas flow, said gas flow sensor being connected to a gas outlet port on a surface of the apparatus and adapted to be connected to the respiratory tract of a person, said gas flow sensor sensing the commencement of inhalation, the duration of oxygen containing gas flow, and the termination of inhalation, during each inhalation phase of the respiratory cycle and transmitting corresponding commencement, duration and termination information to a microcontroller;

(c) a programmed low voltage microcontroller for receiving a first electrical signal from the gas flow sensor upon detection by the gas flow sensor of the commencement of inhalation, and for transmitting said first electric signal to the step control relay of sufficient duration to cause the step control relay to move to said open gas flow position; and

for receiving a second electrical signal from the gas flow sensor upon detection by the gas flow sensor of the termination of inhalation, and for transmitting said second electric signal to the step control relay of sufficient duration to cause the step control relay to move to said closed non-gas flow position;

(d) a portable low voltage rechargeable lithium battery for supplying electrical power for operating the low voltage gas flow sensor, the low voltage step control relay, and the low voltage microcontroller;

(e) a liquid crystal display panel on the surface of the apparatus connected to the microcontroller and the gas flow sensor for displaying programmed data from said microcontroller, and data received from said gas flow sensor;

(f) a keyboard on the surface of the apparatus connected to said microcontroller for enabling manual commands to be conveyed to said microcontroller; and

(g) a cannula or mask connected to said gas outlet port, gas pressure changes in said mask or cannula being sensed by said gas flow sensor, which responds to gas pressure changes indicative of the commencement or termination of inhalation, and transmits corresponding electrical signals to the microcontroller; and

(h) said apparatus having a total mass capable of being carried by a single person.