Mask free delivery of oxygen and ventilatory monitoring

• US 6,938,619 B1
• Filed: 06/13/2000
• Issued: 09/06/2005
• Est. Priority Date: 06/13/2000
• Status: Expired due to Term

• Current Assignee: Scott Laboratories, Inc.
• Original Assignee: Scott Laboratories, Inc.
• Inventors: Hickle, Randall S.
• Primary Examiner(s): Dawson, Glenn K.
• Assistant Examiner(s): Erezo, Darwin P
• Application Number:
  US09/592,943
• Time in Patent Office: 1,911 Days
• Field of Search: 128/204.18, 128/204.22, 128/204.23, 128/205.25, 128/207.18, 128/207.14, 128/200.24, 128/201.18, 128/202.22, 128/203.22, 128/204.26, 482/13, 600/538, 600/539, 600/543
• US Class Current: 128/207.18
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61B 5/6819 Nose
• 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 16/024 including calculation means, e.g. using a processor
• 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 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 16/0808 Condensation traps
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 2205/0216 Materials providing elastic properties, e.g. for facilitating deformation and avoid breaking
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2210/0618 Nose
• CPC Class Codes: A61M 2210/0625 Mouth
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)
• CPC Class Codes: A61M 2230/437 the anaesthetic agent concentration

Abstract

Disclosed is an apparatus and method for the delivery of supplemental oxygen gas to a person combined with the monitoring of the ventilation of the person with both being accomplished without the use of a sealed face mask. Preferred embodiments of the present invention combine an oxygen delivery device, a nasal airway pressure sampling device, an oral airway pressure sampling device, and a pressure analyzer connected to the sampling devices to determine the phase of the person'"'"'s respiration cycle and the person'"'"'s primary airway. The oxygen delivery device is connected to a controller such that it delivers a higher flow of oxygen to the person during the inhalation phase of the person'"'"'s respiratory cycle. The invention thus increases end tidal oxygen concentrations with improved efficiency comparative to known open airway devices. Embodiments of the invention can include carbon dioxide sampling tubes that continuously sample air from the nose and mouth to determine carbon dioxide concentration during exhalation.

Claims

1. A method for supplying supplemental oxygen to a person, the method comprising the steps of:

determining whether the person is in an exhalation or inhalation phase of a respiratory cycle;

delivering a higher flow of oxygen to the person during the inhalation phase of the respiratory cycle;

comparative sampling of nasal and oral gases for and monitoring the ventilation of the person in accordance with the determination of the person'"'"'s primary respiratory site.

2. The method of claim 1 wherein the oxygen is delivered to the person in the area of the person'"'"'s nose and mouth.

3. The method of claim 2, wherein said oxygen is delivered to the areas of the person'"'"'s nose and mouth using a mask-free cannula.

4. The method of claim 1 wherein the determining of whether the person is in the exhalation or inhalation phase is accomplished by analyzing pressure in a breath airstream of the person.

5. The method of claim 4 wherein the pressure in the person'"'"'s breath airstream is determined by individually sampling the pressure at a nasal respiratory site and an oral respiratory site of the person, and wherein said individual sampling is also used in said determining of said primary respiratory site.

6. The method of claim 1 wherein the determining of the person'"'"'s primary respiratory site is accomplished by sampling pressures in or near a nasal respiratory site and an oral respiratory site of the person and comparing said pressures to determine a greater one of said pressures.

7. The method of claim 6, wherein said primary respiratory site demonstrates a greater pressure swing during said respiratory cycle.

8. The method of claim 1 wherein the monitoring of the ventilation is accomplished by measuring amounts of CO₂ in end tidal exhalation of the person.

9. The method of claim 8 wherein the measuring is conducted on a continuous basis.

10. The method of claim 1, further comprising setting a higher flow rate of supplemental oxygen and a lower flow rate of supplemental oxygen, said higher flow rate being delivered to the person during the inhalation phase of the respiratory cycle and said lower flow rate being delivered to the person during the exhalation phase of the respiratory cycle.

11. The method of claim 10, wherein the flow of oxygen is gradually increased from said lower flow rate until it reaches said higher flow rate, said gradual increase being triggered by the beginning of said inhalation phase.

13. The apparatus in accordance with claim 9 also comprising a ventilatory sampling device connected to a ventilatory monitor.

14. The apparatus of claim 13 wherein the ventilatory sampling device comprises a nasal ventilatory sampling device and an oral ventilatory sampling device and wherein the person'"'"'s ventilation is monitored from the primary respiratory site.

25. The apparatus of claim 9, wherein said pressure analyzer and said pressure comparator comprise pressure transducers.

12. An apparatus for delivering supplemental oxygen to a person comprising:

an oxygen delivery device;

at least one airway sampling device, said airway sampling device including a nasal sampling device adapted to sample pressure in or near a nasal airway of the person and an oral sampling device adapted to sample pressure in or near an oral airway of the person;

a pressure analyzer connected to said airway sampling device and adapted to determine a phase of a respiratory cycle of the person;

a pressure comparator connected to said oral sampling device and said nasal sampling device and adapted to determine a primary respiratory site of the person; and

a controller coupled to said pressure analyzer;

wherein the oxygen delivery device is operated by said controller to deliver a higher flow of oxygen to the person in accordance with the phase of the person'"'"'s respiratory cycle.

15. An apparatus in accordance with claim 12 wherein the controller delivers a higher flow of oxygen only during the inhalation phase of the person'"'"'s respiratory cycle.

16. The apparatus of claim 12, wherein said oxygen delivery device comprises a mask-free cannula having a diffuser grid for supplying oxygen proximate to the person'"'"'s nose and mouth.

17. The apparatus of claim 12, wherein said oxygen delivery device comprises an oral collection chamber for collecting a volume of expired gases that the person has breathed orally.

18. The apparatus of claim 17, wherein said oral collection chamber is mounted to said oxygen delivery device such that it can be slid to accommodate proportions of the person'"'"'s face.

19. The apparatus of claim 12, further comprising a microphone adapted to capture breathing sounds of the person that can be amplified for hearing by a care giver.

20. The apparatus of claim 12, wherein said oral and said nasal sampling devices each comprise a pair of lumens, the first of said lumens in each said pair comprising a pressure sampling lumen and the second of said lumens in each said pair comprising a ventilatory sampling lumen.

21. The apparatus of claim 20, wherein said lumens are slidably mounted to an oxygen delivery cannula.

22. The apparatus of claim 20, wherein gas sample bypass circuits maintain gas flow rates in said ventilatory sampling lumens if one of said ventilatory lumens becomes occluded or if gas within one of said ventilatory lumens is not being analyzed.

23. The apparatus of claim 22, wherein valves are employed to alternatively connect either of said ventilatory lumens to a gas analyzer under predetermined conditions.

24. The apparatus of claim 20, wherein said lumen pairs are mounted on a cannula, and wherein said controller is adapted to minimize entrainment of supplemental oxygen flow into said ventilatory sampling lumens.

26. A method for mask-free delivery of supplemental oxygen to a patient, said method comprising:

sampling pressure at a nasal respiratory site;

sampling pressure at an oral respiratory site;

comparing said nasal respiratory site pressure and said oral respiratory site pressure to identify one of said sites as a primary respiratory site;

monitoring pressure changes at said respiratory sites to determine when said patient is inhaling; and

delivering a higher flow of oxygen proximate to said respiratory sites only whenever said patient is inhaling.

27. The method according to claim 26, further comprising monitoring ventilation of the patient by analyzing expired gases at the patient'"'"'s primary respiratory site.

28. The method according to claim 26, wherein said steps of sampling pressures comprises determining pressure swings at each respiratory site, and wherein said step of comparing said pressures comprises identifying the site having the greater pressure swing as the primary respiratory site.

29. The method according to claim 26, wherein said primary respiratory site is switched to a new primary respiratory site whenever a preset number of consecutive pressure samples measured at another respiratory site exceeds corresponding pressure samples at said primary respiratory site by a preset multiple.

30. The method according to claim 29, wherein said series of consecutive pressure samples comprises at least four pressure samples in a row.

31. The method according to claim 29, wherein said preset multiple is 3.

32. The method according to claim 26, further comprising setting a higher flow rate of supplemental oxygen and a lower flow rate of supplemental oxygen, said higher flow rate being delivered when the patient is inhaling and said lower flow rate being delivered to the patient at other times.

33. The method according to claim 32, wherein a mask-free cannula is employed to deliver said oxygen and to sample pressure at said respiratory sites.

34. The method according to claim 32, wherein flow of oxygen proximate to said respiratory sites is gradually increased until it reaches said higher flow of oxygen, said gradual increase being triggered when the patient begins to inhale.

35. The method according to claim 26, wherein said nasal respiratory site pressure and said oral respiratory site pressure is added to calculate a total breath pressure, and wherein said total breath pressure is compared with an upper threshold pressure value and a lower threshold pressure value to control delivery of said oxygen during a respiratory cycle of the patient.

36. The method according to claim 35, wherein said higher flow of oxygen is delivered after said total breath pressure meets said upper threshold pressure value and is ceased after said total breath pressure meets said lower threshold pressure value.

37. A method for supplying supplemental oxygen to a person, the method comprising:

determining whether the person is exhaling or inhaling according to a breathing cycle;

automatedly identifying a primary respiratory site of the person;

altering a flow rate of supplemental oxygen being supplied to the person between a preset low flow rate and a preset high flow rate wherein said low flow rate is delivered to the person when exhaling and said high flow rate is delivered to the person when inhaling; and

monitoring ventilation of the person at said primary respiratory site in accordance with delivery of said flow rates.

38. The method according to claim 37, wherein said high flow rate of supplemental oxygen is delivered to the person through a delivery device having a plurality of small holes near respiratory sites of the patient so as to avoid discomfort resulting from an impact of high pressure oxygen.

39. The method according to claim 37, wherein said high flow rate of supplemental oxygen is delivered to the person through a delivery device having a plurality of small holes near respiratory sites of the patient so as to minimize entrained air.

40. The method according to claim 37, wherein oxygen is delivered to the person in the area of the person'"'"'s nose and mouth.

41. The method according to claim 37, wherein the identifying of the person'"'"'s primary respiratory site is accomplished by sampling pressures in nasal and oral respiratory sites of the person and comparing said pressures to determine a greater one of said pressures.

42. The method according to claim 41, wherein comparing said pressures to determine the greater pressure comprises identifying the site demonstrating a greater pressure swing as the primary respiratory site.

43. The method according to claim 37, wherein the determining of whether the person is in the exhalation or inhalation phase is accomplished by analyzing the pressure in the person'"'"'s breath airstream.

44. The method according to claim 43, wherein the pressure in the person'"'"'s breath airstream is determined by individually sampling pressure at nasal and oral respiratory sites and adding said oral and nasal pressures to calculate a breath airstream pressure.

45. The method according to claim 43, wherein said breath airstream pressure is compared with an upper and a lower pressure threshold wherein both of said thresholds are lower than ambient pressure.

46. The method according to claim 45, wherein said upper and lower thresholds serve as triggers for initiating delivery of said high and said low flow rate respectively.

47. The method according to claim 37, wherein said monitoring of the ventilation is accomplished by measuring carbon dioxide levels in exhaled gases of the person.

48. The method according to claim 47, wherein said measuring of the carbon dioxide levels is accomplished by measuring amounts of carbon dioxide in end-tidal exhalation of the person.

49. The method according to claim 37, wherein said monitoring step comprises measuring a concentration of carbon dioxide in expired gases when said person exhales.