Control of supplemental respiratory oxygen

• US 6,561,187 B2
• Filed: 02/14/2002
• Issued: 05/13/2003
• Est. Priority Date: 07/25/1997
• Status: Expired due to Term

• Current Assignee: Minnesota Innovative Technologies and Instruments
• Original Assignee: Minnesota Innovative Technologies and Instruments
• Inventors: Nordman, Catherine A., Schmidt, Matthew F., Buan, John S.
• Primary Examiner(s): Lewis, Aaron J.
• Assistant Examiner(s): MITCHELL, TEENA KAY
• Application Number:
  US10/076,001
• Publication Number:
  US 20020112726A1
• Time in Patent Office: 453 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.23, 128/204.26, 128/205.11, 128/205.23, 128/207.18, 600/323
• US Class Current: 128/204.23
• CPC Class Codes: A61M 16/0051 with alarm devices
• 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 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 16/101 using an oxygen concentrator
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0024 with an on-off output signal, e.g. from a switch
• CPC Class Codes: A61M 2016/0027 pressure meter
• 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
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/63 Motion, e.g. physical activity

Abstract

Methods and systems for supplying supplemental oxygen to patients for use in sub-acute care which maintains healthy blood oxygen content in the patients by controlled dosing of oxygen with a measured response to the patient'"'"'s actual blood oxygen content are disclosed. The dosing can be provided by simple ON/OFF control over the delivery of oxygen or the amount of oxygen delivered to the patient with each inhalation can be varied in response to the patient'"'"'s need as determined by a more sophisticated control scheme, such as a PID loop control algorithm, that utilizes the difference between the patient'"'"'s actual blood oxygen content and a target blood oxygen content and/or trends in the blood oxygen content. The systems and methods are particularly directed at patients receiving supplemental oxygen in a sub-acute care environment.

Claims

1. A method of controlling supplemental oxygen delivery for sub-acute care comprising:

continuously measuring blood oxygen content of a patient to obtain a measured blood oxygen content level;

delivering a variable dose of supplemental oxygen from an oxygen source to the patient when the patient is inhaling, wherein the variable dose is at least partially determined based on the measured blood oxygen content level.

2. A method according to claim 1, wherein the variable dose of supplemental oxygen is at least partially based on a difference between a desired value for the measured blood oxygen content and the measured blood oxygen content.

3. A method according to claim 2, wherein the desired value for the measured blood oxygen content level is about 90%.

4. A method according to claim 1, wherein the variable dose of supplemental oxygen is at least partially based on a trend in measured blood oxygen content as measured at different times.

5. A method according to claim 1, wherein the variable dose includes a zero dose.

6. A method according to claim 1, wherein the supplemental oxygen is delivered through a supplemental oxygen delivery device.

7. A method according to claim 6, wherein the supplemental oxygen delivery device comprises a nasal cannula.

8. A method according to claim 1, further comprising sensing variations in respiration of the patient to determine when the patient is inhaling.

9. A method according to claim 8, wherein the sensing comprises sensing when the patient is inhaling.

10. A method according to claim 8, wherein the sensing is performed using a flow sensor.

11. A method according to claim 10, wherein the flow sensor comprises a bidirectional flow sensor.

12. A method according to claim 1, wherein the method is performed in a residential setting.

13. A method according to claim 1, wherein the measured blood oxygen content level is obtained using a pulse oximeter.

14. A method according to claim 1, further comprising:

determining if the measured blood oxygen content level is invalid; and

delivering a default amount of supplemental oxygen to the patient when the measured blood oxygen content level is invalid.

15. A method according to claim 1, further comprising:

determining if the measured blood oxygen content level is invalid; and

replacing the invalid measured blood oxygen content level with a value based on recent trend in blood oxygen content.

16. A method according to claim 1, wherein the variable dose of supplemental oxygen is at least partially based on a difference between a desired value for the measured blood oxygen content and the measured blood oxygen content, and wherein the method further comprises changing the desired value for the measured blood oxygen content level.

17. A method according to claim 16, wherein changing the desired value for the measured blood oxygen content level comprises monitoring the patient'"'"'s heart rate and changing the desired value for the measured blood oxygen content level in response to change in the patient'"'"'s heart rate.

18. A method of controlling supplemental oxygen delivery for sub-acute care comprising:

continuously measuring blood oxygen content of a patient to obtain a measured blood oxygen content level;

sensing variations in respiration of the patient to determine when the patient is inhaling;

delivering a variable dose of supplemental oxygen from an oxygen source to the patient through a supplemental oxygen delivery device when the patient is inhaling, wherein the variable dose of supplemental oxygen is at least partially based on a difference between a desired value for the measured blood oxygen content level and the measured blood oxygen content level.

19. A method according to claim 18, wherein the variable dose of supplemental oxygen is at least partially based on a trend in measured blood oxygen content level as measured at different times.

20. A method according to claim 18, wherein the variable dose includes a zero dose.

21. A method according to claim 18, wherein the measured blood oxygen content level is obtained using a pulse oximeter and further wherein the method comprises:

determining if the blood oxygen content level obtained by the pulse oximeter is invalid;

delivering a default amount of supplemental oxygen to the patient when the measured blood oxygen content level is invalid.