Automated Oxygen Delivery System

• US 20100224191A1
• Filed: 03/06/2009
• Published: 09/09/2010
• Est. Priority Date: 03/06/2009
• Status: Abandoned Application

• Current Assignee: CareFusion 207, Inc. (Becton Dickinson & Co)
• Original Assignee: Cardinal Health 200 Incorporated (Cardinal Health, Inc.)
• Inventors: Dixon, Paul, Westfall, Thomas
• Application Number:
  US12/399,341
• Publication Number:
  US 20100224191A1
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61M 16/1015 using a gas flush valve, e.g. oxygen flush valve
• CPC Class Codes: A61M 16/107 in the inspiratory path
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2016/1025 the O2 concentration
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/208 pH-value
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

The present invention advantageously provides a system for automatically delivering oxygen to a patient, including a sensor to measure an amount of oxygen in a bloodstream of a patient, a pneumatics subsystem and a control subsystem. The pneumatics subsystem includes an oxygen inlet, an air inlet, a gas mixture outlet, and a gas delivery mechanism to blend the oxygen and air to form a gas mixture having a delivered oxygen concentration, and to deliver the gas mixture to the patient. The control subsystem includes an input device to receive a desired concentration of oxygen in the bloodstream of the patient, a sensor interface to receive measurement data and status information associated with the measurement data from the sensor, a pneumatics subsystem interface to send commands to, and receive data from, the pneumatics subsystem, and a processor to control the delivered oxygen concentration based on the desired oxygen concentration, the measurement data and the status information.

Claims

1. An automated oxygen delivery system, comprising:

a sensor to measure an amount of oxygen in a bloodstream of a patient;

a pneumatics subsystem, including;

an oxygen inlet, an air inlet, a gas mixture outlet, and

a gas delivery mechanism, coupled to the oxygen inlet, the air inlet and the gas mixture outlet, to blend oxygen and air to form a gas mixture having a delivered oxygen concentration, and to deliver the gas mixture to the patient; and

a control subsystem, coupled to the sensor and the pneumatics subsystem, including;

an input device to receive a desired concentration of oxygen in the bloodstream of the patient,

a sensor interface to receive measurement data and status information associated with the measurement data from the sensor,

a pneumatics subsystem interface to send commands to, and receive data from, the pneumatics subsystem, and

a processor, coupled to the input device, the sensor interface and the pneumatics subsystem interface, to control the delivered oxygen concentration based on the desired oxygen concentration, the measurement data and the status information.

2. The automated oxygen delivery system of claim 1, wherein the air inlet receives a mixture of breathable gases.

3. The automated oxygen delivery system of claim 1, wherein the gas delivery mechanism controls a flow rate and a delivery pressure of the gas mixture.

4. The automated oxygen delivery system of claim 1, wherein the delivered oxygen concentration is expressed as a fraction of inspired oxygen, FiO₂.

5. The automated oxygen delivery system of claim 4, wherein the delivered FiO₂ is not less than an FiO₂ threshold.

6. The automated oxygen delivery system of claim 4, wherein the sensor is a pulse oximeter, and the sensor data include a saturation of peripheral oxygen measurement, S_PO₂, a perfusion index and a signal quality index.

7. The automated oxygen delivery system of claim 6, wherein the processor controls the delivered oxygen concentration based on the S_PO₂, the perfusion index and the signal quality index.

8. The automated oxygen delivery system of claim 7, wherein the processor increases the FiO₂ if the measured S_PO₂ is below a lower S_PO₂ threshold, and decreases the delivered FiO₂ if the measured S_PO₂ is above an upper S_PO₂ threshold.

9. The automated oxygen delivery system of claim 7, wherein the processor sets the FiO₂ to a predetermined value if the perfusion index is less than a perfusion threshold.

10. The automated oxygen delivery system of claim 7, wherein the processor sets the FiO₂ to a predetermined value if the signal quality index is less than a signal quality threshold.

11. The automated oxygen delivery system of claim 10, wherein the processor initiates at least one of an audible alarm and a visual alarm if the signal quality index is less than a signal quality threshold.

12. The automated oxygen delivery system of claim 4, wherein the sensor is a transcutaneous gas tension sensor, and the sensor data include an arterial oxygen partial pressure measurement, PtcO₂, and an arterial carbon dioxide partial pressure measurement, PtcCO₂.

13. The automated oxygen delivery system of claim 4, wherein the sensor is an invasive catheter blood analyzer, and the sensor data include a dissolved oxygen in the blood measurement, pO₂, a dissolved carbon dioxide in the blood measurement, pCO₂, a blood acidity pH measurement, and a blood temperature measurement.

14. An automated oxygen delivery system, comprising:

a pulse oximeter sensor to measure saturation of peripheral oxygen, S_PO₂, in a bloodstream of a patient;

a pneumatics subsystem, including;

an oxygen inlet, an air inlet, a gas mixture outlet, and

a gas delivery mechanism, coupled to the oxygen inlet, the air inlet and the gas mixture outlet, to blend oxygen and air to form a gas mixture having a delivered fraction of inspired oxygen, FiO₂, and to deliver the gas mixture to the patient; and

a control subsystem, coupled to the sensor and the pneumatics subsystem, including;

an input device to receive a desired concentration of oxygen in the bloodstream of the patient,

a sensor interface to receive S_PO₂ measurements and status information associated with the measurement from the sensor, the status information including a perfusion index and a signal quality index,

a pneumatics subsystem interface to send commands to, and receive data from, the pneumatics subsystem, and

a processor, coupled to the input device, the sensor interface and the pneumatics subsystem interface, to control the FiO₂ based on the desired oxygen concentration, the S_PO₂, the perfusion index and the signal quality index, and to set the FiO₂ to a predetermined value if the perfusion index value is less than a perfusion threshold or the signal quality index is less than a signal quality threshold.

15. The automated oxygen delivery system of claim 14, wherein the air inlet receives a mixture of breathable gases.

16. The automated oxygen delivery system of claim 14, wherein the gas delivery mechanism controls a flow rate and a delivery pressure of the gas mixture.

17. The automated oxygen delivery system of claim 14, wherein the FiO₂ is not less than an FiO₂ threshold.

18. The automated oxygen delivery system of claim 14, wherein the processor increases the FiO₂ if the measured S_PO₂ is below a lower S_PO₂ threshold, and decreases the FiO₂ if the measured S_PO₂ is above an upper S_PO₂ threshold.

19. The automated oxygen delivery system of claim 14, wherein the perfusion index is a fractional variation in the optical absorption of oxygenated red blood cells between the systole and diastole periods of an arterial pulse.

20. The automated oxygen delivery system of claim 14, wherein the signal quality index provides a confidence metric for the S_PO₂.

21. The automated oxygen delivery system of claim 20, wherein the signal quality index is based on variations in the optical absorption of oxygenated red blood cells.

22. A system for automatically delivering oxygen to a patient, comprising:

a means for measuring an amount of oxygen in a bloodstream of a patient;

a pneumatics subsystem, including;

an oxygen inlet, an air inlet, a gas mixture outlet,

a means for blending oxygen and air to form a gas mixture having a delivered oxygen concentration, and

a means for delivering the gas mixture to the patient; and

a control subsystem, coupled to the means for measuring the amount of oxygen and the pneumatics subsystem, including;

an input device to receive a desired concentration of oxygen in the bloodstream of the patient;

a first interface to receive measurement data and status information associated with the measurement data from the means for measuring the amount of oxygen,

a second interface to send commands to, and receive data from, the pneumatics subsystem, and

a processor, coupled to the first interface and the second interface, to control the delivered oxygen concentration based on the desired oxygen concentration, the measurement data and the status data.