INHALATION ANAESTHESIA DELIVERY SYSTEM AND METHOD

• US 20090050148A1
• Filed: 02/14/2008
• Published: 02/26/2009
• Est. Priority Date: 02/23/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Haggblom, Tom Jak, Heinonen, Erkki Paavo, Halinen, Henriikka
• Granted Patent: US 8,783,248 B2
• Time in Patent Office: Days
• US Class Current: 128/203.140
• CPC Class Codes: A61M 16/01 specially adapted for anaesthetising A61M16/104, A61M16/18 take precedence
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 16/104 specially adapted for anaesthetics A61M16/18 takes precedence
• CPC Class Codes: A61M 16/18 Vaporising devices for anaesthetic preparations
• CPC Class Codes: A61M 16/22 Carbon dioxide-absorbing devices ; Other means for removing carbon dioxidecartridges with absorbing substances for respiratory apparatus A62B19/00
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/0241 Anaesthetics; Analgesics
• CPC Class Codes: A61M 2202/0283 Nitrous oxide (N2O)
• CPC Class Codes: A61M 2202/0291 Xenon
• CPC Class Codes: A61M 2230/435 partial O2 pressure (P-O2)
• CPC Class Codes: A61M 2230/437 the anaesthetic agent concentration

Abstract

An inhalation anaesthesia delivery system and method, whereby the system comprises a fresh gas feeding arrangement connected to a breathing circuit, a monitor device, a control device and an interface unit. The fresh gas feeding arrangement and the ventilator are configured to deliver a desired concentration of gas to the breathing circuit, the desired concentration being set by using the interface unit. The monitor device is configured to monitor gas concentrations in the breathing circuit by analysing gases flowing in the breathing circuit, and the control device is configured to control the fresh gas feeding arrangement on the basis of the data received from the monitor device to keep the desired breathing gas concentration. The monitor device is configured to monitor expired inorganic gas concentration by comparing the measured expired breathing gas concentration with the set target value and changing the fresh gas delivery accordingly to meet the target value.

Claims

1. An inhalation anaesthesia delivery system, comprising:

a fresh gas feeding arrangement connected to a breathing circuit, a monitor device, a control device and an interface unit, whereby the fresh gas feeding arrangement and the ventilator are configured to deliver a desired concentration of gas to the breathing circuit, the desired concentration being set by using the interface unit,

wherein the monitor device is configured to monitor gas concentrations in the breathing circuit by analysing gases flowing in the breathing circuit, and

wherein the control device is configured to control the fresh gas feeding arrangement on the basis of the data received from the monitor device to achieve the desired breathing gas concentration, and

wherein the monitor device is configured to monitor expired inorganic gas concentration by comparing the measured expired breathing gas concentration with the set target value and changing the fresh gas delivery accordingly to meet the target value.

2. The inhalation anaesthesia delivery system of claim 1, wherein the monitor device is configured to measure expired breathing gas mixture for O2, N2O, CO2 and volatile anaesthetic agent.

3. The inhalation anaesthesia delivery system of claim 1, wherein the expired breathing gas target concentration are given to any two of O2, N2O or N2, and volatile anaesthetic agent.

4. The inhalation anaesthesia delivery system of claim 1, wherein the expired breathing gas target concentrations are given to values for oxygen and volatile anaesthetic agent and the control device is configured to compare corresponding measured values to said set values.

5. The inhalation anaesthesia delivery system of claim 1, wherein the expired breathing gas target concentrations are given to values for oxygen, volatile anaesthetic agent and N2O or N2, and the control device is configured to compare corresponding measured values to said set values.

6. The inhalation anaesthesia delivery system of claim 1, wherein the expired breathing gas concentration is end-tidal concentration.

7. The inhalation anaesthesia delivery system of claim 6, wherein the end-tidal value is determined using CO2 waveform.

8. The inhalation anaesthesia delivery system of claim 7, wherein the end-tidal value for CO2 is determined as the maximum value of the waveform during the breath cycle.

9. The inhalation anaesthesia delivery system of claim 7, wherein the end-tidal value is determined as the waveform value at the time of recording the end-tidal CO2.

10. The inhalation anaesthesia delivery system of claim 1, wherein the control device is also configured to monitor SpO2 value and compare said measured value with the allowed minimum SpO2 value set by using the interface unit.

11. The inhalation anaesthesia delivery system of claim 7, wherein the control device is configured to monitor the differences in the measured end-tidal concentrations to the set target concentration.

12. The inhalation anaesthesia delivery system of claim 10, wherein the control device is configured to receive set maximum and minimum values for fresh gas flow.

13. The inhalation anaesthesia delivery system of claim 1, wherein the delivery system further comprises a ventilator.

14. The inhalation anaesthesia delivery system of claim 1, wherein the expired inorganic gas is oxygen, nitrous oxide, nitrogen or xenon.

15. The inhalation anaesthesia delivery system of claim 1, wherein the changing the fresh gas delivery is carried out by changing composition or/and flow rate.

16. A method of operating an inhalation anaesthesia delivery system, the method comprising:

delivering via a fresh gas feeding arrangement and a ventilator a desired concentration of gas to a breathing circuit, wherein the desired concentration is set by an interface unit;

monitoring with a monitor device gas concentrations in the breathing circuit by analysing gases flowing in the breathing circuit;

controlling with a control device the fresh gas feeding arrangement on the basis of the data received from the monitor device to achieve the desired breathing gas concentration;

monitoring expired inorganic gas concentration by comparing a measured expired breathing gas concentration with a set target value; and

changing the fresh gas delivery accordingly to meet the target value.

17. The method of claim 16, further comprising:

measuring an expired breathing gas mixture for O2, N2O, CO2 and a volatile anaesthetic agent.

18. The method of claim 16, further comprising:

giving the expired breathing gas target concentration to any two of O2, N2O or N2, and the volatile anaesthetic agent.

19. The method of claim 16, further comprising:

comparing the expired breathing gas target concentrations given to values for oxygen and the volatile anaesthetic agent and corresponding measured values with said set values.

20. The method of claim 16, further comprising:

comparing the expired breathing gas target concentrations given to values for oxygen, volatile anaesthetic agent and N2O or N2 and corresponding measured values to said set values.

21. The method of claim 16, wherein the expired breathing gas concentration is end-tidal concentration.

22. The method of claim 16, further comprising:

determining the end-tidal value using a CO2 waveform.

23. The method of claim 22, wherein the end-tidal value for CO2 is determined as the maximum value (32) of the waveform during the breath cycle.

24. The method of claim 22, wherein the end-tidal value is determined as the waveform value at the time of recording the end-tidal CO2.

25. The method of claim 16, further comprising:

monitoring SpO2 value; and

comparing said monitored SpO2 value with an allowed minimum SpO2 value.

26. The method of claim 21, wherein the differences in the measured end-tidal concentrations are monitored to the set target concentration.

27. The method of claim 26, wherein maximum and minimum values for fresh gas flow are set.

28. The method of claim 16, wherein the delivery system further comprises a ventilator.

29. The method of claim 16, wherein the expired inorganic gas is oxygen, nitrousoxide, nitrogen or xenon.

30. The method of claim 16, wherein the changing the fresh gas delivery is carried out by changing composition or/and flow rate.