System and method of controlling the delivery of medical gases to a patient

• US 9,233,218 B2
• Filed: 07/06/2012
• Issued: 01/12/2016
• Est. Priority Date: 01/10/2011
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Chapman, Philip E., Tham, Robert Q., Foulis, Michael, Moreau, Wesley
• Primary Examiner(s): Douglas, Steven
• Application Number:
  US13/542,858
• Publication Number:
  US 20120272957A1
• Time in Patent Office: 1,285 Days
• Field of Search: 128/204.21, 128/205.24, 128/205.13, 128/205.12
• US Class Current: 1/1
• CPC Class Codes: A61M 16/0045 Means for re-breathing exhaled gases, e.g. for hyperventilation treatment
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/01 specially adapted for anaesthetising A61M16/104, A61M16/18 take precedence
• 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 16/0891 Closed circuit, e.g. for anaesthesia
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/122 with dilution
• CPC Class Codes: A61M 16/125 Diluting primary gas with ambient air
• CPC Class Codes: A61M 16/18 Vaporising devices for anaesthetic preparations
• CPC Class Codes: A61M 16/208 Non-controlled one-way valves, e.g. exhalation, check, pop-off non-rebreathing valves
• CPC Class Codes: A61M 16/209 Relief valves
• 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 2016/1025 the O2 concentration
• CPC Class Codes: A61M 2016/1035 the anaesthetic agent concentration
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/0241 Anaesthetics; Analgesics
• CPC Class Codes: A61M 2202/025 Helium
• CPC Class Codes: A61M 2202/0283 Nitrous oxide (N2O)
• CPC Class Codes: A61M 2202/0291 Xenon
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/50 : with microprocessors or computers
• CPC Class Codes: A61M 2205/502 : User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 : with memories providing a history of measured variating parameters of apparatus or patient

Abstract

A system for controlling the delivery of medical gases includes a digital signal processor that receives at least one ventilation parameter value change, calculates a fresh oxygen flow rate, total fresh gas flow rate into the breathing circuit, and a reference oxygen flow rate representative of a predetermined oxygen concentration delivered to a patient. A graphical display presents the calculated fresh oxygen flow rate, total fresh gas flow rate, and reference oxygen flow rate. A method of controlling the delivery of medical gases to a patient includes calculating a total fresh gas flow rate into the breathing circuit, calculating a fresh oxygen flow rate into the breathing circuit, calculating a reference oxygen flow rate representative of a predetermined oxygen concentration delivered to the patient and presenting the total fresh gas flow rate, the fresh oxygen flow rate, and reference oxygen flow rate on a graphical display.

Claims

1. A system for controlling the delivery of medical gases during respiratory support of a patient, the system comprising:

a breathing circuit including a patient connection adapted to deliver respiratory support to the patient;

a mixer pneumatically connected to the breathing circuit, the mixer configured to provide at least oxygen and a balance gas to the breathing circuit;

a mechanical ventilator pneumatically connected to the breathing circuit, the mechanical ventilator configured to create fluid pressure waveforms within the breathing circuit to provide respiratory support to the patient;

a digital signal processor communicatively connected to the mixer and the mechanical ventilator, the digital signal processor receives at least one ventilation parameter value change, calculates a fresh oxygen flow rate into the breathing circuit and a total fresh gas flow rate into the breathing circuit with the at least one ventilation parameter value, and calculates a reference oxygen flow rate representative of a predetermined oxygen concentration delivered to the patient with at least the total fresh gas flow rate; and

a graphical display communicatively connected to the digital signal processor, wherein the graphical display presents the calculated fresh oxygen flow rate, the total fresh gas flow rate, and the reference oxygen flow rate.

2. The system of claim 1, wherein the predetermined oxygen concentration is established by a clinician.

3. The system of claim 1, further comprising:

a vaporizer pneumatically connected to the breathing circuit;

wherein the digital signal processor calculates an anesthetic agent consumption rate at least in part from the total fresh gas flow rate, calculates an estimated cost from the anesthetic agent consumption rate, and operates the graphical display to present the estimated cost.

4. The system of claim 3, wherein the digital signal processor calculates an anesthetic agent vapor flow rate in the total gas flow rate.

5. The system of claim 4, wherein the digital signal processor converts the anesthetic agent vapor flow rate into an anesthetic liquid flow rate and uses the anesthetic agent liquid flow rate as the anesthetic agent consumption rate.

6. The system of claim 1, wherein the graphical display presents the fresh oxygen flow rate and total fresh gas flow rate in a single graphical user interface, the single graphical user interface further presents the reference oxygen flow rate as a reference tab on the single graphical user interface.

7. The system of claim 1, wherein the predetermined oxygen concentration is a predetermined hypoxic concentration threshold.

8. The system of claim 1, further comprising:

a respiratory gas monitor pneumatically connected to the breathing circuit, the respiratory gas monitor produces signals indicative of an oxygen concentration inhaled and exhaled by the patient.

9. The system of claim 8, wherein the digital signal processor calculates the predetermined minimum oxygen requirement threshold using at least one of the signals indicative of oxygen concentration inhaled and exhaled by the patient.

10. The system of claim 8, wherein respiratory gas monitor further produces signals indicative of an anesthetic agent vapor concentration inhaled and exhaled by the patient, wherein the digital signal processor uses the signals received from the respiratory gas monitor to calculate an estimated cost of consumed anesthetic agent.

11. A low-flow ventilation system provides repeating breaths of respiratory support to a patient, the system comprising:

a breathing circuit including a patient connection adapted to deliver the respiratory support to the patient;

an input device operable by a clinician to input at least one ventilation parameter value;

a mixer pneumatically connected to the breathing circuit, the mixer configured to provide at least oxygen and a balance gas to the breathing circuit;

a vaporizer pneumatically connected to the breathing circuit;

a digital signal processor communicatively connected to the input device, the digital signal processor receives the at least one ventilation parameter value, calculates a fresh oxygen flow rate into the breathing circuit, calculates total fresh gas flow rate into the breathing circuit, calculates a predicted oxygen concentration delivered to the patient, and compares the predicted oxygen concentration to a predetermined minimum oxygen requirement threshold of the patient;

a graphical display communicatively connected to the digital signal processor, the graphical display presents the calculated fresh oxygen flow rate and total fresh gas flow rate;

wherein if the predicted oxygen concentration is above the predetermined minimum oxygen requirement threshold, the digital signal processor accepts the at least one ventilation parameter value.

12. The system of claim 11, wherein if the predicted oxygen concentration delivered to the patient is below the predetermined minimum oxygen requirement threshold, the digital signal processor calculates at least one additional parameter value such that the predicted oxygen concentration is above the predetermined minimum oxygen requirement threshold, and the digital signal processor accepts the at least one ventilation parameter value and at least one additional parameter value.

13. The system of claim 11, wherein the digital signal processor further calculates a reference oxygen flow rate required to achieve a delivery of a predetermined oxygen concentration to the patient and the graphical display presents a graphical indication of the calculated reference oxygen flow rate in relation to the calculated fresh oxygen flow rate.

14. The system of claim 13, wherein the digital signal processor further calculates a predicted anesthetic vapor flow rate at least in part from the total fresh gas flow rate, the digital signal processor further converts the predicted anesthetic vapor flow rate to an anesthetic agent consumption cost and the graphical display presents the anesthetic agent consumption cost.

15. The system of claim 14, further comprising:

a respiratory gas monitor pneumatically connected to the breathing circuit, the respiratory gas monitor produces signals indicative of an anesthetic agent concentration inhaled and exhaled by the patient;

wherein the digital signal processor calculates the anesthetic vapor flow rate from at least the indicated inhaled and exhaled anesthetic agent concentrations and the total fresh gas flow rate.

16. A method of controlling the delivery of medical gases to a patient receiving ventilatory support from a low-flow mechanical ventilator, the method comprising:

providing ventilatory support to the patient through a breathing circuit pneumatically connected to a mechanical ventilator in a low-flow configuration;

receiving, with a mixer pneumatically connected to the breathing circuit, a flow of medical gas comprising oxygen;

receiving, with a digital signal processor, a ventilation parameter value change;

calculating, with the digital signal processor, a total fresh gas flow rate into the breathing circuit from the received ventilation parameter value change;

calculating, with the digital signal processor, a fresh oxygen flow rate into the breathing circuit from the received ventilation parameter value change;

calculating, with the digital signal processor, a reference oxygen flow rate into the breathing circuit that achieves a predetermined oxygen concentration as delivered to the patient based upon the total fresh gas flow rate; and

presenting the total fresh gas flow rate, the fresh oxygen flow rate, and the reference oxygen flow rate on a graphical display.

17. The method of claim 16, further comprising:

providing a graphical indication of the calculated reference oxygen flow rate on a single graph with the fresh oxygen flow rate and the total fresh gas flow rate on the graphical display.

18. The method of claim 16, further comprising:

calculating a predicted oxygen concentration delivered to the patient with the digital signal processor based upon the ventilation parameter value change;

comparing the predicted oxygen concentration to the predetermined oxygen concentration with the digital signal processor;

accepting, with the digital signal processor, the ventilation parameter value if the predicted oxygen concentration is above the predetermined oxygen concentration;

rejecting, with the digital signal processor, the ventilation parameter value if the predicted oxygen concentration is below the predetermined oxygen concentration.

19. The method of claim 18, wherein predetermined oxygen concentration is a predetermined hypoxic concentration threshold.

20. The method of claim 16, further comprising:

determining an amount of anesthetic agent consumed by operation of a vaporizer pneumatically connected to the breathing circuit at the total fresh gas flow rate;

calculating an equivalent cost for the consumed anesthetic agent with the digital signal processor; and

presenting the calculated equivalent cost on the graphical display.