Microprocessor-controlled ventilator system and methods

• US 5,692,497 A
• Filed: 05/16/1996
• Issued: 12/02/1997
• Est. Priority Date: 05/16/1996
• Status: Expired due to Fees

• Current Assignee: Children's Medical Center Corporation, The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: Children's Medical Center Corporation, The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Thompson, John E., Schnitzer, Jay J.
• Primary Examiner(s): Millin, Vincent
• Assistant Examiner(s): SRIVASTAVA, VIRENDRA KUMAR
• Application Number:
  US08/649,068
• Time in Patent Office: 565 Days
• Field of Search: 128/204.18, 128/204.21, 128/204.22, 128/204.23, 128/205.11, 128/205.23, 128/205.24, 128/201.14, 128/201.18
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/042 with separate conduits for in-and expiration gas, e.g. for limited dead volume
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2016/0042 in the expiratory circuit
• CPC Class Codes: A61M 2016/1025 the O2 concentration
• CPC Class Codes: A61M 2202/0275 Nitric oxide [NO]
• CPC Class Codes: A61M 2205/16 with back-up system in case of failure
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)
• CPC Class Codes: A61M 2230/435 partial O2 pressure (P-O2)

Abstract

A microprocessor controlled ventilator controls a patient'"'"'s breathing selectively. In a preferred aspect, the ventilator utilizes intratracheal pulmonary ventilation and a reverse thrust catheter to provide all patient inspiration. The microprocessor connects to a pneumatic subsystem which includes a variety of sensors and actuators and the catheter disposed in the patient'"'"'s trachea. A feedback control loop provides a basis for controlling selected actuators within the subsystem to control the patient'"'"'s breathing. The microprocessor provides the selective venting of expiration gases, and the selective mixing of treatment gases, such as anesthesia. The ventilator has a plurality of possible ventilating modes, each selectable by the user, thereby reducing the number of hospital equipment needed to all forms of ventilation required by a patients.

Claims

1. A ventilator system, comprising:

A. a pneumatic subsystem for receiving one or more gases and for establishing a flow path to a patient insert at a distal end,

B. at least one sensor,

C. at least one actuator operatively coupled to the pneumatic subsystem; and

D. a microprocessor subsystem connected to receive information from the sensor and to control the actuator, the microprocessor subsystem having means for selecting at least one ventilation mode and for controlling gas flow in the flow path of the pneumatic subsystem in a manner corresponding to the mode and for controlling the actuator in response to signals generated from the sensor to vary at least one of the group consisting of inspiratory-to-expiratory ratio (I;

E), (ii) a respiratory rate and the I;

E ratio, and (iii) an intratracheal pulmonary flow to establish predetermined carinal pressures in a patient.

2. A ventilator system according to claim 1, wherein the microprocessor subsystem further comprises means for storing the signals for subsequent review by a user of the ventilator system.

3. A ventilator system according to claim 1, wherein the microprocessor subsystem further comprises means for displaying the signals for concurrent review by a user of the ventilator system.

4. A ventilator system according to claim 1, wherein the means for selecting at least one ventilation mode further comprises means for selecting a plurality of modes selected from the group of (i) assist control mode ventilation (ACMV), (ii) synchronized intermittent mandatory ventilation (SIMV), (iii) continuous positive airway pressure (CPAP), (iv) pressure-control ventilation (PCV), (v) pressure support ventilation (PSV), (vi) proportional assist ventilation (PAV), (vii) volume assured pressure support (VAPS), and (viii) intratracheal pulmonary ventilation (ITPV).

5. A ventilator system according to claim 1, further comprising means for monitoring selected patient information including one or more of the following:

physiological trends, compositions, flow rates, pressures, volumes, and dynamic compliance data.

6. A ventilator system according to claim 5, further comprising means for notifying a user of the ventilator system that the information corresponds to a preselected value.

7. A ventilator system according to claim 5, further comprising means for warning a user of the ventilator that the information corresponds to a preselected value, thereby providing enhanced safety for the patient.

8. A ventilator system according to claim 7, wherein the means for warning comprises one or more of an audible and visible alert.

9. A ventilator system according to claim 5, further comprising means for conveying a signal to the microprocessor indicating that the information corresponds to a preselected value, the microprocessor responding to the signal to automatically adjust the actuator.

10. A ventilator system according to claim 1, further comprising means for controlling I:

E to be in the approximate range 0.00;

1 to 99.99;

1 in increments of about 0.01.

11. A ventilator system in accordance with claim 10, further comprising means for establishing respiratory rates in the approximate range 0-900 breaths per minute.

12. A ventilator system according to claim 11, further comprising means for establishing respiratory rates exceeding about 120 breaths per minute.

13. A ventilator system according to claim 1, further comprising a flow and oxygen control subsystem for regulating incoming gas flow, oxygen concentration, and humidity in said flow path of said pneumatic subsystem.

14. A ventilator system according to claim 1, wherein the patient insert comprises a reverse thrust catheter and wherein the pneumatic subsystem comprises means for providing substantially all of the patient'"'"'s inspiration.

15. A ventilator system according to claim 1, wherein the patient insert comprises an endotracheal tube and wherein the pneumatic subsystem comprises means for operating a plurality of ventilating modes selectively.

16. A ventilator system according to claim 1, further comprising alarm means for informing a user of the system that a preselected event has occurred.

17. A ventilator system according to claim 1, further comprising alarm means for detecting an unsafe condition and failsafe means for operating the system as a CMV in the event the unsafe condition is detected.

18. A ventilator system according to claim 17, wherein the failsafe means comprises a power supply to provide power to the system in the event of power failure.

30. A ventilator system according to claim 1, wherein the microprocessor subsystem further comprises means for continually flowing the gas in the flow path of the pneumatic subsystem, the gas flow being controlled by the microprocessor subsystem as a function of gas composition, flow rate and pressure.

31. A ventilator system according to claim 13, further comprising means for automatically regulating incoming gas flow, oxygen concentration, and humidity in said flow path.

19. A method of controlling intratracheal pulmonary ventilation, comprising the steps of:

monitoring the inspiratory and expiratory flow rates of a patient during the ventilation to determine an I;

E ratio; and

controlling the flow rates to select an I;

E ratio from about 0.00;

1 to about 99.99;

1.

20. A method according to claim 19, wherein the step of monitoring the flow rates comprises the step of monitoring the flow rates with a flow rate sensor connected to a microprocessor.

21. A method according to claim 19, wherein the step of controlling the flow rates comprises the step of regulating the flow rate from a microprocessor, the microprocessor being selectively responsive to a signal generated by a flow rate sensor connected in fluid communication with the patient.

22. A method according to claim 19, wherein the flow rate sensor is connected to sense the inspiratory flow rate of the patient.

23. A method according to claim 19, wherein the flow rate sensor is connected to sense the expiratory flow rate of the patient.

24. A method according to claim 19, further comprising the step of controlling the flow rates to maintain arterial PaCO₂ while lowering airway pressures.

25. A method according to claim 19, further comprising the step of controlling the flow rates to lower arterial PaCO₂ while maintaining a substantially constant airway pressure.

26. A method according to claim 19, further comprising the step of controlling the flow rates to achieve an I:

E accuracy of about 0.01;

1.

27. A method of ventilating a patient, comprising the steps of:

A. inserting a endotracheal tube whereby a distal tip of said tube is near the carina of the patient,

B. inserting into the endotracheal tube a tube having a reverse thrust catheter at its distal tip, whereby the reverse thrust catheter is near the distal tip of the endotracheal tube,

C. injecting breathable gas through the catheter to replace normal inspiration of the patient,

D. controlling respiratory rates to be in the range 120-900 breaths per minute,

E. controlling at least one of the group consisting of (i) I;

E ratio, (ii) I;

E. ratio and respiratory rate, and (iii) carinal pressures within a patient, and

F. mixing the gas with one or more other treatment gases selected from the group of anesthesia, nitric oxide, helium, hypoxic gas mixtures, diagnostic gases, and mixes thereof.

28. A method according to claim 27 comprising the further step of controlling the inspiratory to expiratory ration (I:

E) to be in the range of 0.00;

1 to about 99.99;

1 in increments of about 0.01;

1.

29. A method according to claim 27 further comprising the step of mixing the gas with one or more other treatment gases.

32. A ventilator system, comprising:

a reverse thrust catheter of the type having a catheter tip and a gas conduit that diverts injected gas away from a patient'"'"'s carina and tracheal walls;

control means connected to the catheter for adjusting at least one of the group consisting of (i) I;

E ratio, (ii) I;

E ratio and respiratory rate, and (iii) carinal pressures within a patient.

33. A ventilator system according to claim 32, wherein the control means comprises means for adjusting the I:

E ratio to between about 0.00;

1 and 99.99;

1 selectively.

34. A ventilator system according to claim 32, wherein the control means comprises means for adjusting the respiratory rate to within the range of about 0-900 breaths per minute.

35. A ventilator system according to claim 32, wherein the control means comprises means for adjusting the respiratory rate to above about 120 breaths per minute.