Method and system for patient-synchronized ventilatory assist with endotracheal through-flow

• US 9,968,750 B2
• Filed: 06/29/2011
• Issued: 05/15/2018
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: St Michael's Hospital (University of Toronto)
• Original Assignee: St Michael's Hospital (University of Toronto)
• Inventors: Sinderby, Christer, Beck, Jennifer
• Primary Examiner(s): Ho, (Jackie) Tan-Uyen T
• Assistant Examiner(s): Boecker, Joseph D
• Application Number:
  US13/806,816
• Publication Number:
  US 20140305434A1
• Time in Patent Office: 2,512 Days
• Field of Search: 12820314, 12820418, 12820423
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0012 by Venturi means
• 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 16/0486 Multi-lumen tracheal tubes
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/125 Diluting primary gas with ambient air
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/161 with means for measuring the humidity
• CPC Class Codes: A61M 16/202 electrically actuated
• CPC Class Codes: A61M 16/205 used for exhalation control
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2210/1014 Diaphragm
• CPC Class Codes: A61M 2230/08 Other bio-electrical signals
• CPC Class Codes: A61M 2230/60 : Muscle strain, i.e. measured on the user

Abstract

A ventilatory assist system and method are disclosed. The system comprises a tube for connection to a patient'"'"'s airway, inspiratory and expiratory tube lumens connected to the tube, an inspiratory air source connected to the inspiration tube lumen, and a controller of air pressure in the expiratory tube lumen. The pressure controller is responsive to a physiological breathing signal representative of patient'"'"'s inspiratory effort to allow air flow through the expiratory tube lumen during a patient'"'"'s expiration phase, partially restricting the air flow through the expiratory tube lumen to a so minimum air flow during a patient'"'"'s inspiration phase. During both respiratory phases, a unidirectional air flow is produced through the inspiratory and expiratory tube lumens to prevent air expired by the patient from being breathed again. The physiological breathing signal allows synchronization of the ventilatory assist with breathing efforts of the patient.

Claims

1. A ventilatory assist system, comprising:

a tube for connection to a patient'"'"'s airway, the tube including (a) an inspiratory tube lumen with a proximal end in fluid communication with the patient'"'"'s airway and a distal end, and (b) an expiratory tube lumen with a proximal end in fluid communication with the patient'"'"'s airway and the proximal end of the inspiratory tube lumen, and a distal end in fluid communication with an exhaust;

an inspiratory air source connected to the distal end of the inspiratory tube lumen for supplying air flow to the inspiratory tube lumen; and

a pressure controller connected to the expiratory tube lumen and using a physiological breathing signal having a level indicative of an inspiratory effort of the patient to indicate expiration and inspiration phases of the patient during breathing cycles of the patient to establish, during each of the breathing cycles, (a) an expiratory pressure in the expiratory tube lumen during the patient'"'"'s expiration phase to allow patient'"'"'s expiration through the expiratory tube lumen while producing a first unidirectional air flow from the inspiratory air source through the inspiratory tube lumen, the expiratory tube lumen and the exhaust, and (b) an inspiratory assist pressure in the expiratory tube lumen during the patient'"'"'s inspiration phase to allow the inspiratory air source to provide ventilatory assist to the patient through the inspiratory tube lumen and the patient'"'"'s airway while producing a second unidirectional air flow from the inspiratory air source through the inspiratory tube lumen, the expiratory tube lumen and the exhaust;

wherein the first and second unidirectional air flows prevent air expired by a patient from being breathed again; and

wherein the pressure controller uses the physiological breathing signal to synchronize the expiratory pressure and the inspiratory assist pressure with the expiration and inspiration phases of the breathing cycles of the patient.

2. The ventilatory assist system of claim 1, wherein:

the pressure controller comprises a valve disposed between the distal end of the expiratory tube lumen and the exhaust, and controlled using the physiological breathing signal.

3. The ventilatory assist system of claim 2, wherein:

the valve is partially closed during the patient'"'"'s inspiration phase to establish the inspiratory assist pressure while producing the second unidirectional air flow.

4. The ventilatory assist system of claim 1, wherein:

the physiological breathing signal is a measure of electrical activation of a patient'"'"'s diaphragm (EAdi).

5. The ventilatory assist system of claim 1, further comprising:

a pressure sensor for sensing a pressure in the expiratory tube lumen; and

a feedback system interposed between the pressure sensor and the inspiratory air source.

6. The ventilatory assist system of claim 5, wherein:

the feedback system comprises a comparator of the pressure sensed by the pressure sensor in the expiratory tube lumen to a target pressure.

7. The ventilatory assist system of claim 6, comprising:

a target pressure adjuster for setting the target pressure in response to the physiological breathing signal.

8. The ventilatory assist system of claim 6, wherein:

the inspiratory air source is adapted to increase an air flow through the inspiratory tube lumen in response to a detection by the comparator that the pressure sensed by the pressure sensor in the expiratory tube lumen is lower than the target pressure.

9. The ventilatory assist system of claim 5, wherein:

the feedback system comprises a minimum flow detector for maintaining at least a minimum air flow through the inspiratory tube lumen.

10. The ventilatory assist system of claim 9, wherein:

the inspiratory air source is adapted to maintain at least the minimum air flow in response to a signal from the minimum flow detector.

11. The ventilatory assist system of claim 1, wherein:

the tube is an endotracheal tube.

12. The ventilatory assist system of claim 1, wherein:

the inspiratory tube lumen is a smaller-diameter tube lumen and the expiratory tube lumen is a larger-diameter tube lumen.

13. The ventilatory assist system of claim 1, comprising:

a gas mixer connected between the inspiratory air source and the distal end of the inspiratory tube lumen.

14. The ventilatory assist system of claim 13, comprising:

an oxygen source connected to the gas mixer.

15. The ventilatory assist system of claim 13, comprising:

a hygrometer connected to the expiratory tube lumen; and

a humidifier controlled by the hygrometer and connected to the gas mixer.

16. The ventilatory assist system of claim 1, comprising:

a gain adjuster interposed between a source of the physiological breathing signal and the pressure controller for adjusting a level of ventilatory assist to the patient.

17. The ventilatory assist system of claim 1, wherein the pressure controller is responsive to the physiological breathing signal to establish the expiratory pressure in the expiratory tube lumen in proportion to the patient'"'"'s inspiratory effort.

18. A ventilatory assist method, comprising:

connecting a tube to a patient'"'"'s airway, the tube including (a) an inspiratory tube lumen with a proximal end in fluid communication with the patient'"'"'s airway and a distal end, and (b) an expiratory tube lumen with a proximal end in fluid communication with the patient'"'"'s airway and the proximal end of the inspiratory tube lumen, and a distal end in fluid communication with an exhaust;

supplying an air flow to the distal end of the inspiratory tube lumen; and

using a physiological breathing signal having a level indicative of an inspiratory effort of the patient to indicate expiration and inspiration phases of the patient during breathing cycles of the patient, establishing during of the each breaching cycles (a) an expiratory pressure in the expiratory tube lumen during the patient'"'"'s expiration phase to allow patient'"'"'s expiration through the expiratory tube lumen and the exhaust while producing a first unidirectional air flow through the inspiratory tube lumen, the expiratory tube lumen and the exhaust, and (b) an inspiratory assist pressure in the expiratory tube lumen during the patient'"'"'s inspiration phase to provide ventilatory assist to the patient through the inspiratory tube lumen and the patient'"'"'s airway while producing a second unidirectional air flow through the inspiratory tube lumen, the expiratory tube lumen and the exhaust;

wherein the first and second unidirectional air flows prevent air expired by a patient from being breathed again; and

wherein the expiratory pressure and the inspiratory assist pressure are synchronized with the expiration and inspiration phases of the breathing cycles of the patient.

19. The method of claim 18, comprising:

sensing a pressure in the expiratory tube lumen; and

adjusting the air flow in the inspiratory tube lumen based on a comparison between the pressure sensed in the expiratory tube lumen and a target pressure.

20. The method of claim 19, wherein:

adjusting the air flow in the inspiratory tube lumen comprises increasing the air flow in the inspiratory tube lumen when the pressure sensed in the expiratory tube lumen is lower than the target pressure and decreasing the air flow in the inspiratory tube lumen when the pressure sensed in the expiratory tube lumen is higher than the target pressure.

21. The method of claim 19, comprising:

adjusting the target pressure based on the physiological breathing signal.

22. The method of claim 18, wherein the expiratory pressure in the expiratory tube lumen is established in proportion to the patient'"'"'s inspiratory effort.