Method And System For Patient-Synchronized Ventilatory Assist With Endotracheal Through-Flow

• US 20140305434A1
• Filed: 06/29/2011
• Published: 10/16/2014
• 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: Beck, Jennifer, Sinderby, Christer
• Granted Patent: US 9,968,750 B2
• Time in Patent Office: Days
• US Class Current: 128/203.14
• 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;

an inspiratory tube lumen connected to the tube;

an expiratory tube lumen connected to the tube;

an inspiratory air source connected to the inspiration tube lumen; and

a controller of the pressure in the expiratory tube lumen, the pressure controller being responsive to a physiological breathing signal representative of patient'"'"'s inspiratory effort for allowing an unrestricted air flow through the expiratory tube lumen during a patient'"'"'s expiration phase and for partially restricting the air flow through the expiratory tube lumen to a minimum air flow during a patient'"'"'s inspiration phase;

wherein, during both the patient'"'"'s inspiration and expiration phases, a unidirectional air flow is produced through the inspiratory tube lumen and the expiratory tube lumen to prevent air expired by the patient from being breathed again.

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

the pressure controller comprises a valve controlled and synchronized using the physiological breathing signal.

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

the valve is for partially restricting the air flow through the expiratory tube lumen.

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

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

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

a sensor of 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 sensed pressure 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.

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

the inspiratory air source is for increasing the air flow based on a low pressure detection from the comparator.

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

the feedback system comprises a minimum flow detector for maintaining at least the minimum air flow.

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

the inspiratory air source is for maintaining at least the minimum air flow based on 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 to the inspiration 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 assistance to the patient.

17. A ventilatory assist method, comprising:

supplying an air flow in an inspiratory tube lumen of a tube connected to a patient'"'"'s airway; and

in response to a physiological breathing signal representative of patient'"'"'s inspiratory effort, controlling an air flow in an expiratory tube lumen of the tube connected to the patient'"'"'s airway, to allow an unrestricted air flow through the expiratory tube lumen during a patient'"'"'s expiration phase and to partially restrict the air flow through the expiratory tube lumen to a minimum air flow during a patient'"'"'s inspiration phase;

wherein, during both the patient'"'"'s inspiration and expiration phases, a unidirectional air flow is produced through the inspiratory tube lumen and the expiratory tube lumen to prevent air expired by the patient from being breathed again.

18. The method of claim 17, 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 sensed pressure and a target pressure.

19. The method of claim 18, wherein:

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

20. The method of claim 18, comprising:

adjusting the target pressure based on the physiological breathing signal.