Apparatus for assisted ventilation and corresponding regulation method

1. An apparatus for assisted ventilation of a subject, the apparatus comprising:

a driver;

at least one ventilatory device connected to and controlled by the driver;

a sensor connected to said driver and adapted to provide the driver with a signal of electrical activity produced by the diaphragm of the subject; and

at least one calculation device connected to said driver, connected to said sensor and connected to said ventilatory device, said calculation device receiving from said sensor a signal of diaphragmatic electrical activity and from said ventilatory device a ventilatory pressure signal, and providing said driver with calibration parameters calculated on a basis of a signal of diaphragmatic electrical activity and a ventilatory pressure signal upon switching-off said ventilatory device so as to cause an expiratory pause.

2. An apparatus for assisted ventilation according to claim 1 , further comprising a switch device connected to said driver and providing said driver with a pause signal which forces said driver to temporarily switch off said ventilatory device so as to cause said expiratory pause.

3. An apparatus for assisted ventilation according to claim 2 , further comprising at least one synchronization device connected to said calculation device and connected to said switch device and providing said calculation device and said switch device with a synchronization signal.

4. An apparatus for assisted ventilation according to claim 3 , wherein said synchronization signal is manually generated or has a frequency established a priori.

5. An apparatus for assisted ventilation according to claim 1 , wherein said calculation device comprises a display for displaying said calibration parameters.

6. An apparatus for assisted ventilation according to claim 1 , wherein:

said ventilatory device provides said ventilatory pressure signal during said expiratory pause, which ventilatory pressure signal corresponds to a value of a spontaneous breathing activity and therefore of a muscle pressure produced by said subject; and

said calculation device provides said calibration parameters for regulating said assisted ventilation provided by said ventilatory device on a basis of said value of the muscle pressure produced by said subject.

7. An apparatus for assisted ventilation according to claim 1 , wherein:

said switching-off of said ventilatory device includes closing inspiratory and expiratory valves of said ventilatory device to cause said expiratory pause.

8. An apparatus for assisted ventilation according to claim 1 , wherein:

said switching-off of said ventilatory device includes blocking a flow of breathing gas into and out of the subject to produce said expiratory pause.

9. A method for regulation of an assisted ventilation comprising the steps of:

providing an apparatus for assisted ventilation comprising at least one ventilatory device controlled by a driver, at least one sensor adapted to provide said driver with a signal of electrical activity produced by the diaphragm of a subject, and a calculation device suitably connected to said driver and also connected to said sensor and connected to said ventilatory device;

providing said driver with a signal of diaphragmatic electrical activity via said sensor;

subsequently providing said calculation device with a ventilatory pressure signal emitted by said ventilatory device and a further signal of diaphragmatic electrical activity (Eadi*) obtained via said sensor during an expiratory pause caused by switching-off said ventilatory device;

calculating, on a basis of said ventilatory pressure signal and of said further signal of diaphragmatic electrical activity during said expiratory pause, a value of a spontaneous breathing activity and therefore of a muscle pressure produced by said subject; and

providing calibration parameters for regulating said assisted ventilation provided by said ventilatory device on a basis of said value of the muscle pressure produced by said subject as calculated.

10. A method according to claim 9 , further comprising a step of synchronizing said steps of providing said ventilatory pressure signal and said signal of diaphragmatic electrical activity and calculating said value of the spontaneous breathing activity by means of a synchronization signal supplied to said calculation device and to said switch device that causes switching-off said ventilatory device.

11. A method according to claim 10 , wherein the method further comprises providing different steps for calculating said value of the spontaneous breathing activity and regulating said assisted ventilation according to a value of assisted ventilation provided by said ventilatory device on a basis of said value of the spontaneous breathing activity as calculated during a plurality of expiratory pauses.

12. A method according to claim 9 , wherein the method further comprises a step of calculating a parameter for assessing the spontaneous breathing activity of said subject as a ratio between said ventilatory pressure signal and said further signal of diaphragmatic electrical activity during said expiratory pause.

13. A method according to claim 12 , wherein the method further comprises a step of estimating for each instant a value of the spontaneous breathing activity of said subject by multiplying said parameter for assessing the spontaneous breathing activity and said signal of diaphragmatic electrical activity.

14. A method according to claim 9 , wherein:

said switching-off of said ventilatory device includes closing inspiratory and expiratory valves of said ventilatory device to cause said expiratory pause.

15. A method according to claim 9 , wherein:

said switching-off of said ventilatory device includes blocking a flow of breathing gas into and out of the subject to produce said expiratory pause.

16. A method for ventilating a subject, the method comprising the steps of:

providing a ventilator;

operating the ventilator to assist flowing breathing gas into and out of the subject;

measuring a diaphragm electrical signal during said flowing of the breathing gas;

measuring a ventilatory pressure of the breathing gas during said flowing;

blocking the flow of the breathing gas into and out of the subject to produce an expiratory pause;

recording a pause value of the diaphragm electrical signal and a pause value of the ventilatory pressure during the expiratory pause;

determining a muscle pressure of the subject representing a respiratory activity of the subject from a ratio of the pause values of the diaphragm electrical signal and the ventilatory pressure;

said operating of the ventilator being performed to assist said flowing of breathing gas as a function of the muscle pressure.

17. A method in accordance with claim 16 , wherein:

said operating of the ventilator is performed to regulate assisted ventilation of the subject by defining a specific percentage of the pressure provided by the ventilator in relation to the muscle pressure produced by the subject.

18. A method in accordance with claim 16 , wherein:

a total pressure of the breathing gas includes breathing gas pressure from the ventilator and breathing gas pressure from the subject;

determining of the breathing gas pressure from the subject is performed using the determined muscle pressure.

19. A method in accordance with claim 18 , wherein:

said operating of the ventilator is performed to regulate assisted ventilation of the subject by defining a specific percentage of the pressure provided by the ventilator in relation to the muscle pressure produced by the subject.