WO2006121372A1

WO2006121372A1 - Respiratory device

Info

Publication number: WO2006121372A1
Application number: PCT/RU2006/000233
Authority: WO
Inventors: Aleksey Monesovich Sudarev; Pavel Semenovich Kantor; Evgeny Vladimirovich Korotich; Igor Aleksandrovich Isaev
Original assignee: Aleksey Monesovich Sudarev
Priority date: 2005-05-06
Filing date: 2006-05-05
Publication date: 2006-11-16
Also published as: RU2291719C1; RU2005113800A

Abstract

The aim of the invention is to provide a single device performing two functions: (a) setting dosed stress on human body while carrying out functional stress testing with breathing hypoxic mixtures under overpressure, and (b) providing respiratory support at acute respiratory failures. The respiratory device contains: gas sources 10 for production of a breathing mixture of a specified partial composition, a mask 40 with an exhalation valve 42, reducers 12 connected to gas flow rate regulation means, an oxygen source selector 14, a control unit 48, a mixer 36, a breathing mixture components selector 16, a compensatory means selector 34, a differential pressure sensor 38, a pressure regulator for compensatory means (28-32), breathing mixture compo- nents flow rate regulators 18, and a mask overpressure regulator (20-26), as well as an emergency oxygen feeding button 44, and an additional inhalation back valve 46.

Description

RESPIRATORY DEVICE

Field of the Invention

The invention concerns the technical area of medical engineering and can be used for testing and training of psychophysiological abilities for breathing hypoxic mixtures under overpressure, as well as for respiratory support of patients with acute respiratory compromises.

Background of the Invention In the aforementioned area, we are familiar with the devices for respiratory support, such as artificial pulmonary ventilation (APV) apparatus comprising one or more sources of breathable gases. They are equipped with a set of supplementary mechanisms implementing medical methods of respiratory support (V.L. Kassil, G. S. Leskin, M.A. Vyzhigina, Respiratory Support, Moscow, Medit- sina, 1997 (russian)). Said devices provide for breathing the oxygen-air mixture under overpressure supplied continuously or synchronously to breathing phases. On the other hand, said technical means can not be used for dosing the stress on the human body whilst carrying out functional stress testing with breathing hypoxic mixture under overpressure. Dosing the stress allows to predict overstress states and failures of control mechanisms at a lowered tolerance with respect to specific stress types.

Another existing breathing apparatus contains a source of breathable gas under the first overpressure, a face mask connected to the gas source and provided with an exhalation valve, and a regulator designed to maintain the required excess pressure in the mask when put on (RU 2003115428 A, publ. 20.10.2004). Other known devices are used for breathing under physical exercises. For example, one known system provides oxygen feeding for crew members of high- manoeuvrability airplanes, in which oxygen is fed synchronously to breathing phases of the pilot. The system contains an oxygen vessel connected to a con- tinuous feeding regulator via an air duct and an oxygen regulator, the regulator being connected via an electro-pneumatic valve and an inhalation/exhalation valve to an oxygen mask, compensatory garment, and an interrupted feeding regulator, which are connected to an air intake device via air ducts (RU 94022325 A1 , publ. 27.06.1996; RU 98116887 A, publ. 20.06.2000). The disadvantage of the abovementioned systems lies in the impossibility of ensuring breathing with hypoxic mixtures under overpressure, as well as that of implementing medical methods of respiratory support.

Another known device is a breathing system for pilots of high-altitude air- crafts (US 4651728, Gupta et a/., 24.03.1987). The device includes a selector for choosing one of three sources of compressed oxygen, a gas flow regulator, a breathing mask, and a device for maintaining pressure in compensatory garment. However, using the breathable gas mixture to provide pressure in the compensatory garment does not allow to ensure the necessary compensation for flight altitude, and an increase of the mixture pressure involves a danger of barotraumas of pilot's lungs. Besides, the device according to the document US 4651728 does not provide for creating a predetermined stress on the human body to carry out functional stress testing with breathing hypoxic mixtures under overpressure; and the control unit operating program does not allow to use the device for respiratory support.

Summary of the Invention

The aim of the present invention is therefore to widen the functionality of a respiratory device by providing a single device performing two functions. These functions are: (a) setting dosed stress on human body while carrying out functional stress testing with breathing hypoxic mixtures under overpressure, and (b) providing respiratory support at acute respiratory failures, which constitutes the technical result of the invention. The aim of the invention is achieved due to the fact that the respiratory device includes a mask with an exhalation valve and compensatory means, at least one connecting pipe for connecting to a source of an oxygen-containing gas, reducers connected to a gas flow control system, a selector of the source of the oxygen-containing gas, and a control unit. The device additionally contains connecting pipes for connecting sources of components of a breathing mixture, a mixer producing a breathing mixture of a predetermined partial composition, selectors of components of the breathing mix- ture, a selector of the type of compensatory means, a differential pressure sensor, a pressure regulator for compensatory means, flow rate regulators for breathing mixture components, an overpressure regulator for the mask exhalation valve, a button for emergency feeding of an oxygen-containing gas, and a back valve for additional inhalation. The connecting pipes of breathing mixture component sources are connected via reducers to the inlets of the breathing mixture components selector, the outlet thereof being connected to the inlets of the compensatory means pressure regulator and of the overpressure regulator for the mask exhalation valve, as well as to mixer inlets via the breathing mixture flow rate regu- lator.

The outlet of the oxygen-containing gas source selector is connected to the mask via the emergency oxygen-containing gas feeding button, and to the first inlet of the mixer via the oxygen-containing gas flow rate regulator, the mixer outlet being connected to the mask, to the outlet of the additional inhalation back valve, and the negative connecting pipe of the differential pressure sensor, the positive connecting pipe thereof being connected to the outlet of the mask overpressure regulator and the exhalation valve inlet, the outlet of the compensatory means pressure regulator being connected to the compensatory means selector. The control unit is provided with a possibility of automated selection of breathing mixture components and compensatory means type, of independent regulation of breathing mixture components flow rates and relative overpressure levels in the mask and the compensatory means, as well as of an emergency pressure release therein.

This design of the device allows to provide the respiratory support at acute respiratory failures in the described operating modes, as well as to perform testing and training when carrying out functional stress testing.

Brief Description of the Drawings

The invention is further disclosed at the attached drawings, where: Figure 1 is a flow chart of the device;

Figure 2 is a flow chart of the control unit algorithm. Detailed description of the preferred embodiments

The respiratory device contains: inlets 10 for connection of sources of components of a breathing mixture (compressed breathable gases), reducers 12, a selector 14 for selection of the source of an oxygen-containing gas, a selector 16 for selection of the source of components of the breathing mixture, and regulators 18 regulating the feed rate of the breathing mixture components, which can be e.g. in the form of a proportional solenoid valves. The device includes an overpressure regulator for the mask exhalation valve, which contains a normally closed electro-pneumatic valve 20 of overpressure feeding, a normally open elec- tro-pneumatic valve 22 for overpressure release, a receiver 24, and an overpressure sensor 26. The device also includes a pressure regulator for compensatory means, which contains a normally closed solenoid valve 28 for compensatory pressure feeding, a normally open solenoid valve 30 for compensatory pressure release, a compensatory pressure sensor 32, and a selector 34 of compensatory means (garment or occlusive cuffs). Besides, the device contains a mixer 36, a differential sensor 38, a face mask 40, an exhalation valve 42, an emergency oxygen feeding button 44, an additional inhalation back valve 46, and a control unit 48.

Pneumatic ducts are represented in full lines; electric connections are in dashed lines.

The device operates as follows.

According to the selected operating mode (testing or respiratory support), two gases are selected. Selectors 14 and 16 connect the inlets 10 of breathing mixture components, the selected gases K1 and K2, to the regulators 18, accord- ing to the said selection. The control unit 48 software (see Figure 2) allows to implement the following operating modes:

• continuous breathing mixture (Q) feeding to the face mask;

• breathing mixture feeding to the face mask synchronously with breathing phases (the "trigger" mode); • automated forced breathing mixture feeding to the face mask at a predetermined per-minute ventilation and the ventilation frequency (artificial pulmonary ventilation, APV); • automated forced breathing mixture feeding to the face mask synchronously with inhalation attempts (subsidiary pulmonary ventilation, SPV);

• interrupted forced breathing mixture feeding to the face mask synchronously with inhalation attempts (interrupted forced pulmonary ventilation, IFPV); • respiratory support using compensatory clothing and/or occlusive cuffs.

If necessary, the above operating modes can be implemented under an overpressure (P1) in the mask 40.

The overpressure is produced by the overpressure regulator. A signal for overpressure feeding arrives from the control unit 48 to the inlet of the valve 20, which provides for the gas flow via the receiver 24 to the exhalation valve 42.

When the specified overpressure value is reached, a signal sent from the sensor

26 via the control unit 48 closes the valve 20. The overpressure is maintained in the valve 42 until a signal sent from the control unit 48 opens the overpressure atmospheric release valve 22. When an atmospheric pressure signal arrives from the sensor 26, the control unit 48 closes the release valve 22.

If the device operates in the continuous breathing mixture feeding to the face mask controlled by signals sent from the control unit 48, regulators 18 provide the required flow rate levels of the breathing mixture, and partial pressure values of the components (gases that constitute the breathing mixture). In the "trigger" mode, a signal arriving from the sensor 38 and corresponding to an inhalation attempt triggers the control unit 48 to send signals, which make regulators 18 to start feeding the breathing mixture at a required flow rate and partial pressure values of the components of the breathing mixture.

In the APV mode, signals produced by the control unit 48 make each of the valves 18 to provide the breathing mixture feeding at a specified frequency and relative lengths of inhalation and exhalation, the required flow rate and partial pressure values of the components of the breathing mixture.

In the SPV mode, signals produced by the control unit 48 make each of the valves 18 to perform a single feeding of the breathing mixture to the face mask at a required flow rate and partial pressure values of the gases, after which a 10 second long period of waiting for an inhalation attempt begins. If, during this period, the sensor 38 produces an inhalation attempt signal, the control unit 48 produces a signal for breathing mixture feeding. If there is no inhalation attempt within 10 seconds, the control unit 48 produces a control signal for breathing mixture feeding similarly to the APV mode.

In the IFPV mode, the control unit 48 specifies a period of independent breathing via the back valve 48, 1 to 120 second long. After the specified inde- pendent breathing period is over, signals produced by the control unit 48 make each of the valves 18 to perform a single feeding of the breathing mixture to the face mask at a required flow rate and partial pressure values of the gases, after which a new independent breathing period begins.

Testing and training of psychophysiological abilities for persons of danger- ous occupations are carried out using oxygen-air or nitrogen-air mixtures. The device selects the gases and feeds a hyperoxic, normally oxic, or hypoxic breathing mixture to the mask 40 according to the chosen medical method of testing and training. The following gases can also be used as additional components of the mixture: nitrous oxide, xenon, helium, carbon dioxide, etc. Simultaneously with feeding the breathing mixture to the mask 40, the device feeds the gas to compensatory means. Signals arriving from the control unit 48 make the valve 28 connect the high pressure gas source to the compensatory means of the type selected using the selector 34; the control unit 48 operates the valve 20 after a delay of up to 3 seconds, which creates an overpressure at the inlet of the exhalation valve 42. Simultaneously, the control unit 48 regulates and maintains a constant ratio of compensatory pressure and overpressure according to the selected type of compensatory means, using the sensors 26 and 32. After the testing and/or training sequence is completed, the control unit 48 uses the valve 22 to start the overpressure release, and, after a delay of up to 3 seconds, uses the valve 30 to start the compensatory pressure release. Introduction of a controllable delay (of 0.5-3 seconds) prevents barotraumas of lungs at the simulation of ascent to or descent from altitudes above 4 thousand meters. At the stages of both feeding and pressure release, the control unit 48 uses sensors 26 and 32 to monitor and maintain the constant ratio of compensatory pressure and over- pressure, the value of this ratio being set according to the selected type of compensatory means. In an emergency situation, such as software failure and/or malfunction of regulator(s) and valve(s), a threshold device installed in the control unit 48 disconnects the electric power circuit, which excludes the possibility of barotraumas.

The additional inhalation valve 46 with a flow cross-section area of at least 176.6 mm² ensures independent breathing in emergency situations of:

• failure of the control unit 48 and regulators 18;

• inadvertent shutoff of the device electric power source.

The emergency oxygen feeding button 44 is used to achieve the same goal: if the subject under test loses consciousness, the operator can provide a short-time breathing with an oxygen-containing gas.

Industrial applicability

Testing of the device revealed that the device is applicable for respiratory support at acute respiratory failures and provides testing and training while carrying out functional stress testing. The device can be implemented according to the above description using technical means and design solutions known to experts in the field. The device allows to evaluate functional resources of the body of a person working in extreme conditions, as well as to predict the states of overstress and exhaustion of regulatory mechanisms at a lowering of tolerance with respect to specific stress types.

Claims

1. A respiratory device that includes a mask with an exhalation valve and compensatory means, at least one connecting pipe for connecting to a source of an oxygen-containing gas, reducers connected to a gas flow control system, a selector of the source of the oxygen-containing gas, and a control unit, characterized in that it additionally contains connecting pipes for connecting sources of components of a breathing mixture, a mixer producing a breathing mixture of a predetermined partial compo- sition, selectors of components of the breathing mixture, a selector of the type of compensatory means, a differential pressure sensor, a pressure regulator for compensatory means, flow rate regulators for breathing mixture components, an overpressure regulator for the mask exhalation valve, a button for emergency feeding of an oxygen-containing gas, and a back valve for additional inhalation, connecting pipes of breathing mixture component sources being connected via reducers to the inlets of the breathing mixture components selector, the outlet thereof being connected to the inlets of the compensatory means pressure regulator and of the overpressure regulator for the mask exhalation valve, as well as to mixer inlets via the breathing mixture flow rate regulator, the outlet of the oxygen-containing gas source selector being connected to the mask via the emergency oxygen-containing gas feeding button and to the first inlet of the mixer via the oxygen-containing gas flow rate regulator, the mixer outlet being connected to the mask, to the outlet of the additional inhalation back valve, and the negative connecting pipe of the differential pressure sensor, the positive connecting pipe thereof being connected to the outlet of the mask overpressure regulator and the exhalation valve inlet, the outlet of the compensatory means pressure regulator being connected to the compensatory means selector, the control unit being provided with a possibility of automated selection of breathing mixture components and compensatory means type, of independent regulation of breathing mixture components flow rates and relative overpressure levels in the mask and the compensatory means, as well as of an emergency pressure release therein.

2. A device according to claim 1 , in which the overpressure regulator for the mask exhalation valve contains a normally closed filling valve, its outlet being connected to a normally open pressure release valve, to a pressure sensor connected to the control unit via a negative feedback circuit, and to a receiver, the inlet of the normally closed filling valve being connected to one of the outlets of the breathing mixture components selector, the outlet of the normally open pressure release valve being connected to the atmosphere, and the outlet of the receiver being connected to the inlet of the exhalation valve.

3. A device according to claim 1 , in which the compensatory means pressure regulator contains a normally closed filling valve, its outlet being connected to a normally open pressure release valve, to the compensatory clothing selector, and to a pressure valve connected to the control unit via a negative feedback circuit, the inlet of the normally closed filling valve being connected to one of the outlets of the breathing mixture components selector, and the outlet of the normally open pressure release valve being connected to the atmosphere.

4. A device according to claim 1 , in which the compensatory means constitute a garment or occlusive cuffs.

5. A device according to claim 1 , in which the control unit is provided with a possibility of regulation of the delay between the stage of pressure raising in the compensatory means and that of overpressure rising in the mask exhalation valve, with the preservation of the predetermined ratio of the pressure levels.

6. A device according to claims 1-5, in which the control unit is provided with a possibility of regulation of the delay between the stage of pressure lowering in the compensatory means and that of overpressure lowering in the mask exhalation valve, with the preservation of the predetermined ratio of the pressure lev- els.