VOLUME DIVIDER AND METHOD OF RESPIRATORY GAS DIVISION

Abstract

The object of the invention is an inspiratory gas volume divider comprising at least two inspiratory lines (18, 19) having inspiratory branches (14,16) at ends thereof and comprising one-way valves (2,3) and at least two expiratory lines (20, 21) having expiratory branches (15,17) at ends thereof and comprising one-way valves (7,12). The inspiratory branches and expiratory branches are in pairs combined with each other in at least two inspiratory- expiratory pairs. The initial portions of the inspiratory lines are connected to the divider valve (23) provided with a control input. In the inspiratory lines, after the volume valve divider, there are included systems measuring gas volume (11,12) with output signals thereof delivered to the controller (22), and the output signal thereof is connected to the volume divider's input. Further, the object of the invention is a method of dividing the inspiratory gas volume in a divider comprising at least two inspiratory lines and two expiratory lines connected to a controlled divider provided with a control input. The method comprises the stages of: setting the desired inspiratory gas volume division, measuring and subsequently re-setting the division in feedback loop via the control input. In the stage of measuring, the volume of gas in each of the inspiratory lines is subjected to measurement, and the measurement signal is converted in an automatic controller to the valve divider's control signal.

Claims

1. An inspiratory gas volume divider comprising at least two inspiratory lines (18, 19) ending with inspiratory branches (14,16) and comprising one-way valves (2, 3) and at least two expiratory lines (20, 21) ending with expiratory branches (15, 17) and comprising one-way valves (7,12), wherein the inspiratory branches and the expiratory branches are in pairs combined with each other in at least two inspiratory-expiratory pairs, while the initial portions of the inspiratory lines are connected to the valve divider (23), characterised in that the valve divider (23) is provided with a control input, and into the inspiratory lines after the valve divider there are interconnected gas volume measurement systems (11,12), the output signals thereof are delivered to the controller (22), the output signal thereof is connected to the volume divider's control input and in that in the expiratory branches there are included volume meters (4,5) the output signals thereof being connected to the monitoring circuit (24).

2. The divider according to claim 1, characterised in that the volume measurement systems are digital meters providing a digital measurement signal, and the controller (22) is provided with digital signal processing means adapted to convert the measurement results into the valve divider's control signal.

3. The inspiratory gas volume divider according to claim 1, characterised in that the expiratory branches are provided with positive end-expiratory pressure valves PEEP (11,13).

4. The inspiratory gas volume divider according to claim 3, characterised in that the in expiratory branches there are included pressure meters (6,8) the output signals thereof being connected to the monitoring circuit (24).

5. A method of inspiratory gas volume division in a divider comprising at least two expiratory lines and two inspiratory lines connected to a controller divider provided with a control input, comprising the step of setting the requested inspiratory gas volume division, the step of measuring, and the step of subsequent resetting in feedback loop, characterised in that subjected to the measurement is the volume of gas in each of the inspiratory lines, and the measurement signal in automatic controller is converted into the valve divider's control signal.

6. The method of inspiratory gas volume division according to claim 5, characterised in that it further comprises the step of measuring the volume of gas in the expiratory lines and displaying the indication on the monitoring circuit.

7. The method of inspiratory gas volume division according to claim 5, characterised in that it further comprises the step of measuring the pressure of gas in the expiratory lines and displaying the indication on the monitoring circuit (24).

Description

[0011] The object of the invention has been shown in embodiments in the drawings, wherein

[0012] FIG. 1 is a schematic diagram of the divider according to the invention,

[0013] FIG. 2 shows an embodiment of the invention having a valve divider provided with acceleration sensor,

[0014] FIG. 3 shows an alternative valve divider, and

[0015] FIG. 4 is a block diagram of the divider according to the invention having such valve divider.

[0016] The object of the invention has been described in embodiments in the drawings, wherein FIG. 1 is a schematic diagram of the apparatus for independent ventilation of two lungs with selective application of positive end-expiratory pressures.

[0017] The volume divider comprises two parallel inspiratory lines 18 and 19, and two parallel expiratory lines 20 and 21. The inspiratory and expiratory lines end with branches, respectively, inspiratory 14 and 16, and expiratory 15 and 17, combined in inspiratory-expiratory pairs. In each pair the inspiratory branch 14 with the expiratory branch 15 and the inspiratory branch 16 with the expiratory branch 17 are connected to each other. The common point of the branches inspiratory 14 and expiratory 15 is connected to one endotracheal tube conduit RD and the common point of the branches inspiratory 16 and expiratory 17 is connected to another endotracheal tube conduit RD.

[0018] In the combined in parallel inspiratory lines 18 and 19 there are respectively arranged one-way pneumatic valves 2 and 3. In the expiratory lines 20 and 21 there are pressure indicators 6 and 8. In the combined in parallel expiratory lines 20 and 21 there are arranged one-way pneumatic valves 7 and 12.

[0019] The one-way valve 7 is connected in series with the volume meter 5, positive end-expiratory pressure valve 11 and the expiratory branch 15 and the one-way valve 12 is connected in series with the volume meter 4 and the expiratory branch 17.

[0020] The common input of one-way valves 2 and 3 is connected to the inspiratory channel IP of the medical ventilator 1, the common output of the one-way valves 7 and 12 is connected to the expiratory channel EP of the medical ventilator 1. Outputs of valves 2 and 3 are connected to the volume valve divider 23 controlled via the controller 22 to which the measurement signals from the volume measuring systems 9, 10 are delivered. In this way, the loop regulating both division as well as magnitude of volume of the inspiratory gas supplied to each of the lungs is closed.

[0021] As the system measuring the gas volume 9, 10 there can be used a flow system with analogue or digital integrating circuit, providing a signal related to the volume of gas introduced into the patient's lungs. As the controller 22 there can be then used analogue circuits, but also a microcontroller or an FPGA device. In digital solutions it is possible to implement more advanced techniques of signal processing and obtain settings with improved accuracy.

[0022] In an alternative embodiment, the systems measuring gas volume 9, 10 are integrated with electrically controlled valve divider shown in FIG. 2. In the stationary housing 30 of the valve there are mounted pneumatic output ends 25 and elastic, preferably made of rubber, tubes 26 deformed by means of a moveable pin 27 mounted on a slider having rolls 28 of a straight line mechanism with bearings in the housing 30. With the threaded hole of the straight line mechanism's rolls 28 there is associated a leadscrew 31 driven by an electric motor 32, preferably a direct current motor, attached to an amplifierpower driver 33. The amplifier control signal comes from a node 34, wherein two signals are being summed: a signal d.sup.2x/dt.sup.2 from the acceleration sensor 35 and a signal from the first controller's output 37, preferably a PID controller, which together with a linear converter 36 of displacement forms a circuit controlling the slider's 28 position x. To the first input of the controller 37 there is delivered an input signal from the converter 36, while to its second input there is delivered the output signal from the second controller 38. Controller's 38 inputs are connected to electric outputs of the converters 39 and 40 of instantaneous value of gas volume supplied to the left L and the right R lung. The described control circuit is cascaded, wherein the inner control loop for displacement x allow, inter alia, to pre-set the pin's 27 position in a position assuring a preliminary division of streams directed to the left L and the right R lung. The second end of elastic tubes 26 is connected to a tee junction 29, to which the gas stream from the medical ventilator is delivered. It should be emphasised that in the described embodiment of the valve divider the disposable element is the whole pneumatic tract, thus the tee junction 29, rubber tubes 26 and output ends 25.

[0023] The operation of the device according to the invention is as follows. In the inspiration phase, the gas flowing out of the inspiratory canal IP of the ventilator 1 is being divided into two inspiratory lines 18 and 19, and flows through the one-way pneumatic valves 2 and 3, and through inspiratory gas volume meters 9 and 10. The gas flowing through the inspiratory line 18 is directed via the inspiratory branch 14 and one of endotracheal tube conduits to one of the lungs, because the expiratory port EP of the ventilator is closed during the inspiration phase. The gas flowing through the inspiratory line 19 is directed via the inspiratory branch 16 and the second endotracheal tube conduit RD to the second lung.

[0024] The increase of pressure in the inspiratory branches 14 and 16 in the inspiration phase and the expiration phase is measured and respectively indicated by pressure indicators 6 and 8. In the expiration phase the inspiration canal IP of the ventilator is closed and the expiration canal EP of the ventilator is open, causing flowing out of gases from lungs. And so the gas flows from one of the lungs through one of the endotracheal tube conduits RD, through the expiratory branch 15, the volume meter 5, the positive end-expiratory pressure valve PEEP 11, the one-way pneumatic valve 7, to the expiratory canal EP of the ventilator. From the other lung the gas flows through the second endotracheal tube conduit RD through the expiratory branch 17, the volume meter 4, the one-way pneumatic valve 12, to the expiratory canal EP of the ventilator. The one-way valves 2, 3, 7, 12 arranged in strictly defined locations in the considered system of connections of the device determine the flow of gases between the medical ventilator and the lungs in respective phases of the respiratory cycleduring inspiration and expirationsuch as described above, this way making possible both independent ventilation of each lung and obtaining positive expiratory pressure only in one of the lungs by means of the PEEP valve 11 or the PEEP valve 13. By means of the volume ratio controller 22 and the valve divider 23 the flow of gas in one of the inspiratory lines is decreased, and increased in the other inspiratory line simultaneously.

[0025] The apparatus according to the invention further comprises the positive end-expiratory pressure valve PEEP 13, by means of which the positive end-expiratory pressure is set in the expiratory branch 17, thus also in the lung connected thereto via the endotracheal tube conduit.

[0026] The above solution also makes possible, except of the independent ventilation of each lung, obtaining of positive end-expiratory pressures independently in both lungs.

[0027] The application of the monitoring circuit 24 and displaying thereon the indications from the meters of pressure and volume in the expiratory lines provides the possibility of enhanced control of the patient's condition and the course of ventilation and also displaying relevant information for the physician. In particular, the subjected to measurement values can be digitized, and the monitoring circuit can be constituted by a typical unit provided with a central unit, memory, data receivers and a display.

[0028] An alternative construction of the valve divider is shown in FIG. 3. On the stepper motor's 51 shaft there is arranged a bar with a pin 55, which enters the opening of a moveable plate 53, rotating on the axis 54. The upper portion of the movable plate 53 clamps the elastic passages 52, arranged in the line of flow for the left L and the right P lung. When the axis of the stepper motor 51 rotates right, the pin 55 slides right, sliding the bottom portion of the moveable plate 53 also right. As a result, the plate 53 rotates around the axis 54 and its upper portion slides left, narrowing the left passage L and opening the right passage P. The degree of opening of the passages depends on the rotation angle of the motor's axis. When the motor's axis 51 rotates left, the right passage P is being narrowed and the left one L is being opened. The position sensor 56 is used to pre-set the control system, that is, to detect the position of zero.

[0029] A block diagram of the arrangement of the inspiratory gas divider with such valve divider is shown in FIG. 4 together with indicated medical ventilator 41 to which it is connected to. The flow generated by the medical ventilator 41 is delivered to the left and to the right passage of the controller 42. The flow after the passages, the left and the right, is measured by means of volume sensors 45 and 46. The control system 47 sets the position of the driving motor 43 according to the applied volume division algorithm.

[0030] It will be apparent to a person skilled in the art that the present invention can be implemented in multiple different ways with the use of numerous components, sensors, meters and signal processing algorithms known in the state of the art, obtaining a solution falling within the scope of protection as defined by the attached claims.