WO2021194345A1

WO2021194345A1 - Ventilator actuator

Info

Publication number: WO2021194345A1
Application number: PCT/NO2021/050071
Authority: WO
Inventors: Nils Harald FLAA; Morten BRØVIG-THOMASSEN
Original assignee: Servi As
Priority date: 2020-03-23
Filing date: 2021-03-22
Publication date: 2021-09-30

Abstract

The present invention relates to an actuator for mechanically actuating manual respiratory aids. The actuator includes an electric arm driving mechanism, a ventilation bag cradle (7), an electric arm driving mechanism control circuit (23), and a pivoted actuator arm (3) with an arch shaped portion. The electric arm driving mechanism is a stepper motor (21), and the actuator arm (3) is directly connected to the stepper motor (21).

Description

Ventilator actuator

The present invention relates to an actuator mechanically actuating manual respiratory aids, typically called ventilation bag-valve masks (BVM) or resuscitators.

Respiratory diseases and pandemics may result in a high volume of patients requiring respiratory aid, thus requiring a high number or respiratory aids.

Full size respirators are large, expensive and typically not available in sufficiently high numbers required during epidemics and pandemics.

With a high number of patients that requires respiratory aid, it is also not possible to manually operating the traditional resuscitators, even for shorter periods of time.

Furthermore, must patients often be moved to different locations while requiring respiratory aid when in transit.

US 2012145151 discloses a device for automatically squeezing and releasing an AMBU-bag. The device has a housing and a mechanical compression squeezer in the housing. A powered actuator powers the compression squeezer. Alarms and signals provide information regarding excessive pressure and regarding bag cycling.

US 2020086075 discloses a breathing support system. The system automates and regulates the use of a bag valve mask. The system uses mechanical actuators, sensors and a smart feedback control mechanism to automate and regulate the operation of an AMBU-bag to implement core functions of mechanical ventilation for life-saving applications.

Solutions for providing mechanical actuators for manual resuscitators have not found widespread use. It is thus the purpose of the present invention to provide improvements to such mechanical actuators to allow them to be produced at high volumes and low cost while maintaining an the best possible functionality and flexibility of use, and by personnel without extensive education in the use of such aids.

It is also a purpose of the present invention to provide a respiration aid that is battery powered and that can operate independently of an external power source for a sufficient period to be useful in transit of patients.

Accordingly, the present invention concerns an actuator for mechanically actuating manual respiratory aids. The actuator includes an electric arm driving mechanism, a ventilation bag cradle, an electric arm driving mechanism control circuit and a pivoted actuator arm. The electric arm driving mechanism is a stepper motor, and the arch shaped pivoted actuator arm is directly connected to the stepper motor.

The actuator may further include a battery pack allowing the actuator to operate at full power for more than 20 minutes.

The control circuit may further include a microprocessor.

The electric arm driving mechanism may be installed in a housing, and a display providing graphical information about operating parameters may be located on the housing.

The actuator may further include data input elements including at least one of a plurality of push buttons, a D-pad, a joystick, a selection wheel, and a pot meter.

The display may be a touch screen, and the operating parameters may be entered on the touch screen.

The actuator may further include a wireless communication unit into allow input and output of parameters and data and to allow wireless monitoring of the operation. The wireless communication unit may include at least one of a Wi-Fi communication unit and a Bluetooth communication unit..

The communication with another unit may alternatively through a wired communication.

The pivoted actuator arm may be arch shaped, and the arch of the arch shaped pivoted actuator arm may be concave on a surface facing the ventilation bag cradle.

The arm may include a convex arch shaped contact area for contact with the ventilation bag.

The convex arch shaped contact area may have a radius of curvature and may span in a range of 160° -200° of a circle.

The convex arch shaped contact area may have a radius of curvature may and span 180° of a circle.

The radius of curvature of the arch shaped contact area may be smaller than the radius of curvature of the ventilation bag.

The ratio between the radius of curvature of the arch shaped contact area and the radius of curvature of the ventilation bag may be in the range 1 : 1 ,4-1 : 1 ,7.

The ratio between the radius of curvature of the arch shaped contact area and the radius of curvature of the ventilation bag may be in the range between 1 : 1 ,5-1 : 1 ,6.

The arm 3 may further include a bight-shaped concave curved portion between the arch shaped contact area and an area around a pivot point of the arm where the arm is secured to a shaft.

Fig. 1 is a perspective view of an actuator of the invention; Fig. 2 is a perspective view of the actuator of fig. 1 the invention from a different angle and with a lid of a housing removed; and

Fig. 3 is a side view of the actuator of the invention, shown in fig. 2 and fig. 3.

Fig. 4 is a side view of the actuator of the invention with an alternative arm design; and

Fig. 5 is a perspective view of the actuator with the arm design of fig. 4.

Fig. 1 shows a ventilator actuator of the invention. A ventilation bag 1 or bladder of a typical ventilation Bag Valve Mask, BVM, is located in a cradle 7 of the actuator. The ventilation bag 1 of the BVM is adapted for manual hand compression. The actuator 2 includes an actuator arm 3 adapted to compress the ventilation bag 1 located in the cradle 7 with a stand 8. The actuator arm is reciprocating up and down and compresses the ventilation bag 1 to pump air from the ventilation bag 1 and to a patient. A display 5 indicates operating parameters fed into the actuator through input buttons 4 and control pad/D-pad 6 on an input panel. The operating parameters include the motion and force of the actuator arm, and the display typically also shows battery charge status, remaining operating time before charging. The display 5 may be a touch screen display and the input buttons 4 and the D-pad 6 may be omitted.

The motion of the arm typically includes the amount of deflection (amplitude/volume/stroke), the speed of the motion (frequency), the force of the arm (pressure) and the ratio between a speed inward and a speed outward. The input buttons 4 and the D-pad 6 may be used to input patient data rather than operating parameters, and the actuator may include a microprocessor with preprogramed parameters for different user. The actuator may be used for ventilation bags 1 of different sizes and the ventilation bag size may also be input. Fig. 2 shows the ventilator actuator of the invention as shown in fig. 1 in perspective view with the ventilation bag 1 located in the cradle 7 with stand 8. A ventilation bag end support element 9 holds an end collar 10 of the ventilation bag 1. The ventilation bag end support element 9 is arch shaped and has an inner diameter adapted to the end collar 10 of the ventilation bag 1. The end support element 9 is open at one end to allow the end collar 10 to be snapped into the end support element. The end support element 9 may be exchangeable for adapting the end support element 9 to different ventilation bags.

The actuator arm 3 is operated directly or through a transmission / gear box 22 by a stepper motor 21. The stepper motor 21 is powered by a rechargeable battery 20. The actuator arm 3 is directly fixed to the stepper motor 21 in the shown embodiment. A control circuit with a microprocessor 23 controls the motion and force of the arm 3 based on the input parameters fed into the control circuit 23 including input from a force sensor. The force may alternatively be deduced from the input current to the stepper motor 21. The actuator 2 also includes a communication unit 25 typically a Wi-Fi or Bluetooth unit to allow input and output of parameters and data and to allow wireless monitoring of the operation. The actuator may be completely operated and monitored wirelessly, and the input buttons and the display may then be omitted. The rechargeable battery 20 may be integrated in the housing along with the stepper motor or may constitute a separate, external battery pack.

An air pressure monitoring sensor may communicate with the control circuit with the microprocessor 23 to ensure that the air is delivered to the patient at the correct pressure. The microprocessor may adjust the stepper motor if the pressure is deviating from set values.

An air mass flow monitoring sensor may communicate with the control circuit with the microprocessor 23 to ensure that the air is delivered to the patient at the correct air mass flow. The microprocessor may adjust the stepper motor if the air mass flow is deviating from set values.

Fig. 3 is a side view of the ventilator actuator of the invention. The actuator arm 3 is arch shaped or curved with a concave side facing the ventilation bag 1. A radius of the actuator arm 3 of the concave side facing the ventilation bag 1 is substantially the same as a radius of ventilation bag 12, and the cradle 7 is provided to secure the ventilation bag 1 sufficiently while providing an opening 11 for easy installation and removal of the ventilation bag 1. The actuator 2 includes a housing 14 for the operating elements including the stepper motor, the battery, the electronic circuits and microprocessors, the display, etc. A separate input wire 13 is used to charge the battery and to allow supply of electricity from an external source. The arch shape of the actuator arm 3 and the cradle 7 replicates the shape of a hand and produces an airflow that fluctuates in a manner similar to the one achieved manually.

The cradle 7 may be adjustable to accommodate for ventilation bags of different sizes. Alternatively, may inserts be installed in the cradle 7 to adapt the cradle 7 to ventilation bags 1 of different dimensions and brands. Different dimensions are used for patients of different sizes/age groups.

The arm 3 may be removable and arms with various radiuses 12 may be installed to adapt the arm the ventilation bags 1 of different dimensions and brands.

The housing 14 may be removably secured to the cradle 7 and may be used on a vide variety of cradles 7.

Fig. 4 shows an embodiment of the invention as described above, but with an alternative design of the arm 3. The arm 3 includes an arch shaped contact area 16 for contact with the ventilation bag 1. The arch shaped contact area 16 has a radius of curvature 15 and spans about 180° of a circle. The radius of curvature 15 of the arch shaped contact area 16 is smaller than the radius of curvature 12 of the ventilation bag 1. A distance 19 between a centre of the ventilation bag 1 and a pivot point of the arm 3 is approximately the same as a distance 18 between the pivot point and the centre of the arch shaped contact area 16. The pivot point defines an axis of rotation coinciding with an axis of rotation of a shaft 27 of the stepper motor.

A U-shaped or bay-shaped concave curved portion 17 of the arm 3 is located between the arch shaped contact area 16 and an area around the pivot point 27 where the arm 1 is secured to the shaft of the actuator motor/the stepper motor, or the transmission. The bay-shaped concave curved portion 17 of the arm 3 ensures that the only the arch shaped contact area 16 of the arm 3 contacts the ventilation bag 1 to prevent unnecessary buckling of the ventilation arm 3 increasing power requirements and wear on the ventilation bag 1 and the actuator.

Fig 5 shows the embodiment shown in fig. 4 in perspective view to show that the arm 3 has a width 28 defining the arch shaped contact area 16 along with the length of the arch. The actual contact area between the ventilation bag 1 and the arch shaped contact area 16 of the arm 3 will depend on the position of the arm 3 in relation to the ventilation bag.

The ratio between the radius of curvature 15 of the arch shaped contact area 16 and the radius of curvature 12 of the ventilation bag 1 is typically in the range 1 : 1 ,4-1 : 1 ,7. The ratio between the radius of curvature 15 of the arch shaped contact area 16 and the radius of curvature 12 of the ventilation bag 1 is even more typically in the range between 1 : 1 ,5-1 : 1 ,6.

In the embodiment shown in figs. 4 and 5 is the force required on the arm 3 somewhat less than the force required in figures 1-3, and the stress and curling of the ventilation bag is reduced.

All surfaces are smooth and easily cleaned or sterilized according to industry standards. The actuator may easily be adapted to accommodate an antiseptic covering.

The actuator of the invention is typically operated by inserting a ventilation bag 1 into the cradle 7 and the end collar of the ventilation bag 1 is snapped in place in the arch shaped end support element 9. Data relating to the patient is entered to the actuator through the input panel. The data is either in the form of breathing parameters such as breathing rate and required air mass flow rate and pressure or as patient data such as weight, sex, or age. The actuator can then be started and the arch shaped actuator arm will start to reciprocate at a given rate, speed, angular displacement force etc. to pump air to the patient. The rate is typically 12 to 20 strokes a minute.

Claims

1. An actuator for mechanically actuating manual respiratory aids, comprising: an electric arm driving mechanism; a ventilation bag cradle (7); an electric arm driving mechanism control circuit (23); a pivoted actuator arm (3); wherein the electric arm driving mechanism is a stepper motor (21); and wherein the pivoted actuator arm (3) is directly connected to the stepper motor (21).

2. The actuator of claim 1 , further including a battery pack allowing the actuator to operate at full power for more than 20 minutes.

3. The actuator of claim 1 or 2, wherein the control circuit (23) further including a microprocessor.

4. The actuator of any of the preceding claims wherein the electric arm driving mechanism is installed in a housing (14), and wherein a display (5) providing graphical information about operating parameters is located on the housing (14).

5. The actuator of any of the preceding claims, further including data input elements (4, 5) including at least one of a plurality of push buttons (4), a D-pad, a joystick, a selection wheel, and a pot meter.

6. The actuator of claim 4, wherein the display (5) is a touch screen, and wherein operating parameters can be entered on the touch screen.

7. The actuator of any of the preceding claims further including a communication unit (25) including at least one of a Wi-Fi communication unit and a Bluetooth communication unit to allow input and output of parameters and data and to allow wireless monitoring of the operation.

8. The actuator of any of the preceding claims wherein pivoted actuator arm is arch shaped, wherein the arch of the arch shaped pivoted actuator arm (3) is concave on a surface facing the ventilation bag cradle (7).

9. The actuator of any of the preceding claims 1-7, wherein the arm (3) includes a convex arch shaped contact area (16) for contact with the ventilation bag (1 ).

10. The actuator of claim 9, wherein the convex arch shaped contact area (16) has a radius of curvature (15) and spans in a range of 160° -200° of a circle.

11. The actuator of claim 10, wherein the convex arch shaped contact area (16) has a radius of curvature (15) and spans 180° of a circle.

12. The actuator of any of the preceding claims 9-11 , wherein the radius of curvature (15) of the arch shaped contact area (16) is smaller than the radius of curvature (12) of the ventilation bag (1).

13. The actuator of any of claim 12, wherein the ratio between the radius of curvature (15) of the arch shaped contact area (16) and the radius of curvature (12) of the ventilation bag (1 ) is in the range 1 : 1 ,4-1 : 1 ,7.

14. The actuator of any of claim 13, wherein the ratio between the radius of curvature (15) of the arch shaped contact area (16) and the radius of curvature (12) of the ventilation bag (1 ) is in the range is in the range between 1 : 1 ,5-1 : 1 ,6.

15. The actuator of any of the preceding claims 9-14, wherein the arm (3) further includes a bight-shaped concave curved portion (17) located between the arch shaped contact area (16) and an area around a pivot point of the arm (3) where the arm is secured to a shaft (27).