Patent Description:
Respiratory disease is one of the leading causes of death in many developing countries. Frequently, there is a shortage of life saving equipment, like ventilators, at hospitals in these countries. As a result, caregivers are often provided with a bag valve mask or Ambu bag and asked to manually ventilate a patient by hand for hours and sometimes days. This arrangement is unreliable can may be life threatening to the patient. <CIT> discloses an electric extrusion device of a breathing bag. The extrusion device is fixed on the periphery of the breathing bag through an upper fixing block and a lower fixing block. The extrusion device comprises two mechanical arms which are driven by a stepping motor, rotary shafts. The stepping motor simultaneously controls extrusion and expansion actions of the two mechanical arms through a gear rotating coaxially with the stepping motor. An upper rack and a lower rack which perform transmission in cooperation with the gear and opposite in transmission direction are arranged at the upper end and the lower end of the gear respectively. The end portion of the upper rack and the end portion of the lower rack are hinged to the end portions of the two mechanical arms through transmission rods, and the other end of each mechanical arm is provided with a manipulator matched with the peripheral face of the breathing bag in shape. <CIT> discloses a device for automatically squeezing and releasing an AMBU-bag. The device has a housing and a mechanical compression squeezer in the housing. There are openings in the housing for inlet tubes and outlet tubes of the AMBU-bag to pass in and out of the housing. A powered actuator powers the compression squeezer. Alarms and signals provide information regarding excessive pressure and regarding bag cycling. <CIT> discloses a system and method for ventilating a patient in association with cardiopulmonary resuscitation procedures. In one exemplary embodiment, a system comprises a ventilator to periodically supply respiratory gases to a patient's lungs. A sensor is provided to detect chest compressions by sensing changes in intrathoracic pressure. A controller is coupled to the sensor and controls actuation of the ventilator after a predetermined number of chest compressions have been detected by the sensor. <CIT> discloses a portable device including a housing comprising a first opening and a second opening and a resuscitator bag. The resuscitator bag is disposed at least partially within the housing and includes an air inlet supported at the first opening of the housing, an air outlet supported at the second opening of the housing, and a self-inflating bag. The portable device also includes a double-sided compression mechanism disposed within the housing. The double-sided compression mechanism includes a pair of arms at least partially surrounding the self-inflating bag. The pair of arms are configured to move towards each other to compress the self-inflating bag to provide positive pressure ventilation via the air outlet and to move away from each other to enable re-inflation of the self-inflating bag via the air inlet; and, a motor coupled to the pair of arms for moving the pair of arms towards and away from each other.

The invention is defined in independent claims <NUM> and <NUM>.

The system includes a bag that is capable of being inflated through an input valve that allows oxygen and/or air to flow into the bag. The bag is further capable of being deflated through an output valve that allows the oxygen and/or the air to flow out of the bag. The system also includes an actuator coupled with a paddle having a convex contact surface capable of compressing the bag to cause the oxygen and/or the air to flow out of the output valve in accordance with prescribed values for one or more respiratory parameters. The one or more respiratory parameter includes tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate of the oxygen and/or the air flowing through the output valve to a patient, the actuator further comprising a spindle that is configured to tighten a strap, the strap being coupled to the paddle having the convex contact surface, the strap also capable of compressing the bag. The system also has a controller configured to control the position of the actuator and/or the speed at which the actuator moves in accordance with the prescribed values for the respiratory parameters. Furthermore, the system includes a pressure sensor coupled to the output valve and configured to determine the pressure of the oxygen and/or the air flowing through the output valve. The pressure sensor is further configured to send a pressure signal to the controller. The system also includes a flow rate sensor coupled to the output valve and configured to determine the flow rate of the oxygen and/or the air flowing through the output valve. The flow rate sensor is further configured to send a flow rate signal to the controller. The controller is configured to receive the pressure signal and/or the flow rate signal, and to determine whether the output tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate are in accordance with the prescribed values for the one or more respiratory parameters. Additionally, the controller is further configured to adjust the position of the actuator and/or the speed at which the actuator moves so as to adjust the output tidal volume, peak pressure, and/or breathing rate to be in accordance with the prescribed values.

In some settings, the bag may be an Ambu bag. The bag may be compressed in accordance with respiratory parameters that include an inhale to exhale ratio. To that end, the bag may be compressed between the paddle and a flat surface. Furthermore, the flat surface may be a fixed surface. Furthermore, the bag may have a longitudinal axis, and the convex contact surface may be configured to extend along the longitudinal axis. The system may perform a calibration process to confirm that the bag is outputting air in accordance with one or more prescribed respiratory parameter.

The strap may have a first end that is fixed, and a second end that is movable.

In some embodiments, the system is configured to operate in a volume control mode. The volume control mode includes a prescribed value for the tidal volume, and a prescribed limit for the peak pressure. Alternatively, the system may be configured to operate in a pressure control mode. The pressure control mode includes a prescribed value for the pressure, and a prescribed volume limit. Among other things, an alert may be trigged and/or the actuator may cease ventilating the patient when the prescribed limit is exceeded.

Additionally, or alternatively, to the flow rate sensor and/or the pressure sensor, the system may also have an oxygen sensor. Each of the sensors may be coupled to a display that shows information relating to the sensor. In some embodiments, the display may be coupled to a user input that allows the user to adjust the oxygen input.

In accordance with yet another embodiment, a method operates a ventilator. The method includes controlling an actuator, coupled to a paddle having a convex contact surface, in accordance with a prescribed value for a respiratory parameter, to compress an inflatable bag to cause oxygen and/or air to flow out of an output valve of the bag. The actuator may further comprise a spindle, the spindle being capable of tightening a strap that is coupled to the paddle having the convex contact surface, the strap also being capable of compressing the bag. The respiratory parameter may include tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate of the oxygen and/or the air flowing through the output valve. The method also senses the pressure flowing through the output valve, and sends a pressure signal to the controller. Additionally, the method senses the flow rate through the output valve, and sends a flow rate signal to the controller. The method also adjusts the compression of the actuator as a function of the flow rate signal and/or the pressure signal to adjust the output tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate to be in accordance with the prescribed value.

In some embodiments, the method couples the paddle has a longitudinal axis. Additionally, the method may substantially align the longitudinal axis of the paddle with a longitudinal axis of the bag. Furthermore, the method may adjust the compression of the actuator by adjusting the position of the actuator and/or the speed at which the actuator moves.

Illustrative embodiments of the invention are implemented as a computer program product having a computer usable medium with computer readable program code thereon. The computer readable code may be read and utilized by a computer system in accordance with conventional processes.

Those skilled in the art should more fully appreciate advantages of various embodiments of the disclosure from the following "Description of Illustrative Embodiments," discussed with reference to the drawings summarized immediately below.

In illustrative embodiments, a ventilation apparatus provides reliable and precise ventilation to a patient in accordance with a set of prescribed respiratory parameters. The apparatus operates on an inflatable bag used to provide positive pressure ventilation to patients who are not breathing adequately. For example, the apparatus may operate with a bag valve mask (also referred to under the proprietary name "Ambu bag"). The operator is allowed to select values for one or more respiratory inputs. Sensors measure the output from the bag, and provide a feedback loop to a controller, which makes corresponding adjustments to an actuator. The actuator has a convex shaped contact surface and is oriented parallel to the longitudinal axis of the bag. Details of illustrative embodiments are discussed below.

<FIG> schematically shows the ventilation device <NUM> and a patient <NUM> in accordance with illustrative embodiments of the invention. The ventilation device <NUM> may have a housing <NUM> that contains the internal components. The housing <NUM> may have two openings 16A and/or 16B that accommodate two valves 21A and 21B, one for air input, and the other for air output, respectively. Preferably, each of these valves 21A and 21B is a one-way valve (e.g., input valve 21A only allows airflow into the device <NUM>, output valve 21B only allows airflow out of the device <NUM>). However, in some embodiments, the one-way valve 21B may additionally, or alternatively, be on the bag (see, for example, <FIG>). Thus, the openings 16A and/or 16B may accommodate tubing that is part of a breathing circuit including the one-way valves 21A and 21B.

In <FIG>, with the air input opening 16A is on the front side of the housing <NUM>, and the air output opening 16B is on the side of the housing <NUM>. It should be understood however that illustrative embodiments may have the openings 16A and 16B in various arrangements and orientations not shown herein, and are not intended to be limited to the arrangement shown herein. Although the term "air" is used with reference to the device <NUM>, it should be understood that illustrative embodiments may use pure oxygen, or various gas combinations not found in the ambient air. Accordingly, the term "air" is not intended to limit illustrative embodiments to use only with ambient air in the environment. Indeed, the term "air" may include, among other things, pure oxygen provided by a commercial gas supplier.

The device <NUM> may be used in hospital or non-hospital settings, such as where the patient is laying on a hospital bed <NUM>, emergency transport, in-field, etc.. A breathing tube <NUM> may couple the output valve 21B to the patient <NUM>. At the end of the breathing tube <NUM> may be another one way valve <NUM>. The one way valve <NUM> may be similar to the valves 16A-16B that are found at the ends of a bag (e.g., the Ambu bag). The valve <NUM> provides one way ventilation that allows air to flow to the patient <NUM> while also preventing back flow of air in to the device <NUM>. Accordingly, the valve(s) <NUM> and 21B may prevent contamination from entering back into the device <NUM>. Additionally, illustrative embodiments may use a mask <NUM> and/or endotracheal tube <NUM> to couple the output valve 21B to the patient <NUM>. The mask <NUM> and/or endotracheal tube <NUM> attaches to the end of one of the breathing tubes and inhibits air from escaping during the ventilation inhalation and exhalation cycle. The one way valve <NUM> may also provide for easy addition of a peep valve that is commonly used in resource-limited hospitals.

Many developing countries do not have an adequate number of ventilators for their patients <NUM>. Instead, hospitals and emergency settings may require the use of the bags. Frequently, medical staff <NUM> or family members may be tasked with ventilating the patient <NUM> using the bag. However, proper ventilation of the patient <NUM> requires precise delivery of a given volume of air, at a given pressure, and at a given tempo for a sustained period of time, which is difficult to achieve even for trained staff <NUM>.

Furthermore, the staff <NUM> may not have feedback about the pressure or flow rate that is used to ventilate the patient <NUM>. Delivering air and/or oxygen in accordance with prescribed values for respiratory parameters is a more effective and safe manner of ventilating patients <NUM>. For example, if the patient <NUM> receives too much tidal volume, the lungs may rupture or collapse. Additionally, if the patient <NUM> receives too much air pressure, the lung could be punctured and the patient <NUM> could have internal bleeding. If the air pressure is too low, the air and/or oxygen may not reach the lungs of the patient <NUM>.

Even if feedback about the output parameters is provided to the staff <NUM>, it is nearly impossible to manually ventilate the patient <NUM> consistently for a sustained period of time in accordance with the respiratory parameters. To further complicate matters, the input parameters for each patient <NUM> differ based on physiological differences in the patient <NUM> (e.g., height, body weight, age, etc.). Thus, even experienced staff <NUM> with feedback may have difficulty ventilating the patient <NUM> in accordance with appropriate parameters for a sustained period of time.

Accordingly, illustrative embodiments of the device <NUM> provide sensors that measure the output of the bag, and that provide feedback to a controller, which automatically adjusts an actuator to ventilate the patient <NUM> in accordance with the prescribed parameters. To that end, the device <NUM> may have a user interface <NUM>, which may include a touch screen and/or a knob. The operator may enter the desired values to control a variety of respiratory parameters. For example, illustrative embodiments allow a user <NUM> to input respiratory parameters, including: Output Volume between about <NUM> and about <NUM>, Pressure Limit- between about <NUM> and about <NUM> H<NUM>O, Breathing rate between about <NUM> and about <NUM> bpm, Inhalation to exhalation ratio of between about <NUM>:<NUM> and about <NUM>:<NUM>, inspiratory time of between about <NUM> and about <NUM> seconds. The user interface <NUM> may provide the user secondary controls, including: switching between Pressure Control and Volume Control, changing power source from battery to power supply, oxygen titration based on %O2 reading on the screen, turning on / off Bluetooth, turning on/ off Wi-Fi, turning Assist Control on/off. Furthermore, the system <NUM> may include alarms (e.g., for low battery, high pressure, disconnection of breathing tube) on the device <NUM>, a display, or a mobile electronic device <NUM>. Alarm tells the actuator to stop and go back to the reset position.

In addition to the user interface <NUM>, illustrative embodiments may use a mobile electronic device <NUM> (such as smartphone <NUM> having a mobile app) to input the respiratory parameters. The values for the respiratory parameters may also be displayed on the mobile electronic device <NUM>.

<FIG> schematically shows the internal components of the device <NUM> in accordance with illustrative embodiments of the invention. The device <NUM> may also include wires and electronics not shown herein for convenience. The device <NUM> may include a base <NUM> on which the internal components rest and/or are mounted. The device <NUM> includes an inflatable bag, such as the bag <NUM> (e.g., an Ambu bag). As described previously, the bag <NUM> may be inflated via air flow coming through input valve 21A. Additionally, the bag <NUM> may be deflated via air flow exiting through output valve 21B. Specifically, the bag <NUM> deflates as it is compressed by paddle <NUM>. In some embodiments, the bag <NUM> is compressed between the paddle <NUM> and a flat surface such as the base <NUM>.

As described further below, illustrative embodiments may include just a single convex contact surface <NUM> (e.g., a single paddle <NUM>) to avoid creating dead space that may otherwise result from multi-directional inward compression (e.g., simultaneous compression from two convex paddles). For example, compressing the cylindrically shaped body of the bag <NUM> between two semi-spherical paddles <NUM> may create unintended dead space in the top and bottom quadrants of the bag <NUM>. However, some other embodiments may include more than one paddle <NUM>.

In illustrative embodiments the paddle <NUM> is coupled with a strap <NUM>. At one end, the strap <NUM> may be fastened to the base <NUM> using a fastener <NUM>. At the other end, the strap <NUM> may be coupled to an actuator that, when activated, tensions the strap <NUM>. Thus, in illustrative embodiments, a first end of the strap <NUM> may be fixed, and a second end of the strap <NUM> may be movable. The inventors were surprised to discover that having one end of the strap <NUM> fixed, and the other end movable, provides the advantage of making the device <NUM> cleaner, smaller and efficient to drive and control precisely. Additionally, in comparison to multi-bar linkages, the strap <NUM> provides a simpler device <NUM> with lower rates of failure and easy maintenance. This is a significant advantage in certain markets where resources are limited. Tensioning the strap <NUM> causes the paddle <NUM> to inwardly radially compress the bag <NUM>. As the bag <NUM> is compressed, air exits from the output valve 21B and the bag <NUM> deflates. It should be understood that the term deflate does not require that the bag <NUM> completely deflate. Indeed, the bag <NUM> may partially deflate in accordance with prescribed parameters.

In illustrative embodiments, the actuator includes a spindle <NUM> coupled to a motor <NUM> through a gear box and adapter <NUM>. The inventors discovered that coupling the paddle <NUM> to the strap <NUM>, and actuating compression of the bag <NUM> using a spindle <NUM> provides various advantages. For example, a paddle that is movable on a hinge undesirably puts a lot of load on the motor <NUM>, which makes the device <NUM> more likely to fail. Given the emergency settings that the device <NUM> may be used in, it is desirable to have a robust device <NUM> that is easy to maintain, with fewer moving parts and lower rates of failure. In addition to requiring that the motor <NUM> work harder to achieve the same effects as illustrative embodiments using the strap <NUM>, in the hinge arrangement the motor <NUM> moves very little to compress the bag a significant amount. Accordingly, illustrative embodiments using the strap <NUM> provide for convenient precision control of the volume of the bag.

Although not shown in <FIG>, a controller may be coupled to the motor <NUM>. The controller receives feedback from one or more sensors, and controls the output of the motor <NUM>. For example, illustrative embodiments may include a flow sensor <NUM> coupled to the output valve 21B. Additionally, or alternatively, the device <NUM> may include a pressure sensor <NUM> coupled to the output valve 21B. Furthermore, an oxygen sensor <NUM> may additionally or alternatively be coupled to the output valve 21B. Although the various sensors <NUM>, <NUM>, and <NUM> are described as being coupled to the output valve 21B, it should be understood that they may not be directly coupled to the output valve 21B. For example, the sensors <NUM>, <NUM>, and <NUM> may be downstream of the valve 21B and connected via tubing <NUM>. Accordingly, the sensors <NUM>, <NUM>, and <NUM> described herein advantageously provide information relating to the air output from the bag <NUM>. These measurements can be directly correlated to specific respiratory parameters.

<FIG> schematically show the paddle <NUM> in accordance with illustrative embodiments of the invention. Specifically, <FIG> schematically shows a perspective view of the paddle <NUM>. <FIG> schematically shows a left-side view of the paddle <NUM>, and <FIG> schematically shows a top view of the paddle <NUM>. The paddle <NUM> has a coupling portion <NUM>, through which the paddle <NUM> is coupled to the strap <NUM>. On the other end of the paddle <NUM> is a contact surface <NUM> that faces and compresses the bag <NUM>.

The inventors were surprised to find that providing a convex contact surface <NUM> resulted in advantages over flat or concave contact surfaces <NUM>. For example, a flat paddle <NUM> deforms the bag in a non-linear motion, meaning that the patient <NUM> experiences a sudden jump in flow rate and pressure. Additionally, flat paddles <NUM> create stress concentrations at the edges of the paddle and at the folding area of the bag <NUM>. This could lead to faster degradation of the bag <NUM> and even critical leaks or tears over longer periods of time. A concave contact surface <NUM> leaves a large amount of dead space in the bag <NUM>. Additionally, the concave contact surface <NUM> also causes a large spike in pressure and flow rate at the beginning of the compression cycle.

Accordingly, illustrative embodiments have a convex contact surface <NUM>. Although the paddle <NUM> is described as having a convex contact surface <NUM>, it should be understood that at least some portion of the surface area may be flat. Generally, however, the convex contact surface <NUM> allows for smaller buildup of pressure and flow, which is preferred in clinical settings. The concave contact surface <NUM> generally provides more precise deformation/compression of the bag <NUM>, and leaves less dead space than other configurations.

In illustrative embodiments, the paddle <NUM> has a longitudinal axis <NUM> defined by its length. As shown in <FIG>, the bag <NUM> also has a longitudinal axis <NUM> running through its length (e.g., an axis running through input valve 21A and output valve 21B). In illustrative embodiments, the longitudinal axis <NUM> of the paddle <NUM> is aligned with the longitudinal axis <NUM> of the bag <NUM> to inhibit the formation of dead space that may otherwise form during compression of the bag <NUM>. By arranging the paddle <NUM> and the bag <NUM> so that their longitudinal axes <NUM> and <NUM> are substantially aligned, the bag <NUM> is more evenly compressed.

In some embodiments, the longitudinal axes <NUM> and <NUM> are less than <NUM> degrees offset from one another. Preferably, the longitudinal axes <NUM> and <NUM> are no more than <NUM> degrees offset from one another. In some embodiments, the longitudinal axes <NUM> and <NUM> are no more than <NUM> degrees offset from one another. In some embodiments, the longitudinal axes <NUM> and <NUM> are less than <NUM> degrees offset from one another. Additionally, to assist with reduction of dead space, in some embodiments, the length of the paddle <NUM> is at least <NUM>% of the length of the body of the bag <NUM>. More preferably, the length of the paddle <NUM> is greater than <NUM>%, <NUM>%, <NUM>%, or <NUM>% of the length of the body of the bag <NUM>.

<FIG> schematically shows a block diagram of a system <NUM> for ventilation in accordance with illustrative embodiments of the invention. Air enters the system <NUM> and optionally go through a filter, which filters contamination such as dust. The air may be received from the environment, and/or through connected gas cylinders that are commercially available (e.g., through commercial entities such as Airgas or equipment such as air compressors). In illustrative embodiments, the air may pass through input valve 21A. The air then reach the insides of the body of the bag <NUM>. The bag <NUM> is compressed by the paddle <NUM>, which causes the air to flow through the output valve 21B of the bag <NUM> towards the mask <NUM>.

In some embodiments, the paddle <NUM> has a convex shape. Specifically, as discussed previously, the paddle <NUM> may have a convex contact surface <NUM>. Additionally, the paddle <NUM> may be oriented relative to the bag <NUM> such that their longitudinal axes <NUM> and <NUM> are substantially aligned. Thus, as the actuator (e.g., the motor <NUM>) causes the strap <NUM> to tighten, the paddle <NUM> compresses the bag <NUM> and the bag <NUM> deforms in a predictable manner. The inventors discovered that the arrangement of the convex paddle <NUM> aligned with the longitudinal axis of the bas <NUM> minimizes dead space and allows for precision control of the volume expelled. Furthermore, in illustrative embodiments, the strap <NUM> provides a mechanically robust system <NUM> that provides precision control of the speed and volume of compression.

As the air flows out of the bag <NUM>, it flows through the pressure sensor <NUM>, the flow rate sensor <NUM>, and/or the oxygen sensor <NUM>. The pressure sensor <NUM>, the flow rate sensor <NUM>, and/or the oxygen sensor <NUM> send a signal to the controller <NUM>. The controller <NUM> controls, among other things, the movement of the actuator based on the input values set in the beginning (e.g., by the user <NUM> or by automatically by the device <NUM>). The input values include, for example, tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and breathing rate. These values are evaluated by the encoder and the controller <NUM> to move the actuator.

The signals are fed back to the controller <NUM>, as is described further below. The controller <NUM> may evaluate the signals and adjust the movement of the actuator, and thus, the amount of air output by the bag <NUM>. The quantified air is passed through the sensors <NUM>, <NUM>, and/or <NUM> optionally to a second filter, and then to a breathing tube circuit <NUM>, which is connected to the patient <NUM>. The controller <NUM> also provides values for flow rate, peak pressure, minute volume and oxygen saturation over time, which can be displayed in a graphical or numeric form on the display, the user interface of the device <NUM>, and/or on the mobile app.

In some embodiments, the sensors <NUM>-<NUM> may send a message to the controller <NUM>, the display, and/or the alarm. The message may be triggered by a sensor measurement that is not in accordance with the prescribed value for the respiratory parameter (e.g., pressure or volume). The controller <NUM> may then adjust compression of the bag <NUM> by the paddle <NUM> to put the respiratory parameter in accordance with the prescribed value.

<FIG> schematically shows details of the controller <NUM> that receives feedback from the one or more sensors <NUM> and <NUM>, and that controls the output of the motor <NUM> in accordance with illustrative embodiments of the invention. The controller <NUM> is configured to, among other things, control the output of the motor <NUM>. To that end, the controller has an actuator control module <NUM>. The actuator control module <NUM> controls the torque, velocity, position, and/or speed output of the motor <NUM>. Thus, the actuator control module <NUM> indirectly controls the pressure and flow rate output by the bag <NUM> (the motor <NUM> controls position and speed of the paddle <NUM>).

The controller also has a memory <NUM>. The memory <NUM> may store information relating to the input parameters, the data received from the sensor interface, and/or formulas used to calculate respiratory parameters.

The controller <NUM> controls the motor <NUM> in accordance with prescribed values for various respiratory parameters. To that end, the controller <NUM> has a user interface engine <NUM>, which may receive inputs, for example, from the physical user interface <NUM>. Additionally, the user interface engine <NUM> may communicate with the user interface <NUM> and/or the display <NUM>. For example, the user interface engine <NUM> may receive a message from the signal interface <NUM> indicating that one or more of the sensors <NUM>, <NUM>, and/or <NUM> is detecting an out of parameter condition. For example, the oxygen sensor <NUM> may detect that the oxygen is too low. As an additional example, the pressure sensor <NUM> may detect that the pressure is too high. The user interface engine <NUM> may send an alarm to the physical user interface <NUM>, the electronic mobile device <NUM>, or another display, informing the user <NUM> that the out of condition state exists. Additionally, in some embodiments, the out of parameter condition may be sent to the actuator control module <NUM>. The actuator control module <NUM> may adjust the operation of the actuator (e.g., by stopping the compression of the bag <NUM> completely).

The user interface engine <NUM> receives the user <NUM> selection of one or more respiratory parameters, including Output Volume, Pressure Limit, Breathing rate, Inhalation to exhalation ratio, and/or inspiratory time. The user <NUM> may enter specific values for each of the respiratory parameters, and the motor <NUM> is correspondingly controlled to output air from the bag <NUM> in accordance with those parameters.

Alternatively, the user <NUM> may enter information about the patient <NUM> (e.g., height, weight, sex), and a parameter calculation module <NUM> may calculate appropriate respiratory parameters for the patient <NUM>. To that end, the calculation module <NUM> may communicate with the memory to access formulas known in the literature.

The controller <NUM> also has a calibration module <NUM>. As will be described further below, with reference to <FIG>, the device <NUM> may use a calibration process. The calibration module receives respiratory parameters and/or a ventilation mode from the user interface engine <NUM>. The calibration module <NUM> instructs the actuator control module <NUM> to begin ventilation. A sensor interface <NUM> interfaces with the various sensors <NUM>, <NUM>, and/or <NUM>, and receives data about the output air (e.g., pressure, flow rate, oxygen level, etc.). The calibration module <NUM> determines if the output air is in compliance with prescribed values for the respiratory parameters. If not, the calibration module <NUM> sends a signal to the actuator control module <NUM> to adjust the signal sent to the motor <NUM>.

Each of the above-described components is operatively connected by any conventional interconnect mechanism. <FIG> simply shows a bus <NUM> communicating each of the components. Those skilled in the art should understand that this generalized representation can be modified to include other conventional direct or indirect connections. Accordingly, discussion of a bus is not intended to limit various embodiments.

Indeed, it should be noted that <FIG> only schematically shows each of these components. Those skilled in the art should understand that each of these components can be implemented in a variety of conventional manners, such as by using hardware, software, or a combination of hardware and software, across one or more other functional components. For example, the actuator control module <NUM> may be implemented using a plurality of microprocessors executing firmware. As another example, the calibration module <NUM> may be implemented using one or more application specific integrated circuits (i.e., "ASICs") and related software, or a combination of ASICs, discrete electronic components (e.g., transistors), and microprocessors. Accordingly, the representation of the components in a single box of <FIG> is for simplicity purposes only. In fact, in some embodiments, the actuator control module <NUM> is distributed across a plurality of different machines-not necessarily within the same housing or chassis. Additionally, in some embodiments, components shown as separate (such as the calculation module <NUM> and the calibration module <NUM>) may be replaced by a single component. Furthermore, certain components and subcomponents in <FIG> are optional. For example, some embodiments may not use the parameter calculation module <NUM>.

It should be reiterated that the representation of <FIG> is a significantly simplified representation of the ventilation controller <NUM>. Those skilled in the art should understand that such a device may have other physical and functional components, such as central processing units, other packet processing modules, and short-term memory. Accordingly, this discussion is not intended to suggest that <FIG> represents all of the elements of the ventilation controller <NUM>.

<FIG> shows one embodiment of a process <NUM> of ventilating the patient <NUM>, which is not part of the invention, in accordance with prescribed values for respiratory parameters. It should be noted that this process is substantially simplified from a longer process that normally would be. As such, the process may have additional steps that are not discussed. In addition, some steps may be optional, performed in a different order, or in parallel with each other. For example, step <NUM> may come after step <NUM>. As another example, step <NUM> may start after step <NUM>. Furthermore, some of these steps may be optional in some embodiments. Accordingly, discussion of this process is illustrative and not intended to limit various embodiments of the disclosure.

Accordingly, the process <NUM> is merely exemplary of one process in accordance with illustrative embodiments of the disclosure. Those skilled in the art therefore can modify the process as appropriate.

The process <NUM> begins at step <NUM>, which couples the output of the device <NUM> with the patient's <NUM> respiratory tract. Specifically, the output valve 21B shown in <FIG> is securely connected via the tubing <NUM> and the mask <NUM> over the patient's <NUM> mouth and nose. The process then proceeds to step <NUM>, which receives the respiratory parameters. As mentioned previously, the user may manually enter values for the respiratory parameters through the user interface <NUM>, and/or the parameter calculation module <NUM> may generate values for the parameters after providing information about the patient <NUM>. In order to receive the respiratory parameters, the device <NUM> may be powered on using the on and off switch (not shown). The user interface <NUM> may comprise an LCD screen that displays instructions. Additionally, or alternatively, the user interface <NUM> may be on a user's mobile device (e.g., smartphone). In some embodiments, step <NUM> may come after the device <NUM> is calibrated.

The user <NUM> inputs the respiratory parameters (e.g., the user <NUM> may rotate the knob(s) to adjust the inputs) based on the patient's <NUM> clinical state. The respiratory parameters may include, for example, tidal volume, peak pressure, breathing rate, and/or I:E ratio. In illustrative embodiments, the user <NUM> may input one or more respiratory parameters including: tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate of the oxygen and/or the air flowing through the output valve 21B to the patient <NUM>. For example, the user <NUM> may input tidal volume. Alternatively, the user <NUM> may input the tidal volume and the pressure. Furthermore, the user <NUM> may input all of the above described respiratory parameters. Specifically, in some embodiments the user <NUM> may set the tidal volume from between about <NUM> and about <NUM>, peak pressure from between about <NUM> and about <NUM> H2O, breathing rate from about <NUM> to about <NUM> breaths/min. The user <NUM> may then confirm the settings by pressing a confirmation button.

The process <NUM> then proceeds to step <NUM>, where the user <NUM> selects the ventilation mode. The user <NUM> may select between volume controlled ventilation, which compresses the bag <NUM> to deliver air at a selected volume, and/or pressure controlled ventilation, which compresses the bag <NUM> to deliver air at a selected pressure. Within volume controlled ventilation, there is an additional option to set control ventilation, where the device <NUM> delivers constant parameters if the patient <NUM> is not breathing on their own. Alternatively, under volume controlled ventilation, the user <NUM> may select assist-control ventilation, where the device <NUM> synchronizes its compressions with the patient's <NUM> own breathing rhythm.

In pressure control ventilation mode, the user <NUM> provides a prescribed value for pressure of the airflow output by the bag <NUM>. The pressure sensor # measures the output pressure to confirm that it is in accordance with the prescribed value. In some embodiments, the prescribed value may be a range or a target value having a built in +/- tolerance. Furthermore, pressure control ventilation may ask the user <NUM> to select a peak tidal volume and/or peak volume limit.

Volume controlled ventilation delivers a precise amount of volume per inspiration. For example, volume controlled ventilation mode adjusts the output tidal volume (e.g., <NUM>), and allows the user <NUM> to set limits for peak pressure, breathing rate (e.g., how many breaths in a minute), inspiratory time (e.g., how long to deliver the <NUM>-<NUM> breathing), and/or I:E ratio.

The system may also be configured to operate in a pressure controlled ventilation mode. Pressure controlled ventilation mode adjusts the pressure, tidal volume limit, breathing rate, and inspiratory time.

In control ventilation mode, the device <NUM> is configured to compress the bag <NUM> on a repeating time cycle. The controller <NUM> receives the input respiratory parameter values. In some embodiments, the controller <NUM> assigns a specific distance for the actuator to move based on a calibrated zero value (e.g., using the actuator control module <NUM>). Additionally, the controller <NUM> may pre-select the time between cycles where the actuator sits at the zero (e.g., bag <NUM> uncompressed) position. Furthermore, the controller <NUM> may monitor the speed of the actuator for inhale and exhale cycle over time (e.g., using the calibration module <NUM>). In addition, the controller <NUM> may take receive real-time data from the sensors through the sensor interface <NUM>. The real-time sensor data may be sent to the actuator control module <NUM> and used to adjust the compression parameters (e.g., speed) to produce the prescribed flow rate and pressure rate (e.g., by communicating the calibration module <NUM> with the sensor interface <NUM> and/or memory <NUM>).

In a similar manner to control ventilation, in assist control ventilation mode the device <NUM> may also be configured to compress the bag <NUM> on a repeating time cycle. Accordingly, the patient <NUM> may be ventilated at a particular breathing rate. However, assist control ventilation may also be trigged by the patient's <NUM> attempt to inhale on their own. This may find clinical applications, for example, when the patient <NUM> is not totally sedated. In such a circumstance, the patient may have consciousness and may breathe on their own accord. Illustrative embodiments may provide additional respiratory support that matches the patient's <NUM> breathing rate. This provides enhanced comfort to the patient <NUM>. Additionally, if the patient <NUM> cannot breath, or stops drawing breath, on their own, the device <NUM> may ventilate the patient <NUM> at the prescribed breathing rate (e.g., selected by the user <NUM>). Thus, in illustrative embodiments, assist control ventilation mode may send the patient <NUM> a new breath unless the patient <NUM> overrides it.

In some embodiments, assist control ventilation is triggered when the
patient attempts to inhale while the actuator is at the zero position (e.g., bag <NUM> is uncompressed) and there is time left before the cycle begins. In assist control ventilation, the sensor continuously monitors for a backflow reading from outlet side (i.e., from the patient <NUM>). If the patient <NUM> attempts to inhale the values for flow and pressure go beyond the noise threshold and the reading is recorded by the controller <NUM>. The controller <NUM> may then reset the actuation cycle and appropriately change the time delay between each cycle depending on the patient's <NUM> inhalation time. The controller <NUM> then rests the actuation cycle and appropriately changes the time delay between each cycle depending on the patient's <NUM> inhalation time.

In both assist control ventilation mode and control ventilation mode, the user <NUM> provides a prescribed value for volume of the air output by the bag <NUM>. The flow rate sensor <NUM> measures the output air to confirm that it is in accordance with the prescribed value. In some embodiments, the prescribed value may be a range or a target value having a built in +/- tolerance. Furthermore, assist control ventilation mode and control ventilation mode may ask the user <NUM> to select a peak pressure.

Steps <NUM>-<NUM> calibrate the device <NUM> when it is initially operated and/or when the values for one or more respiratory parameters are changed. Additionally, this calibration process may occur passively during the operation of the device <NUM>, even after it has been calibrated, to ensure that the device <NUM> is operating in accordance with the intended respiratory parameters.

At step <NUM> ventilation begins. Illustrative embodiments compress the bag <NUM> so that it deforms and collapses in on itself. The inventors discovered that driving a convexly shaped paddle <NUM> optimized the evacuation of the air volume inside the bag <NUM>. Specifically, illustrative embodiments orient the longitudinal axis <NUM> of the paddle <NUM> substantially in parallel to the longitudinal axis <NUM> of the bag <NUM>. The strap <NUM> is also partly wrapped around the body of the bag <NUM>. Accordingly, illustrative embodiments aid in consistent and precise delivery of the desired volume at a set pressure while minimizing dead space.

The controller <NUM> sends a signal to the motor <NUM> that winds the strap <NUM> around the spindle <NUM> at a predetermined velocity. The power delivered to the spindle <NUM> is governed by the flow rate measured during this step, i.e., if low flow rate is detected, the motor <NUM> is given more power. Conversely, if high flow is detected the power is reduced (e.g., tapered off gradually). Once the target output volume is achieved, the velocity profile and target positions (amount of rotation required by the motor <NUM>) are recorded as the base compression profile for the start of ventilation. These may be stored in the memory <NUM> of the controller <NUM>.

After the settings are chosen, the device <NUM> completes at least one cycle to calibrate based on inputs. For calibration, the actuator exerts force on the bag <NUM> until a slight flow of air and/or oxygen is detected by the flow rate sensor <NUM> and/or pressure sensor <NUM>.

At step <NUM>, the air pressure and/or flow rate data from the air coming out of the bag <NUM> is received by the controller <NUM>. As described previously, the device <NUM> may have pressure sensor <NUM> and/or flow rate sensor <NUM>. These sensors <NUM> and <NUM> measure the pressure and flow rate, respectively, and provide that data to the controller <NUM>. The device <NUM> uses dynamic pressure and flow sensor data that is collected in real time to adjust the compression of the bag <NUM>. This data is forwarded to the controller <NUM>. Illustrative embodiments may review data from the last few compression cycles to determine whether the device <NUM> reaches a steady state governed by the prescribed respiratory parameters (e.g., input by the user or calculated by the calculation module <NUM>).

The process then moves to step <NUM>, which asks whether the pressure, the flow rate, and/or the respiratory parameters are in compliance with the prescribed values. If the input parameters (e.g., tidal volume, peak pressure, breathing rate, etc.) or external variables (e.g., resistance/compliance of the patient's lungs) are causing any of the variables to be out of compliance with the prescribed values, the process <NUM> moves to step <NUM>.

At step <NUM>, the process <NUM> compensates for the variance in the pressure, the flow rate, and/or the respiratory parameters by adjusting the speed and/or distance that the actuator moves. For example, the controller <NUM> may send a signal to the motor <NUM> requiring that the actuator stroke should be increased.

As an example of volume control adjustment, the device <NUM> may be set to achieve a tidal volume of <NUM> with every inspiration of the patient <NUM>. After calibration, the device <NUM> may output the tidal volume of <NUM>. If the patient <NUM> changes their position on the hospital bed (e.g., as the anesthesia begins to wear off), there may be an increased resistance in the lungs. Accordingly, the actual volume of air that reaches the patient's <NUM> lungs drops below the desired parameter due to the increased resistance. The feedback mechanism of illustrative embodiments of the invention uses sensors to detect the decrease, and instructs the actuator to move faster and/or more forcefully in real-time to meet the tidal volume goal. This dynamic adjustment of the actuator may continue during the current and future breathing cycles.

As an example of pressure control adjustment, the device <NUM> may be set to reach a desired pressure of <NUM> H2O. In order to achieve this value, the actuator dynamically course-corrects its velocity throughout the duration of the compression to deliver <NUM> H2O.

After calibration is complete, the user interface <NUM> (e.g., LCD) may instruct the user <NUM> to put the mask on or connect the endotracheal tube to the patient <NUM>, if it is not already on the patient <NUM>. The device <NUM> then begins to deliver the desired amount of air and/or oxygen to the patient <NUM> in accordance with the prescribed respiratory parameters. If the settings need to be changed, the user <NUM> may pause the device <NUM> and re-adjust the input settings. The user <NUM> may then re-start the device <NUM>, which delivers the new levels of desired air and/or oxygen.

If the pressure, the flow rate, and/or the respiratory parameters are in compliance with the prescribed parameters, the process moves to step <NUM>, where ventilation is continued until the user <NUM> stops the device <NUM>.

Optionally, the process may move to step <NUM>, where the device <NUM> sends a signal (e.g., to a mobile device application) where the flow rate and pressure data are recorded and displayed over time. This provides users <NUM> with information relating to the ventilation delivery pattern of the patient <NUM>. To turn the device <NUM> off, the user takes the mask/endotracheal tube off the patient and turns off the power switch.

Additionally, the process may optionally move to step <NUM>. In case the values of the desired air and/or oxygen delivered deviates, step <NUM> causes alarms to be triggered to notify the user <NUM>. These alarms will trigger if the readings are, for example, above and/or below tidal volume input and peak pressure. Although shown near the end of process <NUM>, steps <NUM>-<NUM> may be ongoing from the beginning of the process.

A person of skill in the art should understand that illustrative embodiments provide a number of advantages. For example, illustrative embodiments provide superior control over the ventilation delivered to the patient by the bag <NUM>. Specifically, feedback sensors <NUM> and <NUM> for pressure and flow rate are detected and used to adjust the tidal volume, peak pressure, breathing rate and/or I:E ratio to match the selected inputs. Illustrative embodiments also increase patient safety by using alarm sensors to detect whether an accurate amount of air and/or oxygen is delivered to the patient.

Illustrative embodiments provide a further advantage in that they integrate with equipment already in common use in the hospital. In some embodiments, the output valves are able to integrate with both ends of the breathing circuit and mask, which allows the device to be easily used in a hospital setting. Furthermore, illustrative embodiments are portable. To that end, the device may be formed from light materials, including plastics, and the components may be compactly arranged.

Other advantages of illustrative embodiments include simple functionality. For example, the input controls may include three knobs, one confirmation button, and one slider switch to change between ventilation modes and a power button. Furthermore, a LCD may be placed on the device <NUM> to display real time readings. Illustrative embodiments are also user friendly. For example, two back doors allow for easy access to internal components, including the bag <NUM> and the batteries. Furthermore, many of the components of the device are available in low resource settings, such as the bag <NUM>, batteries, and other internal components.

Yet another advantage of illustrative embodiments is remote monitoring of ventilation data. This is achieved, for example, via a mobile application. Illustrative embodiments have a graphical display of data, such as tidal volume, I:E ratio, peak pressure, breathing rate, % oxygen saturation and minute volume ventilation. This provides real time monitoring of the patient's <NUM> condition to the doctor and is especially useful in hospitals that are understaffed.

Various embodiments of the invention may be implemented at least in part in any conventional computer programming language. For example, some embodiments may be implemented in a procedural programming language (e.g., "C", "Python", etc.), or in an object oriented programming language (e.g., "C++"). Other embodiments of the invention may be implemented as preprogrammed hardware elements (e.g., application specific integrated circuits, FPGAs, and digital signal processors), or other related components.

In an alternative embodiment, the disclosed apparatus and methods (e.g., see the various flow charts described above) may be implemented as a computer program product for use with a computer system. Such implementation may include a series of computer instructions fixed either on a tangible, non-transitory medium, such as a computer readable medium (e.g., a diskette, CD-ROM, ROM, or fixed disk). The series of computer instructions can embody all or part of the functionality previously described herein with respect to the system.

Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems. Furthermore, such instructions may be stored in any memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies.

Among other ways, such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web). In fact, some embodiments may be implemented in a software-as-a-service model ("SAAS") or cloud computing model. Of course, some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention are implemented as entirely hardware, or entirely software. Accordingly, the invention should not be viewed as being limited to the disclosed embodiments.

Claim 1:
A system for ventilating a patient comprising:
an input valve (21A),
an output valve (21B),
a bag (<NUM>) that is capable of being inflated through the input valve (21A) that allows oxygen and/or air to flow into the bag, the bag further capable of being deflated through the output valve (21B) that allows the oxygen and/or the air to flow out of the bag;
characterised by:
an actuator (<NUM>) comprising a spindle (<NUM>) that is configured to tighten a strap (<NUM>), the strap being coupled with a paddle (<NUM>) having a convex contact surface capable of compressing the bag to cause the oxygen and/or the air to flow out of the output valve in accordance with prescribed values for one or more respiratory parameters, the one or more respiratory parameters including tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate of the oxygen and/or the air flowing through the output valve to a patient;
a controller configured to control the position of the actuator and/or the speed at which the actuator moves in accordance with the prescribed values for the one or more respiratory parameters;
a pressure sensor (<NUM>) coupled to the output valve and configured to determine the pressure of the oxygen and/or the air flowing through the output valve, the pressure sensor further configured to send a pressure signal to the controller;
a flow rate sensor (<NUM>) coupled to the output valve and configured to determine the flow rate of the oxygen and/or the air flowing through the output valve, the flow rate sensor further configured to send a flow rate signal to the controller;
the controller configured to receive the pressure signal and/or the flow rate signal, and to determine whether the output tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate are in accordance with the prescribed values, the controller further configured to adjust the position of the actuator and/or the speed at which the actuator moves so as to adjust the output tidal volume, peak pressure, and/or breathing rate to be in accordance with the prescribed values for the one or more respiratory parameters.