Patent Description:
For making CPR circulate blood effectively, guidelines by medical experts such as the American Heart Association provide parameters for the chest compressions. The parameters include the frequency, the depth reached, fully releasing after a compression, and so on. Frequently the depth is to exceed <NUM> (<NUM> in. The parameters also include instructions for the rescue breaths.

Traditionally, CPR has been performed manually. A number of people have been trained in CPR, including some who are not in the medical professions, just in case they are bystanders in an emergency event. Manual CPR might be ineffective, however. Indeed, the rescuer might not be able to recall their training, especially under the stress of the moment. And even the best trained rescuer can become fatigued from performing the chest compressions for a long time, at which point their performance might be degraded. In the end, chest compressions that are not frequent enough, not deep enough, or not followed by a full release may fail to maintain the blood circulation required to forestall organ damage and death.

The risk of ineffective chest compressions has been addressed with CPR chest compression machines. Such machines have been known by a number of names, for example CPR chest compression machines, CPR machines, mechanical CPR devices, cardiac compressors and so on.

CPR chest compression machines hold the patient supine, which means lying on his or her back. Such machines then repeatedly compress and release the chest of the patient. In fact, they can be programmed so that they will automatically compress and release at the recommended rate or frequency, and can reach a specific depth within the range recommended by the guidelines.

The repeated chest compressions of CPR are actually compressions alternating with releases. The compressions cause the chest to be compressed from its original shape. During the releases the chest is decompressing, which means that the chest is undergoing the process of returning to its original shape. This process is not immediate upon release, and it might not be completed by the time the next compression is due. In addition, the chest may start collapsing due to the repeated compressions, which means that it might not fully return to its original height even if it had the opportunity.

Some CPR chest compression machines compress the chest by a piston. Some may even have a suction cup at the end of the piston, with which they lift the chest at least during the releases. This lifting may actively assist the chest in decompressing faster than the chest would accomplish by itself. This type of lifting is sometimes called active decompression.

Active decompression may improve air circulation in the patient, which is a component of CPR. The improved air circulation may be especially critical, given that the chest could be collapsing due to the repeated compressions, and would thus be unable by itself to intake the necessary air.

Document <CIT> discloses a CPR system that uses sensors to gather compression data and provides corrective prompts based on non-parametric, information-theoretic analysis to improve CPR performance.

According to the invention, the problem posed is solved by the CPR machine of claim <NUM>.

In embodiments, a Cardio-Pulmonary Resuscitation ("CPR") machine is configured to perform on a patient's chest compressions alternating with releases. The CPR machine includes a compression mechanism configured to perform the compressions and the releases, and a driver system configured to drive the compression mechanism.

In some of these embodiments, a compression force is sensed, and the driving is adjusted accordingly if there is a surprise. According to the invention, driving is automatic according to a motion-time profile, which is adjusted if the compression force is not as expected. The lifting mechanism may lift the chest between the compressions, to assist actively the decompression of the chest. A lifting force may be sensed, and the motion-time profile can be adjusted if the compression force or the lifting force is not as expected. An advantage is that a changing condition in the patient or in the retention of the patient within the CPR machine may be detected and responded to.

The chest-lifting device is included to assist actively the decompression of the chest. In some embodiments a failure detector may detect if the chest-lifting device fails to thus lift the chest. If such a failure is detected, the CPR machine may react accordingly. For instance, an inference may be made from the detected failure that the chest-lifting device has been detached from the patient, is malfunctioning, or its operation is obstructed. A motion-time profile of the driver may be adjusted accordingly. Or an action may be taken by an electronic component, such as a user interface, a memory or a communication module.

In some of these embodiments, the CPR machine has a retention structure and a tether coupled to the retention structure. The patient may be placed supine within the retention structure. The retention structure can be configured to retain the patient supine, while the compressions are performed. The tether may lift the chest when the compressions are not being performed. An advantage is that the decompression of the chest is thus assisted actively.

In some embodiments, the CPR machine has a retention structure, a chest-lifting inflatable bladder coupled to the retention structure, and a fluid pump configured to inflate the bladder. Inflating the bladder may lift the chest when the compressions are not being performed. An advantage is that the decompression of the chest can be thus assisted actively, even in CPR machines where the compression mechanism does not use a piston whose operation can be reversed.

The chest-lifting device is included so as to assist actively the decompression of the chest. The driver system is configured to drive the compression mechanism and to cause the chest-lifting device to lift the chest above its resting height. The lifting may be performed while none of the compressions is being performed, and only occasionally, for example only once while four or more successive compressions are performed. An advantage is that sets of successive compressions may be performed at proper speed, while the equivalent of a rescue breath may be delivered in between.

The chest-lifting device is included so as to assist actively the decompression of the chest. The driver system is configured to drive the compression mechanism, and further to cause the chest-lifting device to lift the chest above its resting height. In some embodiments, the lifting may be performed to various heights, such as progressively increasing heights or adjustable heights. The heights may be set specifically for the patient, whether by detecting the patient's resting height or by a user interface. An advantage is that therapy can thus be customized to the patient.

The chest-lifting device is included so as to assist actively the decompression of the chest. The driver system is configured to drive the compression mechanism, and further to cause the chest-lifting device to lift the chest above its resting height. In some embodiments, lifting the chest may start after a lifting delay compared to compressions from the compression mechanism.

The chest-lifting device is included so as to assist actively the decompression of the chest. In some embodiments, in addition, the CPR machine includes a communication module and may cooperate with a ventilator. The CPR machine and the ventilator may exchange signals as to synchronize when the chest will be lifted with an infusion of air from the ventilator.

In some embodiments, the compression mechanism includes a piston that is coupled to a retention structure. A position sensor detects the resting height of the patient's chest. In some embodiments, then, the CPR machine is capable of adjusting the compression depth in view of the size of the patient. For example, if the patient's body is larger than a threshold, the chest has a higher resting height, and the compressions are correspondingly deeper.

In some embodiments, a chest-lifting device and an input mechanism are also provided, and the compression mechanism includes a piston. A size value for a size of the patient may be input by the input mechanism, for example by a rescuer. In some embodiments, then, the CPR machine is capable of adjusting the active decompression height achieved by the lifting, in view of the size of the patient. For example, if the patient's body is larger than a threshold, the chest has a higher resting height, and the active decompression liftings above the resting height are correspondingly higher.

These and other features and advantages of this description will become more readily apparent from the Detailed Description, which proceeds with reference to the associated drawings in which:.

As has been mentioned, the present description is about Cardio-Pulmonary Resuscitation ("CPR") chest compression machines, methods and software that can perform automatically CPR chest compressions on a patient. Embodiments are now described in more detail.

<FIG> is a diagram of components <NUM> of an abstracted CPR machine according to embodiments. The abstracted CPR machine can be configured to perform on a chest of a supine patient <NUM> compressions alternating with releases.

Components <NUM> include a back plate <NUM>. In <FIG> an abstracted version of back plate <NUM> is shown. Patient <NUM> may be placed supine on back plate <NUM>. A midpoint <NUM> of back plate <NUM> is also shown. An elevation axis <NUM> starts from midpoint <NUM>, and will be used for determining a resting height of the chest, etc..

Back plate <NUM> is typically part of a retention structure. An abstracted retention structure <NUM> of a CPR chest compression machine is shown in <FIG>. Patient <NUM> is placed supine within retention structure <NUM>. Retention structure <NUM> retains the body of patient <NUM> on back plate <NUM>. While retention structure <NUM> typically reaches the chest and the back of patient <NUM>, it does not reach the head <NUM>.

Retention structure <NUM> may be implemented in a number of ways. Some embodiments are disclosed in <CIT> to Jolife AB such embodiments are being sold by Physio-Control, Inc. under the trademark LUCAS®. In other embodiments retention structure <NUM> includes a backboard, of which back plate <NUM> is a part, and a belt that can be placed around the patient's chest.

Components <NUM> also include a compression mechanism <NUM>. Compression mechanism <NUM> can be configured to perform the compressions to the chest, and then the releases after the decompressions.

Components <NUM> also include a driver system <NUM>. Driver system <NUM> can be configured to drive compression mechanism <NUM> automatically. This driving may cause the compressions and the releases to be performed repeatedly.

Compression mechanism <NUM> and driver system <NUM> may be implemented in combination with retention structure <NUM> in a number of ways. In the above mentioned example of <CIT> compression mechanism <NUM> includes a piston, and driver system <NUM> includes a rack- and-pinion mechanism. The piston is also called a plunger. In embodiments where retention structure <NUM> includes a belt, compression mechanism <NUM> may include a spool for collecting and releasing the belt so as to correspondingly squeeze and release the patient's chest, and driver system <NUM> can include a motor for driving the spool with respect to the back plate.

Components <NUM> may further include a controller <NUM>. Driver system <NUM> may be controlled by a controller <NUM> according to embodiments. Controller <NUM> may include a processor <NUM>. Processor <NUM> can be implemented in a number of ways, such as with a microprocessor, Application Specific Integration Circuits (ASICs), programmable logic circuits, general processors, etc. While a specific use is described for processor <NUM>, it will be understood that processor <NUM> can either be standalone for this specific use, or also perform other acts, operations or process steps.

In some embodiments controller <NUM> additionally includes a memory <NUM> coupled with processor <NUM>. Memory <NUM> can be implemented by one or more memory chips. Memory <NUM> can be a non-transitory storage medium that stores programs <NUM>, which contain instructions for machines. Programs <NUM> can be configured to be read by processor <NUM>, and be executed upon reading. Executing is performed by physical manipulations of physical quantities, and may result in functions, processes, actions, operations and/or methods to be performed, and/or processor <NUM> to cause other devices or components to perform such functions, processes, actions, operations and/or methods. Often, for the sake of convenience only, it is preferred to implement and describe a program as various interconnected distinct software modules or features, individually and collectively also known as software. This is not necessary, however, and there may be cases where modules are equivalently aggregated into a single program. In some instances, software is combined with hardware in a mix called firmware.

While one or more specific uses are described for memory <NUM>, it will be understood that memory <NUM> can further hold additional data <NUM>, such as event data, patient data, data of the CPR machine, and so on. For example, data gathered according to embodiments could be aggregated in a database over a period of months or years and used to search for evidence that one pattern or another of CPR is consistently better (in terms of a criterion) than the others, of course correlating with the patient. Data could be de-identified so as to protect the patient privacy. If so, this could be used to adapt the devices to use that pattern either continuously or at least as one of their operating modes.

Controller <NUM> may include or cooperate with a communication module <NUM>, which may communicate with other modules or functionalities wirelessly, or via wires. Controller <NUM> may include or be communicatively coupled with a User Interface <NUM>, for receiving user instructions and settings, for outputting data, for alerting the rescuer, etc..

Communication module <NUM> may further be communicatively coupled with an other communication device <NUM>, an other medical device <NUM>, and also transmit data <NUM> to a post-processing module <NUM>. Wireless communications may be by Bluetooth, Wi-Fi, cellular, near field, etc. Data <NUM> may also be transferred via removable storage such as a flash drive. Other communication device <NUM> can be a mobile display device, such as a tablet or smart phone. Other medical device <NUM> can be a defibrillator, monitor, monitor-defibrillator, ventilator, capnography device, etc..

In other embodiments, communication module <NUM> can be configured to receive transmissions from such other devices or networks. Therapy can be synchronized, such as ventilation or defibrillation shocks with the operation of the CPR machine. For example, the CPR machine may pause its operations for delivery of a defibrillation shock, afterwards detection of ECG, and whether operation needs to be restarted. If the defibrillation shock has been successful, then operation of the CPR machine might not need to be restarted.

Post-processing module <NUM> may include a medical system network in the cloud, a server such as in the LIFENET® system, etc. Data <NUM> can then be used in post event analysis to determine how the CPR machine was used, whether it was used properly, and to find ways to improve performance, training, etc..

Controller <NUM> can be configured to control driver system <NUM> according to embodiments. Controlling is indicated by arrow <NUM>, and can be implemented by wired or wireless signals and so on. Accordingly, compressions can be performed on the chest of patient <NUM> as controlled by controller <NUM>.

In some embodiments, one or more physiological parameters of patient <NUM> are sensed, for example measured end tidal CO2, ROSC detection, pulse oximetry, etc. Upon a physiological parameter being sensed, a value of it can be transmitted to controller <NUM>, as is suggested via arrow <NUM>. Transmission can be wired or wireless. The transmitted values may further affect how controller <NUM> controls driver system <NUM>.

Controller <NUM> may be implemented together with retention structure <NUM>, in a single CPR chest compression machine. In such embodiments, arrows <NUM>, <NUM> are internal to such a CPR chest compression machine. Alternately, controller <NUM> may be hosted by a different machine, which communicates with the CPR chest compression machine that uses retention structure <NUM>. Such communication can be wired or wireless. The different machine can be any kind of device, such as other communication device <NUM> or other medical device <NUM>. One example is described in <CIT>, titled "COOPERATING DEFIBRILLATORS AND EXTERNAL CHEST COMPRESSION MACHINES," Similarly, User Interface <NUM> may be implemented on the CPR chest compression machine, or on another device.

In embodiments, the compressions are performed automatically in one or more series, and perhaps with pauses between them, as controlled by controller <NUM>. A single resuscitation event can be sets of compressions for a single patient.

Driver system <NUM> can be configured to drive the compression mechanism automatically according to a motion-time profile. The motion-time profile can be such that the driving can cause the compression mechanism to repeatedly perform the compressions and the releases. The chest can be compressed downward from the resting height for the compressions, and then decompress at least partially during the releases. Several of the compressions can thus compress the patient's chest by at least <NUM> downward from the resting height, and frequently more, such as <NUM> or <NUM>.

In some embodiments, a force sensing system <NUM> is included. In embodiments, force sensing system <NUM> can be configured to sense an amount of a compression force exerted by driver system <NUM> when the chest of the patient has been compressed downward by a certain amount from the resting height. That certain amount can be, for example, <NUM>, <NUM> or more.

Force sensing system <NUM> may be implemented in different ways, depending on the rest of the embodiments. For example, if may include a force sensor. Or, it may include a strain gauge or a measuring spring with a known spring constant. Such a strain gauge or a measuring spring can be coupled between compression mechanism <NUM> and driver system <NUM> or retention structure <NUM>. In some embodiments the driver system operates by receiving an electrical current, and the force sensing system includes an electrical detector configured to detect an amount of the electrical current. In some embodiments, force sensing system <NUM> includes an accelerometer, a force-sensing resistor, a piezoelectric force sensor, a pressure sensor within a suction cup and/or in a back plate of retention structure <NUM>. In some embodiments, force sensing system <NUM> measures a difference between forces, and infers a force on the patient. In some embodiments a force on a patient stabilization strap is measured, which may have a lateral component, for example from the patient shifting within retention structure <NUM>.

<FIG> is a composite diagram made by individual diagrams <NUM> and <NUM>, which are bridged by thick curved arrows for easier comprehension. At the bottom is a diagram <NUM> with a horizontal time axis. A major vertical axis indicates elevation above ground, for those times T1, T2. In the case of <FIG>, the ground is a convenient reference elevation level, which has the vertical elevation value of <NUM>. Other reference elevation levels may be used; for example, when the patient is placed supine within a retention structure, then the reference elevation level may be defined with respect to the retention structure. For instance, if the retention structure includes back plate <NUM> (of <FIG>) on which the patient's back is placed, then the reference elevation level may be midpoint <NUM> of the back plate, and the vertical axis corresponds to axis <NUM>. Or, the reference elevation level may be another effective level if the retention structure cradles the patent's torso also from the sides, etc..

In diagram <NUM>, torso cross-sections <NUM>-A and <NUM>-B are shown supine on the ground, or on a back plate, at times T1, T2, respectively. A sample compression mechanism <NUM> includes a piston <NUM>, although a different compression mechanism <NUM> may be used.

The height of the patient's chest may be measured from the top part of the torso when the patient is supine. The patient's chest may have a resting height above the reference elevation level. The resting height can be determinable at a moment when none of the compressions is being performed by the CPR machine.

At time T1, piston <NUM> merely contacts torso cross-section <NUM>-A at the top, without a compression being performed. The bottom of piston <NUM> is at elevation level EAGO, which is sometimes called the zero point or zero position of the travel. The travel is also known as stroke and displacement. The chest resting height is thus at EAGO.

At time T2, compression mechanism <NUM> is performing a compression, which means that piston <NUM> presses into torso cross-section <NUM>-B. The chest now is compressed, and has an elevation level EAG1 that is less than EAGO.

In embodiments where the compression mechanism is caused to repeatedly perform the compressions and the releases, the positions of times T1 and T2 would alternate repeatedly. In diagram <NUM>, a minor vertical axis <NUM> indicates depth, meaning depth of compressions. Its zero point is level EAGO of the major vertical axis. Compression depth may be measured downward from the resting height in the minor vertical axis. At time T1 the depth is <NUM>. At time T2 the depth is D1. Depth D1 can be <NUM>, <NUM>, <NUM>, the maximum depth reached that is also known as the full depth (FD), etc..

In such embodiments, the force sensing system can be configured to sense an amount of a compression force exerted by the driver system when the chest has been compressed downward by a certain amount from the resting height, for example at least <NUM>.

An example is shown in a diagram <NUM> of <FIG>, where sensing is at more points. The horizontal axis measures, in the direction to the left, the chest depth reached. Similarly, in diagram <NUM>, a minor vertical axis <NUM> measures, in a downward direction, the chest depth reached. In diagram <NUM> the vertical axis measures, in a downward direction, the compression force that is sensed by force sensing system <NUM>. The origin of diagram <NUM> corresponds to time T1. As time passes, the force increases during a compression. At time T2, as the depth has become D1, the force has become F1. The more time passes thereafter, the more force is sensed. A line <NUM> is plotted accordingly, during the compression. The force can be measured for one or more points in the travel, and inferred for others, to arrive at line <NUM>. Inferring for points of interest may be performed, for example, by interpolation. (It should be noted that line <NUM> might not be repeated for a release. Indeed, if the release of piston <NUM> is faster than the decompressing speed of the chest, no force will be measured, and a different line may be traced in diagram <NUM>.

In such embodiments, the motion-time profile may be adjusted in view of the sensed amount of the compression force. An adjustment may be made if the sensed amount of the compression force represents a surprise, for example it is unexpected upon starting, or has changed since starting, etc..

Such an adjustment to the motion-time profile may be performed in a number of ways. Examples are now described where the motion-time profile is adjusted by changing a maximum depth, but other parameters can change, such as frequency, etc..

In some embodiments, the motion-time profile includes a maximum depth below the resting height, to which the chest is compressed. In such embodiments, the motion-time profile can be adjusted by adjusting the maximum depth. For example, the maximum depth may be adjusted according to the sensed amount of the compression force. The sensed amount of the compression force may communicate information about the current state of the patient that is thus taken into account. In some instances, the maximum depth may be determined by compressing the chest downward until the sensed amount of the compression force meets a compression force threshold. Such would ensure that the same force is applied to all compressions, and the maximum depth is thus determined ultimately by the patient's chest at the time.

Attention is now drawn to line <NUM>. In <FIG> it is shown as linear, but that need not be the case. In embodiments, an alert condition can be met if line <NUM> differs from what is expected, or changes while the compressions are taking place. In embodiments, a user interface such as user interface <NUM> can be configured to emit an alert, if the sensed amount of the compression force meets the alert condition. The alert condition may indicate situations for which alerting is advised, such as the compressions reaching too deeply, one or more ribs breaking, the patient migrating with respect to the retention structure, or the resting height changing as the patient's chest loses its compactness due to the compressions. The alert can be an audio warning or prompt, visual indicators, and so on. Individual examples are now described for these conditions.

<FIG> is another composite diagram, for illustrating embodiments where compression depth may be adjusted. At the bottom is a diagram <NUM> with a horizontal time axis, a major vertical axis indicating elevation above ground, and a minor vertical axis <NUM> indicating compression depth, similarly with diagram <NUM>. The motion-time profile below EAGO is shown for two groups <NUM>, <NUM> of compressions. These compressions are shaped substantially as sinusoids, although they could be shaped otherwise such as square waves, triangles, etc..

The compressions of group <NUM> reach a maximum compression depth D4. Different examples of alert conditions are now described, arising from differences in what was shown in diagram <NUM>.

In <FIG>, there are also diagrams <NUM>, <NUM>. Their vertical axes measure, in a downward direction, the sensed compression force. Their horizontal axes measure, in a direction to the left, the chest depth reached.

COMPRESSIONS TOO DEEP: As seen in diagram <NUM>, the sensed amount of the compression force is plotted as a line <NUM> that is different from line <NUM>. In other words, the sensed amount of the compression force is different from what was expected, or from what was previously sensed in the same session. Line <NUM> may indicate that, past some depth, resistance to compressions increases very much, and the extra compression depth is likely not helpful. As a result of detecting that compressions attempt to go too deeply, the maximum depth for subsequent compressions group <NUM> has been adjusted to a shallower value D3. An approximate value of D3 is also seen in diagram <NUM>.

RIBS POSSIBLY BREAKING or PATIENT POSSIBLY MIGRATING: As seen in diagram <NUM>, the sensed amount of the compression force is plotted as a line <NUM> that is different from line <NUM>. In other words, the sensed amount of the compression force is different from what was expected, or from what was previously sensed in the same session. Line <NUM> may indicate that, past some depth, resistance to compressions increases less per unit of depth reached. This is consistent with ribs unfortunately breaking, in the effort to save the patient's life. Or, it could be that the patient's body has migrated from the patient's sternum to soft abdominal tissue. As a result, subsequent compressions group <NUM> may have a shallower maximum depth D3.

In some embodiments, if the sensed amount of the compression force meets an alert condition, the motion-time profile is adjusted by discontinuing driving the compression mechanism. For example, when it is detected that the patient could have migrated, operation may thus stop, instead of being adjusted as shown in <FIG>.

<FIG> is a composite diagram similar to that of <FIG>, but for illustrating embodiments where an adjustment can be made for diminished chest resting height. <FIG> has a diagram <NUM> measuring the same quantities as diagram <NUM>, and a diagram <NUM> measuring the same quantities as diagram <NUM>.

CHEST LOSING COMPACTNESS: As seen in diagram <NUM>, the compressions of a group <NUM> start from the initially determined chest resting height (EAGO), and reach a maximum compression depth D5, measured on minor axis <NUM>. As seen in diagram <NUM>, the sensed amount of the compression force is plotted as a line <NUM> that is different from line <NUM>. In other words, the sensed amount of the compression force is different from what was expected, or from what was previously sensed in the same session. This could indicate that the resting height has changed, and it is now lower, at depth D2. This change can happen because the chest may lose its compactness, and start breaking down, due to the chest compressions.

The resting height lowering means that the compressions of group <NUM>, which start from the earlier-determined chest resting height EAGO, now impact the chest as their depth crosses the value of D2. In embodiments, the resting height is determined at a first time instant, such as at the beginning of a session with the patient. The resting height may then be determined from an output of the force sensing system at a second time instant, which occurs after a set of the compressions and the releases has been performed after the first time instant. The resting height in the second instant may be updated from what was determined in the first instant. In the example of diagram <NUM>, the updated resting height is thus determined, after compressions group <NUM>, to be at D2. In such embodiments, the motion-time profile can be adjusted in view of the resting height determined at the second time instant. In the example of <FIG>, the motion-time profile is adjusted by setting the new resting height at D2, or EAG2, and thus resetting the zero point of the CPR machine to a new value.

The updated resting height may be discovered also in different ways. The CPR machine may pause occasionally, and search for it, for example with small oscillations.

In some embodiments, a force value is stored in memory <NUM>. The force value may encode the sensed amount of the compression force, especially if an alert condition has been met. The force value can be of one point, or many, such as in creating line <NUM>. In some embodiments, communication module <NUM> is configured to communicate the force value.

All of the above describes only a compression portion of an operation of a CPR machine according to embodiments. All of the above may be taking place with or without lifting the chest, for example as described below.

In some embodiments, a CPR machine additionally includes a chest-lifting device. Such a chest-lifting device can be configured to lift the chest, preferably faster than the chest would be lifted unassisted, during its decompression. Sample embodiments of a chest-lifting device are a suction cup, one or more tethers, one or more inflatable bladders, a component with an adhesive material, a combination of such devices, and so on. In the example of <FIG>, a generic chest-lifting device <NUM> is shown. In some of these embodiments, lifting is performed by operating in reverse the compression mechanism, such as raising a piston.

In such embodiments, the driver system may be further configured to drive the chest-lifting device according to the motion-time profile so as to cause the chest-lifting device to lift the chest. Lifting can be performed at least while none of the compressions is being performed. In embodiments, the chest is thus lifted during one or more of the releases. Lifting will be understood with respect to a suitable vertical level while the patient is retained within the CPR machine, such as the reference elevation level or other level.

Lifting can be by any amount from where the chest is at the time. For example, lifting may take place because the lifting mechanism thus lifts the chest faster than how fast the chest would naturally decompress without assistance. In addition, the chest-lifting device may lift the chest above the resting height, by <NUM>, or more.

In such embodiments, the force sensing system is further configured to sense an amount of a lifting force that is exerted by the chest-lifting device, while the chest-lifting device is thus lifting the chest. At least what was written above for the force sensing system sensing the compression force may be implemented also for sensing the amount of the lifting force.

In embodiments that include such a chest-lifting device, the motion-time profile may be adjusted in view of the sensed amount of the lifting force, instead of the sensed amount of the compression force. Or, the motion-time profile may be adjusted in view of the sensed amount of the lifting force in addition to the sensed amount of the compression force.

In some embodiments, the chest-lifting device is coupled to the compression mechanism. In such embodiments, the sensed amount of the lifting force is an amount of force exerted by the driver system.

It will be recognized that diagram <NUM> is inadequate for showing lifting to heights above the resting height, and also for showing corresponding forces at such heights. A more complex diagram is now employed for this purpose.

<FIG> is a composite diagram similar to that of <FIG>, for the purpose of discussing embodiments where the chest is compressed and actively decompressed. <FIG>, diagram <NUM> has axes that are similar to those of diagrams <NUM>, <NUM>, <NUM>, but they extend beyond the origin. In particular, the vertical axis indicates, in the upward direction the sensed lifting force. Moreover, the horizontal axis indicates, in the right direction, the chest height reached above the chest resting height.

<FIG>, diagram <NUM> shows has a major vertical axis indicating the elevation above ground, and a major time axis. In addition, it has a minor vertical axis <NUM> indicating depth of chest compression, and height of active decompression. In diagram <NUM> cross-sections <NUM>-A, <NUM>-B, <NUM>-C, <NUM>-D of a torso are shown at times T1, T2, T3, T4, respectively. A sample compression mechanism <NUM> includes a piston <NUM>, although the compression mechanism may be implemented differently. In the example of diagram <NUM>, compression mechanism <NUM> also includes a chest-lifting suction cup <NUM>, which is adhered to the bottom of piston <NUM> and to the chest of the patient.

At time T1, piston <NUM> merely contacts torso cross-section <NUM>-A at the top, without a compression being performed. The bottom of piston <NUM> is at elevation level EAGO. The chest resting height is thus at EAGO. Similarly, at time T3, piston <NUM> contacts torso cross-section <NUM>-C at the top, without a compression being performed.

At time T2, compression mechanism <NUM> is performing a compression, which means that piston <NUM> compresses torso cross-section <NUM>-B. The chest now is compressed, and has an elevation level EAG1 that is lower than EAGO. On the minor height axis, this corresponds to depth D1.

At time T4, chest-lifting suction cup <NUM> is lifting the chest, which is as shown in torso cross-section <NUM>-D. The chest is at an elevation level EAG2 that is higher than EAGO, i.e. higher than the resting height. On the minor height axis, this corresponds to height H2.

In embodiments where the compression mechanism is caused to repeatedly perform the compressions and the releases, the torso cross-sections could be rotating among the positions shown at times T1, T2, T3, T4. In these cases, however, there could be forces exerted also during times T1 and T3. In particular, at time T3 the lifting of the chest could be faster than the speed with which the chest would be naturally increasing in height, if it were decompressing without assistance from its compressed state of time T2. And at time T1 the compression could be faster than the speed with which the chest would be naturally losing height from the lifted state of time T4, if it were recovering without assistance.

In diagram <NUM>, line <NUM> could be the same as line <NUM>. It should be remembered that the upward lifting force could be measured for height values that are below the chest resting height.

As mentioned above, operation of the CPR machine may cause the torso cross-sections to rotate through the states shown at times T1, T2, T3, T4. Seen in diagram <NUM>, the measured compression and lifting forces may trace back and forth the composite line made from lines <NUM>, <NUM>. Or one or both of lines <NUM>, <NUM> could be part of a lobe that is being traced, which is different for the phase of downward motion than the upward motion.

In such embodiments, the motion-time profile may be adjusted in view of the sensed amount of the lifting force, or the compression force, if there is a surprise or irregularity. The sensed amount of the lifting force may communicate information about the current state of the patient that is thus taken into account.

This adjustment of the motion-time profile may be performed in a number of ways. Examples are now described where the motion-time profile includes a maximum height above the reference elevation level, to which the chest is lifted. In such embodiments the motion-time profile can be adjusted by adjusting the maximum height, but other parameters can also change.

In some instances, the maximum height may be determined by lifting the chest until the sensed amount of the lifting force meets a lifting force threshold. The lifting force threshold can be determined from the sensed amount of the compression force, or another way.

<FIG> is a diagram <NUM> similar to diagram <NUM> of <FIG>, for illustrating embodiments where the maximum height of decompression can be adjusted. Two groups <NUM>, <NUM> of cycles are shown. In each cycle of group <NUM> there is a compression <NUM> followed by a release, a lifting <NUM> above EAGO followed by a release, and an optional pause <NUM>, that helps determine the duty cycle. The compressions <NUM> with their releases below EAGO are shaped substantially as sinusoids in this example.

Liftings <NUM> in group <NUM> reach a maximum height H1, seen in minor vertical axis <NUM>. Different examples of alert conditions are now described, arising from differences in what was shown in diagram <NUM>.

REACHING THE "CEILING": The sensed amount of the lifting force may indicate that, past some height, resistance to lifting increases very much. This threshold height can be called the "ceiling. " As a result of detecting that too-high a lifting is attempted, the maximum height reached by the liftings of subsequent group <NUM> has been adjusted to a lower value, for example H2.

In some embodiments, the motion-time profile is adjusted by discontinuing driving the lifting mechanism, if the sensed amount of the lifting force meets a stop condition. An example is now described.

CHEST-LIFTING DEVICE DETACHED: <FIG> is a diagram <NUM> that is similar to diagram <NUM> of <FIG>, but instead for illustrating embodiments where there may be detachment. Two groups <NUM>, <NUM> of cycles are shown. In each cycle of group <NUM> there is a compression <NUM> followed by a release, a lifting <NUM> above EAGO followed by a release, and an optional pause <NUM>. The compressions <NUM> with their releases below EAG0 are shaped substantially as sinusoids in this example. The sensed amount of the lifting force may indicate that the chest-lifting device has become detached. For instance, the sensed amount of the lifting force attributable to active decompression could be <NUM> for times between T2 and T4 of <FIG>. As a result of detecting the detachment, the liftings are not continued. In subsequent group <NUM>, each cycle includes only a compression <NUM> followed by a release, and the optional pause <NUM>.

PATIENT's WHOLE BODY BEING LIFTED: The sensed amount of the lifting force may indicate that the patient is being lifted. For example, if the lifting force remains constant while there is still upward displacement, it may indicate that the patient is being lifted off of the backboard (perhaps because the patient is lightweight) rather than the patient's chest being expanded.

Adjustments of the motion-time profile may involve the frequency of the chest compressions. For example, with a "slow" waveform, the heart may be filled with more blood, perhaps requiring a larger compression force and a smaller lifting force than when the heart is less filled with blood. Conversely, a fast waveform may serve to "empty" the heart, in which it may be more effective to have a smaller compression force but a larger lifting force.

In some embodiments, the choice of how to respond is programmed in the CPR machine. In some embodiments, the choice can be made by a user, for example via a User Interface. The user can be a medical director in setting the parameters of the machine, or a rescuer in the field. Additional measures may be taken. For example, in some embodiments, a user interface is configured to emit an alert, if the sensed amount of the lifting force meets an alert condition. Upon perceiving the alert, a rescuer may pause the CPR machine and make adjustments. Adjustments may include, in addition, changing the timing of ventilation that might be affecting intra-thoracic pressure.

<FIG> shows a flowchart <NUM> for describing methods according to embodiments. The methods of flowchart <NUM> may also be practiced by embodiments described elsewhere in this document, such as CPR machines, storage media, etc. In addition, the operations of flowchart <NUM> may be enriched by the variations and details described elsewhere in this document.

According to an operation <NUM>, a compression mechanism is driven automatically according to a motion-time profile. Driving can be performed by a driver system, and may cause the compression mechanism to repeatedly perform compressions and releases. At least two of the compressions may thus compress a patient's chest by at least <NUM> downward from its resting height.

According to another operation <NUM>, an amount of a compression force exerted by the driver system may be sensed. Such sensing may take place when the chest is compressed downward, by any amount of travel from the resting height, such as <NUM>, longer, etc..

According to another, optional operation <NUM>, it is determined whether the sensed amount of the compression force meets an alert condition. If so, then according to another, optional operation <NUM>, an alert is emitted via the user interface.

Even if, at operation <NUM>, it is not determined that the alert condition has been met, then according to another operation <NUM>, the motion-time profile can be adjusted, for example if there is a surprise as mentioned above. Adjustment can be performed in a number of ways, such as in view of the sensed amount of the compression force, or a sensed amount of a lifting force as sensed in the later described operation <NUM>, both such forces, etc..

In some embodiments, after operation <NUM>, execution returns to operation <NUM>. Additional operations are possible in embodiments where the CPR machine further includes a chest-lifting device. For example, according to another, optional operation <NUM>, the chest-lifting device can be driven according to the motion-time profile. Such driving can be by the driver system, and can cause the chest-lifting device to lift the chest, especially while none of the compressions is being performed.

According to another, optional operation <NUM>, an amount of a lifting force can be sensed, which is exerted by the chest-lifting device while the chest-lifting device is thus lifting the chest. Such sensing may be performed by the force sensing system.

According to another, optional operation <NUM>, it is determined whether the sensed amount of the lifting force meets an alert condition. If not, then execution may return to operation <NUM>. If yes, then an alert can be emitted, for example according to operation <NUM>.

In some embodiments, a chest-lifting device is included and the driver system is configured to drive the compression mechanism automatically according to a motion-time profile, so as to cause the compression mechanism to perform repeatedly the compressions and the releases. The driver system may be further configured to concurrently drive the chest-lifting device according to the motion-time profile, so as to cause the chest-lifting device to lift the chest, especially while none of the compressions is being performed. In some embodiments, the chest is thus lifted during at least one of the releases. In fact, the chest-lifting device may be coupled to the compression mechanism. In some embodiments, the driver system is further configured to drive the chest-lifting device so as to cause the chest to be lifted above the resting height, by <NUM> or another distance.

In addition, the CPR machine may include a failure detector, which can be configured to detect if the chest-lifting device fails to thus lift the chest. Such a failure detector may be implemented in a number of ways. For example, the failure detector may include a force sensing system, such as described above. Other examples are now described.

<FIG> is a diagram of a sample compression mechanism <NUM>. Compression mechanism <NUM> is part of a CPR machine (not shown), and includes a piston <NUM> and a suction cup <NUM>. Compression mechanism <NUM> also includes a failure detector <NUM>.

Failure detector <NUM> may be a light sensor or photodetector, which thus senses either the ambient light (detachment), or less than that (attachment). In some embodiments, an LED is also provided so as to generate the light that is to be sensed.

Alternately, failure detector <NUM> may be an air pressure sensor, which thus senses either the atmospheric pressure (detachment), or less than that (attachment). If the lifting force does not exceed a threshold, it may be an indication that there is air in the suction cup, even though detachment may not have occurred, in which case the rescuer could be alerted. The rescuer might even apply adhesive between the suction cup and the chest, to improve adherence of the suction cup during active decompression. The adhesive can be adhesive material, a hydrocolloid dressing such as Duoderm® a double-sided adhesive tape or sticker, a pad that has adhesive on both sides, Velcro, etc. The adhesive may prevent migration, i.e., movement or "walking" of the piston down the patient's chest toward the patient's abdomen during the operation of the CPR machine.

<FIG> is a diagram of a sample compression mechanism <NUM>. Compression mechanism <NUM> is part of a CPR machine (not shown), and includes a piston <NUM> and a pad <NUM> with adhesive material. Compression mechanism <NUM> also includes a failure detector <NUM>. Failure detector <NUM> may be a contact pressure sensor, a capacitance meter, or a proximity detector, configured similarly to the examples described above.

In embodiments that include a failure detector, as the driver system drives according to a motion-time profile, this motion-time profile may be adjusted, responsive to the failure detector detecting that the chest-lifting device fails to thus lift the chest. There is a number of ways of making this adjustment. For example, the motion-time profile may include a maximum height above the reference elevation level at which the chest-lifting device lifts the chest, and the motion-time profile can be adjusted by adjusting the maximum height, or by stopping driving the chest-lifting device, for example as seen in <FIG>.

According to an operation <NUM>, a compression mechanism is driven automatically according to a motion-time profile, and a chest-lifting device is concurrently driven according to the motion-time profile. Driving can be performed by a driver system, and may cause the compression mechanism to repeatedly perform compressions and releases. At least two of the compressions may thus compress a patient's chest by at least <NUM> downward from its resting height. Driving may further cause the chest-lifting device to lift the chest while none of the compressions is being performed.

According to another, optional operation <NUM>, it is detected whether the chest-lifting device subsequently fails to thus lift the chest. Detecting may be performed by the failure detector. If not, then execution may return to operation <NUM>.

If yes, then according to another operation <NUM>, the motion-time profile may be adjusted. Adjustment can be responsive to detecting that the chest-lifting device fails to thus lift the chest, for example as seen above.

In embodiments of CPR machines that include a failure detector, the CPR machine may further include an electronic component, examples of which were seen in <FIG>. The electronic component can be configured to take an action responsive to the failure detector detecting that the chest-lifting device fails to thus lift the chest. Examples are now described.

The electronic component can be user interface <NUM>. The action can be that user interface <NUM> emits an alert.

The electronic component can be memory <NUM>. The action can be that a record is stored in memory <NUM> of an event that the chest is not lifted by at least <NUM> above the resting height.

The electronic component can be communication module <NUM>. The action can be that communication module <NUM> transmits a message about the chest not being lifted by at least <NUM> above the resting height.

According to an operation <NUM>, a compression mechanism is driven automatically according to a motion-time profile, and a chest-lifting device is driven concurrently according to the motion-time profile. Driving can be performed by a driver system, and may cause the compression mechanism to repeatedly perform compressions and releases. At least two of the compressions may thus compress a patient's chest by at least <NUM> downward from its resting height. Driving may further cause the chest-lifting device to lift the chest while none of the compressions is being performed.

If yes, then according to another operation <NUM>, an action may be taken via an electronic component. The action may be taken responsive to detecting that the chest-lifting device fails to thus lift the chest. Examples of such components and corresponding actions are given above.

In some embodiments, the CPR machine has a retention structure and a tether coupled to the retention structure. The tether may lift the chest when the compressions are not being performed. Examples are now described.

<FIG> is a diagram <NUM> of only some of the components of a sample CPR machine according to embodiments. The CPR machine may include a retention structure, in which the patient may be placed supine. Of the retention structure, only a backboard <NUM> is shown for simplicity. While backboard <NUM> is shown as flat, sometimes it may be curved so that its ends may be slightly higher than the middle portion.

The components additionally include a compression mechanism <NUM> coupled to the retention structure. Compression mechanism <NUM> is shown generically, and it could be a piston, a squeezing belt, and so on. In diagram <NUM>, a compression is being performed on the patient, for example as in moment T2 of <FIG>. In diagram <NUM>, the torso cross-section is <NUM>-B. As seen from a vertical depth axis <NUM>, the chest is being compressed from the resting height D0 to a depth D1.

The components further include a chest-lifting tether, which is also sometimes called simply a tether. In the example of <FIG>, the chest-lifting tether is provided in two tether segments <NUM>. The chest-lifting tether may be coupled to the retention structure. In the example of <FIG>, chest-lifting tether segments <NUM> are coupled to backboard <NUM> at respective junctions <NUM>.

The tether is configured to lift the chest, as will be explained below. In some embodiments, a substantially rigid member is attached to the tether, to assist with the lifting. The remainder of how tether segments <NUM> are coupled to the retention structure is not shown because diagram <NUM> is only generic.

The components moreover include a driver system <NUM>. Driver system <NUM> can be configured to drive compression mechanism <NUM> automatically, so as to cause the compression mechanism to repeatedly perform compressions and releases, as has been described above. Driver system <NUM> can be further configured to drive the chest-lifting tether concurrently with driving compression mechanism <NUM>. Driving the chest-lifting tether can be such as to cause the chest-lifting tether to lift the chest. This lifting may take place while none of the compressions is being performed, as seen immediately below.

<FIG> is a diagram <NUM> of the components of <FIG>. Diagram <NUM> is at a time when none of the compressions of <FIG> is being performed, for example as in moment T4 of <FIG>. In fact, the chest is thus lifted during one of the releases of compression mechanism <NUM>. In diagram <NUM>, the torso cross-section is <NUM>-D. As seen from a vertical depth axis <NUM>, the chest is being lifted to a height H2, which is above the resting height D0.

<FIG> is an example of embodiments where the chest-lifting tether lifts the chest by substantially biasing a side of the patient. It is also an example of embodiments where driver system <NUM> is configured to drive the chest-lifting tether so as to cause the chest to be lifted above resting height D0. Indeed, height H2 could be at least <NUM> above D0.

The chest-lifting tether may lift the chest in a number of ways. Two examples are now described that correspond to <FIG>.

<FIG> is a diagram <NUM> showing how the embodiments of <FIG> may be further implemented with a pulley. More particularly, <FIG> is a diagram <NUM> of only some of the components of a sample CPR machine according to an embodiment. The CPR machine may include a retention structure, of which only a backboard <NUM> is shown for simplicity. The components additionally include a compression mechanism <NUM> and a driver system <NUM>, which may operate similarly with what was written for compression mechanism <NUM> and driver system <NUM>.

The components further include a chest-lifting tether, which is provided in two tether segments <NUM>. Tether segments <NUM> are coupled to backboard <NUM> at respective junctions <NUM>.

The components additionally include at least one pulley that is configured to roll. In diagram <NUM> two pulleys <NUM> are shown. The chest-lifting tether is partially wrapped around pulleys <NUM>.

Driving the chest-lifting tether, which may be performed by driver system <NUM>, includes rolling pulleys <NUM>, which lifts the chest. In diagram <NUM>, the torso cross-section is <NUM>-D. As seen from a vertical depth axis <NUM>, the chest is thus lifted to a height H3, which is above the resting height D0. During compressions, pulleys <NUM> are rolled in the opposite direction, which releases tether segments <NUM> and permits the patient to be lowered.

<FIG> is a diagram <NUM> showing how the embodiments of <FIG> may be further implemented. More particularly, <FIG> is a diagram <NUM> of only some of the components of a sample CPR machine according to an embodiment. The CPR machine may include a retention structure, of which only a backboard <NUM> is shown. The components additionally include a compression mechanism <NUM>, which is a piston <NUM> that can perform compressions. It will be understood that the piston may have a termination at the bottom that is suitable for contacting the patient's chest during the compressions, but such is not shown for simplicity. The components moreover include a driver system <NUM>, which can drive piston <NUM> similarly with what was written for compressions.

The components further include a chest-lifting tether, which is provided in two tether segments <NUM>. Tether segments <NUM> are coupled to backboard <NUM> at respective junctions <NUM>. In <FIG>, the chest-lifting tether is coupled to compression mechanism <NUM>.

Driving the chest-lifting tether, which may be performed by driver system <NUM>, includes driving compression mechanism <NUM> upwards with enough lifting force to lift tether segments <NUM>. In other words, piston <NUM> is driven in reverse. When lifted this way, tether segments <NUM> in turn lift the patient during the releases of compression mechanism <NUM>. In diagram <NUM>, the torso cross-section is <NUM>-D. As seen from a vertical depth axis <NUM>, the chest is thus lifted to a height H4, which is above the resting height D0. During compressions, tether segments <NUM> are automatically lowered.

In the above embodiments, during compressions the tether may be slack, or not. Having the tether not be slack may advantageously increase the intra-thoracic pressure.

In some embodiments, the CPR machine has a retention structure, a chest-lifting inflatable bladder coupled to the retention structure, and a fluid pump configured to inflate the bladder. Inflating the bladder may lift the chest when the compressions are not being performed. Examples are now described.

<FIG> is a diagram <NUM> of only some of the components of a sample CPR machine according to embodiments. The CPR machine may include a retention structure <NUM>, in which the patient may be placed supine.

The components additionally include a compression mechanism <NUM> coupled to retention structure <NUM>. Compression mechanism <NUM> is shown generically, and it could be a piston, a squeezing belt, and so on. In diagram <NUM>, a compression is being performed on the patient, for example as in moment T2 of <FIG>. In diagram <NUM>, the torso cross-section is <NUM>-B. As seen from a vertical depth axis <NUM>, the chest is being compressed from the resting height D0 to a depth D5.

The components of <FIG> further include at least one chest-lifting bladder, which is coupled to retention structure <NUM>. In the example of diagram <NUM> two chest-lifting bladders <NUM>, <NUM> are provided. In the example of <FIG>, chest-lifting bladders <NUM>, <NUM> are coupled to retention structure <NUM> so that they contact the sides of patient's <NUM>-B torso.

The components additionally include a fluid pump <NUM>. Fluid pump <NUM> can be configured to inflate bladders <NUM>, <NUM> via a system of pipes <NUM>. It is understood that, for lifting the patient's chest, bladders <NUM>, <NUM> will be caused to be alternatingly inflated and deflated. Inflating can be with a fluid such as a liquid, air, or other gas from fluid pump <NUM>. If using a liquid, a reservoir may be further provided to store the fluid during the deflations.

The components of <FIG> moreover include a driver system <NUM>. Driver system <NUM> can be configured to drive compression mechanism <NUM> automatically, so as to cause the compression mechanism to repeatedly perform compressions and releases, as has been described above. Driver system <NUM> can be further configured to operate the fluid pump concurrently with driving compression mechanism <NUM>. Operating fluid pump <NUM> can be such as to cause fluid pump <NUM> to inflate chest-lifting bladders <NUM>, <NUM> so as to cause chest-lifting bladders <NUM>, <NUM> to lift the chest. In this example, bladder <NUM> is configured to operate substantially in unison with chest-lifting bladder <NUM>. This lifting may take place while none of the compressions is being performed, as seen immediately below.

<FIG> is a diagram <NUM> of the components of <FIG> is at a time when none of the compressions of <FIG> is being performed, for example as in moment T4 of <FIG>. In fact, the chest is thus lifted during one of the releases of compression mechanism <NUM>. In diagram <NUM>, the torso cross-section is <NUM>-D. As seen from vertical depth axis <NUM>, the chest is being lifted to a height H5, which is above the resting height D0. The chest is being thus lifted because chest-lifting bladders <NUM>, <NUM> have been inflated via fluid pump <NUM>, and are biasing the torso from the side.

<FIG> is an example of embodiments where chest-lifting bladders <NUM>, <NUM> lift the chest by substantially biasing a side of the patient. It is also an example of embodiments where driver system <NUM> is configured to drive chest-lifting bladders <NUM>, <NUM> so as to cause the chest to be lifted above resting height D0. Indeed, height H5 could be at least <NUM> above D0.

The chest may be lifted also in other ways, for example using a magnetic or ferrous metal tape or sticker adhesively applied to the chest of the patient, or a combination of both adhesive and magnetic materials. In magnetic embodiments, the suction cup could include a magnet that would attract the tape to improve the adherence of the suction cup during the liftings. In other embodiments, the piston would include an electromagnet to provide the attractive force to the tape.

A tape adhered to the patient's chest could have additional uses. For example, the tape may include a graphical indication for placement or positioning of the suction cup on the patient's chest. For instance, the graphical indication could be drawn as a target, include a circle slightly larger than the perimeter of the suction cup, have colors and other drawings, etc. The rescuer can apply the tape so that the target was properly positioned on the chest, and then position the patient within the retention structure so that the suction cup attaches to the patient according to the target.

In enhancements, the tape or sticker includes a defibrillation electrode pad, with the other defibrillation pad being arranged and configured on the back plate or in a lateral stabilization structure on the back plate.

In embodiments, the chest may be lifted between every pair of compressions, or not. In some embodiments, the chest might be lifted substantially fewer times than it is compressed. An example is now described.

<FIG> is a time diagram plotting elevation above ground over time, and shows the time evolution of two sets <NUM>, <NUM> of compressions. The chest is not lifted above the resting height EAGO, except for only one lifting <NUM> between sets <NUM>, <NUM>. Lifting <NUM> may correspond to occasional breaths that a rescuer is expected to deliver to a patient between sets of compressions. <FIG> is thus an example of where the chest is lifted only once while four successive compressions are performed, two from set <NUM> and two from set <NUM>. Lifting <NUM> may be to a height above the resting height.

The example of <FIG> may be implemented in a number of embodiments. For instance, a driver system can be configured to drive the compression mechanism and to drive the chest-lifting device so as to cause the chest to be lifted only occasionally. For example, lifting might be only once while four or more successive compressions are performed, even though the driver system could lift the chest between compressions without needing to perform the compressions more slowly. The chest-lifting device may be a tether, suction cup, or otherwise.

The example of <FIG> may be implemented well where the lifting mechanism needs more time to lift effectively than is provided within the space of two successive compressions. For instance, driver system <NUM> can be configured to drive compression mechanism <NUM> and to operate fluid pump <NUM> so as to cause the chest to be lifted only once while four or more successive compressions are performed. In other words, the motion-time profile need not generate liftings for every release from every compression.

In some embodiments, CPR machines lift the chest to the same height substantially every time. In other embodiments, however, they lift the chest to different heights. In the following examples, a CPR machine may have a compression mechanism, a chest-lifting device, and a driver system. The driver system can be configured to drive the compression mechanism automatically according to a motion-time profile as also described previously. The driver system can be further configured to concurrently drive the chest-lifting device according to the motion-time profile.

Driving the compression mechanism and the chest-lifting device according to the motion-time profile can cause the chest-lifting device to lift the chest to different heights. In some of these embodiments these heights increase progressively from smaller heights to larger heights, so as to stretch the torso gradually. For example, if one focuses on a certain two of the compressions, driving the chest-lifting device according to the motion-time profile may cause the chest-lifting device to:.

Examples are now described, where the liftings of the chest can be characterized in terms of when they occur with respect to the compressions, and especially with respect to the certain two compressions. In some instances, the certain two compressions are successive, in others not. In some instances the chest is lifted additional times between when it is lifted to the first height and when it is lifted to the second height. In other instances, it is not.

<FIG> is a time diagram of a sample motion-time profile <NUM>, for illustrating embodiments where the chest is lifted to ascending heights between compressions. In the vertical axis, the positive upward pointing semi-axis indicates height above the resting height, while the negative downward pointing semi-axis indicates compression depth.

In <FIG>, compressions <NUM>, <NUM>, <NUM>,. all reach substantially the same depth. Compressions <NUM>, <NUM> may be considered to be the certain two compressions. The chest is lifted above the resting height (<NUM>) in liftings <NUM>, <NUM>, <NUM>,. It will be appreciated that liftings <NUM>, <NUM>, <NUM> can reach heights that can be as described above for the first, second and third heights. Full height FH is reached for the first time at lifting <NUM>.

<FIG> is a time diagram of a sample motion-time profile <NUM>, with axes similar to those of <FIG>, for illustrating embodiments where the chest is lifted to ascending heights and compressed to descending depths. Compressions <NUM>, <NUM>, <NUM>, reach progressively deeper depths, which may reduce reperfusion injury. Any two of them may be considered to be the certain two compressions. The depths are called descending because they reach progressively lower; in fact, their magnitudes are progressively increasing.

In <FIG>, the chest is lifted above the resting height (<NUM>) in liftings <NUM>, <NUM>, <NUM>,. Liftings <NUM>, <NUM>, <NUM> can reach heights that can be as described above for the first, second and third heights. Full height FH is reached for the first time at lifting <NUM>.

<FIG> is a time diagram of a sample motion-time profile <NUM>, with axes similar to those of <FIG>, for illustrating embodiments where the chest is lifted to ascending heights and compressed to descending depths. The chest is lifted above the resting height (<NUM>) in liftings <NUM>, <NUM>, <NUM>,. Liftings <NUM>, <NUM>, <NUM> can reach heights that can be as described above for the first, second and third heights. Compressions <NUM>, <NUM>, <NUM>, reach progressively deeper depths, as in <FIG>, except that they start after the liftings have reached their full height FH.

Some of these features may be programmable if a user interface is provided. For example, the user interface can be configured to receive a configuration input, and one or more of the first, second and third heights may become adjusted responsive to the configuration input. For another example, the user interface can be configured to receive a cancel input, and the second and the third heights may become substantially the same responsive to the cancel input being received.

The first, second and third heights can be determined with reference to the resting height. In some embodiments, a value for the resting height is input, and the second height becomes determined in response to the input value for the resting height. The resting height may be detected, and the value for the resting height could be determined from the detection. The resting height could be detected before any of the compressions are performed.

<FIG> shows a flowchart <NUM> for describing methods according to embodiments. The methods of flowchart <NUM> may also be practiced by embodiments described elsewhere in this document, such as CPR machines that include a compression mechanism, a chest-lifting device and a driver system. In addition, the operations of flowchart <NUM> may be enriched by the variations and details described elsewhere in this document.

The operations of flowchart <NUM> may be performed by driving, for example via the driver system. Driving can be of the compression mechanism, automatically according to a motion-time profile. Such driving may cause the compression mechanism to perform at least a certain two compressions, of the type described above. Driving can also be of the chest-lifting device according to the motion-time profile, concurrently with driving the compression mechanism. Such driving may cause the chest to be compressed and lifted.

According to an operation <NUM>, the chest-lifting device may be driven so as to lift the chest to the first height. Operation <NUM> may take place before operations <NUM> and <NUM>.

According to other operations <NUM>, <NUM>, the compression mechanism may be driven so as to cause a first certain compression and a second certain compression, respectively.

According to another operation <NUM>, the chest-lifting device may be driven so as to lift the chest to a second height above the resting height. The second height can be at least <NUM>% higher than the first height. Operation <NUM> may take place between the certain two compressions of operations <NUM>, <NUM>.

According to another operation <NUM>, the chest-lifting device may be driven so as to lift the chest to a third height above the resting height. The third height can be at least <NUM>% higher than the second height. Operation <NUM> may take place after the certain two compressions of operations <NUM>, <NUM>.

In some embodiments, a CPR machine includes a height input port that is configured to receive a height input. The driver system can be configured to drive the compression mechanism and the chest-lifting device according to the motion-time profile as described previously. In addition, driving the chest-lifting device according to the motion-time profile may cause the chest-lifting device to lift the chest to a full height above the reference elevation level, and the full height may be determined from the received height input.

The height input port may be implemented in a number of ways. It can be external, for receiving data from outside the CPR machine. It can be part of a user interface. It can be internal, implemented within circuits. In some embodiments, a user interface may be provided, which can be configured to receive a patient input. The received height input may be determined from the received patient input. In some instances, the patient input is itself the height input.

<FIG> shows an example of a user interface <NUM> that may be provided for the operation of a CPR machine according to embodiments. User interface <NUM> has actuators <NUM>, <NUM>, <NUM>, which can be physical pushbuttons, buttons on a touchscreen, settings of a dial, and so on.

Actuator <NUM> can be labeled "AUTOMATIC MODE", and may control operational parameters in an AUTOMATIC MODE, of which only a set <NUM> is shown. In other words, if actuator <NUM> is actuated, then all the operational parameters are set in a single setting.

In the example of <FIG>, parameters <NUM> include whether prior compressions have been received by the patient (2251A), with a sample value of YES/NO; an amount of a delay to start lifting the chest after compressions start (as is explained later in this document) (2251B), with a sample value of <NUM> sec; the full height for lifting during active decompression (2251C), with a sample value of <NUM>, which can be the parameter described above; the time to achieve full height (2251D) if the heights are expected to increase progressively, with a sample value of <NUM> sec; the lifting waveform shape, whether sinusoidal (S-S), square, or other (2251E); and how often to lift, whether every <NUM> compression or more compressions than one (2251F), a YES/NO input as to whether a target compression depth/and or decompression height are to computed by the CPR machine (<NUM>) as described later; and a size value for the patient, such as estimated weight (<NUM>), if <NUM> is YES. It will be recognized that parameters <NUM> are mostly related to the operation of the chest-lifting device, while other parameters may deal with the compressions, the duty cycle, etc..

It will be recognized that these operational parameters control the motion-time profile. It will be further recognized that if the time to achieve the full height is <NUM> sec or longer, than the heights will progressively increase, and become the above described first, second and third heights. In addition, even the third height can be less than the full height, for example as was the case in <FIG>.

Returning to <FIG>, actuator <NUM> can be labeled "MANUAL MODE", and may control a set <NUM> of operational parameters in a MANUAL MODE, i.e. if actuator <NUM> is actuated, then each of the shown operational parameters 2251A-2251F may be set individually. Of course, a starting value may be proposed by the system, and so on.

Actuator <NUM> can be labeled "TURBO MODE", and may be used for a TURBO MODE, where parameters can be chosen to increase aggressively. Such may prove beneficial, for example if the patient does not seem to respond to standard protocols of CPR therapy under the AUTOMATIC MODE or the MANUAL MODE, and higher risks are thus justified.

The height input may be received in additional ways. For example, the resting height may be detected, and the received height input may be determined from the detected resting height. The resting height may be detected even before any of the compressions are performed.

According to an optional operation <NUM>, a height input may be received. The height input may be received by a height input port.

According to another operation <NUM>, the compression mechanism may be driven so as to cause the compression mechanism to perform a compression. The compression mechanism can be driven by the driver system.

According to another operation <NUM>, the chest-lifting device may be driven so as to cause the chest-lifting device to lift the chest to a full height above a reference elevation level. The full height may be determined from the received height input.

Execution may then return to operation <NUM>, and thus operations <NUM>, <NUM>, <NUM> may be performed repeatedly, automatically, according to a motion-time profile. If optional operation <NUM> is indeed performed and a new height input is thus received, then a subsequent execution of operation <NUM> may be performed to an updated full height that is determined from the received height input.

In some of embodiments, a chest-lifting device is included. The driver system is configured to drive the compression mechanism, and further to cause the chest-lifting device to lift the chest above its resting height. Lifting the chest may start after a lifting delay after the compressions from the compression mechanism have started being performed. The lifting delay may be part of the motion-time profile, for example as hinted in parameters <NUM>, while other parameters may be similar or different.

In such embodiments, the chest may be thus lifted by the chest-lifting device during at least one of the releases, even before the chest is lifted above the resting height. In some of these embodiments, the chest may be thus lifted above the resting height, for example by at least <NUM>. Examples are now described.

<FIG> is a time diagram <NUM>, which shows a motion-time profile with axes similar to those of <FIG>, for illustrating embodiments where a chest is compressed, and lifted but with a lifting delay. Compressions <NUM> are performed, starting at time <NUM>. In this example, all compressions <NUM> are of the same depth (FD), but that need not be the case; for example, the compressions could start by becoming progressively deeper until they reach full depth FD. In addition, liftings <NUM>, <NUM>, <NUM>, <NUM>,. start after a lifting delay <NUM>.

Lifting delay <NUM> may be beneficial because, at the beginning of a resuscitation session, if cardiac arrest has occurred a minute or more before beginning of compressions, or possibly if there has been a gap in compressions of at least <NUM>-<NUM> seconds, the right heart may have become distended. Since the active decompression component of CPR increases return of blood from the veins to the right heart, and since the right heart may be already over full at the beginning of compressions. Lifting delay <NUM> may be at least <NUM> sec, at least <NUM> sec, etc. Good values for it can be say, <NUM> to <NUM> seconds.

<FIG> is a time diagram <NUM>, which shows a motion-time profile with axes similar to those of <FIG>, for illustrating embodiments where a chest is compressed, and lifted but with a lifting delay. Compressions <NUM> are performed, starting at time <NUM>, and starting by becoming progressively deeper until they reach full depth FD. In addition, liftings <NUM>, <NUM>, <NUM>, <NUM>,. start after a lifting delay <NUM>.

In corresponding methods for a CPR machine, operations may include driving, via a driver system, a compression mechanism automatically according to a motion-time profile so as to cause the compression mechanism to repeatedly perform compressions and releases. At least two of the compressions thus compress the patient's chest by at least <NUM> downward from the resting height, similarly with other operations and methods in this description. Operations may further include concurrently driving a chest-lifting device according to the motion-time profile so as to cause, after a lifting delay after the compressions have started being performed, the chest-lifting device to lift the chest with respect to a reference elevation level while none of the compressions is being performed. The lifting delay can be as above.

CPR machines according to embodiments may further cooperate with ventilators, so as to synchronize the lifting of the chest by the chest-lifting device with an infusion of air by the ventilator. Examples are now described.

<FIG> is a diagram of components <NUM> of an abstracted CPR machine according to embodiments. The abstracted CPR machine can be configured to cooperate with a ventilator <NUM> according to embodiments.

Many of components <NUM> are similar to components <NUM> in <FIG>. More particularly, components <NUM> include a retention structure <NUM>, in which a patient <NUM> having a head <NUM> may be placed supine. Components <NUM> also include a compression mechanism <NUM>, a chest-lifting device <NUM>, a driver <NUM>, and a controller <NUM>. Controller <NUM> may include a processor <NUM> and a memory <NUM>, which stores programs <NUM> and data <NUM>. Components <NUM> may further include or cooperate with a communication module <NUM> and a user interface <NUM>.

Ventilator <NUM> includes a tube <NUM> coupled to the mouth of patient <NUM>. Ventilator <NUM> also includes a communication module that can establish a communication link <NUM> with communication module <NUM>. Communication link <NUM> may be wireless or wired, for example by connecting a cable. Signals (not shown) may be exchanged via communication link <NUM>. The CPR machine and ventilator <NUM> may cooperate, for example by one of them controlling the other, etc..

In embodiments, the CPR machine with components <NUM> is configured to operate in cooperation with ventilator <NUM>. Ventilator <NUM> can be configured to transmit ventilator signals in conjunction with biasing air into the mouth of patient <NUM> though tube <NUM>. These ventilator signals may communicate exactly when air is being biased, which results in an infusion or air, or breath. Ventilations can be timed to expand the chest during chest lifting, to reduce the required lifting force. In embodiments, the compressions and the liftings may be synchronized with the rate of the respirator. The compression force and the lifting force can be adjusted depending on whether the respirator has filled the patient lungs. Caution should be exercised in case the chest resting height becomes redefined if air has been pushed into the patient's lungs.

Driver system <NUM> can be further configured to drive chest-lifting device <NUM> in response to the received ventilator signals, so as to cause chest-lifting device <NUM> to lift the chest of patient <NUM> to a certain height above a reference elevation level. Lifting can be at a certain moment when the air is being biased into the patient's mouth.

Of course, the chest can be thus lifted at a time between two compressions. The chest can be thus lifted in advance of its decompression, and even above the resting height, for example by at least <NUM> above the resting height. In some embodiments, the certain height can even be determined from the ventilator signals.

In some embodiments, the ventilator is configured to receive timing signals from the CPR machine, and bias air accordingly. For example, in <FIG>, similarly to what was described previously, driver system <NUM> can be configured to drive chest-lifting device <NUM> so as to cause the chest-lifting device to lift the chest to a height above the reference elevation level. Lifting can be at a certain moment between when the certain two compressions are being performed. In addition, communication module <NUM> can be configured to transmit ventilator signals that indicate when the certain moment occurs.

<FIG> is a diagram of sample components <NUM> of a CPR machine intended for use with a patient <NUM>. Components <NUM> include a retention structure <NUM> that includes a back plate <NUM>. Back plate <NUM> has a midpoint <NUM>. Patient <NUM> may be placed supine on the plate <NUM>; when this happens, the chest of patient <NUM> thus has a resting height. The resting height can be measured on axis <NUM> as the distance between midpoint <NUM> and point RH27.

Components <NUM> also include a driver system <NUM>, and a piston <NUM> that is coupled to retention structure <NUM> via driver system <NUM>. Piston <NUM> is configured to perform, when driven by driver system <NUM>, compressions alternating with releases on the chest, while patient <NUM> is supine on back plate <NUM>. Piston <NUM> has a bottom end <NUM> that is configured to be coupled to patient <NUM> during the compressions. The coupling can be either by direct contact or via a chest lifting device. The resting height of the chest of patient <NUM> is determinable at a moment when none of the compressions is being performed.

Similarly with the description of prior embodiments, driver system <NUM> can be configured to drive piston <NUM> automatically, so as to cause piston <NUM> to repeatedly perform the compressions and the releases. The compressions thus compress the patient's chest to respective compression depths. These compression depths can be defined to be in a downward direction from the resting height. These depths may depend on a size of the patient, as is now described in more detail.

Components <NUM> additionally include a position sensor <NUM>. Position sensor <NUM> can be configured to detect a certain distance of bottom end <NUM> of piston <NUM> to midpoint <NUM> of back plate <NUM>. Accordingly, position sensor <NUM> has the opportunity to render a reading for the resting height of the chest. This resting height can be used as a reference, a "proxy", for the size of the patient's body; indeed, the larger the patient, the higher will be the resting height of their chest.

Position sensor <NUM> can be implemented in a number of ways. For example, where piston <NUM> is driven by driver system <NUM>, the position sensor need only measure the location of piston <NUM> relative to driver system <NUM>, because driver system <NUM> can be fixed relative to retention structure <NUM>. It is known how to do this location, for example when driver system <NUM> drives piston <NUM> by a rack and pinion mechanism, etc..

In embodiments, a nominal resting height value can be determined from the detected certain distance. Once determined, the nominal resting height value can be stored in a memory, and so on.

The nominal resting height value can be determined in a number of ways. For example, the CPR machine can further include an actuator, for instance as part of a user interface <NUM>. The actuator can be a physical switch, a key, an image that needs to be manipulated on a touchscreen, and so on. The actuator can configured to be actuated by a rescuer at a certain moment, and the certain distance can be detected at the certain moment. For example, a rescuer may manually lower piston <NUM>, until bottom end <NUM> touches patient <NUM> at point RH27. At that time, bottom end <NUM> will correspond to the resting height; either it will coincide with it, or it will have a fixed distance from it, for instance if a chest lifting device is included in piston <NUM>. At that certain moment, the rescuer may actuate the actuator, which signifies to the CPR machine that the detected certain distance corresponds to the resting height. The actuator can advantageously be implemented together with a "START COMPRESSIONS" button or another part of an interface.

For another example, the CPR machine can further include a force sensing system, for example as described elsewhere in this document. The force sensing system can be configured to sense an amount of a compression force exerted by driver system <NUM> during the compressions. The compression force will be due to the physical resistance that the chest of patient <NUM> will present to the compressions by piston <NUM>. In embodiments, the certain distance can be detected at a moment when the sensed amount of the compression force indicates that bottom end <NUM> is at the resting height of the chest, in other words, reached point RH27. For instance, as part of a session of delivering chest compressions, the CPR machine may lower automatically piston <NUM> from a fully retracted position. The initial lowering will initially encounter no resistance from the patient. The resistance will start once the patient's chest is reached at point RH27, which is how the sensed amount of the compression force may indicate that bottom end <NUM> is at the resting height of the chest.

<FIG> is a composite diagram made from individual diagrams <NUM>, <NUM> and <NUM>, which are bridged by thick curved arrows and horizontal dotted lines. Piston <NUM> is shown against axis <NUM> for two scenarios <NUM>, <NUM>. In scenario <NUM>, a smaller patient <NUM> has a resting height with a value RH1. Patient <NUM> receives compressions represented by a downward-pointing vector VCD1. In scenario <NUM>, a larger patient <NUM> has a resting height with a value RH2, which is larger than RH1. Patient <NUM> receives compressions represented by a downward-pointing vector VCD2, which has a magnitude larger than that of VCD1 because the compressions for patient <NUM> are deeper than for patient <NUM>.

In <FIG>, diagram <NUM> shows a possible relationship that can express different behaviors according to embodiments. The horizontal axis plots resting heights. The vertical axis plots compression depths, in a downward direction. Two points P1, P2 represent the behaviors at scenarios <NUM>, <NUM>, respectively, as indicated by the thick curved arrows. Values CD1 and CD2 are the numerical values of vectors VCD1, VCD2, respectively. For at least a certain range between points P1 and P2, increasing the resting height increases the compression depth. The increase may be linear as shown in the example of <FIG>, or otherwise. CD1 and CD2 may have suitable values, such as <NUM>, and <NUM>. It will be understood that such values are targets, and the actual depths of the compressions may have small statistical variations among them.

In embodiments, a resting height threshold may be chosen on the horizontal axis of diagram <NUM>, and a compression depth threshold can be chosen on its vertical axis. The depths of the compressions can be determined in terms of aggregate statistics. One such statistic can be to consider any four of any seven consecutive compressions. For example, the depths of the compressions can be such that, if the nominal resting height value is less than a resting height threshold, then an average depth of compression depths of at least four of any seven consecutive ones of the compressions can be less than a compression depth threshold. However, if the nominal resting height value is larger than the resting height threshold, then the average depth can be at least <NUM>% larger than the compression depth threshold, such as <NUM>% or even higher.

<FIG> shows a flowchart <NUM> for describing methods according to embodiments. The methods of flowchart <NUM> may also be practiced by embodiments described elsewhere in this document, such as CPR machines that include a retention structure with a back plate, a piston, a driver system, a position detector, etc. In addition, the operations of flowchart <NUM> may be enriched by the variations and details described elsewhere in this document.

According to an operation <NUM>, a certain distance of the bottom end of the piston to a midpoint of a back plate may be detected. Detecting may be performed by a position sensor.

According to another operation <NUM>, a nominal resting height value may be determined from the certain distance detected at operation <NUM>.

According to another operation <NUM>, the piston may be driven, by the driver system, automatically so as to cause the piston to repeatedly perform compressions and releases, the compressions thus compressing the patient's chest to respective compression depths. The compression depths may be as above.

<FIG> is a diagram of sample components <NUM> of a CPR machine intended for use with a patient <NUM>. Components <NUM> include a retention structure <NUM> that includes a back plate <NUM>. Back plate <NUM> has a midpoint <NUM>. Patient <NUM> may be placed supine on the plate <NUM>; when this happens, the chest of patient <NUM> thus has a resting height. The resting height can be measured on axis <NUM> as the distance between midpoint <NUM> and point RH30.

Components <NUM> also include a driver system <NUM>, and a piston <NUM> that is coupled to retention structure <NUM> via driver system <NUM>. Piston <NUM> is configured to perform, when driven by driver system <NUM>, compressions alternating with releases on the chest, while patient <NUM> is supine on back plate <NUM>.

Components <NUM> moreover include a chest-lifting device <NUM> coupled to piston <NUM>. In the particular example of <FIG>, chest-lifting device <NUM> is depicted as a suction cup, but other implementations are also possible. Piston <NUM> has a bottom end, to which suction cup <NUM> is attached, but that is not necessary. Indeed, other types of chest lifting devices might not attach to the bottom end of piston <NUM>. The bottom end of piston <NUM> can be configured to be coupled to patient <NUM> during the compressions. The coupling can be either by direct contact or via chest lifting device <NUM>. The resting height of the chest of patient <NUM> is determinable at a moment when none of the compressions is being performed.

Similarly with the description of prior embodiments, driver system <NUM> can be configured to drive piston <NUM> automatically, so as to cause piston <NUM> to repeatedly perform the compressions and the releases. Driver system <NUM> can be configured to further drive piston <NUM> so as to cause chest-lifting device <NUM> to lift the chest while none of the compressions is being performed. The chest can thus be lifted repeatedly to resulting heights above the resting height. These heights may depend on a size of the patient, as is now described in more detail.

Components <NUM> also include an input mechanism <NUM>. Input mechanism <NUM> can be configured to input a size value for a size of patient <NUM>, such as from a rescuer. Moreover, a nominal resting height value may be determined from the size value. This way, an adjustment in the height of the decompressions above the resting height can be made, which ultimately depends on the size of the patient.

The input mechanism may be implemented in a number of ways. In some embodiments, the CPR machine also includes a processor, such as a microprocessor, etc. The input mechanism can further include a user interface, such as user interface <NUM>. The user interface can be configured to input the size value from a rescuer. An example was seen with reference to <FIG>, where a size value for the patient <NUM> is <NUM>. The processor can be configured to compute a target height from the size value, for example by a computation, looking up a table, and so on. Accordingly, the average height can be within <NUM>%, or even within <NUM>%, of the target height.

In other embodiments, the input mechanism includes a position sensor such as was described above. The position sensor may detect a certain distance of the bottom end of the piston to the midpoint of the back plate, and the size value can be determined from the certain distance. There can be an actuator, or a force sensing system, etc., as described above.

<FIG> is a composite diagram made from individual diagrams <NUM>, <NUM> and <NUM>, which are bridged by thick curved arrows and horizontal dotted lines. Piston <NUM> is shown against axis <NUM> for two scenarios <NUM>, <NUM>. In scenario <NUM>, a smaller patient <NUM> has a resting height with a value RH3. Patient <NUM> receives compressions, and is also lifted above resting height RH3. These liftings are represented by an upward-pointing vector VLH1. In scenario <NUM>, a larger patient <NUM> has a resting height with a value RH4, which is larger than RH3. Patient <NUM> receives compressions, and is also lifted above resting height RH4. These liftings are represented by an upward-pointing vector VLH2, which has a magnitude larger than that of VLH1 because the liftings for patient <NUM> are higher than for patient <NUM>.

In <FIG>, diagram <NUM> shows a possible relationship that can express different behaviors according to embodiments. The horizontal axis plots resting heights. The vertical axis plots lifting heights that result from the liftings, above the resting height. Two points L1, L2 represent the behaviors at scenarios <NUM>, <NUM>, respectively, as indicated by the thick curved arrows. Values LH1 and LH2 are the numerical values of vectors VLH1, VLH2, respectively. For at least a certain range between points L1 and L2, increasing the resting height increases the height of the liftings above the resting height. The increase may be linear as shown in the example of <FIG>, or otherwise. LH1 and LH2 may have suitable values, such as <NUM>, and <NUM>.

In embodiments, a resting height threshold may be chosen on the horizontal axis of diagram <NUM>, and a lifting height threshold can be chosen on its vertical axis. The resulting heights can be determined in terms of aggregate statistics. One such statistic can be to consider any four of any seven consecutive times the chest is lifted. For example, the heights resulting from thus lifting the chest are such that, if the nominal resting height value is less than a resting height threshold, then an average height of heights resulting from thus lifting the chest at least four of any seven consecutive times can be less than a lifting height threshold. However, if the nominal resting height value is larger than the resting height threshold, then the average height is at least <NUM>% larger than the lifting height threshold, or even larger, such as <NUM>% larger.

<FIG> shows a flowchart <NUM> for describing methods according to embodiments. The methods of flowchart <NUM> may also be practiced by embodiments described elsewhere in this document, such as CPR machines that include a retention structure with a back plate, a piston, a chest-lifting device, a driver system, an input mechanism, etc. In addition, the operations of flowchart <NUM> may be enriched by the variations and details described elsewhere in this document.

According to an operation <NUM>, a size value for a size of the patient may be input. Inputting can be, for example, via the input mechanism by a rescuer using the CPR machine.

According to another operation <NUM>, a nominal resting height value may be determined from the size value that was input at operation <NUM>.

According to another operation <NUM>, the piston may be driven, by the driver system, automatically so as to cause the piston to repeatedly perform compressions and releases, and to further drive the piston so as to cause the chest-lifting device to lift the chest while none of the compressions is being performed. The chest can thus be lifted repeatedly to resulting heights above the resting height. The resulting heights may be as above.

In the methods described above, each operation can be performed as an affirmative step of doing, or causing to happen, what is written that can take place. Such doing or causing to happen can be by the whole system or device, or just one or more components of it. In addition, the order of operations is not constrained to what is shown, and different orders may be possible according to different embodiments. Moreover, in certain embodiments, new operations may be added, or individual operations may be modified or deleted. The added operations can be, for example, from what is mentioned while primarily describing a different system, apparatus, device or method.

A person skilled in the art will be able to practice the present invention in view of this description, which is to be taken as a whole. Details have been included to provide a thorough understanding. In other instances, well-known aspects have not been described, in order to not obscure unnecessarily the present invention.

This description includes one or more examples, but that does not limit how the invention may be practiced. Indeed, examples or embodiments of the invention may be practiced according to what is described, or yet differently, and also in conjunction with other present or future technologies.

In this document, the phrases "constructed to" and/or "configured to" denote one or more actual states of construction and/or configuration that is fundamentally tied to physical characteristics of the element or feature preceding these phrases and, as such, reach well beyond merely describing an intended use. Any such elements or features can be implemented in any number of ways, as will be apparent to a person skilled in the art after reviewing the present disclosure, beyond any examples shown in this document.

Claim 1:
A Cardio-Pulmonary Resuscitation ("CPR") machine configured to perform chest compressions on a chest of a patient, the chest having a resting height relative to a reference level, the resting height measured when no chest compressions are being performed, the CPR machine comprising:
a compression mechanism (<NUM>, <NUM>, <NUM>,<NUM>);
a chest-lifting device (<NUM>, <NUM>) configured to lift the chest; and
a driver system (<NUM>, <NUM>, <NUM>) configured to drive the compression mechanism and the chest-lifting device according to a motion-time profile so as to cause the chest-lifting device to lift the chest a first distance from the resting height, the driver system further configured to drive only the compression mechanism for a chest-lift delay period and drive the chest-lifting device when the chest-lift delay period has elapsed.