Patent ID: 12257206

DETAILED DESCRIPTION

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.1is a diagram of components100of an abstracted CPR machine according to embodiments. The abstracted CPR machine can be configured to perform on a chest of a supine patient182compressions alternating with releases.

Components100include a back plate139. InFIG.1an abstracted version of back plate139is shown. Patient182may be placed supine on back plate139. A midpoint138of back plate139is also shown. An elevation axis137starts from midpoint138, and will be used for determining a resting height of the chest, etc.

Back plate139is typically part of a retention structure. An abstracted retention structure140of a CPR chest compression machine is shown inFIG.1. Patient182is placed supine within retention structure140. Retention structure140retains the body of patient182on back plate139. While retention structure140typically reaches the chest and the back of patient182, it does not reach the head183.

Retention structure140may be implemented in a number of ways. Good embodiments are disclosed in U.S. Pat. No. 7,569,021 to Jolife AB which is incorporated by reference; such embodiments are being sold by Physio-Control, Inc. under the trademark LUCAS®. In other embodiments retention structure140includes a backboard, of which back plate139is a part, and a belt that can be placed around the patient's chest.

Components100also include a compression mechanism148. Compression mechanism148can be configured to perform the compressions to the chest, and then the releases after the decompressions.

Components100also include a driver system141. Driver system141can be configured to drive compression mechanism148automatically. This driving may cause the compressions and the releases to be performed repeatedly.

Compression mechanism148and driver system141may be implemented in combination with retention structure140in a number of ways. In the above mentioned example of U.S. Pat. No. 7,569,021 compression mechanism148includes a piston, and driver system141includes a rack-and-pinion mechanism. The piston is also called a plunger. In embodiments where retention structure140includes a belt, compression mechanism148may include a spool for collecting and releasing the belt so as to correspondingly squeeze and release the patient's chest, and driver system141can include a motor for driving the spool with respect to the back plate.

Components100may further include a controller110. Driver system141may be controlled by a controller110according to embodiments. Controller110may include a processor120. Processor120can 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 processor120, it will be understood that processor120can either be standalone for this specific use, or also perform other acts, operations or process steps.

In some embodiments controller110additionally includes a memory130coupled with processor120. Memory130can be implemented by one or more memory chips. Memory130can be a non-transitory storage medium that stores programs132, which contain instructions for machines. Programs132can be configured to be read by processor120, 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 processor120to cause other devices or components to perform such functions, processes, actions, operations anchor 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 memory130, it will be understood that memory130can further hold additional data134, 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.

Controller110may include or cooperate with a communication module190, which may communicate with other modules or functionalities wirelessly, or via wires. Controller110may include or be communicatively coupled with a User Interface114, for receiving user instructions and settings, for outputting data, for alerting the rescuer, etc.

Communication module190may further be communicatively coupled with an other communication device192, an other medical device194, and also transmit data134to a post-processing module196. Wireless communications may be by Bluetooth, Wi-Fi, cellular, near field, etc. Data134may also be transferred via removable storage such as a flash drive. Other communication device192can be a mobile display device, such as a tablet or smart phone. Other medical device194can be a defibrillator, monitor, monitor-defibrillator, ventilator, capnography device, etc.

In other embodiments, communication module190can 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 module196may include a medical system network in the cloud, a server such as in the LIFENET® system, etc. Data134can 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.

Controller110can be configured to control driver system141according to embodiments. Controlling is indicated by arrow118, and can be implemented by wired or wireless signals and so on. Accordingly, compressions can be performed on the chest of patient182as controlled by controller110.

In some embodiments, one or more physiological parameters of patient182are 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 controller110, as is suggested via arrow119. Transmission can be wired or wireless. The transmitted values may further affect how controller110controls driver system141.

Controller110may be implemented together with retention structure140, in a single CPR chest compression machine. In such embodiments, arrows118,119are internal to such a CPR chest compression machine. Alternately, controller110may be hosted by a different machine, which communicates with the CPR chest compression machine that uses retention structure140. Such communication can be wired or wireless. The different machine can be any kind of device, such as other communication device192or other medical device194. One example is described in U.S. Pat. No. 7,308,304, titled “COOPERATING DEFIBRILLATORS AND EXTERNAL CHEST COMPRESSION MACHINES,” the description of which is incorporated by reference. Similarly, User Interface114may 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 controller110. A single resuscitation event can be sets of compressions for a single patient.

Driver system141can 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 2 cm downward from the resting height, and frequently more, such as 5 cm or 6 cm.

In some embodiments, a force sensing system149is included. In embodiments, force sensing system149can be configured to sense an amount of a compression force exerted by driver system141when the chest of the patient has been compressed downward by a certain amount from the resting height. That certain amount can be, for example, 1 cm, 2 cm or more.

Force sensing system149may 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 mechanism148and driver system141or retention structure140. 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 system149includes 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 structure140. In some embodiments, force sensing system149measures 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 structure140.

FIG.2is a composite diagram made by individual diagrams270and271, which are bridged by thick curved arrows for easier comprehension. At the bottom is a diagram270with a horizontal time axis. A major vertical axis indicates elevation above ground, for those times T1, T2. In the case ofFIG.2, the ground is a convenient reference elevation level, which has the vertical elevation value of 0. 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 plate139(ofFIG.1) on which the patient's back is placed, then the reference elevation level may be midpoint138of the back plate, and the vertical axis corresponds to axis137. 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 diagram270, torso cross-sections282-A and282-B are shown supine on the ground, or on a back plate, at times T1, T2, respectively. A sample compression mechanism248includes a piston251, although a different compression mechanism248may 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, piston251merely contacts torso cross-section282-A at the top, without a compression being performed. The bottom of piston251is at elevation level EAG0, 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 EAG0.

At time T2, compression mechanism248is performing a compression, which means that piston251presses into torso cross-section282-B. The chest now is compressed, and has an elevation level EAG1that is less than EAG0.

In embodiments Where the compression mechanism is caused to repeatedly perform the compressions and the releases, the positions of times T1and T2would alternate repeatedly. In diagram270, a minor vertical axis275indicates depth, meaning depth of compressions. Its zero point is level EAG0of the major vertical axis. Compression depth may be measured downward from the resting height in the minor vertical axis. At time T1the depth is 0. At time T2the depth is D1. Depth D1can be 0.5 cm, 1 cm, 2 cm, 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 1 cm.

An example is shown in a diagram271ofFIG.2, where sensing is at more points. The horizontal axis measures, in the direction to the left, the chest depth reached. Similarly, in diagram270, a minor vertical axis275measures, in a downward direction, the chest depth reached. In diagram271the vertical axis measures, in a downward direction, the compression force that is sensed by force sensing system149. The origin of diagram271corresponds 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 line272is 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 line272. Inferring for points of interest may be performed, for example, by interpolation. (It should be noted that line272might not be repeated for a release. Indeed, if the release of piston251is faster than the decompressing speed of the chest, no force will be measured, and a different line may be traced in diagram271.)

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 line272. InFIG.2it is shown as linear, but that need not be the case. In embodiments, an alert condition can be met if line272differs from what is expected, or changes while the compressions are taking place. In embodiments, a user interface such as user interface114can 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.3is another composite diagram, for illustrating embodiments where compression depth may be adjusted. At the bottom is a diagram370with a horizontal time axis, a major vertical axis indicating elevation above ground, and a minor vertical axis375indicating compression depth, similarly with diagram270. The motion-time profile below EAG0is shown for two groups310,320of compressions. These compressions are shaped substantially as sinusoids, although they could be shaped otherwise such as square waves, triangles, etc.

The compressions of group310reach a maximum compression depth D4. Different examples of alert conditions are now described, arising from differences in what was shown in diagram271.

InFIG.3, there are also diagrams371,381. 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 diagram371, the sensed amount of the compression force is plotted as a line372that is different from line272. 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. Line372may 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 group320has been adjusted to a shallower value D3. An approximate value of D3is also seen in diagram371.

RIBS POSSIBLY BREAKING or PATIENT POSSIBLY MIGRATING: As seen in diagram381, the sensed amount of the compression force is plotted as a line382that is different from line272. 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. Line382may 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 patients life. Or, it could be that the patients body has migrated from the patients sternum to soft abdominal tissue. As a result, subsequent compressions group320may 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 inFIG.3.

FIG.4is a composite diagram similar to that ofFIG.3, but for illustrating embodiments where an adjustment can be made for diminished chest resting height.FIG.4has a diagram470measuring the same quantities as diagram370, and a diagram471measuring the same quantities as diagram371.

CHEST LOSING COMPACTNESS: As seen in diagram470, the compressions of a group410start from the initially determined chest resting height (EAG0), and reach a maximum compression depth D5, measured on minor axis475. As seen in diagram471, the sensed amount of the compression force is plotted as a line472that is different from line272. 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 group410, which start from the earlier-determined chest resting height EAG0, 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 diagram471, the updated resting height is thus determined, after compressions group410, 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 ofFIG.4, 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 memory130. 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 line272. In some embodiments, communication module190is 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 ofFIG.1, a generic chest-lifting device152is 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 0.5 cm, 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 diagram471is 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.5is a composite diagram similar to that ofFIG.2, for the purpose of discussing embodiments where the chest is compressed and actively decompressed.FIG.5, diagram571has axes that are similar to those of diagrams271,371,471, 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.5, diagram570shows has a major vertical axis indicating the elevation above ground, and a major time axis. In addition, it has a minor vertical axis575indicating depth of chest compression, and height of active decompression. In diagram570cross-sections582-A,582-B,582-C,582-D of a torso are shown at times T1,T2,T3,T4, respectively. A sample compression mechanism548includes a piston551, although the compression mechanism may be implemented differently. In the example of diagram570, compression mechanism548also includes a chest-lifting suction cup552, which is adhered to the bottom of piston551and to the chest of the patient.

At time T1, piston551merely contacts torso cross-section582-A at the top, without a compression being performed. The bottom of piston551is at elevation level EAG0. The chest resting height is thus at EAG0. Similarly, at time T3, piston.551contacts torso cross-section582-C at the top, without a compression being performed.

At time T2, compression mechanism548is performing a compression, which means that piston551compresses torso cross-section582-B. The chest now is compressed, and has an elevation level EAG1that is lower than EAG0. On the minor height axis, this corresponds to depth D1.

At time T4, chest-lifting suction cup552is lifting the chest, which is as shown in torso cross-section582-D. The chest is at an elevation level EAG2that is higher than EAG0, 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 T1and T3. In particular, at time T3the 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 T1the 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 diagram571, line572could be the same as line272. 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 diagram571, the measured compression and lifting forces may trace back and forth the composite line made from lines572,573. Or one or both of lines572,573could 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.6is a diagram670similar to diagram370ofFIG.3, for illustrating embodiments where the maximum height of decompression can be adjusted. Two groups610,620of cycles are shown. In each cycle of group610there is a compression612followed by a release, a lifting614above EAG0followed by a release, and an optional pause616, that helps determine the duty cycle. The compressions612with their releases below EAG0are shaped substantially as sinusoids in this example.

Liftings614in group610reach a maximum height HI, seen in minor vertical axis675. Different examples of alert conditions are now described, arising from differences in what was shown in diagram571.

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 group620has been adjusted to a lower value, for example H2.

In some embodiments, the motion-lime 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.7is a diagram770that is similar to diagram670ofFIG.6, but instead for illustrating embodiments where there may be detachment. Two groups710,720of cycles are shown. In each cycle of group710there is a compression712followed by a release, a lifting714above EAG0followed by a release, and an optional pause716. The compressions712with their releases below EAG0are 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 0 for times between T2and T4ofFIG.5. As a result of detecting the detachment, the liftings are not continued. In subsequent group720, each cycle includes only a compression712followed by a release, and the optional pause716.

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.8shows a flowchart800for describing methods according to embodiments. The methods of flowchart800may also be practiced by embodiments described elsewhere in this document, such as CPR machines, storage media, etc. In addition, the operations of flowchart800may be enriched by the variations and details described elsewhere in this document.

According to an operation810, 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 2 cm downward from its resting height.

According to another operation820, 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 1 cm, longer, etc.

According to another, optional operation830, it is determined whether the sensed amount of the compression force meets an alert condition. If so, then according to another, optional operation840, an alert is emitted via the user interface.

Even if, at operation830, it is not determined that the alert condition has been met, then according to another operation850, 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 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 operation870, both such forces, etc.

In some embodiments, after operation850, execution returns to operation810. Additional operations are possible in embodiments where the CPR machine further includes a chest-lifting device. For example, according to another, optional operation860, 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 operation870, 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 operation880, it is determined whether the sensed amount of the lifting force meets an alert condition. If not, then execution may return to operation810. If yes, then an alert can be emitted, for example according to operation840.

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 0.5 cm 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.9is a diagram of a sample compression mechanism948. Compression mechanism948is part of a CPR machine (not shown), and includes a piston951and a suction cup952. Compression mechanism948also includes a failure detector954.

Failure detector954may 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 detector954may 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.10is a diagram of a sample compression mechanism1048. Compression mechanism1048is part of a CPR machine (not shown), and includes a piston1051and a pad1052with adhesive material. Compression mechanism1048also includes a failure detector1054. Failure detector1054may 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 inFIG.7.

FIG.11shows a flowchart1100for describing methods according to embodiments. The methods of flowchart1100may also be practiced by embodiments described elsewhere in this document, such as CPR machines, storage media, etc. In addition, the operations of flowchart1100may be enriched by the variations and details described elsewhere in this document.

According to an operation1110, 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 2 cm 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 operation1120, 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 operation1110.

If yes, then according to another operation1130, 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 inFIG.1. 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 interface114. The action can be that user interface114emits an alert.

The electronic component can be memory130. The action can be that a record is stored in memory130of an event that the chest is not lifted by at least 0.5 cm above the resting height.

The electronic component can be communication module190. The action can be that communication module190transmits a message about the chest not being lifted by at least 0.5 cm above the resting height.

FIG.12shows a flowchart1200for describing methods according to embodiments. The methods of flowchart1200may also be practiced by embodiments described elsewhere in this document, such as CPR machines, storage media, etc. In addition, the operations of flowchart1200may be enriched by the variations and details described elsewhere in this document.

According to an operation1210, 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 2 cm 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 operation1220, 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 operation1210.

If yes, then according to another operation1230, 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.13Ais a diagram1302of 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 backboard1344is shown for simplicity. While backboard1344is 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 mechanism1348coupled to the retention structure. Compression mechanism1348is shown generically, and it could be a piston, a squeezing belt, and so on. In diagram1302, a compression is being performed on the patient, for example as in moment T2ofFIG.5. In diagram1302, the torso cross-section is1382-B. As seen from a vertical depth axis1375, the chest is being compressed from the resting height DO to a depth D1.

The components further include a chest-lifting tether, which is also sometimes called simply a tether. In the example ofFIG.13A, the chest-lifting tether is provided in two tether segments1354. The chest-lifting tether may be coupled to the retention structure. In the example ofFIG.13A, chest-lifting tether segments1354are coupled to backboard1344at respective junctions1355.

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 segments1354are coupled to the retention structure is not shown because diagram1302is only generic.

The components moreover include a driver system1341. Driver system1341can be configured to drive compression mechanism1348automatically, so as to cause the compression mechanism to repeatedly perform compressions and releases, as has been described above. Driver system1341can be further configured to drive the chest-lifting tether concurrently with driving compression mechanism1348. 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.13Bis a diagram1304of the components ofFIG.13A. Diagram1304is at a time when none of the compressions ofFIG.13Ais being performed, for example as in moment T4ofFIG.5. In fact, the chest is thus lifted during one of the releases of compression mechanism1348. In diagram1304, the torso cross-section is1382-D. As seen from a vertical depth axis1375, the chest is being lifted to a height H2, which is above the resting height DO.

FIG.13Bis 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 system1341is configured to drive the chest-lifting tether so as to cause the chest to be lifted above resting height DO. Indeed, height H2could be at least 0.5 cm above DO.

The chest-lifting tether may lift the chest in a number of ways. Two examples are now described that correspond toFIG.13B.

FIG.14is a diagram1404showing how the embodiments ofFIG.13Amay be further implemented with a pulley. More particularly,FIG.14is a diagram1404of 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 backboard1444is shown for simplicity. The components additionally include a compression mechanism1448and a driver system1441, which may operate similarly with what was written for compression mechanism1348and driver system1341.

The components further include a chest-lifting tether, which is provided in two tether segments1454. Tether segments1454are coupled to backboard1444at respective junctions1455.

The components additionally include at least one pulley that is configured to roll. In diagram1404two pulleys1457are shown. The chest-lifting tether is partially wrapped around pulleys1457.

Driving the chest-lifting tether, which may be performed by driver system1441, includes rolling pulleys1457, which lifts the chest. In diagram1404, the torso cross-section is1482-D. As seen from a vertical depth axis1475, the chest is thus lifted to a height H3, which is above the resting height DO. During compressions, pulleys1457are rolled in the opposite direction, which releases tether segments1454and permits the patient to be lowered.

FIG.15is a diagram1504showing how the embodiments ofFIG.13Amay be further implemented. More particularly,FIG.15is a diagram1504of 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 backboard1544is shown. The components additionally include a compression mechanism1548, which is a piston1548that can perform compressions. It will be understood that the piston may have a termination at the bottom that is suitable for contacting the patients chest during the compressions, but such is not shown for simplicity. The components moreover include a driver system1541, which can drive piston1548similarly with what was written for compressions.

The components further include a chest-lifting tether, which is provided in two tether segments1554. Tether segments1554are coupled to backboard1544at respective junctions1555. InFIG.15, the chest-lifting tether is coupled to compression mechanism1548.

Driving the chest-lifting tether, which may be performed by driver system1541, includes driving compression mechanism1548upwards with enough lifting force to lift tether segments1554. In other words, piston1548is driven in reverse. When lifted this way, tether segments1554in turn lift the patient during the releases of compression mechanism1548. In diagram1504, the torso cross-section is1582-D. As seen from a vertical depth axis1575, the chest is thus lifted to a height H4, which is above the resting height DO. During compressions, tether segments1554are 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.16Ais a diagram1602of only some of the components of a sample CPR machine according to embodiments. The CPR machine may include a retention structure1640, in which the patient may be placed supine.

The components additionally include a compression mechanism1648coupled to retention structure1640. Compression mechanism1648is shown generically, and it could be a piston, a squeezing belt, and so on. In diagram1602, a compression is being performed on the patient, for example as in moment T2ofFIG.5. In diagram1602, the torso cross-section is1682-B. As seen from a vertical depth axis1675, the chest is being compressed from the resting height DO to a depth D5.

The components ofFIG.16Afurther include at least one chest-lifting bladder, which is coupled to retention structure1640. In the example of diagram1602two chest-lifting bladders1651,1652are provided. In the example ofFIG.16A, chest-lifting bladders1651,1652are coupled to retention structure1640so that they contact the sides of patient's1682-B torso.

The components additionally include a fluid pump1656. Fluid pump1656can be configured to inflate bladders1651,1652via a system of pipes1657. It is understood that, for lifting the patient's chest, bladders1651,1652will be caused to be alternatingly inflated and deflated. Inflating can be with a fluid such as a liquid, air, or other gas from fluid pump1656. If using a liquid, a reservoir may be further provided to store the fluid during the deflations.

The components ofFIG.16Amoreover include a driver system1641. Driver system1641can be configured to drive compression mechanism1648automatically, so as to cause the compression mechanism to repeatedly perform compressions and releases, as has been described above. Driver system1641can be further configured to operate the fluid pump concurrently with driving compression mechanism1648. Operating fluid pump1656can be such as to cause fluid pump1656to inflate chest-lifting bladders1651,1652so as to cause chest-lifting bladders1651,1652to lift the chest. In this example, bladder1652is configured to operate substantially in unison with chest-lifting bladder1651. This lifting may take place while none of the compressions is being performed, as seen immediately below.

FIG.16Bis a diagram1604of the components ofFIG.16A.FIG.16Bis at a time when none of the compressions ofFIG.16Ais being performed, for example as in moment T4ofFIG.5. In fact, the chest is thus lifted during one of the releases of compression mechanism1648. In diagram1604, the torso cross-section is1682-D. As seen from vertical depth axis1675, the chest is being lifted to a height H5, which is above the resting height DO. The chest is being thus lifted because chest-lifting bladders1651,1652have been inflated via fluid pump1656, and are biasing the torso from the side.

FIG.16Bis an example of embodiments where chest-lifting bladders1651,1652lift the chest by substantially biasing a side of the patient. It is also an example of embodiments where driver system1641is configured to drive chest-lifting bladders1651,1652so as to cause the chest to be lifted above resting height DO. Indeed, height H5could be at least 0.5 cm above DO.

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.17is a time diagram plotting elevation above ground over time, and shows the time evolution of two sets1710,1720of compressions. The chest is not lifted above the resting height EAG0, except for only one lifting1745between sets1710,1720. Lifting1745may correspond to occasional breaths that a rescuer is expected to deliver to a patient between sets of compressions.FIG.17is thus an example of where the chest is lifted only once while four successive compressions are performed, two from set1710and two from set1720. Lifting1745may be to a height above the resting height.

The example ofFIG.17may 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 ofFIG.17may 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 system1648can be configured to drive compression mechanism1648and to operate fluid pump1656so 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:a) lift the chest to a first height above the resting height before the certain two compress 10 ns,b) lift the chest to a second height above the resting height that is at least 5% higher than the first height between the certain two compressions, andc) lift the chest to a third height above the resting height that is at least 5% higher than the second height after the certain two compressions.

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.18is a time diagram of a sample motion-time profile1800, 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.

InFIG.18, compressions1811,1812,1813, . . . all reach substantially the same depth. Compressions1812,1813may be considered to be the certain two compressions. The chest is lifted above the resting height (0) in liftings1841,1842,1843, . . . ,1847, . . . . It will be appreciated that liftings1841,1842,1843can 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 lifting1847.

FIG.19is a time diagram of a sample motion-time profile1900, with axes similar to those ofFIG.18, for illustrating embodiments where the chest is lifted to ascending heights and compressed to descending depths. Compressions1911,1912,1913, 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.

InFIG.19, the chest is lifted above the resting height (0) in liftings1941,1942,1943, . . . ,1947, . . . . Liftings1941,1942,1943can 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 lifting1947.

FIG.20is a time diagram of a sample motion-time profile2000, with axes similar to those ofFIG.18, for illustrating embodiments where the chest is lifted to ascending heights and compressed to descending depths. The chest is lifted above the resting height (0) in liftings2041,2042,2043. . . . Liftings2041,2042,2043can reach heights that can be as described above for the first, second and third heights. Compressions2011,2012,2013, reach progressively deeper depths, as inFIG.19, 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.21shows a flowchart2100for describing methods according to embodiments. The methods of flowchart2100may 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 flowchart2100may be enriched by the variations and details described elsewhere in this document.

The operations of flowchart2100may 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 operation2110, the chest-lifting device may be driven so as to lift the chest to the first height. Operation2110may take place before operations2120and2140.

According to other operations2120,2140, the compression mechanism may be driven so as to cause a first certain compression and a second certain compression, respectively.

According to another operation2130, 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 5% higher than the first height. Operation2130may take place between the certain two compressions of operations2120,2140.

According to another operation2150, 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 5% higher than the second height. Operation2150may take place after the certain two compressions of operations2120,2140.

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, fix 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.22shows an example of a user interface2214that may be provided for the operation of a CPR machine according to embodiments. User interface2214has actuators2241,2242,2243, which can be physical pushbuttons, buttons on a touchscreen, settings of a dial, and so on.

Actuator2241can be labeled “AUTOMATIC MODE”, and may control operational parameters in an AUTOMATIC MODE, of which only a set2251is shown. In other words, if actuator2241is actuated, then all the operational parameters are set in a single setting.

In the example ofFIG.22, parameters2251include 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 30 sec; the full height for lifting during active decompression (2251C), with a sample value of 3 cm, 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 30 sec; the lifting waveform shape, whether sinusoidal (S-S), square, or other (2251E); and how often to lift, whether every 1 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 (2251G) as described later; and a size value for the patient, such as estimated weight (2251H), if2251G is YES. It will be recognized that parameters2251are 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 5 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 inFIG.18.

Returning toFIG.22, actuator2242can be labeled “MANUAL MODE”, and may control a set2252of operational parameters in a MANUAL MODE. i.e. if actuator2242is actuated, then each of the shown operational parameters2251A-2251F may be set individually. Of course, a starting value may be proposed by the system, and so on.

Actuator2243can 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.

FIG.23shows a flowchart2300for describing methods according to embodiments. The methods of flowchart2300may 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 flowchart2300may be enriched by the variations and details described elsewhere in this document.

According to an optional operation2310, a height input may be received. The height input may be received by a height input port.

According to another operation2320, 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 operation2330, 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 operation2310, and thus operations2310,2320,2330may be performed repeatedly, automatically, according to a motion-time profile. If optional operation2310is indeed performed and a new height input is thus received, then a subsequent execution of operation2330may be performed to an updated full eight 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 parameters2251, 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 0.5 cm. Examples are now described.

FIG.24is a time diagram2400, which shows a motion-time profile with axes similar to those ofFIG.18, for illustrating embodiments where a chest is compressed, and lifted but with a lifting delay. Compressions2418are performed, starting at time 0. In this example, all compressions2418are 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, liftings2441,2442,2443,2444, . . . start after a lifting delay2477.

Lifting delay2477may 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 30-60 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 delay2477may be at least 15 sec, at least 45 sec, etc. Good values for it can be say, 30 to 120 seconds.

FIG.25is a time diagram2500, which shows a motion-time profile with axes similar to those ofFIG.18, for illustrating embodiments where a chest is compressed, and lifted but with a lifting delay. Compressions2518are performed, starting at time 0, and starting by becoming progressively deeper until they reach full depth FD. In addition, liftings2541,2542,2543,2544, . . . start after a lifting delay2577.

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 2 cm 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.26is a diagram of components2600of an abstracted CPR machine according to embodiments. The abstracted CPR machine can be configured to cooperate with a ventilator2694according to embodiments.

Many of components2600are similar to components100inFIG.1. More particularly, components2600include a retention structure2640, in which a patient2682having a head2683may be placed supine. Components2600also include a compression mechanism2648, a chest-lifting device2652, a driver2641, and a controller2610. Controller2610may include a processor2620and a memory2630, which stores programs2632and data2634. Components2600may further include or cooperate with a communication module2690and a user interface2614.

Ventilator2694includes a tube2695coupled to the mouth of patient2682. Ventilator2694also includes a communication module that can establish a communication link2697with communication module2690. Communication link2697may be wireless or wired, for example by connecting a cable. Signals (not shown) may be exchanged via communication link2697. The CPR machine and ventilator2694may cooperate, for example by one of them controlling the other, etc.

In embodiments, the CPR machine with components2600is configured to operate in cooperation with ventilator2694. Ventilator2694can be configured to transmit ventilator signals in conjunction with biasing air into the mouth of patient2682though tube2695. 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 system2641can be further configured to drive chest-lifting device2652in response to the received ventilator signals, so as to cause chest-lifting device2652to lift the chest of patient2682to 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 0.5 cm 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, inFIG.26, similarly to what was described previously, driver system2641can be configured to drive chest-lifting device2652so 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 module2690can be configured to transmit ventilator signals that indicate when the certain moment occurs.

FIG.27is a diagram of sample components2700of a CPR machine intended for use with a patient2782. Components2700include a retention structure2740that includes a back plate2739. Back plate2739has a midpoint2738. Patient2782may be placed supine on the plate2739; when this happens, the chest of patient2782thus has a resting height. The resting height can be measured on axis2737as the distance between midpoint2738and point RH27.

Components2700also include a driver system2741, and a piston2748that is coupled to retention structure2740via driver system2741. Piston2748is configured to perform, when driven by driver system2741, compressions alternating with releases on the chest, while patient2782is supine on back plate2739. Piston2748has a bottom end2749that is configured to be coupled to patient2782during the compressions. The coupling can be either by direct contact or via a chest lifting device. The resting height of the chest of patient2782is determinable at a moment when none of the compressions is being performed.

Similarly with the description of prior embodiments, driver system2741can be configured to drive piston2748automatically, so as to cause piston2748to 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.

Components2700additionally include a position sensor2769. Position sensor2769can be configured to detect a certain distance of bottom end2749of piston2748to midpoint2738of back plate2739. Accordingly, position sensor2769has 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 sensor2769can be implemented in a number of ways. For example, where piston2748is driven by driver system2741, the position sensor need only measure the location of piston2748relative to driver system2741, because driver system2741can be fixed relative to retention structure2740. It is known how to do this location, for example when driver system2741drives piston2748by 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 interface114. 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 piston2748, until bottom end2749touches patient2782at point RH27. At that time, bottom end2749will 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 piston2748. 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 system2741during the compressions. The compression force will be due to the physical resistance that the chest of patient2782will present to the compressions by piston2748. In embodiments, the certain distance can be detected at a moment when the sensed amount of the compression force indicates that bottom end2749is 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 piston2748from 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 end2749is at the resting height of the chest.

FIG.28is a composite diagram made from individual diagrams2870,2871and2872, which are bridged by thick curved arrows and horizontal dotted lines. Piston2748is shown against axis2737for two scenarios2871,2872. In scenario2871, a smaller patient2881has a resting height with a value RHI. Patient2881receives compressions represented by a downward-pointing vector VCD1. In scenario2872, a larger patient2882has a resting height with a value RH2, which is larger than RHI. Patient2882receives compressions represented by a downward-pointing vector VCD2, which has a magnitude larger than that of VCD1because the compressions for patient2882are deeper than for patient2881.

InFIG.28, diagram2870shows 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, P2represent the behaviors at scenarios2871,2872, respectively, as indicated by the thick curved arrows. Values CDI and CD2are the numerical values of vectors VCDI, VCD2, respectively. For at least a certain range between points P1and P2, increasing the resting height increases the compression depth. The increase may be linear as shown in the example ofFIG.28, or otherwise. CDI and CD2may have suitable values, such as 4.0 cm, and 6.0 cm. 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 diagram2870, 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 15% larger than the compression depth threshold, such as 30% or even higher.

FIG.29shows a flowchart2900for describing methods according to embodiments. The methods of flowchart2900may 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 flowchart2900may be enriched by the variations and details described elsewhere in this document.

According to an operation2910, 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 operation2920, a nominal resting height value may be determined from the certain distance detected at operation2910.

According to another operation2930, 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.30is a diagram of sample components3000of a CPR machine intended for use with a patient3082. Components3000include a retention structure3040that includes a back plate3039. Back plate3039has a midpoint3038. Patient3082may be placed supine on the plate3039; when this happens, the chest of patient3082thus has a resting height. The resting height can be measured on axis3037as the distance between midpoint3038and point RH30.

Components3000also include a driver system3041, and a piston3048that is coupled to retention structure3040via driver system3041. Piston3048is configured to perform, when driven by driver system3041, compressions alternating with releases on the chest, while patient3082is supine on back plate3039.

Components3000moreover include a chest-lifting device3052coupled to piston3048. In the particular example ofFIG.30, chest-lifting device3052is depicted as a suction cup, but other implementations are also possible. Piston3048has a bottom end, to which suction cup3052is attached, but that is not necessary. Indeed, other types of chest lifting devices might not attach to the bottom end of piston3048. The bottom end of piston3048can be configured to be coupled to patient3082during the compressions. The coupling can be either by direct contact or via chest lifting device3052. The resting height of the chest of patient3082is determinable at a moment when none of the compressions is being performed.

Similarly with the description of prior embodiments, driver system3041can be configured to drive piston3048automatically, so as to cause piston3048to repeatedly perform the compressions and the releases. Driver system3041can be configured to further drive piston3048so as to cause chest-lifting device3052to 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.

Components3000also include an input mechanism3061. Input mechanism3061can be configured to input a size value for a size of patient3082, 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 interface114. The user interface can be configured to input the size value from a rescuer. An example was seen with reference toFIG.22, where a size value for the patient2251H is 80 kg. 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 10%, or even within 5%, 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.31is a composite diagram made from individual diagrams3170,3171and3172, which are bridged by thick curved arrows and horizontal dotted lines. Piston3048is shown against axis3037for two scenarios3171,3172. In scenario3171, a smaller patient3181has a resting height with a value RH3. Patient3181receives compressions, and is also lifted above resting height RH3. These liftings are represented by an upward-pointing vector VLH1. In scenario3172, a larger patient3182has a resting height with a value RH4, which is larger than RH3. Patient3182receives compressions, and is also lifted above resting height RH4. These linings are represented by an upward-pointing vector VLH2, which has a magnitude larger than that of VLH1because the liftings for patient3182are higher than for patient3181.

InFIG.31, diagram3170shows 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, L2represent the behaviors at scenarios3171,3172, respectively, as indicated by the thick curved arrows. Values LH1and LH2are the numerical values of vectors VLH1, VLH2, respectively. For at least a certain range between points L1and 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 ofFIG.31, or otherwise. LH1and LH2may have suitable values, such as 1.5 cm, and 2.5 cm.

In embodiments, a resting height threshold may be chosen on the horizontal axis of diagram3170, 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 25% larger than the lifting height threshold, or even larger, such as 40% larger.

FIG.32shows a flowchart3200for describing methods according to embodiments. The methods of flowchart3200may 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 flowchart3200may be enriched by the variations and details described elsewhere in this document.

According to an operation3210, 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 operation3220, a nominal resting height value may be determined from the size value that was input at operation3210.

According to another operation3230, 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. Plus, any reference to any prior art in this description is not, and should not be taken as, an acknowledgement or any form of suggestion that this prior art forms parts of the common general knowledge in any country.

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. Other embodiments include combinations and sub-combinations of features described herein, including for example, embodiments that are equivalent to: providing or applying a feature in a different order than in a described embodiment; extracting an individual feature from one embodiment and inserting such feature into another embodiment; removing one or more features from an embodiment; or both removing a feature from an embodiment and adding a feature extracted from another embodiment, while providing the features incorporated in such combinations and sub-combinations.

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.

The following claims define certain combinations and subcombinations of elements, features and steps or operations, which are regarded as novel and non-obvious. Additional claims for other such combinations and subcombinations may be presented in this or a related document.