Method and system for recognizing a cardiocirculatory arrest in an individual based on monitoring kinematic variables and method for consequently triggering an aid request

Abstract

There is described a method for recognizing a cardiocirculatory arrest in an individual, based on monitoring kinematic variables. The method comprises continuously detecting in real time an angular velocity or angular acceleration vector related to perceptible movements on the body surface of the individual, by an angular velocity or acceleration detection device 2 worn by the individual on the body surface. The aforesaid angular velocity or angular acceleration vector comprises three components corresponding to the angular velocity, or angular acceleration, respectively, detected on a respective axis of an orthogonal set of three Cartesian axes (X, Y, Z). The method then comprises the steps of generating a signal representative of angular velocity or angular acceleration, Sg, indicative of the values of the aforesaid detected angular velocity or angular acceleration components, by the angular velocity or acceleration detection device 2, and of receiving the aforesaid signal representative of angular velocity or angular acceleration, Sg, by a portable processing device 4 of the individual, in communication with the angular velocity or acceleration detection device 2. The method then comprises, by means of the portable processing device 4, the steps of determining an angular velocity variation, corresponding to a variation in the angular velocity vector modulus or to angular velocity variations on each of the three Cartesian axes (X, Y, Z), or corresponding to the angular acceleration modulus or to angular accelerations on each of said three Cartesian axes (X, Y, Z), based on the aforesaid signal representative of angular velocity or angular acceleration Sg; and recognizing a possible state of cardiocirculatory arrest, based on a real-time analysis of the aforesaid angular velocity variation. A method for remotely monitoring a cardiac arrest and then triggering an aid request, using the aforesaid method of recognizing a cardiac arrest, is also described. A system for recognizing a cardiocirculatory arrest in an individual, capable of performing the aforesaid methods, is also described.

Description

[0001] Method and system for recognizing a cardiocirculatory arrest in an individual based on monitoring kinematic variables and method for consequently triggering an aid request.

[0002] DESCRIPTION

[0003] TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0004] Field of application.

[0005] The present invention generally relates to the technical field of electronic systems for monitoring the cardiovascular health of an individual during normal daily life, at rest or during physical exercise.

[0006] In particular, the invention relates to a method and a system for detecting the absence of a cardiac pulse, or even arterial pulse, indicative of a very serious condition commonly referred to as "cardiovascular arrest" and associated with underlying serious cardiac arrhythmias (such as Ventricular Fibrillation, Rapid Ventricular Tachycardia, Pulseless Electrical Activity, Asystole) but also with non-cardiac causes such as serious trauma which leads to severe internal or external bleeding (severe hypovolemia which leads to the absence of a pulse for the rapid loss of a large volume of blood from the vascular circuit), better characterized by the term "absence of an effective pulse” in an individual, resulting in triggering an immediate request for aid.

[0007] Description of the prior art

[0008] In the medical-cardiological field, it is known that the risk of a cardiovascular arrest is not very predictable; due to the most frequent causes which trigger it, i.e., acute coronary syndrome or genetically determined or idiopathic arrhythmic diseases, the risk increases up to three times during physical exercise with respect to the standard resting condition; however (for the greater time spent at rest in 24 hours) it is during the resting condition, in theoretically low- risk subjects, which most cardiovascular arrests occur in absolute numbers. In 80% of cases, the cardiovascular arrest also occurs when the subject is alone and no one can witness the episode to trigger a timely alarm.

[0009] Therefore, a system capable of verifying automatically and in real time the sudden and unpredictable disappearance of the cardiac / arterial pulse, i.e., the main event which defines cardiovascular arrest which inevitably results in an immediate loss of consciousness, should be usable at any time of the day, whether it be periods of normal rest, work or periods of physical exercise, in order to send a request for aid automatically and promptly as soon as such a lack of pulse condition is detected.

[0010] It is further known that a cardiovascular arrest, for example caused by severe tachyarrhythmias or bradyarrhythmias, will be invariably fatal if intervention is not in an extremely timely manner, for example in the case of tachyarrhythmic origin thereof (85% of cases) by carrying out a defibrillation on the spot within 8-10 minutes maximum; it is estimated that, for every minute elapsed from the moment of the cardiovascular arrest, the chances of survival are reduced by 10%, which are zeroed after about ten minutes, in the absence of an appropriate aid intervention.

[0011] This window of 8-10 minutes is more than sufficient in most first aid systems to bring aid (and an external defibrillator) to the site of the accident, if the warning of the loss of pulse could be promptly sent automatically (although the subject is unconscious and is not able to send it), including geolocation data.

[0012] Therefore, in the state of the art, if the cardiocirculatory arrest occurs in a place where no other individual can witness it and therefore no one can promptly trigger aid (starting the so- called emergency chain), the chances of survival are substantially nil.

[0013] In 80% of cases of cardiovascular arrest, this is precisely the scenario of the cardiovascular arrest, without witnesses, often inside the subject's home, at a time when there are no others present.

[0014] Therefore, the importance and opportunity to have easily usable, wearable and lightweight methods and systems is evident, that are usable even intermittently (there is no need when in public places) and do not prevent normal daily life, and are adapted to recognize the onset of a cardiocirculatory arrest completely automatically, so as to launch an alarm and / or an automatic aid request directly on the site of the event when appropriate. Such a solution would be useful both for healthy individuals who practice sports alone, and especially for those who are at increased risk of dangerous arrhythmias in their daily lives, such as any patient who has had a myocardial infarction in the past or is suffering from diabetes, obesity and other common risk factors.

[0015] Obviously, for reasons of cost, size and convenience of widespread usability, the use of sophisticated medical devices fortracing cardiac activity, such as those available in the hospital, which require total immobility in bed, or medical devices which can be implanted in the body, is completely impossible in this context, as well as very expensive, potentially dangerous (for example, due to risk of infections), and practically impossible especially for healthy people. Therefore, the need is felt to devise monitoring systems and methods which have limited cost and size and can in practice be carried by an individual (i.e., a user of the method or system) during daily life and / or during physical exercise with easy self-application and removal, or be an integral part of subcutaneously monitoring devices implantable under the skin.

[0016] In this respect, several multi-sensor systems or devices are already commercially available which can be worn on various parts of the body, capable of monitoring biological parameters, including heart rate, electrocardiogram, oxygen saturation, with the possible use of other devices with auxiliary functions (for example, accelerometers, gyroscopes, magnetometers, IM Us, used to detect not the heartbeat but movement data over time, which can be used as auxiliary information for discriminating false positives). Such multi-sensor systems or devices can be capable of interoperating (generally by Bluetooth communication) with receiving applications on smartphones or other mobile devices.

[0017] Such sensors are generally used for monitoring heart rate and / or activities during daily life.

[0018] Most smartwatches, bands, rings or other wearable monitoring devices use, for continuous or long-term monitoring of cardiac activity, heart rate detection based on the photoplethysmography method (PPG) or the different variants thereof, which are not technologically suitable for detecting arrhythmias which generate cardiovascular arrest, and prone to look for a pulse even when not present by adapting the thresholds dynamically and easily causing "oversensing", or on the contrary losing the detection of the pulse even in the case of non-serious arrhythmias or for various causes other than the presence of a cardiovascular arrest (for example, banally, a dark color of the skin, an incorrect position of the detector on the wrist or on the part chosen for monitoring, which can also move frequently during running or physical exercise, or during a fall) leading to a poor reliability of such a system for the purpose of detecting such rare, but serious events, such as cardiovascular arrest.

[0019] Even if heart rate monitoring devices with bands / belts (typically worn in front on the chest) which use cardiac electrical signals (ECGs) were used, the problem of reliability in the recognition of a cardiovascular arrest condition would not be easily solved, in particular, but not only, in resting conditions.

[0020] Such band monitoring devices do not allow per se a reliable diagnosis and detection of the causative arrhythmias of cardiac arrest especially at rest, even if solutions are known (for example, from Italian patent application IT102016000033756 "Metodo e sistema per monitoraggio di arresto cardiaco durante esercizio fisico di un utente e conseguente attivazone di richiesta di soccorso", i.e., "Method and system for monitoring cardiac arrest during physical exercise of a user and consequent activation of a rescue request”) based on the analysis of abnormal heart rate behavior - measured with a heart rate monitor with ECG band - during the simulation of lethal arrhythmias, which base the heart rate analysis algorithm thereof on the specific response produced by specific heart rate monitors tested in these conditions of cardiac rhythms most often detected in cardiac arrest.

[0021] Therefore, such known solutions remain heavily dependent (and thus with a potentially different operation over time, for the periodic hardware and software updating of the devices) on the specific hardware and specific firmware used, because such a response is not in fact linked to the method, but to the specific "malfunction" of the device on those occasions when it is confronted with a pathological rhythm (not included in the same specifications as the normal heart rate monitor devices designed for simple exercise monitoring) which accompanies cardiac arrest.

[0022] To partially mitigate such a problem, a further technical solution is known, still from aforesaid Italian patent application IT102016000033756, which relies on the need for a second movement analysis mechanism, coupled with the first mechanism of heart rate analysis, to try to minimize the occurrence of "false alarms” also referred to as "false positives" which are inevitable if only the first, imperfect, mechanism based on heart rate were used. Based on this inseparable double mechanism (heart rate analysis + movement analysis), such a solution thus includes an exclusive use during sports activities involving movement, since movement is a sine qua non condition for minimizing false positives of the system as a whole.

[0023] In summary, the prior art suggests on the one hand solutions which are reliable (medical intra-hospital cardiac monitoring devices) but not portable and thus not usable for use during normal daily life and physical activity, or on the other hand solutions which are theoretically easy to use (for example, a wrist or chest strap detector) which do not ensure reliability in detecting a cardiovascular arrest, and which moreover, if they were used in such a way, would be excessively prone to trigger false alarms, especially if used outside the specific physical exercise (at rest or during activities in which the individual does not actively move).

[0024] In light of the above, the need to arrange monitoring methods and systems adapted to detect a cardiovascular arrest is strongly felt, which a) can be actively employed over 24 hours and not only during the short period of physical exercise, better if b) independent of the behavior and limitations of the specific hardware and firmware used in the sensor devices, and therefore c) which simultaneously reduce (ideally, eliminate) the possibility of "false alarms".

[0025] SUMMARY OF THE INVENTION

[0026] It is the object of the present invention to provide a method for recognizing a cardiocirculatory arrest in an individual, which allows at least partially obviating the drawbacks complained of above with reference to the prior art, and responding to the aforementioned needs particularly felt in the technical field considered.

[0027] Such an object is achieved by a method according to claim 1.

[0028] Further embodiments of this method are defined by claims 2-17.

[0029] It is a further object of the present invention to provide a method for remotely monitoring a cardiac arrest and then triggering an aid request, using inter alia the aforesaid method for recognizing a cardiocirculatory arrest.

[0030] Such an object is achieved by a method according to claim 18 or claim 19. The present invention further relates to a system for recognizing a cardiocirculatory arrest in an individual, based on kinematic monitoring.

[0031] Such a system is defined in claim 20.

[0032] Further embodiments of the system are defined by claims 21-32.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further features and advantages of the methods and systems according to the invention will become apparent from the following description of preferred embodiments, given by way of non-limiting indication, with reference to the accompanying drawings, in which:

[0035] - Figure 1 shows a simplified block diagram of a monitoring system according to an embodiment of the present invention;

[0036] - Figure 2 shows a trend of electrical signals representative of angular velocities detected by a detection device placed on the chest, in conditions of normality at rest (the deflections caused by the heartbeat are noteworthy), and in conditions of movement and of cardiac arrest (or detachment of the device) - reported in the diagram in the ordinate axis (measurement unit: dps, i.e., degrees per second) as a function of time (the notches in the abscissa represent angular velocity detection / sampling moments);

[0037] - Figure 3 shows a trend of electrical signals representative of angular velocities detected by a detection device, with patterns representative of conditions of: (a) in the diagram above, repeated falls to the ground of the individual, (b) in the diagram below, repeated removal or detachment of the detection device from the support to which it is connected (representative of a condition of removal or detachment of the device from the user).

[0038] DETAILED DESCRIPTION

[0039] With reference to Figures 1-3, a method for recognizing a cardiocirculatory arrest in an individual, based on monitoring kinematic variables, is now described.

[0040] The method comprises continuously detecting in real time an angular velocity or angular acceleration vector related to perceptible movements on the body surface of the individual, by an angular velocity or acceleration detection device 2 worn by the individual on the body surface. The aforesaid angular velocity or angular acceleration vector comprises three components corresponding to the angular velocity, or angular acceleration, respectively, detected on a respective axis of an orthogonal set of three Cartesian axes (X, Y, Z).

[0041] The method then comprises the steps of generating a signal representative of angular velocity or angular acceleration, Sg, indicative of the values of the aforesaid detected angular velocity or angular acceleration components, by the angular velocity or acceleration detection device 2, and of receiving the aforesaid signal representative of angular velocity or angular acceleration, Sg, by a portable processing device 4 of the individual, in communication with the angular velocity or acceleration detection device 2.

[0042] The method then comprises, by means of the portable processing device 4, the steps of determining an angular velocity variation, corresponding to a variation in the angular velocity vector modulus or to angular velocity variations on each of the three Cartesian axes (X, Y, Z), or corresponding to the angular acceleration modulus or to angular accelerations on each of said three Cartesian axes (X, Y, Z), based on the aforesaid signal representative of angular velocity or angular acceleration Sg; and recognizing a possible state of cardiocirculatory arrest, based on a real-time analysis of the aforesaid angular velocity variation.

[0043] According to an implementation option of the method, the angular velocity or acceleration detection device 2 is worn by the individual / user preferably in the precordial region, for the purpose of measuring the cardiac pulse.

[0044] According to another implementation option of the method, the angular velocity or acceleration detection device 2 is worn by the individual / user in other areas of the body for a measurement of the peripheral pulse.

[0045] Note that, according to an implementation option, the method includes monitoring the variations of the angular velocities of the device (i.e., detected by the device), representative of the user's cardiac pulse.

[0046] In fact, the method aims to recognize various situations of serious cardiac arrhythmias, which underlie cardiocirculatory arrest, in which, as known in the medical field, regardless of the abnormality of rhythm and heart rate, too high or too low, the final common feature is the absence of measurable cardiac-sphygmic pulse wave production (defined as gyrocardiogram wave in a gyroscope), the absence of which is the true ultimate effector of cardiocirculatory arrest and death after prolonging beyond about 8-10 minutes of such a cardiocirculatory arrest condition.

[0047] According to an embodiment of the method, the angular velocity or angular acceleration vector comprises a body movement component, due to movements of the individual, and a resting component, better isolable at rest, always present in the normal condition of absence of cardiocirculatory arrest, associated with perceptible movements on the individual’s body surface due to the individual's pulse, even in the absence of other movements by the individual.

[0048] According to an embodiment of the method, the aforesaid recognizing step comprises recognizing a state of cardiocirculatory arrest when the angular velocity variation is and remains lower, for a predefined monitoring period, than a predefined angular velocity variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement of the individual and heartbeat or pulse of the individual.

[0049] In accordance with an embodiment of the method, the aforesaid detecting step comprises continuously detecting in real time, by the angular velocity detection device 2 worn by the individual on the body surface, an angular velocity vector related to perceptible movements on the body surface of the individual, comprising three components corresponding to the angular velocity detected on the respective axis of the orthogonal set of three Cartesian axes (X, Y, Z).

[0050] Furthermore, the aforesaid generating step comprises generating a signal representative of angular velocity Sg, indicative of the values of the detected angular velocity components; and the aforesaid determining step comprises determining the angular velocity variation as the variation of the angular velocity vector modulus, based on the aforesaid signal representative of angular velocity Sg.

[0051] In accordance with another embodiment of the method, the aforesaid detecting step comprises continuously detecting in real time, by an angular velocity detection device 2 worn by the individual on the body surface, an angular velocity vector related to perceptible movements on the body surface of the individual, comprising three components corresponding to the angular velocities detected on the respective axis of the orthogonal set of three Cartesian axes (X, Y, Z).

[0052] Furthermore, the aforesaid generating step comprises generating a signal representative of angular velocity Sg, indicative of the values of the aforesaid detected angular velocity components; and the aforesaid determining step comprises determining the angular velocity variation as the largest among the angular velocity variations detected on the three Cartesian axes (X, Y, Z), based on the aforesaid signal representative of angular velocity Sg.

[0053] According to another embodiment of the method, the aforesaid detecting step comprises continuously detecting in real time an angular acceleration vector related to perceptible movements on the body surface of the individual, by means of an angular acceleration detection device 2 worn by the individual on the body surface, in which the angular acceleration vector comprises three components corresponding to the angular accelerations detected on a respective axis of the orthogonal set of three Cartesian axes (X, Y, Z).

[0054] Furthermore, the aforesaid generating step comprises generating a signal representative of angular acceleration Sg, indicative of the values of the detected angular acceleration components; and the aforesaid determining step comprises determining the angular velocity variation as dependent on the angular acceleration modulus or on angular accelerations on each of the three Cartesian axes (X, Y, Z), based on the aforesaid signal representative of angular acceleration Sg.

[0055] According to an embodiment of the method, the step of continuously detecting an angular velocity or angular acceleration vector in real time comprises detecting a plurality of angular velocity or angular acceleration samples, according to a given sampling frequency.

[0056] The step of generating a signal Sg representative of angular velocity or angular acceleration consists in generating a signal comprising a sequence of values of such angular velocity or angular acceleration samples.

[0057] The step of determining an angular velocity variation comprises calculating, within a predefined measurement period, a plurality of differences between values of consecutive angular velocity samples, according to a measurement frequency equal to or different from the aforesaid sampling frequency, and determining the angular velocity variation, to be considered in the next recognizing step, as the largest variation of the angular velocity variations calculated within the aforesaid predefined measurement period, or as the difference between the maximum angular velocity and the minimum angular velocity detected within said predefined measurement period.

[0058] The aforesaid recognizing step comprises recognizing a possible state of cardiocirculatory arrest based on a comparison of the determined angular velocity variation with a preset threshold.

[0059] According to an embodiment of the method, the aforesaid determining step comprises determining a plurality of angular velocity variation values detected in a respective plurality of measurement windows, within the aforesaid monitoring period, each measurement window having a duration equal to the measurement period.

[0060] In such a case, the aforesaid recognizing step comprises recognizing a state of cardiocirculatory arrest when all the values of the aforesaid plurality of angular velocity variation values, detected in all the measurement windows included in the monitoring period, are lower than the aforesaid predefined angular velocity variation threshold.

[0061] According to an implementation option of the aforesaid embodiment, the aforesaid monitoring periods comprise separate, consecutive and equally long static monitoring windows, within the monitoring period.

[0062] According to another implementation option of the aforesaid embodiments, the monitoring periods comprise dynamic windows, i.e., moving monitoring windows, obtained dynamically by eliminating the least recent detected angular velocity or acceleration samples, and replacing it with the most recent angular velocity or acceleration sample acquired.

[0063] According to an implementation option of the method, the aforesaid predefined monitoring period has a duration between 10s and 20s.

[0064] According to an implementation example, said predefined monitoring period is 10 s.

[0065] According to an implementation option of the method, the aforesaid predefined measurement period has a duration between 0.5s and 2s. According to a specific implementation example, such a predefined measurement period is preferably 1 s.

[0066] According to an implementation option of the method, the aforesaid predefined sampling frequency is between 26 Hz and 416 Hz (compatible and in line with the performance provided by known velocity / acceleration detection devices that are commercially available).

[0067] According to a specific implementation example, such a predefined sampling frequency is 52 Hz.

[0068] According to an implementation option of the method, the aforesaid angular velocity variation threshold, in absolute value, is in a range between 0.4 dps and 0.8 dps (quantity expressed in dps or Adps, in any case dimensionally measurable, in degrees per second or radians per second), understood as the maximum difference (in the chosen examination period, for example between 0.5 and 1.5 seconds) in at least one axis.

[0069] According to a specific implementation example, such an angular speed variation threshold, in absolute value, is preferably set at 0.6 dps.

[0070] With reference to the embodiments shown above, it is worthwhile being noted that, during periods of movement of the user, the angular velocity variations detected by the device 2 and sent to the portable processor 4 are, even for small movements, of greater by different orders of magnitude than those caused by the heartbeat, which are in turn about 8-10 times greater than those recordable in cardiocirculatory arrest conditions, in this case representative of the background noise of the sensor itself or of the very small pulse wave generated by extreme tachyarrhythmia or bradyarrhythmia which, precisely because of this reduced amplitude and hemodynamic ineffectiveness, is the very cause of cardiocirculatory arrest.

[0071] Therefore, in the aforesaid embodiments of the method, the cardiocirculatory arrest condition is excluded when the signal representative of the angular velocity (or angular velocity variation) is large (in the order of magnitude reasonably associated with a normal movement of the individual) or is small but perceptible (different from the background noise of the detection device, and associable with a condition of an individual at rest but with the presence of a heartbeat and therefore a pulse).

[0072] The two aforesaid conditions are shown in the central part and in the left part, respectively, of the diagram in Figure 2, while the right part of such a diagram shows a condition of cardiac arrest (or sensor removal).

[0073] In light of the above, to exclude a condition of recognition of cardiocirculatory arrest (and therefore also to suppress a possible triggering of an aid request) it is sufficient to detect the presence of angular velocity variations greater than a threshold established as representative of the absence of both movement and heartbeat. In accordance with an embodiment of the method, the recognizing step comprises:

[0074] - continuously detecting the difference in angular velocities on each of the three Cartesian axes (X,Y,Z) detected in consecutive time intervals;

[0075] - selecting the greatest angular velocity variation, among the angular velocity variations detected on a single axis, as the selected angular velocity difference to be considered;

[0076] - comparing such a selected difference with one or more variation thresholds on a single axis, predetermined as adapted to define the absence of a cardiac pulse;

[0077] - recognizing a state of cardiocirculatory arrest when the aforesaid difference is less than said one or more variation thresholds for a predetermined number of times over the duration of a predetermined number of consecutive time intervals.

[0078] Note that, in this embodiment, an abnormal absence of the cardiac pulse is evaluated, which is a pathognomonic signal of the occurrence of a cardiocirculatory arrest condition.

[0079] According to an implementation example of the aforesaid embodiment, the angular velocities are detected with a data point sampling frequency of at least 26Hz; the angular velocity variation thresholds on a single axis are + 0.6 dps or ~0.6 dps, between any of the variations detected in the measurement period of, for example, 1s (where the variations are considered on that axis which has the greatest variation among the variations detected in the three axes); the duration for which such an anomaly must be continuously detected is, for example, 15 consecutive seconds.

[0080] In the embodiments shown above, three different time periods (or frequencies) have been considered:

[0081] - a sampling period Tc, corresponding to a sampling frequency fc = 1 / Tc, typical of the detection device (for example, gyroscope);

[0082] - a measurement period (lasting, for example, one second) in which the difference between the maximum angular velocity and the minimum angular velocity is considered as a velocity variation, among the N angular velocities detected in the measurement period (for example, among the 26 angular velocity samples acquired in 1 second by a device operating at 26 Hz); this measurement period, as already shown, can correspond to a "moving observation window";

[0083] - a monitoring period (for example, 20 s) on which it is evaluated, for the purpose of recognizing the possible state of cardiovascular arrest, whether the minimum threshold of angular velocity variation is reached at least once or not.

[0084] According to other implementation examples of the aforesaid embodiment, the aforesaid parameters (angular velocity variation thresholds, measurement time, monitoring period, i.e., predetermined number of seconds during which the threshold must be exceeded at least once) can assume different values from those previously indicated by way of example, but, in any case, preconfigured.

[0085] In accordance with an embodiment, the method comprises the further steps of verifying whether in a previous period, within a predetermined time interval, the angular velocities or angular accelerations detected have an abnormal pattern associated with a detachment of the angular velocity detection device from the individual; if the presence of such an abnormal pattern occurs, the method includes classifying the situation as a false positive, and inhibiting the recognition of cardiac arrest.

[0086] According to an implementation option of the aforesaid embodiment, the aforesaid abnormal angular velocity or angular acceleration pattern comprises a detection of a first angular velocity or angular acceleration, positive or negative, having an absolute value greater than a false positive verification angular velocity or angular acceleration threshold, on any of the three axes (X,Y,Z); and a subsequent detection, within a false positive verification period, on any of the three axes (X,Y,Z), also different from the axis on which said first angular velocity or angular acceleration was previously detected, of a respective second angular velocity, or angular acceleration, having an absolute value greater than the aforesaid false positive verification angular velocity or angular acceleration threshold, and having a positive or negative sign opposite with respect to said first angular velocity or angular acceleration.

[0087] In fact, based on the Applicant's experience, if a peak angular velocity signal (for example, gyroscopic signal) is detected on any of the three axes which Is greater than, for example, 400 dps and, within a short time (for example within 1 second), even an angular velocity less than, for example, -400 dps, this pattern can be considered with high reliability as a typical "signature" of detaching the angular velocity detection device from the band or belt or patch (or even of detaching the band with the device still installed thereon).

[0088] In fact, such values do not occur, nor are they approached, while a human body falls, however suddenly, and not even when a human body makes other movements. The acceleration imposed on the device (which is typically a few grams, and is therefore much lower than the weight of the person) reaches the aforesaid values, precisely for the small mass, when the device is detached.

[0089] Such a situation is shown in Figure 3, which shows typical differences that can be found between the situations (a) fall to the ground of the individual (in the upper diagram in Figure 3), (b) removal or detachment events of the detection device from the support from which It is connected, representative of removal or detachment conditions of the device from the user (in the lower diagram in Figure 3).

[0090] According to an implementation option of the aforesaid embodiment, the aforesaid abnormal pattern is an abnormal angular velocity pattern, and the angular velocity threshold is greater than or equal to 400 dps, and the false positive verification period is between 1s and 3s, and is preferably 1.5s.

[0091] In accordance with an embodiment of the method, the aforesaid receiving, determining and recognizing steps are performed by a software program or application 40 stored and executable by the portable processing device 4.

[0092] Advantageously, the aforementioned decision criteria, parameters and recognition thresholds can be set flexibly, by virtue of the software application, also taking into account the type of angular velocity detection device used, and the manners in which contact with the body surface is ensured.

[0093] According to an embodiment of the method, the aforesaid signal representative of angular velocity or angular acceleration Sg comprises one or more electrical signals adapted to be transmitted wirelessly, and the communication between the angular velocity or angular acceleration detection device 2 and the portable processing device 4 is a wireless-type communication. For example, such wireless communication is Bluetooth-type communication, exploiting the advantages of such well-known and widespread short-range wireless communication technology.

[0094] According to an implementation option, the signal representative of angular velocity or angular acceleration Sg comprises three electrical signals (Sgx, Sgy, Sgz) representative of the angular velocity detected along a respective axis (X, Y, Z), respectively.

[0095] In accordance with an embodiment of the method, the angular velocity or acceleration detection device 2 is worn and kept in close contact with the body surface of the individual by means adapted to connect and keep the angular velocity or acceleration detection device in contact with the body surface of the individual.

[0096] According to an optional embodiment of the method, the angular speed or acceleration detection device 2 comprises a gyroscope or an angular velocity and / or acceleration sensor.

[0097] A method for remotely monitoring a cardiac arrest and then triggering an aid request is described below.

[0098] Such a method includes performing a method for recognizing a cardiocirculatory arrest in an individual, according to any of the embodiments shown above; in the case of recognition of a cardiocirculatory arrest, the method further provides that the portable processing device 4 triggers an aid request RS.

[0099] According to an embodiment, the aforesaid method further comprises verifying whether in a previous period, within a predetermined time interval, the detected angular velocity variations have an abnormal pattern associable with a detachment of the angular velocity detection device from the individual.

[0100] The method further includes triggering the aid request RS when the aforesaid angular velocity variation is and remains lower, for a predefined period of time, than a predefined angular velocity variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement by the individual and heartbeat or pulse of the individual, only if said abnormal angular velocity variation pattern in the aforesaid previous predetermined time interval has not been detected.

[0101] According to an embodiment of the aforesaid method, the step of triggering an aid request RS comprises sending an aid request message MS by a mobile communication device 5 of the user interoperating with the portable processing device 4, after receiving the aid request RS generated by the portable processing device 4.

[0102] According to an implementation example of the method, the portable processing device 4 and the mobile communication device 5 are made and integrated into a smartphone.

[0103] In such a case, the software processing program 40, previously mentioned, can be made available in the form of an application ("app") for smartphones.

[0104] According to a further embodiment, the method comprises the further step of providing the user, before triggering the aid request, with a visual and / or acoustic message for deactivating the aid request procedure, so that the user, if conscious and healthy, can deactivate the aid request procedure.

[0105] In such a case, the method includes proceeding with the step of triggering the aid request if, after a predefined period of time, the user does not respond to the message to deactivate the aid request procedure.

[0106] According to an embodiment, the method comprises the further step of determining the position of the user by means of a geo-location system integrated in the portable processing device 4 or in the mobile communication device 5 of the user.

[0107] In such a case, the step of triggering the aid request procedure comprises sending information about the user's location.

[0108] A system 1 for recognizing a cardiocirculatory arrest in an individual, based on monitoring kinematic variables, is now described.

[0109] Such a system comprises an angular velocity or angular acceleration detection device 2 wearable by the individual, and a portable processing device 4 of the individual, adapted to communicate with the angular velocity or angular acceleration detection device 2.

[0110] The angular velocity or angular acceleration detection device 2 is configured to perform the following actions:

[0111] - continuously detecting an angular velocity or angular acceleration vector related to perceptible movements on the body surface of the individual, in which the angular velocity or angular acceleration vector comprises three components corresponding to the angular velocity or angular acceleration detected on a respective axis of an orthogonal set of three Cartesian axes (X, Y, Z);

[0112] - generating a signal (Sg) representative of angular velocity or angular acceleration, indicative of the values of the aforesaid detected angular velocity or angular acceleration components;

[0113] The portable processing device 4 of the individual is configured to perform the following actions:

[0114] - receiving the signal representative of angular velocity or angular acceleration Sg;

[0115] - determining an angular velocity variation, corresponding to a variation in the angular velocity vector modulus or to angular velocity variations on each of the three Cartesian axes (X, Y, Z), or corresponding to the angular acceleration modulus or to angular accelerations on each of the three Cartesian axes (X, Y, Z), based on the aforesaid signal representative of angular velocity or angular acceleration (Sg);

[0116] - recognizing a possible state of cardiocirculatory arrest, based on a real-time analysis of the aforesaid angular velocity variation.

[0117] According to an embodiment, the system comprises a software program or application 40, stored and executable by the portable processing device 4, in which the software program or application is capable of carrying out the aforesaid steps of receiving, determining and recognizing.

[0118] In accordance with an implementation option of the system, the angular velocity or angular acceleration detection device 2 comprises a gyroscope or an angular velocity or acceleration sensor, and further comprises means adapted to keep the angular velocity or angular acceleration detection device in close contact with the body surface of the individual.

[0119] According to an implementation option, the aforesaid means adapted to keep the angular velocity detection device in close contact with the body surface of the individual comprise an elastic band, and / or a tight-fitting garment, and / or a patch.

[0120] According to another embodiment of the system, the aforesaid angular velocity or angular acceleration detection device 2 comprises an angular velocity or angular acceleration sensor implantable under the skin of the individual.

[0121] In an embodiment of the system, both the angular velocity detection device 2 and the portable processing device 4 comprise a wireless receiver-transmitter, and the communication between the angular velocity or angular acceleration detection device 2 and the portable processing device 4 is a wireless communication. According to an implementation example, the aforesaid wireless transceivers are short- range wireless type transceivers, for example Bluetooth.

[0122] According to an embodiment, the system further comprises a mobile communication device 5 of the user interoperating with the portable processing device 4.

[0123] In accordance with an embodiment of the system 1, the portable processing device 4 and the mobile communication device 5 are made and integrated into a smartphone or smartwatch if provided with direct mobile connectivity.

[0124] According to an embodiment of the system, the portable processing device 4 is further configured to carry out the further actions of:

[0125] - verifying whether in a previous period, within a predetermined time interval, the detected angular velocity variations have an abnormal pattern associable with a detachment of the angular velocity or acceleration detection device from the individual;

[0126] - triggering the aid request RS when said angular velocity variation is and remains lower, for a predefined period of time, than a predefined angular velocity or angular acceleration variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement by the individual and heartbeat or pulse, only if said abnormal angular velocity variation pattern in said previous period within a predetermined time interval has not been detected.

[0127] According to several possible implementation examples, the system 1 is configured to perform a method according to any one of the embodiments shown above.

[0128] As can be seen, the object of the present invention is fully achieved by the method and system disclosed above by virtue of the functional and structural features thereof, as shown in detail in the description above.

[0129] Those skilled in the art may make changes and adaptations to the embodiments of the methods and systems described above or can replace elements with others which are functionally equivalent in order to meet contingent needs without departing from the scope of the following claims. Each of the features described as belonging to a possible embodiment can be achieved irrespective of the other embodiments described.

Claims

CLAIMS1 . A method for recognizing a cardiocirculatory arrest in an individual, based on monitoring kinematic variables, comprising the steps of:- continuously detecting in real time an angular velocity vector or angular acceleration vector related to perceptible movements on the body surface of the individual, by an angular velocity or acceleration detection device (2) worn by the individual on the body surface, said angular velocity vector or angular acceleration vector comprising three components corresponding to the angular velocity or angular acceleration, respectively, detected on a respective axis of an orthogonal set of three Cartesian axes (X, Y, Z);- generating a signal (Sg) representative of angular velocity or angular acceleration, indicative of the values of said detected angular velocity or angular acceleration components, by the angular velocity or acceleration detection device (2);- receiving said signal (Sg) representative of angular velocity or angular acceleration by a portable processing device (4) of the individual, in communication with the angular velocity or acceleration detection device (2);- determining, by the portable processing device (4), an angular velocity variation, corresponding to a variation in the angular velocity vector modulus or to angular velocity variations on each of said three Cartesian axes (X, Y, Z), or corresponding to the angular acceleration modulus or to angular accelerations on each of said three Cartesian axes (X, Y, Z), based on said signal (Sg) representative of angular velocity or angular acceleration;- recognizing a possible state of cardiocirculatory arrest, by the portable processing device (4), based on a real-time analysis of said angular velocity variation.

2. A method according to claim 1 , wherein the angular velocity vector or angular acceleration vector comprises a body movement component, due to movements of the individual, and a resting component, associated with perceptible movements on the body surface of the individual due to the individual's pulse, even in the absence of other movements, wherein said recognizing step comprises recognizing a state of cardiocirculatory arrest when said angular velocity variation is and remains lower, for a predefined monitoring period, than a predefined angular velocity variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement of the individual and heartbeat or pulse of the individual.

3. A method according to claim 1 or claim 2, wherein:said detecting step comprises continuously detecting in real time, by an angular velocity detection device (2) worn by the individual on the body surface, an angular velocity vector related to perceptible movements on the body surface of the individual, comprising three components corresponding to the angular velocity detected on the respective axis of the orthogonal set of three Cartesian axes (X, Y, Z); said generating step comprises generating a signal (Sg) representative of angular velocity, indicative of the values of said detected angular velocity components; said determining step comprises determining the angular velocity variation as the variation in the angular velocity vector modulus, based on said signal (Sg) representative of angular velocity.

4. A method according to claim 1 or claim 2, wherein: said detecting step comprises continuously detecting in real time, by an angular velocity detection device (2) worn by the individual on the body surface, an angular velocity vector related to perceptible movements on the body surface of the individual, comprising three components corresponding to the angular velocities detected on the respective axis of the orthogonal set of three Cartesian axes (X, Y, Z); said generating step comprises generating a signal (Sg) representative of angular velocity, indicative of the values of said detected angular velocity components; said determining step comprises determining the angular velocity variation as the greatest of the angular velocity variations detected on the three Cartesian axes (X, Y, Z), based on said signal (Sg) representative of angular velocity.

5. A method according to claim 1 or claim 2, wherein: said detecting step comprises continuously detecting in real time an angular acceleration vector related to perceptible movements on the body surface of the individual, by means of an angular acceleration detection device (2) worn by the individual on the body surface, said angular acceleration vector comprising three components corresponding to the angular accelerations detected on a respective axis of the orthogonal set of three Cartesian axes (X, Y, Z);- said generating step comprises generating a signal (Sg) representative of angular acceleration, indicative of the values of said detected angular acceleration components;- said determining step comprises determining the angular velocity variation as dependent on the angular acceleration modulus or on angular accelerations on each of said three Cartesian axes (X, Y, Z), based on said signal (Sg) representative of angular acceleration.

6. A method according to any one of claims 1-5, wherein:- the step of continuously detecting an angular velocity or angular acceleration vector in real time comprises detecting a plurality of angular velocity or angular acceleration samples, according to a given sampling frequency;- the step of generating a signal (Sg) representative of angular velocity or angular acceleration consists in generating a signal comprising a sequence of values of said angular velocity or angular acceleration samples;- the step of determining an angular velocity variation comprises calculating, within a predefined measurement period, a plurality of differences between values of consecutive angular velocity samples, according to a measurement frequency equal to or different from said sampling frequency, and determining the angular velocity variation, to be considered in the next recognizing step, as the largest variation of the angular velocity variations calculated within said predefined measurement period, or as the difference between the maximum angular velocity and the minimum angular velocity detected within said predefined measurement period;- said recognizing step comprises recognizing a possible state of cardiocirculatory arrest based on a comparison of said determined angular velocity variation with a preset threshold.

7. A method according to claim 2 and claim 6, wherein said determining step comprises determining a plurality of angular velocity variation values detected in a respective plurality of measurement windows detected, within said monitoring period, each measurement window having a duration equal to said measurement period; and wherein said recognizing step comprises recognizing a state of cardiocirculatory arrest when all the values of said plurality of angular velocity variation values, detected in ail the measurement windows included in the monitoring period, are lower than said predefined angular velocity variation threshold.

8. A method according to claim 7, wherein said monitoring periods comprise separate, consecutive, static monitoring windows of equal duration within the monitoring period.

9. A method according to claim 7, wherein said monitoring periods comprise dynamic windows, i.e. , moving monitoring windows, obtained dynamically by eliminating the least recent of the detected angular velocity or acceleration samples, and replacing it with the most recent angular velocity or acceleration sample acquired.

10. A method according to any one of claims 2-9, wherein said predefined monitoring periodhas a duration between 10s and 20s, and / or wherein said predefined measurement period has a duration between 0.5s and 2s, and / or wherein said predefined sampling frequency is between 26 Hz and 416 Hz.

11. A method according to any one of claims 2-10, wherein the absolute value of said angular velocity variation threshold is in a range between 0.4 dps (degrees per second) and 0.8 dps (degrees per second).

12. A method according to any one of the preceding claims, wherein the recognizing step comprises:- continuously detecting the difference in angular velocities on each of the three Cartesian axes (X,Y,Z) detected in consecutive time intervals;- selecting the greatest angular velocity variation, among the angular velocity variations detected on a single axis, as the selected angular velocity difference to be considered;- comparing said selected difference with one or more variation thresholds on a single axis, predetermined as suitable to define the absence of a cardiac pulse;- recognizing a state of cardiocirculatory arrest when said difference is less than said one or more variation thresholds for a predetermined number of times over the duration of a predetermined number of consecutive time intervals.

13. A method according to any one of the preceding claims, comprising the further steps of:- verifying whether in a previous period, within a predetermined time interval, the detected angular velocities or angular accelerations have an abnormal pattern associable with a detachment of the angular velocity detection device from the individual;- if the presence of said abnormal pattern occurs, classifying the situation as a false positive, and inhibiting the recognition of cardiac arrest.

14. A method according to claim 13, wherein said abnormal angular velocity or angular acceleration pattern comprises:- detecting a first positive or negative angular velocity pattern or angular acceleration having an absolute value greater than a false positive verification angular velocity or angular acceleration threshold, on any one of the three axes (X,Y,Z);- subsequently detecting, within a false positive verification period, on any of the three axes (X,Y,Z), even different from the axis on which said first angular velocity or angularacceleration was previously detected, a respective second angular velocity, or angular acceleration, having an absolute value greater than said false positive verification angular velocity or angular acceleration threshold, and having a positive or negative sign opposite with respect to said first angular velocity or angular acceleration.

15. A method according to claim 14, wherein said abnormal pattern is an abnormal angular velocity pattern, wherein said angular velocity threshold is greater than or equal to 400 dps, and wherein said false positive verification period is between 1s and 3s, and is preferably 1.5s.

16. A method according to any one of the preceding claims, wherein said signal (Sg) representative of angular velocity or angular acceleration comprises one or more electrical signals adapted to be transmitted wirelessly, and wherein the communication between the angular velocity or angular acceleration detection device (2) and the portable processing device (4) is a wireless-type communication.

17. A method according to claim 16, wherein said signal (Sg) representative of angular velocity or angular acceleration comprises three electrical signals (Sgx, Sgy, Sgz) representative of the angular velocity detected along a respective axis (X, Y, Z), respectively.

18. A method for remotely monitoring a cardiac arrest and then triggering an aid request, comprising:- performing a method for recognizing a cardiocirculatory arrest in an individual, according to any one of claims 1-17;- if a cardiocirculatory arrest is recognized, triggering an aid request (RS) by the portable processing device (4).

19. A method according to claim 18, comprising the further step of:- verifying whether in a previous period, within a predetermined time interval, the detected angular velocity variations have an abnormal pattern associable with a detachment of the angular velocity detection device from the individual;- triggering the aid request (RS) when said angular velocity variation is and remains lower, for a predefined period of time, than a predefined angular velocity variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement by the individual and heartbeat or pulse of the individual, only if said abnormal angular velocity variation pattern in said previous predetermined time interval has not beendetected, wherein the step of triggering an aid request (RS) comprises sending an aid request message (MS), by a mobile communication device (5) of the individual interoperating with the portable processing device (4), after receiving the aid request (RS) generated by the portable processing device (4).

20. A system (1) for recognizing a cardiocirculatory arrest in an individual, based on monitoring kinematic variables, comprising: an angular velocity or angular acceleration detection device (2) wearable by the individual, configured to:- detect continuously an angular velocity vector or angular acceleration vector related to perceptible movements on the body surface of the individual, said angular velocity vector or acceleration vector comprising three components corresponding to the angular velocity or angular acceleration, respectively, detected on a respective axis of an orthogonal set of three Cartesian axes (X, Y, Z);- generate a signal (Sg) representative of angular velocity or angular acceleration, indicative of the values of said detected angular velocity or angular acceleration components;- a portable processing device (4) of the individual, adapted to communicate with the angular velocity or angular acceleration detection device (2), the portable processing device (4) being configured to:- receive said signal (Sg) representative of angular velocity or angular acceleration;- determine an angular velocity variation, corresponding to a variation in the angular velocity vector modulus or to angular velocity variations on each of said three Cartesian axes (X, Y, Z), or corresponding to the angular acceleration modulus or to angular accelerations on each of said three Cartesian axes (X, Y, Z), based on said signal (Sg) representative of angular velocity or angular acceleration;- recognize a possible state of cardiocirculatory arrest, based on a real-time analysis of said angular velocity variation.

21. A system according to claim 20, wherein the angular velocity vector or angular acceleration vector comprises a body movement component, due to movements of the individual, and a resting component, associated with perceptible movements on the body surface of the individual due to the individual’s pulse, even in the absence of other movements, wherein said recognizing action, carried out by the portable processing device (4) of theindividual, comprises recognizing a state of cardiocirculatory arrest when said angular velocity variation is and remains lower, for a predefined monitoring period, than a predefined angular velocity variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement of the individual and heartbeat or pulse of the individual.

23. A system (1) according to any one of claims 20-22, comprising a software program or application (40), stored and executable by the portable processing device (4), the software program or application (40) being capable of carrying out the aforesaid receiving, determining, and recognizing steps.

24. A system (1) according to any one of claims 20-22, wherein said angular velocity or angular acceleration detection device (2) comprises a gyroscope or an angular velocity or acceleration sensor.

25. A system (1) according to any one of claims 20-22, wherein said angular velocity or angular acceleration detection device (2) comprises an angular velocity or angular acceleration sensor implantable under the skin of the individual, or an angular velocity or angular acceleration sensor, having the same functions as the former but included in another subcutaneously implantable medical device.

26. A system according to any one of claims 20-25, further comprising means adapted to keep the angular velocity or acceleration detection device in close contact with the body surface of the individual, comprising an elastic band, and / or a tight-fitting garment, and / or a patch.

27. A system (1) according to any one of claims 20-26, wherein both the angular velocity or acceleration detection device (2) and the portable processing device (4) comprise a wireless transceiver, and wherein the communication between the angular velocity or acceleration detection device (2) and the portable processing device (4) is a wireless communication.

28. A system according to claim 27, wherein said wireless transceiver is a Bluetooth-type transceiver.

29. A system (1) according to any one of claims 20-28, further comprising a mobile communication device (5) of the individual, interoperating with the portable processing device (4), wherein the portable processing device (4) and the mobile communication device (5) aremade and integrated into a smartphone.

30. A system (1) according to any one of ciaims 20-29, wherein the portable processing device (4) is further configured to carry out the further actions of: - verifying whether in a previous period, within a predetermined time interval, the detected angular velocity variations have an abnormal pattern associable with a detachment of the angular velocity or acceleration detection device from the individual;- triggering the aid request (RS) when said angular velocity or acceleration variation is and remains lower, for a predefined period of time, than a predefined angular velocity or angular acceleration variation threshold, predetermined based on the criterion of being representative of a condition of absence of both movement by the individual and heartbeat or pulse, only if said abnormal angular velocity pattern in said previous period within a predetermined time interval has not been detected.

32. A system (1) according to any one of claims 20-31 , configured to perform a method according to any one of claims 1-19.

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