THORACIC DEVICE WITH NON-INVASIVE SENSORS FOR MEDICAL MONITORING AND

CLINICAL FEEDBACK OF VITAL SIGNS

Technical field

[0001] A system is described which provides real-time adaptive feedback of noninvasive physiological and mechanical parameters for CPR administration (cardiopulmonary resuscitation).

Background

[0002] Sudden cardiac arrest is one of the leading causes of death worldwide, causing each year more than 1 million deaths on Europe and USA, with international mortality rates between 70 and 98 %. Cardiopulmonary resuscitation (CPR) is a medical emergency technique used as an effort to preserve cerebral functions during a cardiac arrest, strongly time-dependent as well as on a correct diagnostic to apply urgent therapeutic measures, such as cardiac defibrillation.

[0003] The American Heart Association (AHA) and European Resuscitation Council (ERC) official guidelines from 2015 concerning CPR and Advanced Life Support (ALS), recommend ECC (external cardiac compressions) to be performed on sternum, with a 100 compressions/minute rate, 5 cm of minimum depth and two insufflations each 30 compressions, for patient's ventilation. Both these entities highlight how important is a correct and time-efficient clinical monitoring, as well as the need to get a real-time feedback about the patient's clinical outcome, based on the emergency team's CPR and ALS procedures.

[0004] To provide CPR is a physically demanding task, performed in a life or death event, and must be oriented according with international guidelines. Considering this, it is extremely important to perform the manoeuvre as quick and effective as possible, being the quality of the CPR strongly affected by the lack of informative support concerning the physiological status of the patient, due to the strong technical handicaps of the current available technologies.

[0005] There are few available devices on market able to provide CPR feedback, despite some existing patents and provisory patent requests, such as:

Programmable cardiopulmonary resuscitation (CPR) detection device (US 2012/0226204 Al)

CPR feedback system (GB20080020508)

Monitoring the efficacy of chest compressions (GB20070010460)

Cardiopulmonary resuscitation device (US 9,358,178 Bl)

Real-time evaluation of CPR performance (US 9,241,666 B2)

Cardiopulmonary resuscitation (CPR) meter (US D609,813 S)

Peel and stick CPR assistance device (US 2015/0045697 Al)

Defibrillator that monitors CPR treatment and adjusts protocol (WO 2006/105398 Al)

Alerting users of CPR feedback device of detected magnetic interference (US 2013/0225972 Al)

Cardiopulmonary resuscitation (CPR) feedback systems and methods (US 2015/0272820 Al)

Cardiopulmonary resuscitation support device (US 2016/0184180 Al)

[0006] Despite this, most of these systems can't provide essential physiological and/or clinical parameters. Besides, many of them reveal completely inappropriate to be used in a real situation, either for its complexity/hard to use and for its preparing time.

[0007] Cerebral oxygen saturation (rS02) is a critical parameter on a context of CPR. Its continuous monitoring during a non-ROSC (return of spontaneous circulation) situation is a direct way to evaluate CPR manoeuvres' effectiveness. A study by Ingrid Meex et al. (2013) "Feasibility of absolute cerebral tissue oxygen saturation during cardiopulmonary resuscitation") has reported an immediate increase on cerebral tissue's oxygen saturation absolute levels, after ROSC, as well as a significant increase of these levels on patients with permanent ROSC, comparatively to the patients on which additional efforts of CPR hadn't been applied. This strongly supports a direct correlation between changes on cerebral oxygen saturation and the quality of the thoracic compressions, during the CPR manoeuvres.

[0008] Other studies by Filippo Sanfilippo et al. (2015) "Cerebral oximetry and return of spontaneous circulation after cardiac arrest: A systematic review and meta-analysis" and Adam J Singer et al. (2014) "Cerebral oximetry levels during CPR are associated with return of spontaneous circulation following cardiac arrest: an observational study", unequivocally demonstrate that the continuous monitoring of cerebral oximetry using NIRS, during CPR manoeuvres, is possible and doesn't interfere or interrupt the resuscitation efforts. In addition, the same studies show that ROSC is linked with higher average levels of rS02, once ROSC rarely occurs when rS02 levels are below 30 %, thus demonstrating how important is a permanent monitoring of this physiological parameter.

[0009] The same conclusion is shared by Alexis Cournoyer et al. (2016) on the paper "Near-infrared spectroscopy monitoring during cardiac arrest: a systematic review and meta-analysis" and by Akram Ibrahim et al. (2015) on the paper "Cerebral Oximetry as a Real-Time Monitoring Tool to Assess Quality of In-Hospital Cardiopulmonary Resuscitation and Post Cardiac Arrest Care".

[0010] It was still evidenced that the accomplishment of the AHA updated guidelines (faster and deeper thoracic compressions, less ventilations and minimum interruptions during the manoeuvres) lead to higher rS02 levels, with significant improvements on the survival rates and on the neurologic outcome of the patients (Adam J Singer et al. (2014) "Cerebral oximetry levels during CPR are associated with return of spontaneous circulation following cardiac arrest: an observational study").

[0011] These facts are described to better illustrate the technical problem that is addressed by the disclosure. General Description

[0012] It is described a biomedical device for medical monitoring and clinical feedback of vital signals, with thoracic placement, usable for cardiac arrest in hospital and prehospital medical emergency context.

[0013] The device has a flexible material in polyethylene foam has an interface pad, anatomically adaptable, auto-adhesive and hypoallergenic, that assembles all the sensors and electrodes into a single structure, with adapters for external cabling connexion.

[0014] This device comprises non-invasive sensors for detection and record of the mechanical parameters of the external cardiac compressions; cardiac defibrillation electrodes; and non-invasive sensors for patient's physiological data monitoring. The physiological sensors will provide clinical information about the following parameters: peripheric and regional oximetry, arterial pulse, C0 ₂ partial pressure, temperature, electrocardiography, heart rate, thoracic impedance, frequency and respiratory volume and cardiac output.

[0015] It is described a biomedical device for CPR and vital signals real-time feedback and monitoring, able to assist cardiopulmonary resuscitation manoeuvres and to acquire, measure, monitoring and recording physiological signals, in a context of emergency medical assistance of patients who suffer a cardiac arrest, consisting of several non-invasive sensors assembled into a single interface pad, attached to patient's thorax.

[0016] It is disclosed a biomedical device for cardiopulmonary resuscitation of a patient, CPR, and vital signal monitoring and feedback, comprising an interface covering pad, flexible and anatomically adaptable for placing on the patient's thorax,

wherein the pad has an upper zone and a lower zone which are symmetrical along a vertical axis,

wherein the pad comprises an adhesive surface for adhering to the patient's thorax, two electrically conductive areas for defibrillation discharge or cardiac pacing, a reinforced compression area for the sternum, and one or more sensors for CPR and vital signal feedback, anatomically distributed over said pad.

[0017] In an embodiment, the pad comprises two visible anatomical references placed at the proximal locations to the wishbone and the xiphoid process locations.

[0018] In an embodiment, the pad comprises two notches placed at the pad proximal locations to the wishbone and the xiphoid process locations.

[0019] In an embodiment, the pad comprises two lateral extensions each with a sensor for monitoring the left and right carotid arteries.

[0020] In an embodiment, the two lateral extensions are upwardly extensible for conforming to the patient's anatomy.

[0021] In an embodiment, the sensor is a regional cerebral oximetry monitoring sensor, a cardiac output monitoring sensor, and/or a temperature sensor.

[0022] An embodiment comprises an accelerometer or a flexible positioning sensor for the assessment of external cardiac compressions.

[0023] An embodiment comprises a pressure sensor arranged for calculating hands position and the applied force on thorax.

[0024] In an embodiment, the pad has a non-rectilinear rim for providing free anatomic access to the second intercostal space of the left and right mid-clavicular lines of the thorax, for pneumothorax emergency procedure, in particular pneumothorax drainage, or for CVC placement, suprasternal echocardiographic window or FAST exam.

[0025] In an embodiment, the two electrically conductive areas are placed:

[0026] at the right side of the sternum, occupying the first right intercosta l space; and

[0027] at the left side of the sternum, on the cardiac apical projection, occupying the fifth left intercostal space and the confluence with the anterior axillar line. [0028] An embodiment comprises a disposable adhesive surface with two electrically conductive areas in gel, allowing a defibrillation discharge or cardiac pace, particularly with a minimum extension of 100 cm2 and a maximum extension of 200 cm2.

[0029] In an embodiment, the reinforced compression area is arranged to have suction effect on the thoracic zone, particularly with a reinforcement of its adhesiveness.

[0030] In an embodiment, the reinforced compression area is reinforced with between 20 and 50 cm2 of polymer.

[0031] An embodiment comprises a cardiac output sensor which is an electrical bioreactance sensor or a Doppler ultrasonography sensor.

[0032] It is described a biomedical device for CPR and vital signals feedback, comprising of sensors able to identify and monitoring:

Correct hands positioning during the external cardiac compressions;

Number, frequency, depth and recoil of the external cardiac compressions;

Fraction - % of time spent on compression manoeuvres;

Alignment of the external cardiac compressions;

Electrocardiography derivations and heart rate;

Arterial pulse;

Peripheric temperature;

Regional and peripheric oximetry;

Assisted and spontaneous ventilation;

Respiratory volume;

Carbon dioxide partial pressure;

Cardiac output.

[0033] It is described a biomedical device for CPR and vital signals feedback, consisting of an interface (pad) made of a polyethylene foam flexible material, anatomically adaptable, auto-adhesive and hypoallergenic, assembling all the sensors and electrodes.

[0034] It is described a biomedical device for CPR and vital signals feedback, where the interface has an adhesive and disposable surface pad in acrylic, easy to attach and to remove, that will be in contact with the patient's thorax, for human use, non-cytotoxic, non-irritating and hypoallergenic.

[0035] It is described a biomedical device for CPR and vital signals feedback, where the interface pad is attached considering two anatomical references, the wishbone and the xiphoid process and it contains two exclusive notches for a proper conformation and adjust to the thorax, considering both these anatomical structures.

[0036] It is described a biomedical device for CPR and vital signals feedback, where the interface has a non-rectilinear rim whose conformation will provide free anatomic access to the second intercostal space of the left and right mid-clavicular lines of the thorax, regarding the possibility to perform an emergency procedure in case of pneumothorax (pneumothorax drainage).

[0037] It is described a biomedical device for CPR and vital signals feedback, where the interface has a concentric compressions area (on the sternum) properly identified, reinforced with 20-50 cm ² of a polymer whose mechanical properties are compatible with an increase of the structural strength, an increase of the auto-adhesiveness and a suction effect on the thoracic zone, with structural consequences and extensible upper and lower zones, in order to reach the spaces between the sternum and the midclavicular line, between the fourth and sixth intercostal spaces.

[0038] It is described a biomedical device for CPR and vital signals feedback, where the upper and lower zones provide the interface with a symmetry that allows to the user an easier reference for the orientation and positioning of this interface, besides it allows a greater stability during CPR manoeuvres, avoiding its displacement over the thorax. [0039] It is described a biomedical device for CPR and vital signals feedback, where the interface has two extensible zones above the compressions area (over the sternum), consisting of two lateral extensions, that allow the regional cerebral oximetry monitoring as well as the monitoring of cardiac output and temperature in extra- thoracic areas, namely on the left and right carotid arteries, kept together by an extensible zone for a correct anatomical conformation to each patient.

[0040] It is described a biomedical device for CPR and vital signals feedback, where the disposable adhesive surface has two electrically conductive areas in a solid gel, with a minimum extension of 100 cm ² and a maximum extension of 200 cm ² , allowing a defibrillation discharge or cardiac pace. Both these areas assembled into the interface are located: a) at the right side of the sternum, occupying the first right intercostal space; b) at the left side of the sternum, on the cardiac apical projection, occupying the fifth left intercostal space and the confluence with the anterior axillar line.

[0041] It is described a biomedical device for CPR and vital signals feedback, where the disposable adhesive surface contains electrodes which allow the communication between the sensors of the interface and the biologic surface of the patient.

[0042] It is described a biomedical device for CPR and vital signals feedback, where all the electrodes and sensors isolate electrically the device, in order to be possible a defibrillation electrical discharge or cardiac pace.

[0043] It is described a biomedical device for CPR and vital signals feedback, where the sensor for the assessment of the external cardiac compressions may be a 3-axes accelerometer, using gravity as a reference, or alternately a flexible positioning sensor (potentiometer).

[0044] It is described a biomedical device for CPR and vital signals feedback, where the blood oximetry and arterial pulse are estimated by transmission, by regional infrared spectroscopy (cerebral, abdominal or carotidal), using wavelengths between 690 and 880 nm or, alternatively, with peripheric origin, by reflexion, on thoracic zone (central). [0045] It is described a biomedical device for CPR and vital signals feedback, where the body temperature sensor is activated by direct contact with the patient's skin (peripheric temperature), and is incorporated on the surface of the thoracic interface and/or on the blood regional/peripheric oximetry sensor.

[0046] It is described a biomedical device for CPR and vital signals feedback, where the number of electrodes used to perform an electrocardiography and to estimate heart rate will be 12, acquiring the derivations I, II and III, AvF, AvR, AvL, VI, V2, V3, V4, V5, V6.

[0047] It is described a biomedical device for CPR and vital signals feedback, where the electrocardiography electrodes, being in contact with the patient's thorax and through thoracic impedance, can estimate the frequency of the spontaneous or assisted ventilation, the respiratory volume and the heart rate.

[0048] It is described a biomedical device for CPR and vital signals feedback, where the hands position on thorax and the applied force are calculated through a sensor of pressure.

[0049] It is described a biomedical device for CPR and vital signals feedback, where the number, the frequency, the depth and the recoil of the compressions are calculated by sensors of displacement, which may be based on the electrical resistance of extensometers.

[0050] It is described a biomedical device for CPR and vital signals feedback, where the partial pressure of carbon dioxide is measured by transcutaneous optical or electrochemical methods.

[0051] It is described a biomedical device for CPR and vital signals feedback, where the cardiac output is obtained by electrical bioreactance or by Doppler ultrasonography and the sensors may be assembled into the surface of the thoracic interface or into the blood regional/peripheric oximetry sensor. [0052] It is described a biomedical device which provides real-time feedback of noninvasive mechanical and physiological parameters of a patient under a cardiac arrest, in a medical context of cardiopulmonary resuscitation (CPR), for professional use by the medical emergency teams (paramedics, nurses and medical doctors), in a prehospital or intra-hospital scenario.

[0053] The presented medical device has technical features that fulfil with efficacy the described medical emergency context:

1. Functional ergonomics for human thorax conformation either for adult and paediatric patients, both sexes;

2. Specific design of the sensors and defibrillation inclusion zones, as well as of the exclusion zones for invasive clinical procedures or others equally relevant, such as thoracic and pneumothorax drainage, cardiac tamponade, CVC placing, suprasternal echocardiographic window and FAST exam;

3. Incorporation of exclusively non-invasive clinical monitoring sensors, with fast placing and operationalization;

4. Real-time feedback of the mechanical parameters from the external thoracic compressions as well as of the patient's physiological parameters in a context of peri-cardiac arrest, through the external processing unit;

5. Full assembling into a single flexible structure, self-adhesive and hypoallergenic, with technically distinct areas such as external cardiac compression, defibrillation/pace and blood regional oximetry.

[0054] The device will provide real-time useful information to the emergency team during a CPR. The described solution provides real-time feedback either about the quality of the compressions performed (number, frequency, depth, force, recoil, compression alignment, frequency of ventilation and cardiac fraction) and about the physiological parameters of the patient (ECG, heart rate, arterial pulse, Sp0 ₂ , rS0 ₂ , PtcC0 ₂ , cardiac output, respiratory volume/frequency and temperature).

[0055] The device has a mechanism to evaluate CPR manoeuvres' quality and it can assemble sensors of pressure to check hand's position and applied force, accelerometers to calculate the orientation of the compressions and extensometers or sensors of displacement to calculate the number, frequency, depth and recoil of the compressions. Using ECG electrodes, it will be possible, through signal processing algorithms, to obtain the heart rate, 0 ₂ saturation and C0 ₂ partial pressure (PtcC0 ₂ ). To calculate 0 ₂ saturation and arterial pulse, pulse oximetry (Sp0 ₂ ), transmission (finger), reflective central (sternum, next to the other sensors), as well as infrared spectroscopy regional oximetry sensors (rS0 ₂ - abdominal, carotidal or cerebral), may be used. It will be also important to measure patient's body temperature - despite not directly predictive about the patient's evolution, it may conditionate the intervention of the healthcare provider (hypothermic patients will have a higher recovery probability). Besides, the device must be safe either for the patient and for the emergency professionals, as well as fully operational simultaneously with defibrillation, not compromising functions such as assessment of CPR manoeuvres' quality and physiological parameters' monitoring.

Brief Description of the Drawings

[0056] The figures provide preferred embodiments for illustrating the description and should not be seen as limiting the scope of invention.

[0057] Figure 1 illustrates an embodiment of the instrumentation blocks of the device. Figure 2 illustrates the device placement on the patient according to an embodiment of the disclosure. Figure 3 illustrates different views of device placement on the patient according to an embodiment of the disclosure, wherein the following are represented: 1 - Mid-clavicular line, 2 - Anterior axillar line, 3 - Pneumothorax points, 4 - Thoracic drainage points, 5 - First intercostal space, 6 - Second intercostal space, 7 - Fourth intercostal space, 8 - Fifth intercostal space, 9 - Sixth intercostal space, 10 - Cardiac tamponade point, 11 - ECG electrodes, 12 - Cardiac output electrodes, 13 - Cerebral regional oximetry sensor, 14 - Defibrillation electrodes. Figure 4 illustrates the device placed on the patient according to an embodiment of the disclosure (dimensions in cm). Detailed Description

[0058] Figure 1 represents the instrumentation bloc for the described biomedical device. From 1 it is possible to extract information concerning the alignment of the compressions, using gravity as reference. From 2 are extracted data about electrocardiography derivations and heart rates. From 3 is extracted the peripheric temperature of the patient on the thorax area. From 4 are extracted values of partial oxygen concentration (regional or peripheric) and of a rterial pulse. From 5 are extracted data about spontaneous/assisted ventilation and respiratory volume. From 6 it is obtained hand's position and applied force. From 7 the number, frequency, depth and recoil of the compressions, are obtained. From 8 it is calculated C0 ₂ partial pressure. From 9, cardiac output is estimated. From 10, a defibrillation electric discharge is induced.

[0059] On Figure 2 it is possible to observe how the device is placed on a patient. The device includes an interface (pad) made of a polyethylene foam flexible material, anatomically adaptable, non-conductive and hypoallergenic, which assembles all the sensors and electrodes. All the electrodes and sensors electrically isolate the device to allow, simultaneously, a defibrillation electrical discharge or cardiac pace. This interface still contains an acrylic adhesive and a disposable surface, easy to apply and to remove, that will be in contact with the thorax of the patient and that must be non- cytotoxic, non-irritating and hypoallergenic. This disposable adhesive surface has two electrically conductive areas in a solid gel, with a minimum extension of 100 cm ² and a maximum extension of 200 cm ² , allowing a defibrillation discharge or cardiac pace, at the right side of the sternum, occupying the first intercostal space and at the left side of the sternum, on the cardiac apical projection, on the mid-axillar line. Furthermore, all the electrodes which allow the communication between the sensors of the interface and the biological surface of the patient, will be embedded into this surface.

[0060] For a proper adaptability and adjustment to the patient, the interface has a height that corresponds to the average distance between two anatomical references, the wishbone and the xiphoid process and it contains two exclusive notches for a proper conformation and adjust to the thorax, considering both these anatomical structures (1). Regarding the possibility to perform an emergency procedure in case of pneumothorax (pneumothorax drainage), this interface may have a non-rectilinear rim whose conformation will provide free anatomic access to the second intercostal space of the left and right mid-clavicular lines of the thorax (2). The interface has a concentric compressions area (on the sternum) properly identified, reinforced with 20- 50 cm ² of a polymer whose mechanical properties are compatible with an increase of the structural strength, as well as of the auto-adhesiveness (3). The upper and lower zones (4 and 5) provide the interface with a symmetry that allows to the user an easier reference for the orientation and positioning of this interface, besides it allows a greater stability during CPR manoeuvres, avoiding its displacement over the thorax. Besides, the interface has an extensible zone above the compressions area (over the sternum), consisting of two lateral extensions (6), that allow the regional cerebral oximetry monitoring as well as the monitoring of cardiac output and temperature in extra-thoracic areas, namely on the left and right carotid arteries.

[0061] On Figure 3 are schematically represented: (A) relevant anatomic points; (B) the positioning of the device regarding the relevant anatomic points; (C) the step concerning the placing of the device on thorax; (D) the complete setup with the device placed on the patient.

[0062] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to thereof. The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. The above described embodiments are combinable. The following claims further set out particular embodiments of the disclosure.