(19)
(11)EP 3 033 062 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
17.05.2017 Bulletin 2017/20

(21)Application number: 14750517.6

(22)Date of filing:  13.08.2014
(51)Int. Cl.: 
A61H 31/00  (2006.01)
(86)International application number:
PCT/EP2014/067376
(87)International publication number:
WO 2015/022387 (19.02.2015 Gazette  2015/07)

(54)

CARDIO PULMONARY RESUSCITATION QUALITY FEEDBACK SYSTEM

RÜCKMELDUNGSSYSTEM FÜR DIE HERZ.-LUNGEN-REANIMATIONSQUALITÄT

SYSTÈME DE RÉTROACTION DE LA QUALITÉ DE RÉANIMATION CARDIO-RESPIRATOIRE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 13.08.2013 EP 13180271

(43)Date of publication of application:
22.06.2016 Bulletin 2016/25

(73)Proprietor: Koninklijke Philips N.V.
5656 AE Eindhoven (NL)

(72)Inventors:
  • AELEN, Paul
    NL-5656 AE Eindhoven (NL)
  • ORDELMAN, Simone Cornelia Maria Anna
    NL-5656 AE Eindhoven (NL)
  • WOERLEE, Pierre Hermanus
    NL-5656 AE Eindhoven (NL)

(74)Representative: Roche, Denis 
Philips IP&S High Tech Campus 5
5656 AE Eindhoven
5656 AE Eindhoven (NL)


(56)References cited: : 
EP-A2- 2 343 097
US-A1- 2010 198 118
US-A1- 2012 259 156
US-A- 5 496 257
US-A1- 2012 010 543
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The present invention relates to a system for providing compression feedback based on a new quality measure for cardio pulmonary resuscitation.

    BACKGROUND OF THE INVENTION



    [0002] Cardiac arrest (CA) is one of the main causes of death in the western world. After the heart has stopped pumping, death is unavoidable unless acute medical care is available. The resulting ischemia disturbs a wide range of cell processes; this eventually leads to cell death. It has been reported that the probability for survival after cardiac arrest decreases exponentially with time. To slow down this decay, Cardio Pulmonary Resuscitation (CPR) has to be performed to obtain a minimum amount of perfusion to vital organs. Cardio Pulmonary Resuscitation (CPR) guidelines prescribe a standard compression depth and frequency (i.e. 100 compressions per minute at a depth of 5.0 cm). This prescribed depth and frequency are person independent. However, the compression depth and frequency that generate optimal blood flows vary between people. To optimally resuscitate a patient, the quality of CPR has to be assessed in some way. In the experimental setting this can be done by measuring blood flows (e.g. carotid or aortic flow) or coronary perfusion pressure (CPP).The CPP measures the pressure drop over the coronary vessels of the heart (Aortic pressure - Right Atrial pressure). However these values require precise and timely placement of measurement catheters, which is not practical during normal clinical practice. In clinical practice, some non- or minimally invasive techniques are being used as surrogate marker of CPR quality. The highest point of expired carbon dioxide trace (End tidal CO2, ETCO2) of a breath is believed to give some information on the quality of CPR. ETCO2 is shown to rise when the heart starts beating on its own (Return of Spontaneous Circulation, ROSC). While giving some indication of the CPR quality, the ETCO2 is influenced by changes in ventilation minute volume (i.e. ventilation frequency and volume), ventilation/perfusion ratio and medication. Further, it takes a significant amount of time (tens of seconds) for ETCO2 to reach a new steady state. Giving feedback on this parameter is therefore not an easy task. No quantitative feedback algorithms / methods exist yet for using this parameter. In this disclosure it is proposed to use certain features of the blood pressure as quality of CPR indicator.

    [0003] There are a number of devices that measure CPR quality in term of guideline adherence, i.e. giving the prescribed compression depth and frequency. These feedback devices are however not suitable for personalization of CPR.

    [0004] A system for providing feedback on chest compression in CPR is for example described in EP 1 932 502. The system measures and processes chest compressions and provide feedback to the user with respect to the characteristics of the compressions.

    [0005] An apparatus for indicating cardiac output comprises means for monitoring a patient's transthoracic impedance and generating a corresponding impedance signal is described in WO2009/109595.

    [0006] US 2012/259156 A1 describes a device for coordinated resuscitation perfusion support. A system capable of providing electromagnetic stimulation of physiological tissue to supplement the effect of manual CPR is described. Use of different physiological input signals and different compression parameters are proposed.

    [0007] US 2007/060785 A1 describes a medical device for assisting a user in manually delivering e.g. CPR. In an embodiment, an ultrasonic sensor for blood flow is mentioned in combination with CPR, wherein an estimated blood flow is used to determine timing of feedback cues delivered to a user.

    [0008] The inventor of the present invention has appreciated that an improved system, apparatus and method is of benefit, and has in consequence devised the present invention.

    SUMMARY OF THE INVENTION



    [0009] It would be advantageous to achieve a device or system to provide physiological CPR quality feedback to persons performing resuscitation or to automatically optimize CPR compression depth. In general, the invention preferably seeks to mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination. In particular, it may be seen as an object of the present invention to provide a system that solves the above mentioned problems, or other problems, of the prior art or at least provides an alternative solution to the prior art.

    [0010] To better address one or more of these concerns, in a first aspect of the invention a system for providing feedback regarding chest compressions in Cardio Pulmonary Resuscitation (CPR) in accordance with claim 1 is proposed. The system comprises a measuring unit providing a measure of arterial blood pressure of a patient. The measuring unit may provide the measure at a single point in time, or over a period of time, while CPR is being performed. The system may further comprise a processor registering data from the measuring unit, the processor being configured to obtain arterial blood pressure of the patient for a time period while CPR is being performed, and the processor being configured to calculate a blood pressure CPR quality indicator using the blood pressure as a function of time. This data may be stored in a memory or data storage. The processor may be configured to calculate a Blood Pressure CPR Quality Indicator (BPCPRQI), using features of the arterial blood pressure data as a function of time. Possible features are the diastolic or mean blood pressure over a single or multiple CPR compression(s). With the use of a blood pressure related CPR quality indicator, the actual quality of CPR can be monitored and optimized for specific patients. By doing this, the patient receives optimal care and successful outcome chance improves. An additional advantage of using a blood pressure related CPR quality indicator is the instantaneous effect of the parameter; a change in CPR quality is immediately seen in the quality parameter, without having a delay or time interval to reach steady state. The BPCPRQI may be compared to a criterion, such as a threshold or target interval. Instead of using a fixed threshold or interval, this threshold or interval might change as of trends in the signal over time. The BPCPRQI may be calculated in a number of ways which will be discussed further in the present text. Based on the BPCPRQI the processor may, if the BPCPRQI is below a quality threshold or outside the target interval, transmit a low-quality indication signal. This may be used as an indication that the CPR is not performed satisfactory. Further, if the BPCPRQI is above the threshold or inside the target interval, the processor may transmit a high quality indication signal. This indication may be used to indicate that CPR is performed satisfactory. The system may comprise an indicator unit providing an indication of the blood pressure CPR quality indicator. The BPCPRQI may be used to visually indicate the response from the check, in that the system may comprise a visual indicator configured to provide visual indication of the low quality indication signal and/or high quality indication signal and/or blood pressure CPR quality indicator. Additionally, the current BPCPRQI and or history of the BPCPRQI may be shown to show current CPR quality or trends in CPR quality.

    [0011] In the present disclosure the optimum blood pressure CPR quality indicator, BPCPRQI, may be defined as the maximum possible value of this indicator. Alternatively the optimum BPCPRQI may be defined as a target BPCPRQI that is related to good CPR physiology that is related to improved CPR outcome. In general a range of good CPR physiology for a diastolic BPCPRQI may be defined to be between 20 and 40 mmHg and the range for good CPR physiology of mean BPCPRQI may be defined to be between 40 mmHg and 80mmHg.

    [0012] In the present disclosure trend feedback may be provided to the user, e.g. via a screen or other suitable display.

    [0013] In the present disclosure history of compression depth and frequency may be linked to the BPCPRQI and specific user feedback may then be given with respect to compression depth and frequency to the user to improve the BPCPRQI.

    [0014] In an embodiment, the invention provides a system for providing feedback regarding chest compressions in CPR, wherein the system comprises:

    a measuring unit providing a measure of arterial blood pressure of a patient,

    a processor registering data from the measuring unit, the processor being configured to obtain arterial blood pressure of the patient for a time period while CPR is being performed, and the processor being configured to calculate a blood pressure CPR quality indicator using the blood pressure as a function of time,

    an indicator unit providing an indication of the blood pressure CPR quality indicator, and

    a sensor for registering depth of compression of CPR and a display for displaying a signal indicating depth of compression,

    wherein the processor is further configured to indicate that in order to obtain an optimal compression depth, a step up and a step down of compression depth relative to a previously determined optimal compression depth should be performed, wherein the processor is arranged to register:
    1. 1) a first blood pressure CPR indicator in response to the previously determined optimal compression depth,
    2. 2) a second blood pressure CPR quality indicator in response to a step up in compression depth compared to the previously determined optimal compression depth, and
    3. 3) a third blood pressure CPR quality indicator in response to a step down in compression depth compared to the previously determined compressoin depth, and wherein the processor is arranged to select thereafter a new optimal compression depth based on the first, second and third blood pressure CPR quality indicators obtained, and
    wherein the new optimal compression depth is selected from the three applied compression depths (i.e. the previously determined optimal compression depth, the step up in compression depth, and the step down in compression depth) is defined as the compression depth with the highest blood pressure CPR quality indicator value or as the smallest compression depth with a blood pressure CPR quality indicator value that exceeds a target blood pressure CPR quality indicator value.

    [0015] The system according to the first aspect may incorporate any features mentioned in relation to the second and/or third aspects and other features mentioned throughout the present specification.

    [0016] A second aspect of the present invention relates to an automated resuscitation device according to claim 7.

    [0017] A third aspect of the present invention relates to a computer program according to claim 8.

    [0018] These and other aspects, features and/or advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0019] Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which:

    FIGS. 1 and 2 are schematic illustrations of ACPR devices connected to a blood pressure sensor,

    FIG. 3 schematically outlines illustrated operation of an algorithm,

    FIG. 4 schematically illustrates blood pressure as a function of time,

    FIG. 5 schematically outlines illustrated operation of an algorithm,

    FIG. 6 is a schematic view of a system for providing feedback regarding CPR , where a zoom box illustrates parts of the system,

    FIG. 7 is a schematic illustration of steps of a method.


    DETAILTED DESCRIPTION



    [0020] In Fig. 1 a schematic view of an automated CPR device with a system 10 for providing feedback regarding chest compressions in CPR and a blood pressure measuring device, mounted or connected to a patient is shown. The system 10 may be used as a part of other equipment such as automatic resuscitation equipment or as a stand-alone device, providing feedback to a paramedic or another person performing CPR. The system comprises a measuring unit providing a blood pressure CPR Quality indicator (BPCPRQI) of a patient, here in the form of a measurement unit that measures the arterial blood pressure at the wrist. The measuring unit is preferably a non-invasive device, as it is contemplated that the system is to be used in emergencies where fast access to BPCPRQI is needed. Further, a non-invasive measurement is preferred as the system should be useable by all levels of paramedics, and not all paramedics would be able to place invasive BP measurements. In Fig. 2 a schematic view of a system 10' similar to that in Fig. 1 is illustrated. Here a measure for the BPCPRQI is obtained via cuff based measurement on the arm.

    [0021] The system 10 further comprises a processor registering data from the measuring unit. The processor may be connected to an external memory, such as a RAM or FLASH storage for storing data received from the measuring unit. The processor is configured to obtain arterial blood pressure of the patient for a given time period, while CPR is being performed on the patient. The processor then calculates the blood pressure CPR quality indicator (BPCPRQI) using the blood pressure as a function of time. This indicator is used as a measure of the quality of the CPR operation, i.e. vital organ perfusion, which can be used to improve CPR operation. The BPCPRQI is then checked against a criterion. In one embodiment this criterion may be a threshold, in another embodiment this criterion might be an interval. Furthermore, the BPCPRQI may be continuously monitored, and may be indicated directly to the user to be able to see trends in CPR quality. This can be done, e.g. visually or via an audio signal such as voice or tone. The BPCPRQI may also be continuously monitored by a processor operating an automatic resuscitation device and the ACPR device using the BPCPRQI to optimize CPR compressions.

    [0022] The system may in some instances comprise a sensor for registering depth of compression of CPR and a display for displaying a signal indicating depth of compression. This will provide visual feedback to a person supervising the CPR.

    DESCRIPTION OF SIMPLIFIED EXAMPLES OF EMBODIMENTS


    Advantageous embodiment 1 (CPR quality on an Emergency Care Monitor)



    [0023] In a first advantageous embodiment a non-invasive continuous blood pressure CPR Quality Indicator (BPCPRQI) is used (e.g. tonometry). From the continuous arterial blood pressure, the diastolic period is extracted and the diastolic mean is calculated and used as BPCPRQI. The moving average BPCPRQI over some compressions (e.g. 5 compressions) is shown as a trend on the emergency care monitor. On declining trends the rescuer is warned.

    Advantageous embodiment 2 (Personalized and Automated CPR)



    [0024] In a second advantageous embodiment a non-invasive continuous arterial blood pressure measure is used (e.g. tonometry). From the continuous blood pressure, the diastolic period is extracted and the diastolic mean is calculated and used as blood pressure CPR Quality indicator (BPCPRQI). At the start of automated CPR, compression depth is ramped up (e.g. by 0.1 cm per compression), starting at a certain starting depth (e.g. 2.0cm). For every compression the BPCPRQI is monitored. Compressions are being ramped up until the optimum BPCPRQI is reached. During CPR, repeatedly (e.g. every time 2 minutes) a check is done if compression depth is still optimal by doing a single step size (e.g. 0.5 cm) to both sides of the optimum depth for some time (e.g. 10 seconds) and selecting the depth corresponding to the optimal BPCPRQI for the following time interval. The operation of the algorithm outlined here is schematically illustrated in Fig. 3. In this figure, the line 20 represents the compression depth, and the line 30 represents the BPCPRQI. Compression depth is increased at startup (20a). This results in an increasing BPCPRQI (30a). At some point during the ramp up, the BPCPRQI doesn't increase anymore and even decreases (30b). At that point of change, the compression depth is optimal and that depth is used for the next 2 minutes (20b). After 2 minutes a check is done if compression depth is still optimal, by first going to a 0.5cm lower compression depth for 10 seconds (20c). This results in an decreasing BPCPRQI (30c). Another step to 0.5 cm higher of the starting depth is done (20d) which results in a higher BPCPRQI (30d). The compression depth belonging to the optimal BPCPRQI is used for the next 2 minutes of CPR.

    Advantageous embodiment 3 (Personalized and Automated CPR)



    [0025] In a third advantageous embodiment a cuff based (non-invasive and non-continuous) arterial blood pressure measure is used as blood pressure CPR Quality indicator (BPCPRQI). Automated CPR is started at guideline compression depth (i.e. 5.0cm). Mean blood pressure is used as BPCPRQI. Optimum BPCPRQI is defined as achieving a certain minimum target value of BPCPRQI. A cuff measurement is done regularly (e.g. every 2 minutes) at the current compression depth for the time it takes to do a cuff BP measurement (e.g. 20 seconds).Thereafter compression depth is increased a single step size (e.g. 0.5 cm) and another cuff measurement is done. Thereafter a decrease in step size from the optimum is done and another cuff measurement is done. The smallest compression depth that results in a BPCPRQI value bigger than the target value is used as new optimum depth. If only values lower than the target value is found, the depth that results in the highest BPCPRQI value is used for the following time interval. The operation of the algorithm outlined here is schematically illustrated in Fig. 5. A target BPCPRQI of 60 mmHg is used. Here, at the start T 0, the current compression depth results in a BPCPRQI of 50 mmHg, 40a. At half a cm higher a BPCPRQI of 62 mmHg is measured and at half a cm lower a BPCPRQI of 40 mmHg is measured, see 40b and 40c. As the highest compression depth is the only one that reaches the target BPCPRQI of 62mmHg that compression depth is used for the next 2 minutes. In the second optimization interval, from T 3 to T 4, the current compression depth (which is half a cm higher than before) again results in a BPCPRQI of 62 mmHg, 50a. The half cm higher compression depth results in a BPCPRQI of 75 mmHg, 50b, the half cm lower compression depth results in a BPCPRQI of 50 mmHg, 50c. While the highest compression depth results in the highest BPCPRQI, the middle depth is the lowest depth that results in the BPCPRQI being higher than the target and is therefore used as depth for the next 2 minutes.

    [0026] Returning to the figures, Fig. 6 schematically illustrates a system 100 having a processor 110 connected to an indicator 120. The processor 110 receives signals indicative of the blood pressure of the patient 130. An external memory 140 is used for storing received data for processing. In this view blood pressure is obtained via the cuff 150, but any other suitable means may be used, as discussed elsewhere in the present text. Other suitable means for obtaining blood pressure may be used, e.g. a continuous invasive pressure catheter, a non-invasive regular cuff-measurement or a non-invasive continuous measurement or a combination thereof.

    [0027] If the blood pressure CPR quality indicator is below the quality threshold, i.e. outside an acceptable range relative to the criterion or in case that there is a too large decreasing trend, the processor is configured to transmit or emit a low quality indication signal. This low quality indication signal may be used by other units such as an indicator, either visual or audible to indicate to a person performing CPR that the CPR operation is not going as planned. The signal may also be forwarded to a unit responsible for performing CPR automatically. If the blood pressure CPR quality indicator on the other hand is above the threshold, i.e. within an acceptable range relative to the criterion, the processor may transmit a high quality indication signal, or the indication of high quality may be absence of a signal.

    [0028] Furthermore, the blood pressure CPR quality indicator may be monitored for a period of time, and if the blood pressure CPR quality indicator for that time period shows a negative trend, a decreasing CPR quality-signal may be transmitted. This will further help the person performing the CPR to detect that the CPR is not going as desired.

    [0029] The CPR quality indicator may be based on diastolic blood pressure. Coronary perfusion pressure (CPP) has shown to be related to blood flow and outcome of cardiac arrest. This parameter is calculated by subtracting right atrial blood pressure from aortic blood pressure during the diastolic phase of a CPR compression. Experiments have shown that Right Atrial pressure is very low during diastolic phase of CPR compressions which makes the diastolic aortic pressure also a measure of CPR quality. Instead of using the diastolic blood pressure, the mean blood pressure could be used as indicator of CPR quality.

    [0030] The Blood Pressure CPR Quality Indicator may be determined based on diastolic blood pressure in various ways:
    • The lowest point in the blood pressure curve during the diastolic phase.
    • The average pressure in the blood pressure curve during diastolic phase.
    • The last value of the diastolic phase (end diastole).


    [0031] The average diastolic pressure seems to a good candidate to use for CPR quality as the interest is in the average perfusion of the heart and not some incidental peak value.

    [0032] Further, the slope of the diastolic pressure, when monitored over a period of time, could be used to be used to tune the frequency of chest compressions. As long as the diastolic pressure remains steady, there is no need to initiate a next compression. However, when the diastolic pressure decreases, a following compression should be initiated soon. This is indicated in Fig. 4, where the slope of diastolic pressure is used to tune compression frequency. At t0 diastole starts. There is no need to start compressions at t1 as diastolic pressure is steady. Somewhere between t2 and t3 a next compression should start as the diastolic pressure is decreasing

    [0033] Different sensor modalities can be used for measuring blood pressure, including, but not limited to: invasive catheters to measure continuous aortic blood pressure, an occluding cuff (Riva-Rocci) method to measure blood pressure on regular intervals in which the diastolic value can be determined by Korotkoff sounds or oscillometry, tonometry or volume clamp methods to measure blood pressure in a continuous non-invasive way. Also, a combination of these may be applied. The use of a continuous, noninvasive blood-pressure measurement seems most valuable, because it provides clinical ease-of-use and beat-to-beat (i.e. compression-to-compression) information. For all sensor modalities filtering / averaging techniques may be used to improve the accuracy of the signal. When using a non-continuous measure, only individual diastolic values over a certain time interval are available (i.e. no average over time or end diastolic) and possible feedback can only be done on periodic intervals (i.e. not beat-to-beat).

    [0034] Different sensor locations might be used for measuring blood pressure, including but not limited to the upper arm, the wrist, the ankle and a fingertip.

    Definition of optimum CPR quality.



    [0035] Chest compression depth may be adjusted to optimize CPR quality. Optimum CPR quality may be defined as the maximum value of the Blood Pressure CPR Quality Indicator (BPCPRQI). In this case, the Blood Pressure measurement does not have to be absolute as higher is always better.

    [0036] Optimum CPR quality may be defined as a value of the Blood Pressure CPR Quality Indicator (BPCPRQI) that is related with good resuscitation outcome. Then the minimum chest compression depth that reaches this value is selected as the optimum compression depth. For CPP a value of bigger than 15 mmHg is correlated with high Return Of Spontaneous Circulation (ROSC, i.e. the start of spontaneous activity of the heart), a diastolic blood pressure should be around this value or preferably somewhat larger (20-40 mmHg, such as 25-35 mmHg). When using mean blood pressure values, this pressure should be approximately 60 mmHg (between 40-80 mmHg). With this method absolute values have to be measured (compared to relative values for maximization), so a sensor in this method must be able to measure absolute values, possibly after calibration.

    Use cases for the Blood Pressure CPR Quality Indicator



    [0037] The Blood Pressure CPR Quality Indicator (BPCPRQI) may be used in combination with / included in an ACPR device. The automated resuscitation device (ACPR) repeatedly compresses the chest of a patient. The system comprises a processor configured to operate the chest compression device based on the BPCPRQI, thereby optimizing CPR. This is done by regularly (e.g. every 3 minutes) performing a step up and a step down of compression depth relative to a previously determined optimal compression depth and selecting a new optimal compression depth based on the three CPR quality indicators obtained. For instance the new optimal compression depth may be selected from the three applied compression depths is defined as the depth with the highest blood pressure CPR quality indicator value or as the smallest depth with a blood pressure CPR quality indicator value that exceeds a target blood pressure CPR quality indicator value. This establishes a self-contained unit to be used by health professionals, or even untrained persons. A processor may indicate that, in order to obtain an optimal compression depth, a step up and a step down of compression depth relative to a previously determined optimal compression depth should be performed. A new optimal compression may then be selected depth based on the three CPR quality indicators obtained. In other embodiments a processor may be configured to provide such indication to a user, who then performs the steps.

    [0038] The Blood Pressure CPR Quality Indicator (BPCPRQI) may be used in combination with / included in an emergency care monitoring device. The monitor device may include visual and/or audio feedback to the health care person, or other, performing CPR so that the person may improve his or her CPR of the patient, for the benefit of the patient.
    • In an Emergency Care monitor, the BPCPRQI could be used as a visual indicator of CPR quality which could be shown in real time on the monitor screen.
    • In an Emergency Care monitor, besides showing the BPCPRQI, feedback (i.e. a warning signal) to the user could be given in case the BPCPRQI is falling (trend monitoring).
    • In an Emergency Care monitor, besides showing the BPCPRQI and warning the rescuer, specific feedback (compress (less /more, deep / fast) could be given to the rescuer. In this case the history of the quality parameter should be logged and linked to depth and frequency information.
    • In an ACPR device, the BPCPRQI could be included similarly as in the previous points.
    • In an ACPR device, the BPCPRQI could be included in a feedback system that tunes the compression depth on the start of ACPR, during ramp up of compressions. During ramp up, the compression depth is increased until the optimum in BPCPRQI is reached (within certain limits).
    • In an ACPR device, the BPCPRQI could be included in a closed loop feedback system, that on certain time intervals (e.g. every minute) or on user interaction does an automatic optimization of compression depth, by doing a single step size (e.g. 0.5 cm) to both sides of the optimum for a certain amount of time (e.g. 10 seconds), determines BPCPRQI for that time interval and selects compression depth with the highest BPCPRQI for the following time period.


    [0039] Fig. 7 is a schematic illustration of steps of a method for providing feedback regarding chest compressions in CPR. The method is preferably performed using a system comprising a measuring unit providing a measure of arterial blood pressure of a patient, such as discussed above. The method may be implemented in software for execution on a processor in the system. The method comprises the step of obtaining arterial blood pressure of the patient for a period of time while CPR is being performed on the patient. Further, the method comprises the step of calculating a blood pressure CPR quality indicator using the blood pressure as a function of time, and indicating the blood pressure CPR quality indicator.

    [0040] The method may include any of the steps mentioned in relation to operating the systems as described in the present specification.

    [0041] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.


    Claims

    1. A system (10, 10', 100) for providing feedback regarding chest compressions in CPR, wherein the system comprises:

    a measuring unit (150) providing a measure of arterial blood pressure of a patient (150),

    a processor (120) registering data from the measuring unit 150), the processor being configured to obtain arterial blood pressure of the patient for a time period while CPR is being performed, and the processor being configured to calculate a blood pressure CPR quality indicator (30) using the blood pressure as a function of time,

    an indicator unit (120) providing an indication of the blood pressure CPR quality indicator, and

    a sensor for registering depth of compression (20) of CPR and a display for displaying a signal indicating depth of compression,

    characterized in that the processor (110) is further configured to indicate that in order to obtain an optimal compression depth, a step up (40b) and a step down (40c) of compression depth relative to a previously determined optimal compression depth (40a) should be performed, where after selecting a new optimal compression depth based on the three CPR quality indicators obtained, and
    wherein the new optimal compression depth selected from the three applied compression depths (50a, 50b, 50c) is defined as the depth with the highest blood pressure CPR quality indicator value or as the smallest depth with a blood pressure CPR quality indicator value that exceeds a target blood pressure CPR quality indicator value.
     
    2. The system (10, 10', 100) according to claim 1, wherein if the blood pressure CPR quality indicator (30) is below a quality threshold or outside a target interval, transmitting a low quality indication signal, if the blood pressure CPR quality indicator (30) is above the threshold or inside the target interval, transmitting a high quality indication signal, optionally if the blood pressure CPR quality indicator (30) for a time period shows a negative trend, transmitting a decreasing CPR quality signal.
     
    3. The system (10, 10', 100) according to claim 1, wherein the indicator unit (120) is a visual indicator configured to provide visual indication of the low quality indication signal and/or high quality indication signal and/or present blood pressure CPR quality indicator (30).
     
    4. The system (10, 10', 100) according to claim 1, wherein blood pressure is obtained via a continuous invasive pressure catheter, a non-invasive regular cuff-measurement (150) or a non-invasive continuous measurement or a combination thereon.
     
    5. The system (10, 10', 100) according to claim 1, wherein diastolic blood pressure is used for calculating the blood pressure CPR quality indicator (30) or the mean blood pressure value is used as the blood pressure CPR quality indicator (30), where optional target levels or intervals for the diastolic blood pressure are between 20 and 40 mmHg and target levels or intervals for the mean blood pressure are between 40 and 80 mmHg.
     
    6. The system (10, 10', 100) according to claim 1, wherein the diastolic blood pressure is determined by the minimum value during the diastolic phase of the blood pressure signal or the average value of the diastolic phase of the blood pressure signal or the end value of the diastolic phase of the blood pressure signal.
     
    7. An automated resuscitation device comprising:

    a chest compression device to repeatedly compress the chest of a patient the system (10, 10', 100) according to claim 1 to measure quality of CPR, and

    a processor configured to operate the chest compression device according to claim 4 on regular time intervals or by user interaction.


     
    8. A computer program stored on a medium or distributed via a wired or wireless telecommunication system, wherein the computer program is adapted to, when executed in a processor of a system (10, 10', 100) comprising a measuring unit (150) providing a measure of blood pressure of a patient (130) and an indicator unit (120) providing an indication of a blood pressure CPR quality indicator (30), implement the steps of:

    while CPR is being performed on the patient (130) obtaining for a time period blood pressure of the patient,

    calculating using the blood pressure as a function of time the blood pressure CPR quality indicator (30), and if the blood pressure CPR quality indicator is outside a quality criterion transmitting a low quality indication signal, if the blood pressure CPR quality indicator fulfills the quality criterion the threshold transmitting a high quality indication signal

    registering a depth of compression (20) of CPR and displaying a signal indicating depth of compression,

    indicating that in order to obtain an optimal compression depth, a step up (40b) and a step down (40c) of compression depth relative to a previously determined optimal compression depth (40a) should be performed,

    selecting a new optimal compression depth based on the three CPR quality indicators obtained, wherein the new optimal compression depth is selected from the three applied compression depths (50a, 50b, 50c) is defined as the depth with the highest blood pressure CPR quality indicator value or as the smallest depth with a blood pressure CPR quality indicator value that exceeds a target blood pressure CPR quality indicator value.


     
    9. The computer program of claim 8, wherein a high quality indication signal is transmitted when the blood pressure CPR quality indicator (30) is in a certain high quality range and a low quality signal is transmitted if the blood pressure CPR quality indicator (30) is not in this range.
     
    10. The computer program of claim 8, wherein the system (10, 10', 100) comprises a visual indicator and/or an audio transmitter, the computer program is further adapted to implement the step of indicating a respective low quality indication signal or high quality indication signal via the visual indicator and/or audio transmitter and/or wherein optionally if the blood pressure CPR quality indicator (30) for a time period shows a negative trend, transmitting a decreasing CPR quality signal.
     
    11. The computer program of claim 8, wherein diastolic blood pressure is used for calculating the blood pressure CPR quality indicator (30) or the mean blood pressure value is used as the blood pressure CPR quality indicator (30).
     
    12. The computer program of claim 11, wherein the diastolic blood pressure is determined by the minimum value during the diastolic phase of the blood pressure signal or the average value of the diastolic phase of the blood pressure signal or the end value of the diastolic phase of the blood pressure signal.
     


    Ansprüche

    1. System (10, 10', 100) zur Bereitstellung von Rückmeldungen in Bezug auf Thoraxkompressionen bei der HLW, wobei das System Folgendes umfasst:

    eine Messeinheit (150) zur Bereitstellung eines Messwertes des arteriellen Blutdrucks eines Patienten (130),

    einen Prozessor (120), der Daten von der Messeinheit (150) registriert, wobei der Prozessor konfiguriert ist, um den arteriellen Blutdruck des Patienten über eine Zeitdauer zu erlangen, während die HLW durchgeführt wird, und wobei der Prozessor konfiguriert ist, um einen Blutdruck-HLW-Qualitätsindikator (30) unter Verwendung des Blutdrucks als Funktion der Zeit zu berechnen,

    eine Indikatoreinheit (120), die eine Angabe des Blutdruck-HLW-Qualitätsindikators bereitstellt, und

    einen Sensor zum Registrieren der Kompressionstiefe (20) der HLW und eine Anzeige zum Anzeigen eines die Kompressionstiefe angebenden Signals,

    dadurch gekennzeichnet, dass der Prozessor (110) weiterhin konfiguriert ist, um anzugeben, dass zum Erlangen einer optimalen Kompressionstiefe eine Erhöhung (40b) und eine Verringerung (40c) der Kompressionstiefe in Bezug auf eine zuvor ermittelte optimale Kompressionstiefe (40a) durchgeführt werden sollte, wobei nach dem Auswählen eine neue optimalen Kompressionstiefe basierend auf den drei HLW-Qualitätsindikatoren erlangt wird, und
    wobei die aus den drei angewendeten Kompressionstiefen (50a, 50b, 50c) ausgewählte neue optimale Kompressionstiefe definiert ist als die Tiefe mit dem höchsten Blutdruck-HLW-Qualitätsindikatorwert oder als die kleinste Tiefe mit einem Blutdruck-HLW-Qualitätsindikatorwert, der einen Ziel-Blutdruck-HLW-Qualitätsindikatorwert überschreitet.
     
    2. System (10, 10', 100) nach Anspruch 1, wobei ein Indikatorsignal für niedrige Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) unter einem Qualitätsschwellenwert oder außerhalb eines Zielintervalls liegt; ein Indikatorsignal für hohe Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) über dem Schwellenwert oder innerhalb des Zielintervalls liegt, und optional ein Signal für abnehmende HLW-Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) für eine Zeitdauer einen negativen Trend zeigt.
     
    3. System (10, 10', 100) nach Anspruch 1, wobei die Indikatoreinheit (120) ein visueller Indikator ist, der konfiguriert ist, um eine visuelle Angabe des Indikatorsignals für niedrige Qualität und/oder des Indikatorsignals für hohe Qualität und/oder des vorhandenen Blutdruck-HLW-Qualitätsindikators (30) bereitzustellen.
     
    4. System (10, 10' 100) nach Anspruch 1, wobei der Blutdruck über einen kontinuierlichen invasiven Druckkatheter, eine nicht-invasive reguläre Manschettenmessung (150) oder eine nicht-invasive kontinuierliche Messung oder eine Kombination hiervon erlangt wird.
     
    5. System (10, 10', 100) nach Anspruch 1, wobei der diastolische Blutdruck verwendet wird, um den Blutdruck-HLW-Qualitätsindikator (30) zu berechnen, oder der mittlere Blutdruckwert als der Blutdruck-HLW-Qualitätsindikator (30) verwendet wird, wobei optionale Zielpegel oder -intervalle für den diastolischen Blutdruck zwischen 20 und 40 mmHg liegen und Zielpegel oder -intervalle für den mittleren Blutdruck zwischen 40 und 80 mmHg liegen.
     
    6. System (10, 10', 100) nach Anspruch 1, wobei der diastolische Blutdruck durch den Mindestwert während der diastolischen Phase des Blutdrucksignals oder den Mittelwert der diastolischen Phase des Blutdrucksignals oder den Endwert der diastolischen Phase des Blutdrucksignals ermittelt wird.
     
    7. Automatisierte Wiederbelebungsvorrichtung, umfassend:

    eine Thoraxkompressionsvorrichtung zum wiederholten Komprimieren des Thorax eines Patienten,

    das System (10, 10', 100) nach Anspruch 1 zum Messen der Qualität der HLW, und

    einen Prozessor, der konfiguriert ist, um die Thoraxkompressionsvorrichtung nach Anspruch 4 in regulären Zeitintervallen oder durch Benutzerinteraktion zu betätigen.


     
    8. Computerprogramm, das auf einem Medium gespeichert ist oder über ein drahtgebundenes oder drahtloses Telekommunikationssystem verteilt wird, wobei das Computerprogramm vorgesehen ist, um, wenn es in einem Prozessor eines Systems (10, 10', 100) mit einer Messeinheit (150), die einen Messwert des Blutdrucks eines Patienten (130) bereitstellt, und einer Indikatoreinheit (120), die eine Angabe eines Blutdruck-HLW-Qualitätsindikators (30) bereitstellt, ausgeführt wird, die folgenden Schritte zu implementieren:

    während der Durchführung der HLW an dem Patienten (130) Erlangen des Blutdrucks des Patienten über einen Zeitraum,

    Berechnen des Blutdruck-HLW-Qualitätsindikators (30) als Funktion der Zeit unter Verwendung des Blutdrucks; Übertragen eines Indikatorsignals für niedrige Qualität, wenn der Blutdruck-HLW-Qualitätsindikator außerhalb eines Qualitätskriteriums liegt; Übertragen eines Indikatorsignals für hohe Qualität, wenn der Blutdruck-HLW-Qualitätsindikator das Qualitätskriterium Schwellenwert erfüllt,

    Registrieren einer Kompressionstiefe (20) der HLW und Anzeigen eines die Kompressionstiefe angebenden Signals,

    Angeben, dass zum Erlangen einer optimalen Kompressionstiefe eine Erhöhung (40b) und eine Verringerung (40c) der Kompressionstiefe in Bezug auf eine zuvor ermittelte optimale Kompressionstiefe (40a) durchgeführt werden sollte,

    Auswählen einer neuen optimalen Kompressionstiefe basierend auf den erlangten drei HLW-Qualitätsindikatoren, wobei die neue optimale Kompressionstiefe, ausgewählt aus den drei angewendeten Kompressionstiefen (50a, 50b, 50c), definiert ist als die Tiefe mit dem höchsten Blutdruck-HLW-Qualitätsindikatorwert oder als die kleinste Tiefe mit einem Blutdruck-HLW-Qualitätsindikatorwert, der einen Ziel-Blutdruck-HLW-Qualitätsindikatorwert überschreitet.


     
    9. Computerprogramm nach Anspruch 8, wobei das Indikatorsignal für hohe Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) in einem bestimmten hohen Qualitätsbereich liegt, und ein Signal für niedrige Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) nicht in diesem Bereich liegt.
     
    10. Computerprogramm nach Anspruch 8, wobei das System (10, 10', 100) einen visuellen Indikator und/oder einen Audio-Sender umfasst, wobei das Computerprogramm weiterhin dafür ausgelegt ist, den Schritt des Angebens eines jeweiligen Indikatorsignals für niedrige Qualität oder eines Indikatorsignals für hohe Qualität über den visuellen Indikator und/oder einen Audio-Sender zu implementieren und/oder wobei optional ein Signal für abnehmende HLW-Qualität übertragen wird, wenn der Blutdruck-HLW-Qualitätsindikator (30) für eine Zeitdauer einen negativen Trend zeigt.
     
    11. Computerprogramm nach Anspruch 8, wobei der diastolische Blutdruck zum Berechnen des Blutdruck-HLW-Qualitätsindikators (30) verwendet wird oder der mittlere Blutdruckwert als der Blutdruck-HLW-Qualitätsindikatorwert (30) verwendet wird.
     
    12. Computerprogramm nach Anspruch 11, wobei der diastolische Blutdruck durch den Mindestwert während der diastolischen Phase des Blutdrucksignals oder den Mittelwert der diastolischen Phase des Blutdrucksignals oder den Endwert der diastolischen Phase des Blutdrucksignals ermittelt wird.
     


    Revendications

    1. Système (10, 10', 100) pour fournir un retour d'informations concernant des compressions thoraciques en RCR, dans lequel le système comprend :

    une unité de mesure (150) fournissant une mesure de pression artérielle d'un patient (130),

    un processeur (120) enregistrant des données de l'unité de mesure (150), le processeur étant configuré pour obtenir la pression artérielle du patient pendant une période de temps au cours de laquelle la RCR est effectuée, et le processeur étant configuré pour calculer un indicateur de qualité de la RCR associé à la pression artérielle (30) en utilisant la pression artérielle en fonction du temps,

    une unité indicatrice (120) fournissant une indication de l'indicateur de qualité de la RCR associé à la pression artérielle, et

    un capteur pour enregistrer la profondeur de compression (20) de la RCR et un affichage pour afficher un signal indiquant la profondeur de compression,

    caractérisé en ce que le processeur (110) est en outre configuré pour indiquer qu'afin d'obtenir une profondeur de compression optimale, une augmentation (40b) et une réduction (40c) de profondeur de compression par rapport à une profondeur de compression optimale précédemment déterminée (40a) doivent être assurées, après avoir choisi une nouvelle profondeur de compression optimale sur la base des trois indicateurs de qualité de RCR obtenus, et

    dans lequel la nouvelle profondeur de compression optimale choisie parmi les trois profondeurs de compression appliquées (50a, 50b, 50c) est définie comme la profondeur ayant la valeur d'indicateur de qualité de RCR associé à la pression artérielle la plus élevée ou comme le profondeur la plus faible ayant une valeur d'indicateur de qualité de RCR associé à la pression artérielle qui dépasse une valeur d'indicateur de qualité de RCR associé à la pression artérielle cible.


     
    2. Système (10, 10', 100) selon la revendication 1, dans lequel si l'indicateur de qualité de RCR associé à la pression artérielle (30) est en dessous d'un seuil de qualité ou en dehors d'un intervalle cible, un signal d'indication de faible qualité est transmis, si l'indicateur de qualité de RCR associé à la pression artérielle (30) se situe au-dessus ou à l'intérieur d'un intervalle cible, un signal d'indication de haute qualité est transmis, éventuellement si l'indicateur de qualité de RCR associé à la pression artérielle (30) présente pendant une période de temps une tendance négative, un signal de qualité de RCR détériorée est transmis.
     
    3. Système (10, 10', 100) selon la revendication 1, dans lequel l'unité indicatrice (120) est un indicateur visuel configuré pour fournir une indication visuelle du signal d'indication de faible qualité et/ou du signal d'indication de haute qualité et/ou un indicateur de qualité de RCR associé à la pression artérielle actuelle (30).
     
    4. Système (10, 10', 100) selon la revendication 1, dans lequel la pression artérielle est obtenue via un cathéter de pression invasif en continu, une mesure de brassard standard non invasive (150) ou une mesure en continu non-invasive ou une combinaison de ceux-ci.
     
    5. Système (10, 10', 100) selon la revendication 1, dans lequel la pression artérielle diastolique est utilisée pour calculer l'indicateur de qualité de RCR associé à la pression artérielle (30) ou la valeur de la pression artérielle moyenne est utilisée en tant qu'indicateur de qualité de RCR associé à la pression artérielle (30), où des niveaux ou intervalles cibles éventuels de la pression artérielle diastolique sont compris entre 20 et 40 mmHg et des niveaux ou intervalles cibles de la pression artérielle moyenne sont compris entre 40 et 80 mmHg.
     
    6. Système (10, 10', 100) selon la revendication 1, dans lequel la pression artérielle diastolique est déterminée par la valeur minimale au cours de la phase diastolique du signal de pression artérielle ou la valeur moyenne de la phase diastolique du signal de pression artérielle ou la valeur finale de la phase diastolique du signal de pression artérielle.
     
    7. Dispositif de réanimation automatique comprenant :

    un dispositif de compression thoracique destiné à comprimer de façon répétée le thorax d'un patient,

    le système (10, 10', 100) selon la revendication 1 pour mesurer la qualité de la RCR, et

    un processeur configuré pour activer le dispositif de compression thoracique selon la revendication 4 à intervalles de temps réguliers ou par interaction avec l'utilisateur.


     
    8. Programme informatique stocké sur un support ou distribué via un système de télécommunication filaire ou sans fil, dans lequel le programme informatique est adapté, lorsqu'il est exécuté dans un processeur d'un système (10, 10', 100) comprenant une unité de mesure (150) fournissant une mesure de pression artérielle d'un patient (130) et une unité indicatrice (120) fournissant une indication d'un indicateur de qualité de RCR associé à la pression artérielle (30), pour mettre en oeuvre les étapes suivantes :

    alors que la RCR est en cours d'exécution sur le patient (130), l'obtention au cours d'une période de temps de la pression artérielle du patient,

    le calcul au moyen de la pression artérielle en fonction du temps de l'indicateur de qualité de RCR associé à la pression artérielle (30), et si l'indicateur de qualité de RCR associé à la pression artérielle se situe en dehors d'un critère de qualité, un signal d'indication de faible qualité est transmis, si l'indicateur de qualité de RCR associé à la pression artérielle répond au critère de qualité du seuil, un signal d'indication de haute qualité est transmis,

    l'enregistrement d'une profondeur de compression (20) de RCR et l'affichage d'un signal indiquant la profondeur de compression,

    l'indication du fait qu'afin d'obtenir une profondeur de compression optimale, une augmentation (40b) et une réduction (40c) de la profondeur de compression par rapport à une profondeur de compression optimale précédemment déterminée (40a) doivent être assurées,

    la sélection d'une nouvelle profondeur de compression optimale sur la base des trois indicateurs de qualité de RCR obtenus, dans lequel la nouvelle profondeur de compression optimale sélectionnée parmi les trois profondeurs de compression appliquées (50a, 50b, 50c) est définie comme la profondeur ayant la valeur d'indicateur de qualité de RCR associé à la pression artérielle la plus élevée ou comme la profondeur la plus faible ayant une valeur d'indicateur de qualité de RCR associé à la pression artérielle qui dépasse une valeur d'indicateur de qualité de RCR associé à la pression artérielle cible.


     
    9. Programme informatique selon la revendication 8, dans lequel un signal d'indication de haute qualité est transmis lorsque l'indicateur de qualité de RCR associé à la pression artérielle (30) se situe dans une certaine plage de haute qualité et un signal de faible qualité est transmis si l'indicateur de qualité de RCR associé à la pression artérielle (30) ne se situe pas dans ladite plage.
     
    10. Programme informatique selon la revendication 8, dans lequel le système (10, 10', 100) comprend un indicateur visuel et/ou un émetteur audio, le programme informatique est en outre adapté pour mettre en oeuvre l'étape d'indication d'un signal d'indication de faible qualité ou signal d'indication de haute qualité respectif via l'indicateur visuel et/ou l'émetteur audio et/ou dans lequel éventuellement si l'indicateur de qualité de RCR associé à la pression artérielle (30) présente au cours d'une période de temps une tendance négative, un signal de qualité détériorée de RCR est transmis.
     
    11. Programme informatique selon la revendication 8, dans lequel la pression artérielle diastolique est utilisée pour calculer l'indicateur de qualité de RCR associé à la pression artérielle (30) ou la valeur de pression artérielle moyenne est utilisée en tant qu'indicateur de qualité de RCR associé à la pression artérielle (30).
     
    12. Programme informatique selon la revendication 11, dans lequel la pression artérielle diastolique est déterminée à l'aide de la valeur minimale au cours de la phase diastolique du signal de pression artérielle ou de la valeur moyenne de la phase diastolique du signal de pression artérielle ou de la valeur finale de la phase diastolique du signal de pression artérielle.
     




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    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description