Blood pressure estimation device, cardiopulmonary resuscitation support device

Abstract

An object of the present invention is to provide a device for estimating blood pressure and a device for supporting cardiopulmonary resuscitation in order to perform appropriate chest compressions and ventilation during cardiopulmonary resuscitation. A chest compression data acquisition unit acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest. a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; The blood pressure estimation device is provided with the above.

Description

[Technical Field]

[0001] The present invention relates to a blood pressure estimation device and a cardiopulmonary resuscitation support device. [Background technology]

[0002] CPR requires not only chest compressions at the right timing and with the right depth, but also ventilation, which maintains a certain blood pressure even after chest compressions are stopped and supplies oxygen to the lungs while blood is flowing. However, it is difficult for rescuers who are unfamiliar with CPR to perform appropriate chest compressions and ventilation. In particular, ventilation must be performed at the right time or oxygen will not be supplied to the lungs, resulting in insufficient oxygen supply to the blood even if ventilation is performed.

[0003] Furthermore, when performing chest compressions, rescuers usually need to be rotated every 1-2 minutes to avoid fatigue. This can lead to variations in chest compression techniques depending on the rescuer's experience and skill, making it difficult to continue appropriate CPR.

[0004] Japan's basic life support guidelines are based on those of the American Heart Association (AHA), avoiding the use of medical terminology and catering to a wide range of users. These guidelines describe the rate, number, and depth of chest compressions when performing cardiopulmonary resuscitation (CPR). However, they do not adequately describe the purpose of the techniques, and it is difficult to understand what to pay attention to when performing CPR (see Non-Patent Document 1).

[0005] Research has also been conducted into the relationship between the tempo and depth of chest compressions during cardiopulmonary resuscitation, the duration of chest compression interruptions, and the return of cardiac rhythm, but these have only been evaluated based on individual indicators (see Non-Patent Document 2). Other devices available on the market are capable of measuring the depth of chest compressions, the release of chest compressions, the speed of chest compressions, the duration of chest compression interruptions, and the number of chest compressions, but these only provide a partial view of the current status of each indicator. Furthermore, a cardiopulmonary resuscitation treatment system (see Patent Document 1) that uses an acceleration sensor and a force sensor to measure the depth of cardiac massage and evaluate its reliability even while the vehicle is moving has been disclosed as a cardiopulmonary resuscitation support system, and a device (see Patent Document 2) that derives the depth of chest compressions based on images provided by a camera have both focused on the depth of compressions.

[0006] The inventor has disclosed a health condition judgment support device based on the connections between heart rate, blood pressure, and oxygen saturation as vital signs (see Patent Document 3). This device predicts the current health condition based on the measured heart rate, blood pressure, and oxygen saturation, but does not mention cardiopulmonary resuscitation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2010-509014 [Patent Document 2] Special Publication No. 2019-520868 [Patent Document 3] Japanese Patent Publication No. 2023-143586 [Non-patent literature]

[0008] [Non-Patent Document 1] American Heart Association CRP and ECC Guidelines www.acls.jp / doc / hghlghts_2020eccguidelines_japanese.pdf [Non-patent document 2] Hiroya Wakamatsu et al. Journal of the Japanese Society of Clinical Medicine Vol. 38 No. 3, 347-353, 2018 Summary of the Invention [Problem to be solved by the invention]

[0009] During cardiopulmonary resuscitation (CPR), the efficiency of gas exchange decreases even when alveoli are expanded during positive pressure ventilation. Furthermore, interrupting chest compressions for ventilation can cause a drop in blood pressure. However, during CPR, the timing of chest compression interruptions and ventilation is determined by the rescuer's experience and intuition. Even with conventional CPR support devices, only partial displays of vital signs are provided, and the timing of blood pressure and ventilation is not taken into account. This can lead to ineffective CPR despite the existence of guidelines. Furthermore, it was difficult to estimate blood pressure during chest compressions. This was because peripheral blood vessels were closed during CPR, making accurate blood pressure measurements impossible. Aortic blood pressure is necessary to allow blood to flow through the coronary arteries. Measuring aortic blood pressure requires placing a needle equipped with a blood pressure sensor in the aorta, but placing a blood sensor in the aorta during CPR is not practical, making it difficult to measure blood pressure. Therefore, an object of the present invention is to provide a device for estimating blood pressure and a device for supporting cardiopulmonary resuscitation in order to perform appropriate chest compressions and ventilation during cardiopulmonary resuscitation. [Means for solving the problem]

[0010] As a result of intensive research aimed at solving the above-mentioned problems, the inventors have acquired predetermined chest compression data during chest compressions on a victim in cardiac arrest, estimated blood pressure based on the chest compression data, and discovered a device that can notify a user whether the blood pressure is at an appropriate level to improve blood oxygen saturation based on the estimated blood pressure, thereby completing the present invention.

[0011] That is, the present invention is as follows. [1] A chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest; a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; A blood pressure estimation device comprising: [2] In the blood pressure estimation unit, the tempo of chest compression is calculated from the number of chest compressions per predetermined time, The estimated augmented blood pressure per predetermined number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions is determined in advance when chest compressions are performed that satisfy the conditions of a predetermined depth of chest compressions, a predetermined return of chest compressions, and a predetermined tempo of chest compressions. The blood pressure estimation device according to [1] above, which estimates blood pressure based on the estimated augmented blood pressure per predetermined number of chest compressions and the acquired number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions and the duration of chest compressions. [3] The chest compression data further includes an interruption time of chest compression, and an estimated descending blood pressure per predetermined interruption time is determined in advance. The estimated augmented blood pressure per predetermined number of chest compressions and the acquired number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions and duration of chest compressions, and the estimated descending blood pressure per predetermined interruption time and the acquired interruption time of chest compression; The blood pressure estimation device according to [2] above, which estimates blood pressure based on [4] A chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest; a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; A cardiopulmonary resuscitation support device comprising a notification unit that notifies whether the estimated blood pressure is at an appropriate blood pressure level for increasing blood oxygen saturation through ventilation in cardiopulmonary resuscitation, based on the estimated blood pressure estimated by the blood pressure estimation unit and a predetermined blood pressure threshold value appropriate for increasing blood oxygen saturation. [5] The cardiopulmonary resuscitation support device described in [4] above, characterized in that the notification unit has a display and displays on the display whether the estimated blood pressure estimated by the blood pressure estimation unit or a predetermined estimated blood pressure threshold is an appropriate blood pressure level for improving blood oxygen saturation through ventilation in cardiopulmonary resuscitation, based on the estimated blood pressure estimated by the blood pressure estimation unit or a predetermined estimated blood pressure threshold. [6] A cardiopulmonary resuscitation support device as described in [4] or [5] above, in which the notification unit estimates and notifies the optimal timing of ventilation based on the estimated blood pressure and the predetermined blood pressure threshold appropriate for increasing blood oxygen saturation. [7] The chest compression data further includes an interruption time of chest compression; The cardiopulmonary resuscitation support device according to any one of [4] to [6] above, characterized in that the notification unit displays the estimated blood pressure and the interruption time of chest compressions. [8] A blood pressure estimation program that causes a computer to function as the blood pressure estimation device according to any one of [1] to [3] above. [9] A cardiopulmonary resuscitation support program that causes a computer to function as the cardiopulmonary resuscitation support device described in any one of [4] to [7] above. Furthermore, other aspects of the present disclosure include a computer-readable recording medium having a computer program recorded thereon, the computer program being the blood pressure estimation program described in [8] above, or the cardiopulmonary resuscitation support program described in [9] above. [Effects of the Invention]

[0012] The present invention makes it possible to assist rescuers in appropriate blood pressure estimation and cardiopulmonary resuscitation. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing an embodiment of a blood pressure estimation device. [Figure 2]FIG. 2 is a block diagram illustrating an embodiment of a cardiopulmonary resuscitation assistance device. [Figure 3] FIG. 3 is a diagram showing a flow of estimating blood pressure in the blood pressure estimation unit of the blood pressure estimation device. [Figure 4] FIG. 4 is a diagram showing Example 1 in which a display is used as a notification unit in a cardiopulmonary resuscitation support device and chest compression data is displayed on the display. [Figure 5] FIG. 5 is a diagram showing Example 2 in which a display is used as a notification unit in a cardiopulmonary resuscitation support device and chest compression data is displayed on the display. [Figure 6] FIG. 6 is a diagram showing Example 3 in which a display is used as a notification unit in a cardiopulmonary resuscitation support device and chest compression data is displayed on the display. DETAILED DESCRIPTION OF THE INVENTION

[0014] The contents of all patent and non-patent literature cited herein are hereby incorporated by reference in their entirety.

[0015] The blood pressure estimation device in this specification includes a chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest; a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; The blood pressure estimation device is not particularly limited as long as it is equipped with the above, and hereinafter it will be simply referred to as the "blood pressure estimation device of the present invention." The cardiopulmonary resuscitation support device in this specification also includes a chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest, a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; There are no particular restrictions on the cardiopulmonary resuscitation support device, provided that it is equipped with a notification unit that notifies whether the estimated blood pressure is at an appropriate blood pressure level for increasing blood oxygen saturation through ventilation in cardiopulmonary resuscitation, based on the estimated blood pressure estimated by the blood pressure estimation unit and a predetermined estimated blood pressure threshold, and hereinafter this will be referred to simply as "the cardiopulmonary resuscitation support device in question."

[0016] ◆Vital signs Conventional CPR has lacked understanding of vital signs. As a result, CPR has been performed based on temporary information without considering the relationship between each vital sign and the sequence of events. Therefore, we will first explain vital signs.

[0017] First, in cardiac arrest, there are no vital signs because circulatory dynamics cannot be maintained. The myocardium requires oxygen to function. Oxygen is taken into the body through breathing, where it combines with hemoglobin in the blood in the alveoli and is then transported to each tissue. To supply oxygen to the myocardium, oxygenated blood must be sent to the coronary arteries, which supply oxygen to the myocardium. Blood flows through the coronary arteries during diastole (when the chest wall is fully retracted), oxygenating the myocardium and allowing it to function. Blood pressure is needed to send this blood. A pulse is needed to maintain blood pressure. Therefore, pulse, blood pressure, and oxygen saturation must be maintained appropriately. In other words, the myocardium cannot function without vital signs.

[0018] The 2020 AHA Guidelines state the following five things for high-quality CPR: (1) Begin chest compressions within 10 seconds of confirming cardiac arrest. (2) Press hard and fast: Press at a tempo of 100 to 120 times per minute, with the depth as follows: -To a depth of at least 5cm but not more than 6cm for adults - In children, the depth should be at least 1 / 3 of the chest (approximately 5 cm). - For infants, the depth should be at least 1 / 3 of the chest (approximately 4 cm) (3) Wait until the chest completely recoils after each compression. Do not lean on the chest between compressions. (4) Minimize interruptions in chest compressions (try to keep interruptions in chest compressions to less than 10 seconds). (5) Administer effective artificial respiration. Ventilate over 1 second to allow the victim's chest to rise. Avoid hyperventilation.

[0019] We will consider the above (1) through (5) as vital sign control. (1) Starting chest compressions restores the heart rate (pulse rate) from a state of cardiac arrest. (2) specifies a heart rate of 100–120 beats per minute. Pushing hard and fast increases the systolic blood pressure by contracting the heart through external stimuli such as manual compressions. (3) Retracting the chest expands the heart and increases the diastolic blood pressure. (4) Minimizing interruptions in chest compressions prevents a drop in blood pressure. (5) Raising the chest specifies the ventilation volume. Effective artificial respiration requires gas exchange. Gas exchange requires blood flow. To achieve this, ventilation must be performed while maintaining blood pressure and blood flow. Avoiding hyperventilation is important because it increases intrathoracic pressure, which reduces venous return, making it difficult for blood to return to the heart and reducing cardiac output, thereby preventing poor blood circulation. From the above, each item is related to (1) pulse, (2) systolic blood pressure, (3) diastolic blood pressure, (4) prevention of blood pressure drop, (5) management of oxygen saturation, and maintenance of blood circulation, and can be said to be a technique for creating vital signs.

[0020] Considering the above, appropriate oxygen saturation can be managed by performing ventilation under conditions where a predetermined amount of chest compression is performed to maintain a predetermined blood pressure.

[0021] This blood pressure estimation device The present blood pressure estimation device and the present cardiopulmonary resuscitation support device include a chest compression data acquisition unit and a blood pressure estimation unit.

[0022] 1 shows one embodiment of the blood pressure estimation device 1 of the present disclosure. The blood pressure estimation device 1 includes a chest compression data acquisition unit 11 and a blood pressure estimation unit 12, and is used to determine the estimated blood pressure when a rescuer performs appropriate chest compressions and ventilation when performing cardiopulmonary resuscitation on an injured person.

[0023] (Chest compression data acquisition unit) The chest compression data acquisition unit 11 acquires the number of chest compressions, depth of chest compressions, return of chest compressions, and duration of chest compressions for a victim in cardiac arrest. Furthermore, the unit may acquire the interruption time of chest compressions, the ratio of the number of chest compressions to the number of ventilations, compression speed, compression force, and chest compression fraction (CCF). Each piece of data acquired by the chest compression data acquisition unit may be stored in the memory unit 14.

[0024] The injured person may be a person in cardiac arrest, or a person in respiratory arrest.

[0025] The number of chest compressions is the number of times that chest compressions are performed, counting one cycle from pushing down on the victim's sternum to releasing the compressions and allowing the sternum to return to its natural position.

[0026] Chest compression depth refers to the depth to which the victim's sternum is depressed by chest compressions, or the range of chest movement from the start of chest compressions. The direction in which the victim's sternum is depressed by chest compressions is referred to as the chest compression direction. In cardiopulmonary resuscitation (CPR), the preferred depth of chest compressions is generally 5 to 6 cm in the chest compression direction. Furthermore, for children and infants, a chest compression depth of 1 / 3 of the chest thickness is considered desirable. Insufficient chest compression depth during CPR can result in ineffective blood circulation and reduced oxygen delivery to the blood. On the other hand, chest compressions that are too deep pose a risk of damaging the ribs and other internal organs. Chest compressions are performed by placing the palms of the hands on the lower half of the sternum and pressing down with the fingers interlocked. The arms are extended straight, and compressions are performed using the patient's body weight. A CPR board on which the victim rests may be provided, and the depth of chest compressions may be adjusted based on the fluctuations of the CPR board.

[0027] Restoration of chest compressions refers to the natural return of the sternum to its original position after chest compressions are released. Restoring the sternum to its original position before chest compressions allows time for the heart to refill with blood, enabling effective blood pumping during the next chest compression. Even if a patient intends to release chest compressions after compressions, residual pressure from the palms of the hands on the sternum after release can result in insufficient chest compression return. Insufficient chest compression return reduces the heart's pumping function and prevents adequate blood circulation. Therefore, it is preferable to release sufficient pressure on the sternum after each compression to return the sternum to its approximate pre-compression position. Restoration of chest compressions to 90% or more, preferably 95% or more, more preferably 98% or more, and even more preferably 100% of the depth of chest compressions ensures adequate blood circulation. A cardiopulmonary resuscitation board on which the injured person rests may be provided, and the return of chest compressions may be corrected based on fluctuations in the cardiopulmonary resuscitation board.

[0028] The duration of chest compressions refers to the time that chest compressions are continued from the start of chest compressions, in other words, the time from the start of chest compressions to the end of chest compressions. Note that the duration of chest compressions here does not refer to the duration of one chest compression, i.e., the duration from the start of one chest compression to the end of the compression, but rather the time that chest compressions are repeated at a predetermined tempo.

[0029] The interruption time of chest compressions refers to the time elapsed since chest compressions were stopped for ventilation. Interruption of chest compressions for ventilation can cause a drop in blood pressure. In the absence of blood pressure, even if the alveoli are expanded during positive pressure ventilation, the efficiency of gas exchange decreases. It is generally believed that blood pressure gradually decreases after chest compressions are interrupted. Therefore, the interruption time of chest compressions depends on the blood pressure at the time of interruption, but is preferably less than 10 seconds, and can be less than 5 seconds, 3 seconds, 2 seconds, 1.5 seconds, or 1 second. However, because ventilation does not allow air to enter the lungs during chest compressions, the interruption time of chest compressions can be 0.3 seconds or more, or 0.5 seconds or more. To maintain blood pressure as much as possible, it is preferable to resume chest compressions after the second ventilation and when the patient enters the expiratory phase.

[0030] The time elapsed since resuming chest compressions is the time elapsed since ventilation ended and chest compressions resumed, and is used as a reference for the timing of the next ventilation. Chest compressions are resumed after ventilation has caused the chest to rise.

[0031] The ratio of chest compressions to ventilations can be expressed as 30:2, for example, if 30 chest compressions are given for every 2 ventilations.

[0032] Chest compression ratio (CCF) refers to the duration of chest compressions relative to the duration of cardiopulmonary resuscitation (i.e., the sum of the duration of chest compressions and the time between interruptions). The AHA Guidelines 2020 (AHAG2020) recommend a CCF of 60% or higher, and it is said that a target of 80% is often achievable with good teamwork. A CCF value of 60-80% is said to improve resuscitation rates.

[0033] The rate of chest compressions refers to the number of chest compressions performed on an injured person per given time, and is sometimes called the "frequency of chest compressions" or "speed of chest compressions." For example, the rate of chest compressions (times / minute) can be calculated from the number of chest compressions performed on an injured person and the duration of chest compressions. A rate of 100 to 120 compressions / minute is generally considered desirable for cardiopulmonary resuscitation. If the rate of chest compressions is below 100 compressions / minute, blood pressure does not rise sufficiently, and if it exceeds 120 compressions / minute, diastolic blood pressure begins to drop, resulting in insufficient blood return to the heart.

[0034] The depth of chest compressions, the return of chest compressions, and the number of chest compressions can be measured by estimating the position and speed using sensors such as acceleration sensors, pressure sensors, force sensors, distance sensors, depth sensors, motion sensors, and displacement sensors, as well as images captured by a camera and commercially available chest compression data detection devices (modules) that measure the depth or return of chest compressions, including any of the above sensors or a combination thereof. In this case, chest compressions are applied from the rescuer's hands via the chest compression data detection device. For example, when using an acceleration sensor, the depth and return of chest compressions can be measured by placing a device equipped with the sensor or a commercially available chest compression data detection device on the victim's sternum and placing both hands on it while compressing the chest. Furthermore, the number of chest compressions can be measured based on the depth and return of chest compressions. Chest compressions can be performed by placing the victim face up on a hard surface such as a floor. However, since the victim's back sinks due to compressions in a bed or ambulance, it is preferable to measure the depth and return of chest compressions by taking this sinking amount into account. To prevent this sinking, the victim may be placed face up on a rescue board (CPR board). The CPR board may also be equipped with the above-mentioned sensor to measure the displacement due to sinking and correct the depth and return of chest compressions. When measuring the depth of chest compressions, noise may be removed from the obtained values ​​as needed. The chest compression data detection device itself may be the chest compression data acquisition unit 11, or a device that acquires data obtained from the chest compression data detection device via a wired or wireless connection may be the chest compression data acquisition unit 11.

[0035] The above ventilation refers to supplying air to the injured person's lungs by artificial respiration, thereby performing positive pressure ventilation. By performing positive pressure ventilation in a state where blood is flowing, oxygen binds to hemoglobin in the blood. Ventilation is preferably performed within 1 second per session, preferably within 0.5 seconds. The ventilation volume is preferably 400 to 500 cc. Artificial respiration can be performed using a bag valve mask. The bag valve mask is designed to allow approximately 800cc of air to be expelled when kneaded with one hand, and over 1000cc when kneaded with both hands. Therefore, for example, if you knead the entire mask with one hand, 800cc of air will be expelled, causing hyperventilation. Therefore, if the chest rises due to ventilation, ventilation must be stopped to prevent hyperventilation. Also, because air cannot enter the lungs during chest compressions, ventilation must be performed with chest compressions interrupted. The reason why the ventilation volume is set to be more than the required volume of 400-500cc is that it takes into consideration the amount of air that will be taken in if chest compressions are not interrupted due to an advanced airway management (insertion of an intubation tube, etc.).

[0036] (Blood pressure estimation section) The blood pressure estimation unit 12 estimates the blood pressure of the injured person based on the chest compression data. Among the chest compression data, the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions may be used to estimate blood pressure. Alternatively, one or more pieces of data selected from the group consisting of the interruption time of chest compressions, the ratio of the number of chest compressions to the number of ventilations, the chest compression ratio, and the estimated blood pressure at the start of chest compressions may be used. The chest compression tempo may be calculated from the number of chest compressions and a predetermined time. An estimated augmented blood pressure per predetermined number of chest compressions or an estimated augmented blood pressure per predetermined duration of chest compressions may be determined in advance when chest compressions are performed that satisfy predetermined conditions of the depth of chest compressions, the return of chest compressions, and the tempo of chest compressions. Blood pressure may then be estimated based on the estimated augmented blood pressure per predetermined number of chest compressions, the acquired number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions, and the duration of chest compressions. The estimated augmented blood pressure per predetermined number of chest compressions or per predetermined duration of chest compressions can be determined, for example, as the estimated augmented blood pressure per chest compression or per minute of chest compressions, respectively. Figure 3 shows steps for estimating blood pressure in the blood pressure estimation unit. The estimated blood pressure obtained by the blood pressure estimation unit 12, the predetermined conditions of chest compression depth, chest compression return, and chest compression tempo, the estimated augmented blood pressure per predetermined number of chest compressions or per predetermined duration of chest compressions when chest compressions are performed that satisfy the predetermined conditions of chest compression depth, chest compression return, and chest compression tempo, and a predetermined blood pressure threshold value appropriate for increasing blood oxygen saturation may be stored in the memory unit 14.

[0037] The predetermined conditions for the predetermined chest compression depth, predetermined chest compression return, and chest compression tempo can be determined, for example, from the values ​​in the AHA Guidelines 2020. Specifically, the predetermined chest compression depth can be set to 5 to 6 cm in the direction of chest compression, and in the case of children or infants, it can be set to 1 / 3 of the chest thickness. The predetermined chest compression return can be set to 90% or more of the chest compression depth, preferably 95% or more, more preferably 98% or more, and even more preferably 100%. The predetermined chest compression tempo can be set to 100 to 120 times per minute. For example, if chest compressions are performed 15 times from a cardiac arrest patient, with a depth of 5-6 cm, at a rate of 100-120 compressions per minute, and with a 90-100% return rate, the specified conditions for chest compression depth, return rate, and rate are met. In this case, the estimated augmented blood pressure can be adjusted to any value, but it can be estimated that each chest compression will increase blood pressure by 3-6 mmHg, preferably 4 mmHg. Therefore, if chest compressions are initiated from a state where no blood pressure is present, the increase in blood pressure can be estimated to be 60 mmHg after 15 chest compressions, resulting in an estimated blood pressure of 60 mmHg. Furthermore, if the estimated blood pressure at the start of chest compressions is 20 mmHg, the increase in blood pressure can be estimated to be 60 mmHg after 15 chest compressions, resulting in an estimated blood pressure of 80 mmHg.

[0038] In addition, based on the inventor's experience, when performing cardiopulmonary resuscitation on a victim of cardiac arrest, once the blood pressure exceeds 60 mmHg, the blood pressure gradually becomes less likely to rise, stabilizing at around 80 mmHg and becoming less likely to rise any further. Therefore, in estimating blood pressure, the estimated blood pressure can be set at 70 to 80 mmHg, preferably 80 mmHg, as the upper limit of the estimated blood pressure.

[0039] For example, if the depth of chest compressions is less than 5 cm or more than 6 cm, if the return of chest compressions is less than 90%, or if the frequency of chest compressions is outside the rate range of 100 to 120 per minute, the chest compressions are not judged to meet the specified conditions, and it can be estimated that there is no increase in blood pressure due to the chest compressions, or that the estimated blood pressure decreases by 0 or 1 to 2 mmHg per chest compression. For example, if chest compressions that do not meet the specified conditions are deemed to result in a blood pressure increase of 0 mmHg, and chest compressions are started from a state where there is no blood pressure, if one of 15 chest compressions has a chest compression depth of 4.5 cm, then the chest compressions that meet the specified conditions are counted as 14, the blood pressure increase is 56 mmHg, and the estimated blood pressure can be estimated as 56 mmHg. If chest compressions that do not meet the specified conditions result in a 2mmHg drop in estimated blood pressure, and chest compressions are started when there is no blood pressure, and one of the 15 chest compressions has a depth of 4.5cm, then chest compressions that meet the specified conditions will be counted as 14, and each count will result in a 2mmHg drop, so the blood pressure increase will be 54mmHg, and the estimated blood pressure can be estimated to be 54mmHg.

[0040] Note that blood pressure gradually decreases when chest compressions are interrupted. Therefore, an estimated diastolic blood pressure per predetermined interruption time can be determined in advance, and the estimated diastolic blood pressure can be calculated by further taking into account the estimated diastolic blood pressure per predetermined interruption time and the acquired duration of chest compression interruption. Note that the decrease in blood pressure is gradual for about two seconds after chest compressions are stopped, but becomes more rapid after two seconds. The rate of blood pressure decrease also varies depending on the patient's condition, individual differences, and the equipment installed (ventilator, cardiopulmonary bypass, intravenous drip, syringe pump, vasopressor). Therefore, for example, the estimated diastolic blood pressure (mmHg / sec) when chest compressions are interrupted can be adjusted to any value. Specifically, it can be 1 to 5 mmHg / sec from 0 to 2 seconds after chest compressions are interrupted, 6 to 9 mmHg / sec from 2 to 4 seconds, and 10 to 13 mmHg from 4 to 6 seconds.

[0041] The rescuer continues chest compressions at a predetermined threshold, and when the estimated blood pressure exceeds a predetermined value, interrupts chest compressions and delivers two ventilations. As soon as ventilation is completed, chest compressions are resumed. This process of chest compressions, interruption of chest compressions, ventilation, and resumption of chest compressions is repeated until the ratio of chest compressions to ventilations reaches a predetermined value, for example, 30:2.

[0042] (Estimated blood pressure notification section) The blood pressure estimation device 1 may include an estimated blood pressure notification unit 14 that displays the blood pressure estimated by the blood pressure estimation unit 12. By notifying the estimated blood pressure, the user of the blood pressure estimation device can grasp the estimated blood pressure. Notification means may include visual notification means such as displaying on a display, auditory notification means such as emitting a sound, or tactile notification means such as transmitting by vibration.

[0043] ■Cardiopulmonary resuscitation support device in question In addition to the chest compression data acquisition unit 11 and blood pressure estimation unit 12 of the present blood pressure estimation device 1, the present cardiopulmonary resuscitation support device 2 is equipped with a notification unit 13 that visually or audibly notifies whether the estimated blood pressure is at an appropriate blood pressure level for improving blood oxygen saturation through ventilation in cardiopulmonary resuscitation.

[0044] The notification unit 13 notifies the user whether the estimated blood pressure estimated by the blood pressure estimation unit 12 is at a blood pressure level appropriate for improving blood oxygen saturation through ventilation during cardiopulmonary resuscitation. Examples of notification methods include visual notification, such as displaying the information on a screen, auditory notification, such as emitting a sound, and tactile notification, such as vibration. Whether the estimated blood pressure is at a blood pressure level appropriate for improving blood oxygen saturation through ventilation during cardiopulmonary resuscitation can be determined by whether the estimated blood pressure is equal to or greater than a predetermined blood pressure threshold appropriate for increasing blood oxygen saturation. The threshold can be, for example, 65 to 90 mmHg, with 70 mmHg being a preferred example. As mentioned above, blood pressure drops during interruptions of chest compressions for ventilation. When two ventilations are performed, maintaining a blood pressure of at least 60 mmHg during the second ventilation maintains blood flow, and oxygen delivered to the lungs through ventilation is thought to be delivered to the blood, thereby increasing blood oxygen saturation. Therefore, the threshold can be appropriately set taking into account the drop in blood pressure due to interruptions of chest compressions. In addition, a determination unit may be provided that determines whether the estimated blood pressure is at an appropriate blood pressure level for improving blood oxygen saturation through ventilation in cardiopulmonary resuscitation, and the result of the determination may be notified.

[0045] When the notification unit 13 provides a visual notification, the notification can be displayed on a display, tablet, smartphone, etc. The display 21 can display whether the estimated blood pressure is an appropriate blood pressure level for improving blood oxygen saturation by ventilation in cardiopulmonary resuscitation. In addition, one or more chest compression data selected from a predetermined blood pressure threshold appropriate for increasing blood oxygen saturation, the tempo of chest compressions, the number of chest compressions, the depth of chest compressions, the return of chest compressions, the duration of chest compressions, the interruption time of chest compressions, the ratio of the number of chest compressions to the number of ventilations, and the chest compression ratio, or the determination result of whether the blood pressure level is appropriate for improving blood oxygen saturation by ventilation in cardiopulmonary resuscitation may be displayed.

[0046] Furthermore, if chest compression indices such as the tempo of chest compressions, the number of chest compressions, the depth of chest compressions, the return of chest compressions, the duration of chest compressions, the pause in chest compressions, the ratio of the number of chest compressions to the number of ventilations, and the chest compression ratio, or the estimated suitability of CPR are inappropriate, a message to that effect may be displayed to alert the rescuer to perform appropriate CPR. The AHA Guidelines 2020, etc., can be used as a reference to determine whether or not CPR is appropriate.

[0047] Furthermore, the optimal timing for interrupting chest compressions and for providing ventilation can be predicted based on the estimated blood pressure and the time since chest compressions were resumed, and the timing can be displayed on the notification unit 13 to help the rescuer performing cardiopulmonary resuscitation determine the timing of ventilation. Specifically, a message such as "Please interrupt chest compressions and provide ventilation after three more chest compressions" can be displayed. The timing of ventilation can also be notified to the rescuer by voice.

[0048] Furthermore, if chest compressions temporarily become inappropriate for each indicator, the chest compression data may be displayed individually to indicate that state. Specifically, if any of the five indicators (compression rate, compression depth, return of chest compressions, ventilation, and paused chest compression time) is inappropriate, a message indicating that the indicator is inappropriate can be displayed, prompting the rescuer to adjust the indicator appropriately. Conversely, if all indicators are appropriate, a message such as "Everything is going well" can be displayed to encourage the rescuer to continue with the current state.

[0049] Furthermore, if ventilation becomes insufficient, the ratio of chest compressions to ventilations may be changed from 30:2 and ventilation may be performed when blood pressure appears to have stabilized, and a display for this purpose may be provided. Furthermore, the number of chest compressions with appropriate depth, return, and tempo per a specified period of time, for example, per minute, may be displayed. It may also be determined that ventilations at an appropriate blood pressure level are sufficient if there are at least four, preferably five, and more preferably six, ventilations per minute.

[0050] The notification unit 13 may notify the timing of ventilation based on the following indicators: It is desirable to perform ventilation within 2 seconds, preferably within 1.5 seconds, after chest compressions are discontinued, with one ventilation within 1 second and two ventilations within 1.5 seconds. This is because blood pressure gradually decreases after chest compressions are discontinued, and it is necessary to maintain a level at which oxygen can be supplied to the blood, i.e., 60 mmHg, the standard blood pressure for blood circulation, even during the second ventilation. The duration of chest compression interruption may be adjusted depending on the blood pressure at the time of chest compression interruption. For example, if the blood pressure at the time of chest compression interruption is 80 mmHg or higher, ventilation should be completed within 3 seconds of interruption. If the blood pressure is 70 to 80 mmHg, ventilation should be completed within 1.5 seconds of interruption, thereby ensuring more appropriate oxygen supply to the blood.

[0051] During CPR, blood flow is low, and even slow ventilation, such as artificial respiration, fails to maintain blood pressure and blood oxygen saturation does not increase. However, in typical medical settings, doctors and other medical personnel consider slow ventilation to allow for greater alveolar expansion and gas exchange. As a result, awareness of maintaining an appropriate chest compression tempo and the need to ventilate immediately after stopping chest compressions is low. Consequently, ventilation is often performed when blood pressure is low, resulting in reduced CPR efficiency. Specifically, while ventilation should be within one second per ventilation, in some cases ventilation is performed slowly over two to three seconds, or as long as four to five seconds after chest compressions are stopped to perform two ventilations. This results in insufficient oxygen supply to the blood due to a drop in blood pressure.

[0052] The cardiopulmonary resuscitation support device may be equipped with an oxygen supply estimation unit. First, whether oxygen has entered the lungs can be estimated by using an acceleration sensor, distance sensor, position sensor, etc. to determine whether the chest expands in the opposite direction to the chest compression from its position before chest compressions began. Next, if oxygen is being supplied to the lungs by ventilation when the estimated blood pressure is above a predetermined threshold, it can be estimated that oxygen has been supplied to the blood.

[0053] Furthermore, the appropriateness of CPR can be comprehensively estimated based on the chest compression data, the estimated blood pressure, the estimated blood oxygen supply, and other factors. For example, if appropriate ventilation is performed under appropriate estimated blood pressure conditions, it can be estimated that CPR is being performed appropriately. Conversely, if there are conditions that are inappropriate for CPR or if certain conditions are not met, such as the chest compression tempo, number of chest compressions, depth of chest compressions, return of chest compressions, duration of chest compressions, pauses in chest compressions, ratio of number of chest compressions to number of ventilations, or chest compression ratio, the rescuer's attention can be alerted by notifying the rescuer of the situation or the extent to which the conditions are not met. This alert can be displayed on a display or transmitted audibly. The audio can be generated from the chest compression data acquisition unit 11, the notification unit 13, or a separate speaker. The audio can be verbal, specifically conveying the situation, or simply a beep. The display can be words that convey the specific situation, or simply a red or blue light that indicates a warning. If it is assumed that CPR is being performed properly, it will notify the user that "Everything is going well." If certain conditions are not met, it will notify the user of the problem and how to improve. If the depth of chest compressions exceeds 6 cm, it will notify the user that "Please push more lightly," and if the depth of chest compressions is between 5 and 6 cm, it will notify the user that "This is the appropriate strength."

[0054] In addition, if chest compressions continue to be inappropriate, fatigue or a skill problem may be the cause, and a notification may be issued urging a change of rescuer.

[0055] FIG. 4 shows Example 1, in which the display 21 is used as the notification unit 13. The display 21 displays an example of an estimated blood pressure, bars representing the number and rate of chest compressions, and peaks representing ventilation. For a rescuer in cardiac arrest with a blood pressure of 0, chest compressions are performed at a rate of 120 compressions per minute, a chest compression depth of 6 cm, and 100% chest compression return. The estimated blood pressure (BP) rises and stabilizes at 90 mmHg. A predetermined blood pressure threshold appropriate for increasing blood oxygen saturation is also displayed. The estimated blood pressure exceeds the threshold at a certain stage. Chest compressions are then interrupted and ventilation is performed approximately twice. While chest compressions are interrupted, the estimated blood pressure drops. Chest compressions are then resumed at a rate of 120 compressions per minute, a chest compression depth of 6 cm, and 100% chest compression return. The estimated blood pressure again exceeds the threshold. Additionally, the right side of the display displays the tempo, chest compression depth, chest compression release, chest compression duration, and ventilation as petals. When the petals are normal, it means that the tempo, chest compression depth, chest compression release, chest compression duration, and ventilation all meet the specified conditions. Furthermore, since each of the above chest compression data meets the specified conditions, the top of the screen displays "Everything is going well." By looking at this display 21, the rescuer can determine the depth of chest compressions, chest compression release, chest compression tempo, chest compression duration, and chest compression pause time, and by looking at the estimated blood pressure and threshold, they can appropriately time ventilation.

[0056] FIG. 5 shows Example 2, in which the display 21 is used as the notification unit 13. During the ongoing chest compression stage, the depth of chest compressions falls below 5 cm, and the estimated blood pressure begins to drop. During ventilation, the estimated blood pressure falls below the threshold, and oxygen cannot be supplied to the lungs. Therefore, some of the petals indicating the depth are missing, and the message "Please push harder" is displayed. Instead of displaying "Please push harder," the message may be communicated to the rescuer by voice. Note that FIG. 5 shows the display in a state in which, after the message "Please push harder" is displayed when the estimated blood pressure begins to drop, chest compressions are stopped, ventilation is performed, and then chest compressions are resumed.

[0057] FIG. 6 shows Example 3 in which the display 21 is used as the notification unit 13. Chest compressions continue and the estimated blood pressure exceeds the threshold. Therefore, "Ventilation is possible" is displayed. The rescuer can determine the timing to interrupt chest compressions and provide ventilation by looking at the display 21. Note that immediately after the estimated blood pressure rises above the threshold, the subsequent interruption of chest compressions causes the blood pressure to drop below the threshold, and oxygen cannot be supplied to the lungs even if ventilation is provided. Therefore, immediately after the estimated blood pressure rises above the threshold, a display can be displayed to assist in determining the timing of ventilation, such as "Ventilation is possible with three more chest compressions."

[0058] The cardiopulmonary resuscitation support device 2 can also be used as a training device for cardiopulmonary resuscitation technicians.

[0059] The present blood pressure estimation device 1 and the present cardiopulmonary resuscitation support device 2 may include a wireless communication unit that transmits to the notification unit 13 the chest compression data, estimated blood pressure, and judgment results obtained by the judgment unit as to whether the estimated blood pressure is at an appropriate blood pressure level for improving blood oxygen saturation through ventilation in cardiopulmonary resuscitation.

[0060] ◆ Blood pressure estimation program and cardiopulmonary resuscitation support program The blood pressure estimation program in this specification is not particularly limited as long as it is a blood pressure estimation program characterized by causing a computer to function as the present blood pressure estimation device 1, and is hereinafter also referred to as the "present blood pressure estimation program." Also, the cardiopulmonary resuscitation support program in this specification is not particularly limited as long as it is a cardiopulmonary resuscitation support program characterized by causing a computer to function as the present cardiopulmonary resuscitation support device 2, and is hereinafter also referred to as the "present cardiopulmonary resuscitation support program."

[0061] The present blood pressure estimation program and the present cardiopulmonary resuscitation support program are computer-readable recording media that record the blood pressure estimation program and the cardiopulmonary resuscitation support program.

[0062] The blood pressure estimation program and the cardiopulmonary resuscitation support device program perform predetermined processing based on the number of chest compressions, depth of chest compressions, return of chest compressions, and duration of chest compressions for a victim of cardiac arrest. Specifically, they cause a computer to estimate blood pressure and notify whether the estimated blood pressure is at an appropriate blood pressure level for increasing blood oxygen saturation through ventilation in cardiopulmonary resuscitation.

[0063] This program allows the rescuer to make decisions based on the information from the notification unit and continue appropriate cardiopulmonary resuscitation.

[0064] This program may be recorded on a recording medium such as an optical disk (CD, DVD), magneto-optical disk (MO), magnetic disk, hard disk, magnetic tape, or memory (ROM, flash memory, etc.). For example, the CPU of a computer can read this program from the recording medium and function as the chest compression data evaluation unit. [Explanation of symbols]

[0065] 1...Blood pressure estimation device 2...Cardiopulmonary resuscitation support device 11...Chest compression data acquisition unit 12...Blood pressure estimation section 13…Notification Department 14…Memory Department

Claims

1. a chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest; a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; A blood pressure estimation device comprising:

2. The blood pressure estimation unit calculates a tempo of chest compression from the number of chest compressions per predetermined time, The estimated augmented blood pressure per predetermined number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions is determined in advance when chest compressions are performed that satisfy the conditions of a predetermined depth of chest compressions, a predetermined return of chest compressions, and a predetermined tempo of chest compressions.

2. The blood pressure estimation device according to claim 1, wherein the blood pressure is estimated based on the estimated augmented blood pressure per predetermined number of chest compressions and the acquired number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions and the duration of chest compressions.

3. The chest compression data further includes an interruption time of chest compression, and an estimated diastolic blood pressure per predetermined interruption time is determined in advance. The estimated augmented blood pressure per predetermined number of chest compressions and the acquired number of chest compressions or the estimated augmented blood pressure per predetermined duration of chest compressions and duration of chest compressions, and the estimated descending blood pressure per predetermined interruption time and the acquired interruption time of chest compression; The blood pressure estimation device according to claim 2, wherein the blood pressure is estimated based on the following:

4. a chest compression data acquisition unit that acquires the number of chest compressions, the depth of chest compressions, the return of chest compressions, and the duration of chest compressions for a victim of cardiac arrest; a blood pressure estimation unit that estimates a blood pressure of the injured person based on the chest compression data; A cardiopulmonary resuscitation support device comprising a notification unit that notifies whether the estimated blood pressure is at an appropriate blood pressure level for increasing blood oxygen saturation through ventilation in cardiopulmonary resuscitation, based on the estimated blood pressure estimated by the blood pressure estimation unit and a predetermined blood pressure threshold value appropriate for increasing blood oxygen saturation.

5. 5. The cardiopulmonary resuscitation support device of claim 4, wherein the notification unit has a display and displays on the display whether the estimated blood pressure estimated by the blood pressure estimation unit or a predetermined estimated blood pressure threshold is an appropriate blood pressure level for improving blood oxygen saturation through ventilation in cardiopulmonary resuscitation, based on the estimated blood pressure estimated by the blood pressure estimation unit or a predetermined estimated blood pressure threshold.

6. 6. The cardiopulmonary resuscitation support device of claim 4, wherein the notification unit estimates and notifies the optimal timing of ventilation based on the estimated blood pressure and the predetermined blood pressure threshold appropriate for increasing blood oxygen saturation.

7. Further, a time when chest compressions are interrupted is acquired as the chest compression data.

7. The cardiopulmonary resuscitation support device according to claim 4, wherein the notification unit displays the estimated blood pressure and the time period during which chest compressions are interrupted.

8. A blood pressure estimation program that causes a computer to function as the blood pressure estimation device according to any one of claims 1 to 3.

9. A cardiopulmonary resuscitation support program that causes a computer to function as the cardiopulmonary resuscitation support device according to any one of claims 4 to 7.

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