Patent Publication Number: US-2021186805-A1

Title: Cardiopulmonary  resuscitation  system

Description:
BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates to a cardiopulmonary resuscitation system. 
     2. Discussion of the Background Art 
     As a cardiopulmonary resuscitation (also referred to as CPR) method, a method for combining sternum compression with hands and mouth-to-mouth artificial respiration is known. However, it is difficult to manually perform stable and high-quality cardiopulmonary resuscitation. Therefore, a cardiopulmonary resuscitator for automatically performing sternum compression and artificial respiration has been proposed. For example, the present applicant has proposed an automatic cardiopulmonary resuscitator for performing cardiac massage by repeatedly applying an impact at adjusted regular intervals and supplying respiratory gas for ventilation at adjusted timing and duration (see, for example, Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2000-84028 A 
     SUMMARY 
     Technical Problem 
     Guidelines 2015 (2015 AHA Guidelines for CPR and ECC) for AHA cardiopulmonary resuscitation and emergency cardiovascular treatment (hereinafter also referred to as Guidelines) specify that “After tracheal intubation, sternum compression and artificial respiration are asynchronous, and continuous sternum compression is performed. Sternum compression is performed at least 100 times per minute, and artificial respiration is performed about 10 times per minute to avoid hyperventilation. In a case where a supraglottic respiratory tract device (such as a laryngeal mask) is used, continuous sternum compression may be performed only in a case where adequate ventilation is possible.”, “It is a condition for success not only in basic life support (BLS) but also in advanced life support (ALS) that continuous and efficient sternum compression is performed. Be careful with a procedure of ALS and judgment to avoid degradation of CPR quality and interruption.”, and “Interruption of sternum compression should be avoided as much as possible also in ALS, and it is inevitable to interrupt sternum compression only in a case where artificial respiration is performed, in a case where electrocardiogram (ECG) or return of spontaneous circulation (ROSC) is evaluated, and in a case where an electric shock is applied”. In addition, Guidelines recommend that compression is performed at 100 times/minute or more and the compression depth for an adult is set to 5 cm or more for high-quality sternum compression. 
     CPR includes a synchronous mode in which sternum compression and artificial respiration are alternately performed at a predetermined ratio and an asynchronous mode in which sternum compression and artificial respiration are performed independently and continuously. In the asynchronous mode, sternum compression is continuously performed, and a phenomenon (also referred to as fighting) in which the timing of sternum compression and the timing of artificial respiration are coincident and exhalation of a patient and inhalation by an artificial respirator occur simultaneously occurs. When fighting occurs, a risk such as reduction in cardiac output or coronary perfusion pressure, damage to an alveolus due to a high respiratory tract internal pressure, occurrence of traumatic pneumothorax, or reduction in effective alveolar ventilation amount is expected. Guidelines assume CPR based on a method with hands, and even artificial respiration is performed with hands during sternum compression, the ventilation amount is not increased due to resistance of compression, and therefore a big problem hardly occurs. Meanwhile, in CPR with an apparatus, sternum compression and artificial respiration are surely performed, and therefore a risk due to fighting is increased. 
     Therefore, an object of the present disclosure is to provide a cardiopulmonary resuscitation system capable of avoiding fighting in an asynchronous mode in which sternum compression and artificial respiration are performed independently and continuously. 
     Solution to Problem 
     A cardiopulmonary resuscitation system according to the present disclosure includes: a sternum compression means that includes an impact hammer for compressing the chest of a patient and repeats a sternum compression cycle having, as one cycle, a compression period in which the impact hammer is pressed against the chest and a recoil period in which the impact hammer is separated from the chest; an artificial respiration means that repeats an artificial respiration cycle having, as one cycle, an inhalation period in which respiratory gas is supplied to the patient and an exhalation period in which supply of the respiratory gas is stopped; and a control means that controls the artificial respiration means and the sternum compression means, and is characterized in that the control means executes the artificial respiration cycle a predetermined number of times per unit time while executing the sternum compression cycle a predetermined number of times per unit time, and stops pressing the impact hammer against the chest during the compression period overlapping with the inhalation period. 
     In the cardiopulmonary resuscitation system according to the present disclosure, in a case where the inhalation period is started during the recoil period, the control means preferably extends the recoil period executed at the start time of the inhalation period at least until the inhalation period ends. Fighting can be avoided while the number of times of artificial respiration is secured. 
     In the cardiopulmonary resuscitation system according to the present disclosure, in a case where the inhalation period is started during the compression period and the start time of the inhalation period is in the first half period obtained by temporally dividing the compression period into two equal parts, the control means preferably hastens start of the inhalation period by the same time as the time from the start time of the compression period overlapping with the inhalation period to the start time of the inhalation period. Fighting can be avoided even in a case where the inhalation period is started during the compression period. 
     In the cardiopulmonary resuscitation system according to the present disclosure, in a case where the inhalation period is started during the compression period and the start time of the inhalation period is in the second half period obtained by temporally dividing the compression period into two equal parts, the control means preferably delays start of the inhalation period by the same time as the time from the start time of the inhalation period to the end time of the compression period overlapping with the inhalation period. Fighting can be avoided even in a case where the inhalation period is started during the compression period. 
     In the cardiopulmonary resuscitation system according to the present disclosure, it is preferable that the control means restarts the sternum compression cycle a predetermined time after the end of the inhalation period, and the sternum compression cycle restarted is started from the compression period. By securing the exhalation time after the end of the inhalation period, it is possible to prevent an intrathoracic pressure from becoming too high. 
     In the cardiopulmonary resuscitation system according to the present disclosure, the artificial respiration means and the sternum compression means are preferably configured as an integral device. Portability is improved, and cardiopulmonary resuscitation can be quickly started in an early stage of critical care. 
     In the cardiopulmonary resuscitation system according to the present disclosure, the artificial respiration means and the sternum compression means are preferably configured as individual devices. Cardiopulmonary resuscitation can be performed with higher accuracy. 
     In the cardiopulmonary resuscitation system according to the present disclosure, the control means is preferably mounted on a device constituting the artificial respiration means. The sternum compression means can be small and lightweight, and sternum compression can be quickly started in an early stage of critical care. 
     In the cardiopulmonary resuscitation system according to the present disclosure, it is preferable that the sternum compression means includes an elevating means for vertically reciprocating the impact hammer, and a driving system of the elevating means is a gas driving system, an electric driving system, or a mixed driving system of the gas driving system and the electric driving system. By adopting the gas driving system, the setting width of the sternum compression depth can be wide, and sternum compression by a method with hands can be reproduced. By adopting the electric driving system, a device can be simpler. 
     The present disclosure can provide a cardiopulmonary resuscitation system capable of avoiding fighting in an asynchronous mode in which sternum compression and artificial respiration are performed independently and continuously. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an example of a cardiopulmonary resuscitation system according to the present embodiment. 
         FIG. 2  is a timing chart of a sternum compression cycle and an artificial respiration cycle in a synchronous mode,  FIG. 2( a )  illustrates a compression waveform, and  FIG. 2( b )  illustrates a ventilation waveform. 
         FIG. 3  is a timing chart of a sternum compression cycle and an artificial respiration cycle in an asynchronous mode,  FIG. 3( a )  illustrates a compression waveform, and  FIG. 3( b )  illustrates a ventilation waveform. 
         FIG. 4  is a first example of a timing chart of a sternum compression cycle and an artificial respiration cycle,  FIG. 4( a )  illustrates a compression waveform based on setting,  FIG. 4( b )  illustrates a ventilation waveform based on setting,  FIG. 4( c )  illustrates a compression waveform when fighting is avoided, and  FIG. 4( d )  illustrates a ventilation waveform when fighting is avoided. 
         FIG. 5  is a second example of the timing chart of a sternum compression cycle and an artificial respiration cycle,  FIG. 5( a )  illustrates a compression waveform based on setting,  FIG. 5( b )  illustrates a ventilation waveform based on setting,  FIG. 5( c )  illustrates a compression waveform when fighting is avoided, and  FIG. 5( d )  illustrates a ventilation waveform when fighting is avoided. 
         FIG. 6  is a third example of the timing chart of a sternum compression cycle and an artificial respiration cycle,  FIG. 6( a )  illustrates a compression waveform based on setting,  FIG. 6( b )  illustrates a ventilation waveform based on setting,  FIG. 6( c )  illustrates a compression waveform when fighting is avoided, and  FIG. 6( d )  illustrates a ventilation waveform when fighting is avoided. 
         FIG. 7  is a fourth example of the timing chart of a sternum compression cycle and an artificial respiration cycle,  FIG. 7( a )  illustrates a compression waveform based on setting, and  FIG. 7( b )  illustrates a ventilation waveform based on setting. 
         FIG. 8  is a conceptual diagram of another example of the cardiopulmonary resuscitation system according to the present embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Next, the present disclosure will be described in detail by describing embodiments, but the present disclosure is not construed as being limited to description thereof. As long as an effect of the present disclosure is exhibited, the embodiments may be modified variously. 
       FIG. 1  is a perspective view of an example of a cardiopulmonary resuscitation system according to the present embodiment. As illustrated in  FIG. 1 , a cardiopulmonary resuscitation system  100  according to the present embodiment includes: a sternum compression means  120  that includes an impact hammer  121  for compressing the chest of a patient and repeats a sternum compression cycle having, as one cycle, a compression period in which the impact hammer  121  is pressed against the chest and a recoil period in which the impact hammer  121  is separated from the chest; an artificial respiration means  110  that repeats an artificial respiration cycle having, as one cycle, an inhalation period in which respiratory gas is supplied to the patient and an exhalation period in which supply of the respiratory gas is stopped; and a control means (not illustrated) that controls the artificial respiration means  110  and the sternum compression means  120 , in which the control means executes the artificial respiration cycle a predetermined number of times per unit time while executing the sternum compression cycle a predetermined number of times per unit time, and stops pressing the impact hammer  121  against the chest during the compression period overlapping with the inhalation period. 
     In the cardiopulmonary resuscitation system  100 , as illustrated in  FIG. 1 , the artificial respiration means  110  and the sternum compression means  120  are preferably configured as an integral device. The cardiopulmonary resuscitation system  100  illustrated in  FIG. 1  is an automatic cardiopulmonary resuscitator equipped with an artificial respiration function and a sternum compression function. Portability is favorable, and cardiopulmonary resuscitation can be quickly started in an early stage of critical care. 
     The artificial respiration means  110  is an artificial respiration unit of the cardiopulmonary resuscitator  100 . As illustrated in  FIG. 1 , the artificial respiration means (hereinafter also referred to as a first artificial respiration unit)  110  includes a hose  111  for injecting respiratory gas into a patient and a gas supply system (not illustrated) for supplying respiratory gas to the hose  111 . One end of the hose  111  is connected to a hose insertion port  112  disposed in a housing  101  of the cardiopulmonary resuscitator  100 . The other end of the hose  111  is connected to a mask (not illustrated) attached to a patient or a tracheal intubation tube (not illustrated). The gas supply system of the first artificial respiration unit  110  includes a gas supply source such as a gas cylinder or an air tank and piping connecting the gas supply source to the hose  111 . In the middle of the piping, for example, a ventilation decompressor for decreasing the pressure of driving gas to a pressure suitable for respiration, a ventilation solenoid valve for supplying respiratory gas to the hose  111  and stopping respiratory gas from the hose  111 , and a respiratory tract internal pressure sensor for detecting the pressure in the piping between the ventilation solenoid valve and the hose insertion port  112  are disposed. The respiratory gas is, for example, pure oxygen, oxygen-enriched air, or air. 
     The sternum compression means  120  is a sternum compression unit of the cardiopulmonary resuscitator  100 . As illustrated in  FIG. 1 , the sternum compression means (hereinafter also referred to as a sternum compression unit)  120  includes an arch portion  10 , a vertical rod  20 , and a back plate  30 . 
     The arch portion  10  has a top surface portion  11  and left and right side surface portions  12  and is disposed so as to extend over the chest of a patient. The arch portion  10  includes the impact hammer  121  projecting downward from the top surface portion  11  and movably supported in the vertical direction by the top surface portion  11  and an elevating means (elevating mechanism)  122  for vertically reciprocating the impact hammer  121 . The impact hammer  121  includes an impact hammer rod  121   a  connected to the elevating means  122  and an impact head pad  121   b  attached to a lower end of the impact hammer rod  121   a  and pressed against the chest of a patient. In a case where the driving system of the elevating means  122  is a gas driving system, the elevating means  122  includes a cylinder  123 . The cylinder  123  has a container shape and has a gas supply port (not illustrated) and a gas discharge port (not illustrated). A piston (not illustrated) and a spring (not illustrated) for pushing back the piston at the time of discharge are disposed in an internal space of the cylinder  123 . 
     The driving system (not illustrated) of the elevating means  122  includes a driving gas supply source such as a gas cylinder or an air tank and piping connecting the driving gas supply source to the cylinder  123 . In the middle of the piping, for example, a compression depth adjuster for adjusting the stroke width of the vertical reciprocating motion of the elevating means  122  and a compression solenoid valve for supplying driving gas into the cylinder  123  and discharging driving gas from the cylinder  123  are disposed. The driving gas supply source preferably serves also as a gas supply source of the artificial respiration unit  110 . The compression solenoid valve is, for example, a three-way solenoid valve. 
     A part of the arch portion  10  is preferably the housing  101 . The housing  101  houses the gas supply system of the first artificial respiration unit  110 , the driving system for driving the elevating means  122 , the control means of the cardiopulmonary resuscitator  100 , and the like. 
     A pair of vertical rods  20  is disposed on the left and right sides and is fixed to fixing portions  13  disposed at lower ends of the left and right side surface portions  12  of the arch portion, respectively. For example, the vertical rod  20  is engaged with a ratchet of the fixing portion  13  to support the arch portion  10  so as to be movable in the vertical direction. As illustrated in  FIG. 1 , the vertical rod  20  preferably has a scale  21  displayed. Preferably, the arch portion  10  is pushed down toward the chest of a patient while the arch portion  10  is set on the patient, the scale is read when the impact head pad  121   b  comes into contact with the chest of the patient, and the read scale is recorded as the chest thickness of the patient. Based on this read sternum thickness, the compression depth of the impact hammer  121  can be set. In this way, finer adjustment of the compression depth suitable for each patient can be performed. 
     The back plate  30  is a plate for supporting a lower surface of the chest of a patient. For example, by engaging an engagement portion (not illustrated) such as a groove or a hole formed in the back plate  30  with a projection (not illustrated) formed at a lower end of the vertical rod  20 , the back plate  30  is fixed to the arch portion  10  detachably. 
     The control means (hereinafter also referred to as a first control unit) is, for example, a printed circuit board. The first control unit controls the gas supply system of the first artificial respiration unit  110  and the driving system of the elevating means  122 . 
     The first control unit closes the ventilation solenoid valve in a case where a pressure detected by the respiratory tract internal pressure sensor is equal to or higher than a predetermined pressure. It is thereby possible to prevent injection of high pressure gas into a patient. 
     The first control unit adjusts the frequency (number of times of ventilation) of the artificial respiration cycle by the first artificial respiration unit  110 . Here, the number of times of ventilation is the number of times for performing the artificial respiration cycle in one minute, for example, 6 to 20 times/minute. The flow rate of respiratory gas by the first artificial respiration unit  110  is fixed to, for example, 24 liters/minute. The ventilation amount of respiratory gas is, for example, 200 to 600 ml/time. The length of the inhalation period is, for example, 0.5 to 1.5 seconds. The lengths of the inhalation period and the exhalation period vary depending on the flow rate of respiratory gas, the number of times of ventilation, and the ventilation amount. For example, in a case where the flow rate of respiratory gas is 24 liters/minute, the number of times of ventilation is set to 10 times/minute, and the ventilation amount is set to 200 ml/time, the inhalation period is 0.5 seconds, and the exhalation period is 5.5 seconds. 
     The first control unit controls the compression solenoid valve to supply driving gas into the cylinder  123  or discharge the driving gas from the inside of the cylinder  123 . When the driving gas is supplied into the cylinder  123 , a piston is pushed down against a repulsive force of a spring, and the impact hammer  121  moves downward. When the driving gas is discharged from the inside of the cylinder  123 , the spring expands, the piston is pushed up, and the impact hammer  121  moves upward. By repeating these, the impact hammer  121  reciprocates vertically. 
     In addition, the first control unit adjusts the frequency of the sternum compression cycle (the number of times of compression) and the stroke width of the vertical reciprocating motion of the elevating means  122 . The stroke width is switched, for example, by turning of an adjustment knob  14  by an operator. Here, the number of times of compression is the number of times for performing the sternum compression cycle in one minute, and Guidelines recommend that the number of times of compression is 100 times/minute or more. A compression period and a recoil period preferably have the same length as each other. For example, in a case where the number of times of compression is 100 times/minute, the time per sternum compression cycle is 0.6 seconds, and the compression period and the recoil period are each 0.3 seconds. The stroke width of the vertical reciprocating motion is appropriately adjusted according to a patient, but Guidelines recommend that the stroke width is 5 cm or more in an adult. 
     The cardiopulmonary resuscitator  100  preferably includes a mode switching unit  15 . The mode switching unit  15  is a switch for switching an operation timing mode of each of the first artificial respiration unit  110  and the sternum compression unit  120 . The mode switching unit  15  is, for example, a panel as illustrated in  FIG. 1  or a knob (not illustrated). Although  FIG. 1  illustrates an example in which the mode switching unit  15  is disposed in the arch portion  10 , the present disclosure is not limited thereto, and the mode switching unit  15  may be disposed on the back plate  30 , for example. 
     The operation timing mode of each of the first artificial respiration unit  110  and the sternum compression unit  120  is roughly divided into a synchronous mode and an asynchronous mode. 
       FIG. 2  is a timing chart of a sternum compression cycle and an artificial respiration cycle in a synchronous mode,  FIG. 2( a )  illustrates a compression waveform, and  FIG. 2( b )  illustrates a ventilation waveform. Here, in the timing chart, a compression waveform at the height of “compression” indicates that the compression period is being executed, and a compression waveform at the height of “recoil” indicates that the recoil period is being executed. A ventilation waveform at the height of “inhalation” indicates that the inhalation period is being executed, and a ventilation waveform at the height of “exhalation” indicates that the exhalation period is being executed. In the synchronous mode, as illustrated in  FIG. 2 , the first control unit performs control to alternately execute an execution period  901  in which the sternum compression cycle is executed a predetermined number of times per unit time and a standby period  902  in which execution of the sternum compression cycle is temporarily stopped while the impact hammer  121  is separated from the chest, and executes the artificial respiration cycle a predetermined number of times per unit time during the standby period  902 . 
       FIG. 3  is a timing chart of a sternum compression cycle and an artificial respiration cycle in an asynchronous mode,  FIG. 3( a )  illustrates a compression waveform, and  FIG. 3( b )  illustrates a ventilation waveform. In the asynchronous mode, as illustrated in  FIG. 3 , the first control unit executes the artificial respiration cycle a predetermined number of times per unit time while executing the sternum compression cycle a predetermined number of times per unit time. 
     In  FIG. 3 , the entire compression period P 1  and a part of the compression period P 2  overlap with the inhalation period I 1 , and the entire compression period P 3  and a part of the compression period P 4  overlap with the inhalation period I 2 . Fighting occurs in these overlapping periods. In the present embodiment, when the number of times of compression, the number of times of ventilation, and the ventilation amount are set, in a case where the sternum compression cycle and the artificial respiration cycle are executed based on the setting, the first control unit calculates a compression period overlapping with an inhalation period in advance and shifts the timing of the compression period or the inhalation period such that the inhalation period and the compression period do not overlap with each other. This avoids fighting. Here, the asynchronous mode in the present disclosure for avoiding fighting may be referred to as an “avoidance type asynchronous mode” in order to distinguish the asynchronous mode in the present disclosure from a conventional asynchronous mode in which fighting occurs. 
     The avoidance type asynchronous mode is roughly divided into three patterns depending on whether the start time of the inhalation period is during the recoil period (first example), during the first half period of the compression period (second example), or during the second half period of the compression period (third example). Next, a specific example of avoiding fighting will be described with reference to  FIGS. 4 to 6 . 
     First Example 
       FIGS. 4( a ) and 4( b )  are waveforms in a case where the sternum compression cycle and the artificial respiration cycle are executed based on setting of the number of times of compression, the number of times of ventilation, and the length of the inhalation period. In  FIGS. 4( a ) and 4( b ) , the inhalation period I 3  is started during the recoil period R 1 . In this state, the entire compression period P 5  and a part of the compression period P 6  overlap with the inhalation period I 3 . In this case, as illustrated in  FIGS. 4( c ) and 4( d ) , the first control unit extends the recoil period R 1 ′ executed at the start time of the inhalation period I 3  at least until the inhalation period I 3  ends. As a result, overlapping between the inhalation period I 3  and the compression periods P 5  and P 6  is eliminated, and fighting can be avoided. In a case where the entire compression period P 5  overlaps with the inhalation period I 3 , the first control unit cancels the entire compression period P 5  (indicated by a dotted line in  FIG. 4( c ) ). In a case where a part of the compression period P 6  overlaps with the inhalation period I 3 , the first control unit preferably cancels the entire compression period P 6  (indicated by a dotted line in  FIG. 4( c ) ). Alternatively, the first control unit may cancel only a period overlapping with the inhalation period I 3  in the compression period P 6 . In the first example, the number of times of compression is smaller than a set value by the amount overlapping with the inhalation period, and the number of times of ventilation is the same as a set value. 
     Second Example 
       FIGS. 5( a ) and 5( b )  are waveforms in a case where the sternum compression cycle and the artificial respiration cycle are executed based on setting of the number of times of compression, the number of times of ventilation, and the length of the inhalation period. In  FIGS. 5( a ) and 5( b ) , the inhalation period I 4  is started during the compression period P 7 , and the start time s 2  of the inhalation period I 4  is during the first half period P 71  obtained by temporally dividing the compression period P 7  into two equal parts. In this state, a part of the compression period P 7  and the entire compression period P 8  overlap with the inhalation period I 4 . In this case, as illustrated in  FIGS. 5( c ) and 5( d ) , the first control unit preferably hastens start of the inhalation period I 4 ′ by the same time as the time t 1  from the start time s 1  of the compression period P 7  overlapping with the inhalation period I 4  to the start time s 2  of the inhalation period I 4 . At this time, the first control unit preferably cancels the entire compression periods P 7  and P 8  overlapping with the inhalation period I 4 ′ which has been started earlier (indicated by a dotted line in  FIG. 5( c ) ). The first control unit extends the recoil period R 2  immediately before the compression period P 7  to set the recoil period R 2 ′. As a result, fighting can be avoided even in a case where the inhalation period I 4  is started during the compression period P 7 . 
     The length of the inhalation period I 4 ′ which has been started earlier is the same as the length of the inhalation period I 4  which has been scheduled to be executed before the start time is made earlier. That is, the inhalation period I 4 ′ is temporally shifted forward by the time t 1  with respect to the inhalation period I 4 . In the second example, the number of times of compression is smaller than a set value by the amount overlapping with the inhalation period, and the number of times of ventilation fluctuates with respect to a set value by the amount of shift. The variation in the number of times of ventilation is preferably within ±5% of a set value. 
     Third Example 
       FIGS. 6( a ) and 6( b )  are waveforms in a case where the sternum compression cycle and the artificial respiration cycle are executed based on setting of the number of times of compression, the number of times of ventilation, and the length of the inhalation period. In  FIGS. 6( a ) and 6( b ) , the inhalation period I 5  is started during the compression period P 9 , and the start time s 3  of the inhalation period I 5  is during the second half period P 92  obtained by temporally dividing the compression period P 9  into two equal parts. In this state, a part of the compression periods P 9  and P 11  and the entire compression period P 10  overlap with the inhalation period I 5 . In this case, as illustrated in  FIGS. 6( c ) and 6( d ) , the first control unit preferably delays start of the inhalation period I 5 ′ by the same time as the time t 2  from the start time s 3  of the inhalation period I 5  to the end time e 1  of the compression period P 9  overlapping with the inhalation period I 5 . At this time, the inhalation period I 5 ′ is started after the end of the compression period P 9 , and the compression period P 9  is executed because the compression period P 9  does not overlap with the inhalation period I 5 ′ the start of which has been delayed. The first control unit preferably cancels the entire compression periods P 10  and P 11  overlapping with the inhalation period I 5 ′ the start of which has been delayed (indicated by a dotted line in  FIG. 6( c ) ). The first control unit extends the recoil period R 3  immediately before the compression period P 10  to set the recoil period R 3 ′. As a result, fighting can be avoided even in a case where the inhalation period I 5  is started during the compression period P 9 . 
     The length of the inhalation period I 5 ′ the start of which has been delayed is the same as the length of the inhalation period I 5  which has been scheduled to be executed before the start is delayed. That is, the inhalation period I 5 ′ is temporally shifted backward by the time t 2  with respect to the inhalation period I 5 . In the third example, the number of times of compression is smaller than a set value by the amount overlapping with the inhalation period, and the number of times of ventilation fluctuates with respect to a set value by the amount of shift. The variation in the number of times of ventilation is preferably within ±5% of a set value. 
     As illustrated in  FIGS. 7( a ) and 7( b ) , in a case where the inhalation period I 6  is started during the compression period P 12  and the start time s 4  of the inhalation period I 6  is at a boundary between the first half period P 121  and the second half period P 122  obtained by temporally dividing the compression period P 12  into two equal parts, the first control unit may shift the inhalation period I 6  forward as in the second example to cancel the entire compression periods P 12  and P 13  overlapping with the inhalation period (not illustrated) which has been shifted forward, or may shift the inhalation period I 6  backward as in the third example to cancel the entire compression periods P 13  and P 14  overlapping with the inhalation period (not illustrated) which has been shifted backward. 
     In the first to third examples, as illustrated in  FIGS. 4( c ) and 4( d ) ,  FIGS. 5( c ) and 5( d ) , and  FIGS. 6( c )  and  6 ( d ), the first control unit preferably restarts the sternum compression cycle a predetermined time after the end of each of the inhalation periods I 3 , I 4 ′, and I 5 ′, and the sternum compression cycle restarted is preferably started from the compression period. In other words, the first control unit preferably ends the extended recoil periods R 1 ′, R 2 ′, and R 3 ′ after the inhalation periods I 3 , I 4 ′, and I 5 ′ are ended, respectively. By separating the impact hammer  121  from the chest after the inhalation periods I 3 , I 4 ′, and I 5 ′ are ended, exhalation time Ex can be secured to prevent an intrathoracic pressure from becoming too high. The length of the exhalation time Ex is not particularly limited, and for example, as compared with a recoil period determined based on setting of the number of times of ventilation and the length of the inhalation period, the length of the exhalation time Ex may be the same as the length of the recoil period, may be longer or shorter than the length of the recoil period, or may be longer than the length of the recoil period. 
       FIG. 8  is a conceptual diagram of another example of the cardiopulmonary resuscitation system according to the present embodiment. Up to this point, the form in which the artificial respiration means (first artificial respiration unit)  110  and the sternum compression means (sternum compression unit)  120  are formed into an integral device as illustrated in  FIG. 1  has been described as an example, but the present embodiment is not limited thereto. In a cardiopulmonary resuscitation system  1  according to the present embodiment, as illustrated in  FIG. 8 , the artificial respiration means  200  and the sternum compression means  120  may be configured as individual devices. By using the artificial respiration means  200  and the sternum compression means  120  as individual device, more accurate cardiopulmonary resuscitation can be performed. 
     In  FIG. 8 , the artificial respiration means  200  is an artificial respirator. An artificial respiration means (hereinafter also referred to as an artificial respirator)  200  is, for example, an artificial respirator ANSWER for emergency transport (registered trademark) (manufactured by Kohken Medical Co., Ltd.). As illustrated in  FIG. 8 , the artificial respirator  200  includes: a second artificial respiration unit  210  for injecting respiratory gas into a patient; a second control unit  230  for controlling the second artificial respiration unit  210  and generating an external signal including a remote control signal to a cardiopulmonary resuscitator; an external signal output unit  240  for outputting the external signal generated by the second control unit  230  to an outside; a respiratory tract internal pressure sensor  250  for detecting a respiratory tract internal pressure of a patient; and a housing  201  for housing these. 
     The second artificial respiration unit  210  includes an inhalation hose (not illustrated) for injecting respiratory gas into a patient and a gas supply system (not illustrated) for supplying the respiratory gas. One end of the inhalation hose is connected to a hose insertion port (not illustrated) disposed in the housing  201  of the artificial respirator  200 . The other end of the inhalation hose is connected to a mask (not illustrated) attached to a patient or a tracheal intubation tube (not illustrated). The gas supply system of the second artificial respiration unit  210  has the same basic configuration as the gas supply system of the first artificial respiration unit  110 . A major difference is that a ventilation solenoid valve is disposed in the middle of the piping in the first artificial respiration unit  110 , whereas a flow-controllable valve such as a flow regulating valve is disposed in the middle of the piping in the second artificial respiration unit  210 . 
     The second control unit  230  is, for example, a printed circuit board. The second control unit  230  controls the gas supply system of the second artificial respiration unit  210 . The second control unit  230  generates an external signal. 
     The second control unit  230  adjusts the frequency (number of times of ventilation) of the artificial respiration cycle by the second artificial respiration unit  210 . Here, the number of times of ventilation is, for example, 2 to 40 times/minute. The second control unit  230  adjusts the ventilation amount of respiratory gas and the length of an inhalation period. The first artificial respiration unit  110  includes a ventilation solenoid valve, whereas the second artificial respiration unit  210  includes a flow-controllable valve such as a flow regulating valve. Therefore, the ventilation amount of respiratory gas by the second artificial respiration unit  210  can be adjusted in a wider range than the range of the ventilation amount of respiratory gas by the first artificial respiration unit  110 , and is, for example, 50 to 3000 ml/time. The inhalation period of respiratory gas by the first artificial respiration unit  110  is automatically switched according to the flow rate of respiratory gas, the number of times of ventilation, and the ventilation amount, whereas the inhalation period of respiratory gas by the second artificial respiration unit  210  can be continuously switched alone, for example within a range of 0.3 to 3.0 seconds. Therefore, the second artificial respiration unit  210  can adjust the flow rate more finely than the first artificial respiration unit  110 . 
     The external signal output unit  240  is, for example, a connection terminal of a cable (not illustrated) or a transmission unit of a wireless signal or the like, and outputs an external signal sent from the second control unit  230 . 
     The respiratory tract internal pressure sensor  250  can detect from a negative pressure to a positive pressure, detects a respiratory tract internal pressure of a patient, and outputs a pressure signal to the second control unit  230 . 
     In  FIG. 8 , the sternum compression means  120  is a sternum compression unit of the cardiopulmonary resuscitator  100 . The cardiopulmonary resuscitator  100  has the same basic configuration as the cardiopulmonary resuscitator illustrated in  FIG. 1 , for example. In a case where the cardiopulmonary resuscitator  100  cooperates with the artificial respirator  200 , as illustrated in  FIG. 1 , the cardiopulmonary resuscitator  100  preferably includes an external signal input unit  140  for inputting an external signal including a remote control signal instructing the sternum compression unit  120  to perform sternum compression. The external signal input unit  140  is, for example, a connection terminal of a cable (not illustrated) or a reception unit of a wireless signal or the like. An external signal input from the external signal input unit  140  is sent to a first control unit  130 . The cardiopulmonary resuscitator  100  and the artificial respirator  200  are connected to each other such that an external signal can be transmitted by a signal transmission means  300 . The signal transmission means  300  is, for example, a connection cable or wireless communication. The signal transmission means  300  transmits an external signal from the external signal output unit  240  to the external signal input unit  140 . 
     In the cardiopulmonary resuscitation system  1 , the artificial respirator  200  performs artificial respiration, and the cardiopulmonary resuscitator  100  performs only sternum compression. That is, the sternum compression unit  120  and the second artificial respiration unit  210  are in an operable state, and the first artificial respiration unit  110  is in a stopped state. At this time, the signal transmission means  300  makes it possible to transmit an external signal from the artificial respirator  200  to the cardiopulmonary resuscitator  100 . 
     In the cardiopulmonary resuscitation system  1 , a control means for controlling the artificial respiration means (artificial respirator)  200  and the sternum compression means (sternum compression unit)  120  are preferably mounted on the artificial respirator  200 . By control of the sternum compression unit  120  in addition to the second artificial respiration unit  210  by the second control unit  230 , the cardiopulmonary resuscitator  100  can be small and lightweight, and sternum compression can be quickly started in an early stage of critical care. The second control unit  230  generates, for example, an external signal including a remote control signal instructing the sternum compression unit  120  to perform sternum compression. The external signal including the remote control signal is output from the external signal output unit  240  and input to the external signal input unit  140  by the signal transmission means  300 . The external signal including the remote control signal input by the external signal input unit  140  is sent to the first control unit  130 . Upon input of the remote control signal, the first control unit  130  drives the sternum compression unit  120 . In this way, the second control unit  230  remotely controls the sternum compression unit  120 . In a case where the pressure detected by the respiratory tract internal pressure sensor  250  is a negative pressure, the second control unit  230  outputs a signal for opening a flow regulating valve (not illustrated) to the flow regulating valve (not illustrated) and supplies respiratory gas from the second artificial respiration unit  210 . 
     Avoidance of fighting by the second control unit  230  is performed in a similar manner to those in  FIGS. 4 to 6 . 
     Up to this point, the form in which the elevating means  122  of the sternum compression means  120  is a gas driving system has been described, but the present disclosure is not limited to the driving system of the elevating means  122 . The driving system of the elevating means  122  may be, for example, an electric driving system or a mixed driving system of a gas driving system and an electric driving system. In a case where the driving system of the elevating means  122  is a gas driving system, according to the classification of the medical apparatus law or the like, the sternum compression means  120  may also be referred to as a “mechanical cardiopulmonary artificial resuscitator”. By adopting the gas driving system, the setting width of the sternum compression depth can be wide, and sternum compression by a method with hands can be reproduced. In a case where the driving system of the elevating means  122  is an electric driving system, according to the classification of the medical apparatus law or the like, the sternum compression means  120  may also be referred to as an “electric cardiopulmonary artificial resuscitator”. By adopting the electric driving system, a device can be simpler. The electric driving system is, for example, an internal battery, an external battery, an external power source such as an AC 100 V power source, or a combination thereof. In a case where the electric driving system is adopted as the driving system of the elevating means  122 , the impact hammer  121  reciprocates vertically by motor driving, for example. 
     REFERENCE SIGNS LIST 
     
         
           1  Cardiopulmonary resuscitation system 
           10  Arch portion 
           11  Top surface portion 
           12  Left and right side surface portions 
           13  Fixing portion 
           14  Adjustment knob 
           15  Mode switching unit 
           20  Vertical rod 
           21  Scale 
           30  Back plate 
           100  Cardiopulmonary resuscitation system (cardiopulmonary resuscitator) 
           101  Housing 
           110  Artificial respiration means (first artificial respiration unit) 
           111  Hose 
           112  Hose insertion port 
           120  Sternum compression means (sternum compression unit) 
           121  Impact hammer 
           121   a  Impact hammer rod 
           121   b  Impact head pad 
           122  Elevating means 
           123  Cylinder 
           130  First control unit 
           140  External signal input unit 
           200  Artificial respiration means (artificial respirator) 
           201  Housing 
           210  Second artificial respiration unit 
           230  Second control unit 
           240  External signal output unit 
           250  Respiratory tract internal pressure sensor 
           300  Signal transmission unit 
           901  Execution period 
           902  Standby period 
         I 1 , I 2 , I 3 , I 4 , I 4 ′, I 5 , I 5 ′, and I 6  Inhalation period 
         Ex Exhalation time 
         P 1 , P 2 , P 3 , P 4 , P 5 , P 6 , P 7 , P 8 , P 9 , P 10 , P 11 , P 12 , P 12 , P 13 , and P 14  Compression period 
         P 71 , P 91 , P 121  First half period of compression period 
         P 71 , P 92 , P 122  Second half period of compression period 
         R 1 , R 1 ′, R 2 , R 2 ′, R 3 , and R 3 ′ Recoil period 
         s 1  Start time of compression period 
         s 2 , s 3 , and s 4  Start time of inhalation period 
         e 1  End time of compression period 
         t 1 , t 2  Time