JP2019162315A - Inspection device - Google Patents

Abstract

To suppress confusion of a blood flow due to irregular breathing, thereby improving reliability of a measurement result of intrathoracic pressure.SOLUTION: A pulse wave signal acquisition part 12 acquires a pulse wave signal of a subject. A breathing assisting control part 11 controls an artificial respirator for assisting breathing in an artificial manner, by a non-invasive method from outside of a body of a subject, and assists breathing by a prescribed regular breathing motion in a period in which the pulse wave is acquired by the pulse wave signal acquisition part 12. The control part 14 analyzes the pulse wave signal acquired by the pulse wave signal acquisition part 12 in a condition in which the breathing assisting control part 11 assists breathing, thereby estimating an intrathoracic pressure signal indicating time series waveforms of intrathoracic pressure.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an examination apparatus that estimates intrathoracic pressure from a pulse wave signal observed from a subject.

  The amount of change in intrathoracic pressure associated with respiration is an effective index for diagnosis of respiratory diseases and evaluation of respiratory function. For example, lung compliance, which represents the flexibility of the lung, is used for the evaluation of respiratory function, and measurement of the lung compliance requires measurement of intrathoracic pressure.

  In the past, measurement of intrathoracic pressure has not been easy because it has been a heavy burden on the subject, such as inserting a balloon catheter into the subject's esophagus. However, in recent years, methods have been proposed for measuring intrathoracic pressure without causing pain to the subject by noninvasive means. For example, Patent Document 1 describes a technique for estimating intrathoracic pressure from a pulse wave signal measured by a pulse wave sensor attached to a subject's limbs or the like.

JP 2002-355227 A

  In the method for estimating intrathoracic pressure as described in Patent Document 1, a blood flow change amount in a peripheral part such as a limb of a subject is acquired as a pulse wave signal. However, when blood flow disturbance occurs in the peripheral part due to factors other than respiratory action such as sympathetic nerve activity or muscle tone, the accuracy of intrathoracic pressure estimated from pulse waves may be reduced. Therefore, it is important to breathe with a constant intensity and cycle while the subject is relaxed.

  However, in patients with respiratory disease, the mobility of the rib cage and diaphragm is reduced, and it may be difficult to breathe regularly in a relaxed state. In such a case, sympathetic nerve activity and muscle tone increase during measurement of intrathoracic pressure, and blood flow in the peripheral region may be disturbed. In addition, in children and the elderly, it may be difficult to stably perform breathing with a certain intensity and cycle. The technique described in Patent Document 1 is configured to correct the intrathoracic pressure in consideration of the detected body movement, but does not take into account blood flow disturbances caused by respiratory irregularities.

  The present disclosure has been made to solve the above-described problems. The present disclosure provides a technique for improving the reliability of the measurement result of intrathoracic pressure by suppressing disturbance of blood flow due to respiratory irregularities.

  The inspection apparatus according to an aspect of the present disclosure includes a pulse wave signal acquisition unit (12), a respiratory assistance control unit (11), and an analysis unit (14). Note that the reference numerals in parentheses described in this column and in the claims indicate the correspondence with the specific means described in the embodiment described later as one aspect, and the technical scope of the present disclosure It is not limited.

  The pulse wave signal acquisition unit is configured to acquire the pulse wave signal of the subject. The breathing assistance control unit controls a ventilator that artificially assists breathing from outside the body of the subject by a noninvasive method, and performs a predetermined regularity in a period in which the pulse wave is acquired by the pulse wave signal acquisition unit. It is comprised so that the respiration by breathing action may be assisted. The analysis unit estimates the intrathoracic pressure signal representing the time-series waveform of the intrathoracic pressure by analyzing the pulse wave signal acquired by the pulse wave signal acquisition unit under a condition in which respiration assistance is performed by the respiration assist control unit It is configured as follows.

  According to the inspection apparatus according to the present disclosure, the intrathoracic pressure of the subject is estimated based on the pulse wave signal measured under the condition of assisting the regular breathing of the subject using a noninvasive ventilator. Can do. Thereby, the disturbance of the blood flow in the peripheral portion due to respiratory irregularity due to the influence of respiratory diseases or the like can be suppressed, and the reliability of the measurement result of the intrathoracic pressure can be improved.

It is a block diagram showing the outline | summary of a respiratory function test | inspection system. It is a figure showing the mounting | wearing condition of the apparatus to the test subject at the time of a test | inspection. It is a figure showing the outline | summary of a pulse wave sensor. It is a flowchart showing the procedure of the main process. It is a flowchart showing the procedure of a reliability determination process. It is a flowchart showing the procedure of an analysis process. It is a figure showing the outline | summary of the estimation method of the intrathoracic pressure. It is a figure showing the difference of the test result by the presence or absence of respiratory assistance.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In addition, this indication is not limited to the following embodiment, It is possible to implement in various aspects.
[Description of configuration of respiratory function test system]
The configuration of the respiratory function test system 1 will be described with reference to FIG. The respiratory function testing system 1 estimates the intrathoracic pressure based on the pulse wave signal observed from the peripheral part of the subject, tests the respiratory function based on the estimated intrathoracic pressure, and reports the test result. It is a configured system.

  As illustrated in FIG. 1, the respiratory function testing system 1 includes a respiratory function testing device 5 and each unit connected to the respiratory function testing device 5. The respiratory function inspection device 5 corresponds to the inspection device in the present disclosure. The respiratory function test device 5 is connected to the respiratory drive unit 2, the pulse wave sensor 3, the flow sensor 4, and the notification device 6.

  The respiratory drive unit 2 is an apparatus that drives an external ventilator that performs artificial respiration from outside the body of a subject by a noninvasive method. In this embodiment, it is assumed that a positive / negative pressure external ventilator is used. Specifically, as illustrated in FIG. 2, the chest and upper abdomen of a subject lying on their back on the bed are covered with a torso 21, and the breathing drive unit 2 has negative and positive pressure inside the torso 21. Assists inspiration and expiration by the subject by applying two-phase pressure.

  As illustrated in FIG. 2, the pulse wave sensor 3 is a photoelectric pulse wave sensor that is used by being attached to a peripheral part such as a fingertip of a subject and detects a pulse wave signal by a known photoelectric pulse wave method. A specific configuration of the pulse wave sensor 3 will be described with reference to FIG. As illustrated in FIG. 3, the pulse wave sensor 3 includes a housing 31 attached to the subject's finger, and a light emitting element 32 and a light receiving element 34 provided in the housing 31.

  Each light emitting element 32 is a known light emitting element (for example, a light emitting diode: LED) that emits light of a specific wavelength. As the light emitting element 32, for example, a known infrared LED that irradiates near infrared light having a wavelength of about 900 nm and having a relatively large depth of penetration into a living body is used. The light receiving element 34 is a sensor (for example, a photodiode: PD) that receives light irradiated from the light emitting element 32 and passed through the subject's finger and detects the intensity of the light.

  The light emitting element 32 is disposed at a position facing the light receiving element 34 across the finger on which the housing 31 is mounted. That is, the light emitting element 32 and the light receiving element 34 form a transmission type photoelectric pulse wave sensor that detects transmitted light that has passed through the subject's finger and detects a pulse wave.

  Near-infrared light emitted from the light emitting element 32 passes through the finger and enters the light receiving element 34. In the process, a part of the light emitted from the light emitting element 32 is absorbed by the blood flowing through the capillary passing through the finger, the remaining light repeatedly scatters, and a part of the light enters the light receiving element 34. At this time, the blood flow volume in the capillaries changes in a wave manner due to the pulsation of blood, so that the amount of light absorbed in the blood also changes in a wave manner, and the received light amount detected by the light receiving element changes. The light receiving element 34 outputs a voltage signal corresponding to the amount of light received from the light emitting element 32 to the respiratory function testing device 5 as a sensor output.

  Returning to the description of the block diagram of FIG. The flow sensor 4 is a sensor for measuring the amount of air per unit time flowing in and out from the mouth or nose of the subject by breathing (that is, the respiratory flow rate). As the flow sensor 4, for example, a known flow sensor that detects a respiratory flow rate by a mechanism such as a differential pressure type or a hot wire type can be used. The flow sensor 4 outputs an electrical signal corresponding to the detected respiratory flow rate to the respiratory function testing device 5 as a sensor output.

  The respiratory function testing device 5 is an information processing device configured mainly with a CPU, RAM, ROM, auxiliary storage device, input / output interface, and the like (not shown). The respiratory function testing device 5 performs a respiratory function test based on the estimation of the intrathoracic pressure and controls the notification device 6 based on input signals from the pulse wave sensor 3 and the flow sensor 4. The function of the respiratory function testing device 5 is realized by the CPU executing a program stored in a substantial storage medium such as a ROM or a semiconductor memory.

  The respiratory function testing device 5 includes a respiratory assistance control unit 11, a pulse wave signal acquisition unit 12, a respiratory signal acquisition unit 13, and a control unit 14 as functional components. Note that the method for realizing these elements constituting the respiratory function testing device 5 is not limited to software, and some or all of the elements are realized by using hardware that combines logic circuits, analog circuits, and the like. Also good.

  The breathing assistance control unit 11 assists the subject in regular breathing by driving the breathing driving unit 2 in accordance with the given breathing action setting. The pulse wave signal acquisition unit 12 acquires a pulse wave signal representing a time-series waveform of blood vessel pulsation from the pulse wave sensor 3. The respiratory signal acquisition unit 13 acquires a respiratory signal representing a time-series waveform of the respiratory action based on the sensor output from the flow sensor 4. Specifically, the respiration signal acquisition unit 13 acquires a sensor output representing the respiration flow rate from the flow sensor 4 and integrates the respiration flow rate, whereby the amount of air inhaled by the respiration operation (that is, the inhalation amount). An inspiratory amount signal, which is a signal waveform representing the temporal transition of, is derived as a respiratory signal.

  The control unit 14 derives an intrathoracic pressure signal representing a time-series waveform of the intrathoracic pressure by analyzing the pulse wave signal acquired by the pulse wave signal acquisition unit 12. In addition, the control unit 14 examines the respiratory function based on the respiratory signal acquired by the respiratory signal acquisition unit 13 and the intrathoracic pressure signal. Further, the control unit 14 determines the reliability of the measurement result based on the consistency of the control respiration signal representing the time-series waveform of the operating pressure of the respiration driving unit 2 and the respiration signal acquired by the respiration signal acquisition unit 13. To do. The control unit 14 corresponds to an analysis unit, a determination unit, and a control unit in the present disclosure.

  Intrathoracic pressure varies depending on breathing behavior. However, the intrathoracic pressure signal estimated from the pulse wave signal may reflect a minute blood flow disturbance in the peripheral portion, and thus may have a waveform different from that of the original breathing motion. In particular, it may be difficult for a patient having a respiratory disease, a child, and an elderly person to stably breathe in a relaxed state. In such a case, sympathetic nerve activity and muscle tone increase during measurement of intrathoracic pressure, and blood flow in the peripheral region may be disturbed. Therefore, the respiratory function test apparatus 5 controls the respiratory drive unit 2 to assist regular breathing with a certain intensity and cycle, thereby suppressing blood flow disturbance in the peripheral part and estimating the intrathoracic pressure. Improve the accuracy of results.

  The notification device 6 is a device for notifying the respiratory function test result obtained by the respiratory function test device 5 and information relating to its reliability. The notification device 6 includes, for example, a display device such as a liquid crystal display, a speaker, and the like.

[Description of main processing]
The procedure of main processing executed by the control unit 14 of the respiratory function testing device 5 will be described with reference to the flowchart of FIG. As illustrated in FIG. 2, the main process includes a pulse wave sensor 3, a flow sensor 4, a breathing drive unit 2, and a torso 21 at a predetermined position of the subject, It is assumed that the measurement is performed in a state where the measurement of the pulse wave and the respiratory flow rate can be performed simultaneously.

  In S <b> 100, the control unit 14 performs settings related to the operation of the breathing drive unit 2. Specifically, the control unit 14 sets a respiratory cycle, an inhalation time / expiration time ratio (IE ratio), and a positive pressure / negative pressure related to artificial respiration performed on the subject. As the setting contents, a setting value prepared in advance may be automatically applied according to the condition of the subject, or a setting value based on the judgment of the doctor may be manually input.

  In S <b> 102, the control unit 14 starts recurrent measurement by the respiratory assistance control unit 11, the pulse wave signal acquisition unit 12, and the respiratory signal acquisition unit 13. The prognostic measurement is a preliminary measurement performed as a preliminary stage of the actual measurement for actually estimating the intrathoracic pressure.

  Specifically, the respiratory assistance control unit 11 assists the subject in breathing according to the operation setting set in S100. At that time, the breathing assistance control unit 11 guides breathing in a safe and natural manner that does not impose a burden on the subject by gradually bringing the operating pressure on the breathing drive unit 2 side close to the set value without instantaneously adjusting it to the set value. To do. Moreover, the respiratory assistance control part 11 controls the respiratory drive part 2 so that it may become a smooth pressure change based on the given real data regarding the spontaneous-respiration in a healthy state.

  In addition, in a state where respiration assistance is performed by the respiration assist control unit 11, the pulse wave signal acquisition unit 12 and the respiration signal acquisition unit 13 repeatedly perform pulse waves at a predetermined control cycle (for example, 1/100 second cycle). Data and respiratory flow data.

  Specifically, the pulse wave signal acquisition unit 12 emits pulsed light from the light emitting element 32 of the pulse wave sensor 3 once, and acquires the sensor output output from the light receiving element 34 corresponding to the irradiation. The pulse wave signal acquisition unit 12 converts the acquired sensor output into a digital signal and stores it in a memory as a time series of pulse waves. The respiratory signal acquisition unit 13 acquires the sensor output from the flow sensor 4 (that is, the respiratory flow rate). The respiratory signal acquisition unit 13 converts the acquired sensor output into a digital signal and stores it in the memory as a time series of respiratory flow.

  The data acquisition by the pulse wave signal acquisition unit 12 and the respiratory signal acquisition unit 13 is repeated for a certain time, so that the time series waveform of the pulse wave signal and the time series waveform of the respiratory flow observed at the same time as the pulse wave signal are obtained. And are acquired. The respiratory signal acquisition unit 13 derives a respiratory signal by integrating the time-series waveform of the respiratory flow rate.

  In S104, the control part 14 performs the reliability determination process which determines reliability about the measurement result of the pulse wave signal and respiratory signal which were acquired in the fixed period in the preliminary measurement started in S102. Specifically, the control unit 14 determines the measurement result based on the consistency between the control respiration signal representing the time-series waveform of the operating pressure of the respiration driving unit 2 and the respiration signal acquired by the respiration signal acquisition unit 13. Judge reliability. If the control breathing signal and the breathing signal do not match, the breathing motion by the ventilator and the actual breathing motion of the subject do not match, so there may be some problem in the state where the measurement is being performed. is there. Then, it can suppress that a test | inspection is performed in an inappropriate state by determining reliability based on the consistency of a control respiration signal and a respiration signal. A detailed procedure of the reliability determination process will be described later.

  In S106, the control unit 14 determines whether or not it is determined as “reliable” in the reliability determination process in S104. When it is determined that there is no reliability (S106: NO), the control unit 14 returns the process to S104, and executes a reliability determination process for the measurement result acquired in the next fixed period. On the other hand, when it is determined that there is “reliability” (S106: YES), the control unit 14 moves the process to S108.

  In S108, the control unit 14 starts acquiring the pulse wave signal and the respiratory signal by the main measurement. In this measurement, similarly to the prognosis measurement, the pulse wave signal acquisition unit 12 and the respiration signal acquisition unit 13 repeat the pulse wave with a predetermined control cycle in a state where the respiration assist is performed by the respiration assist control unit 11. Acquire data and respiratory flow data. The control unit 14 records the data acquired in the main measurement in a predetermined memory.

  In S110, the control unit 14 determines whether or not a predetermined measurement period (for example, 1 minute) has expired since the start of the main measurement. When the measurement period has not expired (S110: NO), the control unit 14 returns the process to S110 and continues this measurement until the measurement period expires. On the other hand, when the measurement period has expired (S110: YES), the control unit 14 moves the process to S112.

  In S112, the control unit 14 stops the operations of the breathing drive unit 2, the pulse wave sensor 3, and the flow rate sensor 4, and ends the main measurement and data recording. In S114, the control unit 14 performs a reliability determination process on the measurement results of the pulse wave signal and the respiratory signal acquired in the measurement period of the main measurement. A detailed procedure of the reliability determination process will be described later.

  In S116, the control unit 14 determines whether or not “reliable” is determined in the reliability determination processing in S114. If it is determined that there is “reliability” (S106: YES), the control unit 14 moves the process to S118. In S118, the control unit 14 performs analysis processing on the pulse wave signal acquired in the main measurement. This analysis processing is processing for deriving an intrathoracic pressure signal representing a time series waveform of intrathoracic pressure and deriving lung compliance. The detailed procedure of this analysis process will be described later.

  In S120, the control unit 14 outputs a measurement result including image information and audio information representing the lung compliance and intrathoracic pressure signal derived in the analysis processing of S118 to the notification device 6. On the other hand, in S116, when it is determined as “no reliability” in the reliability determination process (S116: NO), the control unit 14 shifts the process to S122. In S <b> 122, the control unit 14 outputs image information and audio information including a message for prompting remeasurement to the notification device 6 without outputting a respiratory function test result or a measurement result representing an intrathoracic pressure signal.

[Description of reliability judgment processing]
The procedure of the reliability determination process which the control part 14 of the respiratory function test apparatus 5 performs is demonstrated, referring the flowchart of FIG. This reliability determination process is a process executed in S104 and S114 of the main process illustrated in FIG.

  In S200, the control unit 14 derives the peak intensity and period of the control respiratory signal of the respiratory drive unit 2 at the same time as the measurement period of the pulse wave signal and the respiratory signal. In S202, the control unit 14 determines whether or not the intensity and cycle of the control respiratory signal derived in S200 are within a predetermined reference range that represents a normal operation range. When the intensity | strength and period of a control respiration signal are in a reference range (S202: YES), the control part 14 moves a process to S204. On the other hand, when the intensity | strength and period of a control respiration signal are not in the reference | standard range (S202: NO), the control part 14 moves a process to S218.

  In S204, which proceeds when an affirmative determination is made in S202, the control unit 14 derives the intensity and cycle of the peak of the respiratory signal acquired by the respiratory signal acquisition unit 13. In S206, the control unit 14 determines whether or not the intensity and period of the control respiratory signal derived in S200 and the peak intensity and period of the respiratory signal derived in S204 match. When the intensity and cycle of the control respiratory signal and the intensity and cycle of the respiratory signal match (S206: YES), the control unit 14 moves the process to S208. On the other hand, when the intensity | strength and period of a control respiration signal and the intensity | strength and period of a respiration signal do not correspond (S206: NO), the control part 14 moves a process to S218.

  In S208, which proceeds when an affirmative determination is made in S206, the control unit 14 calculates a cross-correlation coefficient between the control respiratory signal and the respiratory signal. In S210, the control unit 14 determines whether or not the cross-correlation coefficient calculated in S208 is greater than a predetermined reference value, and the phase difference between the control respiratory signal and the respiratory signal is less than a predetermined reference value. Determine whether. When the cross-correlation coefficient is greater than the reference value and the phase difference is less than the reference value (S210: YES), the control unit 14 proceeds to S212. On the other hand, when the cross-correlation coefficient is equal to or less than the reference value or the phase difference is above the reference value (S210: NO), the control unit 14 proceeds to S218.

  In S212, which proceeds when an affirmative determination is made in S210, the control unit 14 calculates a cross-correlation coefficient between the respiratory signal and the pulse wave signal. In S214, the control unit 14 determines whether or not the cross-correlation coefficient calculated in S212 is greater than a predetermined reference value and the phase difference between the respiratory signal and the pulse wave signal is less than a predetermined reference value. Determine whether. When the cross-correlation coefficient is greater than the reference value and the phase difference is less than the reference value (S214: YES), the control unit 14 proceeds to S216. On the other hand, when the cross-correlation coefficient is equal to or less than the reference value or the phase difference is above the reference value (S214: NO), the control unit 14 proceeds to S218.

  In S216, which proceeds when an affirmative determination is made in S214, the control unit 14 determines that the measurement result of the pulse wave signal and the respiratory signal is “reliable”. On the other hand, in S218 that proceeds when a negative determination is made in any of S202, S206, S210, and S214, the control unit 14 determines that the measurement result of the pulse wave signal and the respiratory signal is “unreliable”.

[Description of analysis processing]
The procedure of analysis processing executed by the control unit 14 of the respiratory function testing device 5 will be described with reference to the flowchart of FIG. This analysis process is a process executed in S118 of the main process illustrated in FIG.

  In S300, the control unit 14 reads pulse wave signal data acquired in the measurement period of the main measurement. In S302, the control unit 14 performs digital filter processing on the pulse wave signal data read in S300. In order to extract the intrathoracic pressure signal reflected in the pulse wave, the digital filter processing is performed on the pulse wave signal with a frequency component of 3 Hz or more caused by disturbance light noise or the like, and 0 caused by body movement or the like. This is a process of cutting frequency components of 1 Hz or less.

  In S304, the control unit 14 creates a first envelope from the pulse wave signal obtained by the digital filter processing in S302. Specifically, the control unit 14 obtains the peak of the pulse wave for each beat from the waveform of the pulse wave signal. And the peak of a pulse wave for every beat is connected in order, and the 1st envelope which is illustrated with the thick line of Drawing 7 is created. In S306, the control unit 14 creates a second envelope from the first envelope created in S304. Specifically, the control unit 14 obtains the peak of the waveform of the first envelope. And the peak of a 1st envelope is connected in order and the 2nd envelope as illustrated by the thin line of Drawing 7 is created.

  In S308, the control unit 14 derives an intrathoracic pressure signal from the first envelope and the second envelope created in S304 and S306. Specifically, the control unit 14 calculates a difference between the first envelope and the second envelope, and uses the difference as an intrathoracic pressure signal. The principle for estimating the intrathoracic pressure from the envelope of the pulse wave signal is the same as the method for estimating the intrathoracic pressure described in Patent Document 1.

  In S310, the control unit 14 calculates the absolute value of the intrathoracic pressure signal by calibration (that is, calibration). A method for calibrating an intrathoracic pressure signal is disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-226422, and will be briefly described here. In S308 described above, the difference between the first envelope and the second envelope of the pulse wave signal is calculated as an intrathoracic pressure signal. Since this intrathoracic pressure signal is a relative change amount, the absolute value of the intrathoracic pressure signal is separately calculated. To derive. Specifically, the absolute value of the intrathoracic pressure signal is derived using a conversion coefficient for converting how much pressure change the relative change of the intrathoracic pressure signal corresponds to.

  In S312, the control unit 14 determines the state of the respiratory function based on the calibrated intrathoracic pressure signal and the inspiratory amount signal. In the present embodiment, as an example of a respiratory function to be examined, it is assumed that lung compliance representing the ease of lung swelling is estimated. Note that a method for estimating lung compliance based on intrathoracic pressure and inhalation volume is disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-226422, and will be briefly described here.

  In the same subject, it is known that the relationship between different inspiratory amounts in breathing and intrathoracic pressure corresponding to the inspiratory amount is expressed by a linear function (y = ax + b). Here, y is the inhalation amount V and x is the intrathoracic pressure P. In such a linear expression, the slope a, that is, Δ (V / P) is known to indicate the ease of swelling of the lung, that is, lung compliance.

  Therefore, the control unit 14 calculates Δ (V / P) corresponding to the slope of the linear function from a plurality of different inhalation amounts V represented by the inhalation amount signal and the intrathoracic pressure P corresponding to each inhalation amount. Calculate as compliance.

[effect]
According to the respiratory function testing device 5 of the embodiment, the following effects are produced.
The intrathoracic pressure of the subject can be estimated based on the pulse wave signal measured under the condition of assisting the subject's regular breathing using a noninvasive ventilator. Thereby, the disturbance of the blood flow in the peripheral portion due to the respiratory irregularity of the subject can be suppressed, and the reliability of the measurement result of the intrathoracic pressure can be improved. A specific example of the above effect will be described with reference to FIG.

  In the example of FIG. 8, the left column is a graph showing the result of estimating the intrathoracic pressure in a situation where the subject with respiratory illness is aided in breathing by the breathing drive unit 2. From the top of the left column, a graph of a control respiratory signal, a respiratory signal, a pulse wave signal, and an intrathoracic pressure signal is shown. Moreover, the right column is a graph showing the result of estimating the intrathoracic pressure in a situation where the breathing drive unit 2 does not assist breathing for a subject with respiratory disease. From the top of the right column, graphs of the control respiratory signal, the respiratory signal, the pulse wave signal, and the intrathoracic pressure signal are shown.

  As shown in the example of FIG. 8, it can be seen that the waveforms of the pulse wave signal and the intrathoracic pressure signal are largely stable when there is respiratory assistance compared to when there is no respiratory assistance. Therefore, the examination result can be improved by examining the respiratory function under the condition in which the subject's regular breathing is assisted by the respiratory function testing device 5.

  Moreover, the reliability of the measurement result of the pulse wave signal and the respiration signal is determined by determining the consistency between the control respiration signal indicating the operating pressure of the respiration drive unit 2 and the actual respiration signal measured from the respiration of the subject. It is possible to evaluate and distinguish the output mode of the test result of the respiratory function according to the evaluation result. Further, the consistency between the pulse wave signal and the respiratory signal can be determined based on a plurality of indices such as the intensity and period of the signal and a cross-correlation function. In addition to these indices, consistency can be determined based on a plurality of indices such as the respiration rate and peak period specified from the peak of the waveform, and the peak frequency specified by frequency analysis.

[Correspondence with configuration described in claims]
The correspondence between each configuration of the embodiment and the configuration described in the claims is as follows.
The analysis process (see FIG. 6) executed by the control unit 14 corresponds to the process as the analysis unit. The reliability determination process (see FIG. 5) executed by the control unit 14 corresponds to a process as a determination unit. The processing of S116 to S122 executed by the control unit 14 corresponds to the processing as the control unit.

[Modification]
In the above-described embodiment, in the reliability determination process illustrated in FIG. 5, the signal strength and period, the cross-correlation coefficient, and the phase difference are used as indices for determining the consistency between the control respiratory signal and the respiratory signal. Explained the case. In addition to these indicators, for example, frequency analysis may be used as an indicator. Specifically, frequency analysis is performed for each of the control breathing signal and the breathing signal, and each peak frequency is specified. And the consistency of both is determined according to whether the peak frequency of the control respiratory signal and the peak frequency of the respiratory signal specified by the frequency analysis match.

  Alternatively, the reliability determination process illustrated in FIG. 5 is configured to determine the reliability using the signal strength and period, the cross-correlation coefficient, and the phase difference as an index. At least a part of these indices May be omitted.

  In the above-described embodiment, as an example of a non-invasive artificial respiration method, an example has been described in which respiration is assisted by applying air pressure to the torso 21 covering the subject's rib cage and upper abdomen. For example, the configuration may be such that electrodes are attached to the chest and abdomen of the subject, the subject's diaphragm is contracted by electrical stimulation, and inhalation is assisted. Alternatively, a configuration may be adopted in which a belt capable of controlling the tightening pressure is wound around the abdomen of the subject, and inhalation is assisted by controlling the belt winding pressure.

  Moreover, the structure which controls the working pressure of the respiration drive part 2 so that the respiration assistance control part 11 may synchronize with a test subject's spontaneous-respiration may be sufficient. Moreover, the structure which assists respiration in the state which arrange | positions the armor 21 on the bed side and a test subject lies on its face down may be sufficient. By doing so, it is conceivable that breathing can be facilitated by opening the back side of the subject.

  In the above-described embodiment, a case where a transmission type photoelectric pulse wave sensor using near infrared light as the pulse wave sensor 3 is applied has been described. For example, other detection methods such as a reflection type pulse wave sensor using a light source that emits green light having a wavelength of about 520 nm and a transmission type pulse wave sensor using a light source that emits red light having a wavelength of about 660 nm are used. Other pulse wave sensors may be used.

  The functions of one component in each of the above embodiments may be shared by a plurality of components, or the functions of a plurality of components may be exhibited by one component. Moreover, you may abbreviate | omit a part of structure of each said embodiment. In addition, at least a part of the configuration of each of the above embodiments may be added to or replaced with the configuration of the other above embodiments. It should be noted that all aspects included in the technical idea specified from the words described in the claims are embodiments of the present disclosure.

  The present disclosure is realized in various forms such as a system having the respiratory function testing device 5 described above as a constituent, a program for causing a computer to function as the respiratory function testing device, a substantive recording medium recording the program, and a testing method. You can also

  DESCRIPTION OF SYMBOLS 1 ... Respiratory function test | inspection system, 2 ... Respiration drive part, 3 ... Pulse wave sensor, 4 ... Flow rate sensor, 5 ... Respiratory function test | inspection apparatus, 6 ... Notification apparatus, 11 ... Respiration assistance control part, 12 ... Pulse wave signal acquisition part , 13 ... Respiration signal acquisition unit, 21 ... Armor, 31 ... Housing, 32 ... Light emitting element (infrared LED), 34 ... Light receiving element.

Claims (5)

A pulse wave signal acquisition unit (12) configured to acquire a pulse wave signal of a subject;
Breathing by a predetermined regular breathing motion during a period in which a pulse wave is acquired by the pulse wave signal acquisition unit by controlling a ventilator that artificially assists breathing by a non-invasive method from outside the subject's body A respiratory assistance controller (11) configured to assist
An intrathoracic pressure signal representing a time-series waveform of intrathoracic pressure is estimated by analyzing the pulse wave signal acquired by the pulse wave signal acquisition unit under a condition in which respiration assistance is performed by the respiratory assistance control unit. A configured analysis unit (14);
An inspection apparatus comprising: A respiratory signal acquisition unit (13) configured to acquire a respiratory signal representing a time-series waveform of the respiratory motion of the subject at the same time that the pulse wave signal is acquired by the pulse wave signal acquisition unit;
The reliability of the measurement result is determined by determining the consistency between the control respiratory signal representing the time-series waveform of the respiratory motion controlled by the respiratory assistance controller and the respiratory signal acquired by the respiratory signal acquisition unit. A determination unit (14) configured to:
A control unit (14) configured to distinguish the handling of the output of the estimation result of the intrathoracic pressure signal according to the reliability determined by the determination unit;
The inspection apparatus according to claim 1, further comprising: The determination unit is configured to calculate a cross-correlation coefficient between the control respiration signal and the respiration signal, and to determine the reliability according to the calculated cross-correlation coefficient.
The inspection apparatus according to claim 2. The determination unit derives a peak frequency using frequency analysis for each of the control breathing signal and the breathing signal, and the peak frequency of the control breathing signal and the peak frequency of the breathing signal match the peak frequency. Configured to determine reliability,
The inspection apparatus according to claim 2 or 3. As prognosis measurement, respiration assistance by the respiration assist control unit, acquisition of the pulse wave signal by the pulse wave signal acquisition unit, acquisition of the respiration signal by the respiration signal acquisition unit, and reliability of the determination unit Judgment and
On the condition that the determination result of reliability in the recurrent measurement satisfies a predetermined requirement, as the main measurement, respiration assistance by the respiration assist control unit and acquisition of the pulse wave signal by the pulse wave signal acquisition unit; Performing the acquisition of the respiratory signal by the respiratory signal acquisition unit, the determination of reliability by the determination unit, and the estimation of the intrathoracic pressure signal by the analysis unit by the analysis unit,
The control unit is configured to output an estimation result of the intrathoracic pressure signal according to the reliability determined by the determination unit in the main measurement.
The inspection apparatus according to any one of claims 2 to 4.