JP2010000118A - Pulmonary lesion early evaluation apparatus and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a measurement during resting ventilation without efforts of a subject and to execute the measurement non-invasively. <P>SOLUTION: The subject can suck atmospheric air (gas for respiration at the first oxygen concentration equivalent to the atmospheric air) through a four-opening tube 20 and a flow sensor adapter 10, and by controlling a valve 28 to be closed and controlling a valve 36 to be opened, the subject performs the respiration by the gas for the respiration containing O2 for 15% and N2 for the rest. A computer 60 captures data SpO2 (a) relating to the blood oxygen saturation obtained in a first state wherein the subject performs the respiration by the gas for the respiration at the first oxygen concentration equivalent to the atmospheric air and data SpO2 (b) relating to the blood oxygen saturation obtained in a second state wherein the subject performs the respiration by the gas for the respiration at a second oxygen concentration equivalent to the oxygen partial pressure of a steep inclination range in an oxyhemoglobin dissociation curve, and performs the evaluation processing of a pulmonary lesion on the basis of the difference. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lung lesion evaluation apparatus and method capable of detecting an abnormality at an early stage where a lung lesion can be repaired.

  The lungs are guaranteed to have a compensatory function so as not to hinder the oxygen uptake into the body. The first is that there are two lungs, one on each side, and that reserve capacity is secured. The second is that the oxygen hemoglobin dissociation curve has a large S-shape, and the alveolar oxygen partial pressure It is ensured that sufficient hemoglobin saturation can be secured even for a decrease in blood flow. Third, the average red blood cell (hemoglobin) transit time in the alveoli is as long as 0.6 seconds, which is necessary for oxygenation. A sufficient reserve capacity is secured compared to 2 seconds. These points show how oxygen uptake into the body is an important issue for living organisms.

  Therefore, until the lungs are highly damaged, there is no danger signal for lack of oxygen, that is, a danger signal such as dyspnea. In other words, when the patient visits the hospital due to difficulty breathing, the lungs are damaged beyond repair. In the present invention, by placing the lungs in an environment different from the normal atmospheric environment (mild hypoxic load), there is a large difference in arterial oxygen saturation between healthy lungs and lungs with early lung lesions. Is used to detect abnormalities at an early stage where the lung lesions can be repaired and to treat them at an early stage.

  In patients with pulmonary disease who need to travel by aircraft, the risk of lowering arterial oxygen saturation increases with increasing severity, but the following lung lesion evaluation is performed. That is, in order to predict the above risk, a respiratory clinic in the UK puts a mask on the subject's mouth and nose and inhales pure oxygen (100% O2) through this, and then puts 100 in the mask. A method has been reported in which the oxygen concentration is transiently reduced to near 15.1% by mixing% nitrogen, and the decrease in arterial oxygen saturation in the earlobe is measured.

  However, a drawback of this method is that it is extremely difficult to stably supply a mixed gas having a constant concentration for a certain period of time by adjusting the gas flow rate. In addition, the purpose of the development of this measuring device is to predict the risk of air travel for patients who already have advanced lung disorders, and is not intended to detect early lung lesions. Furthermore, since this measuring apparatus does not monitor the ventilation of the subject and also lacks the monitoring of carbon dioxide at the end of expiration, it is easily affected by the difference in ventilation between the subjects, and the obtained arterial blood There is a difficulty that is difficult to specify as the degree of injury of the lung itself due to the decrease in oxygen saturation.

  For the device as described above, the inventors of the present invention connected a pulse oximeter, an expiratory flow meter, and an expiratory CO2 meter to a computer, and stopped breathing for 20 seconds at the functional residual level. A reduction in SpO2 was set as ΔSpO2, and an index for early lung lesion detection was devised (particularly, columns 0020 to 0023 in Patent Document 1).

Although the above method can be performed under atmospheric inhalation and can be said to be an excellent method, it is necessary for the subject to “hold the breath”, which is somewhat difficult from the viewpoint of burden on the subject.
JP 2005-279262 A

  The present invention has been made in view of the current state of the conventional pulmonary function measuring apparatus and method as described above, and its purpose is to enable measurement during rest ventilation without the effort of the subject, An object of the present invention is to provide a lung lesion evaluation apparatus and method that can be performed invasively.

  The lung lesion evaluation apparatus according to the present invention includes a breathing gas supply means for supplying a breathing gas having an oxygen concentration corresponding to an oxygen partial pressure in a range where the slope of the oxygen hemoglobin dissociation curve is steep, and the breathing gas supply means. A switching means for switching the supplied breathing gas and the atmosphere to supply to the subject, an acquisition means for acquiring data relating to the blood oxygen saturation of the subject, and controlling the switching means, A control unit that realizes a first state in which the subject breathes by the atmosphere and a second state in which breathing by the breathing gas is performed; and a first state acquired by the acquisition unit in the first state Evaluation of obtaining blood oxygen saturation in the state and blood oxygen saturation in the second state acquired by the acquisition means in the second state, and performing an evaluation process of lung lesions based on these relationships Processing means The features.

  The lung lesion evaluation apparatus according to the present invention includes a detection unit that detects a carbon dioxide concentration contained in the exhalation of the subject, and the evaluation processing unit stably detects a predetermined carbon dioxide concentration by the detection unit. The blood oxygen saturation information of the first state and the second state is taken in when the user is in the state.

  In the lung lesion evaluation device according to the present invention, the breathing gas supply means supplies a breathing gas having a predetermined concentration of 16% to 14% in oxygen concentration.

  In the lung lesion evaluation apparatus according to the present invention, the evaluation processing means evaluates the difference or ratio between the blood oxygen saturation level in the first state and the blood oxygen saturation level in the second state by comparing the threshold value. It is characterized by performing processing.

  The lung lesion evaluation method according to the present invention includes data relating to blood oxygen saturation obtained in a first state in which a subject has performed breathing with a breathing gas having a first oxygen concentration corresponding to the atmosphere; The blood oxygen saturation obtained in the second state in which the subject breathed with the breathing gas having the second oxygen concentration corresponding to the oxygen partial pressure in the range where the slope in the oxygen hemoglobin dissociation curve is steep is obtained. It is characterized in that such data is taken in, and lung lesion evaluation processing is performed based on the relationship between the blood oxygen saturation data in the first state and the blood oxygen saturation data in the second state.

  The lung lesion evaluation method according to the present invention captures blood oxygen saturation data in the first state and the second state when the carbon dioxide concentration contained in the exhaled breath of the subject is stable to a predetermined level. It is characterized by that.

  According to the lung lesion evaluation apparatus and the lung lesion evaluation method according to the present invention, the subject breathes by the breathing gas having the second oxygen concentration corresponding to the oxygen partial pressure in the range where the slope of the oxygen hemoglobin dissociation curve is steep. Since the data relating to the blood oxygen saturation obtained in the second state performed is taken in, the subject can obtain necessary data without any particular effort. In addition, in breathing with a breathing gas having the second oxygen concentration, since the oxygen hemoglobin dissociation curve corresponds to an oxygen partial pressure in a steep range, data relating to blood oxygen saturation levels of healthy and non-healthy individuals However, the breathing with the breathing gas having the first oxygen concentration corresponding to the atmosphere does not make much difference in the data relating to the blood oxygen saturation of the healthy person and the non-healthy person. The lung lesion can be appropriately evaluated based on the relationship between the blood oxygen saturation data in the first state and the blood oxygen saturation data in the second state, and early lung lesions can be captured.

  Moreover, according to the lung lesion evaluation apparatus and the lung lesion evaluation method according to the present invention, the blood in the first state and the second state when the carbon dioxide concentration contained in the exhalation of the subject is stable to a predetermined level. Since data on intermediate oxygen saturation is taken in, lung lesions can be appropriately evaluated using data during rest breathing.

  The inventors of the present application connect a pulse oximeter, an expiratory flow meter, and an expiratory CO2 meter to a computer, prepare a gas cylinder of 15% oxygen (remaining 85% nitrogen), and put the breathing gas supplied from this into the atmosphere. Functional breathing gas with constant oxygen concentration under the atmosphere of oxygen saturation at rest ventilation and arterial blood oxygen saturation at rest for a certain period of time under atmospheric pressure containing 21% oxygen Arterial blood oxygen saturation (SpO2a) by pulse oximeter seen when resting for a certain period of time at the residual level, and when it is supplied by the previous supply means, it switches to hypoxia and at the functional residual volume level The difference in arterial blood oxygen saturation (SpO2b) by a pulse oximeter that is observed when the patient is ventilated for a certain period of time under almost equivalent ventilation conditions is ΔSpO2 (= SpO2a-SpO2b), which is used as an index for early lung lesion detection Devised. Guarantee that these two measured values were measured under almost equivalent ventilation conditions can be judged by monitoring end tidal carbon dioxide (PetCO2 partial pressure) and constancy of tidal and minute ventilation. There is a feature that facilitates reproducibility of results.

  Although the above method can be performed under atmospheric pressure and requires a low-oxygen supply device with a constant concentration, the subject can receive maximum inhalation, maximum invocation, and effort invocation as in many conventional lung function tests. It can be said that it is an excellent technique that can be performed under quiet ventilation without the need.

  Embodiments of a lung lesion evaluation apparatus and method according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a block diagram of a lung lesion evaluation apparatus according to the present invention. This lung lesion evaluation apparatus includes a cylindrical flow sensor adapter 10, a four-opening tube 20 having a cross-shaped flow path, and a reserve bag 31. A cylinder 32 containing a breathing gas of 15% O2 and N2 is connected to the supply port 33 of the reserve bag 31. The pressure in the reserve bag 31 is the same as the atmospheric pressure (1 atm). This allows breathing (inspiration / expiration) of the breathing gas having a remaining amount of O2 of 15% and N2 in the reserve bag 31 under exactly the same conditions as breathing in the atmosphere. The reserve bag 31 and the cylinder 32 constitute a breathing gas supply means for supplying a breathing gas having an oxygen concentration corresponding to an oxygen partial pressure in a range where the slope in the oxygen hemoglobin dissociation curve is steep.

  A discharge port 34 of the reserve bag 31 is connected to one open end 21 of the four-open tube 20, and a valve 35 for opening and closing a gas flow path at the supply port 33 and the discharge port 34 of the reserve bag 31, respectively. , 36 are provided.

  The 4-opening tube 20 includes open ends 22 to 24 in addition to the open end 21. A one-way valve 26 is provided in the flow path on the inner side of the valve 36 in the flow path near the opening of the open end 21. A one-way valve 27 is provided in the flow path of the open end 22 facing the open end 21, and a valve 28 for opening and closing the gas flow path is provided in the passage of the open end 24, and faces the open end 24. One end side opening of the flow sensor adapter 10 is connected to the opening end 23. The four-opening tube 20 and the valves 28, 35, and 36 constitute a switching unit that switches between the breathing gas supplied from the breathing gas supply unit and the atmosphere and supplies it to the subject.

  The flow sensor adapter 10 is provided with a flow sensor 11 and a CO2 sensor 12, and an opening on a side different from the connection side with the four-opening tube 20 is a mouthpiece 70 that is attached to the mouth of the subject. A mask may be used in place of the mouthpiece 70. The flow sensor 11 can be configured by a sensor that extracts a pressure difference signal at two points in the flow sensor adapter 10, and the differential pressure signal is sent to the amplifier 41. The CO 2 sensor 12 can be constituted by a light emitting element and a light receiving element provided at one point of the flow path in the flow sensor adapter 10, and a detection signal of the light receiving element is sent to the CO 2 meter 42. The carbon dioxide concentration data obtained by the CO2 meter 42 is converted to digital data and sent to the computer 60. The CO2 sensor 12 and the CO2 meter 42 constitute detection means for detecting the carbon dioxide concentration contained in the exhalation of the subject.

  The lung lesion evaluation apparatus includes a pulse oximeter 50 that is an acquisition unit that acquires data relating to blood oxygen saturation. The pulse oximeter 50 is composed of an SpO2 sensor 51 attached to the fingertip of the subject, for example, the third finger of the left hand, and a signal converter 52, and the signal converter 52 digitizes blood oxygen saturation data. Is sent to the computer 60.

  In the amplifier 41 that has received the differential pressure signal, the signal is amplified, sent to the A / D converter 45, digitized, and sent to the integrator 46 and the flow velocity output meter 47. The integrator 46 integrates the differential pressure signal and sends the result to the flow rate output meter 48. The flow velocity output meter 47 calculates the gas flow velocity based on the differential pressure data and sends the flow velocity data to the computer 60. The flow rate output meter 48 obtains the flow rate of the gas based on the integral value of the differential pressure and sends the flow rate data to the computer 60.

  The valves 28, 35, and 36 are opened and closed by a drive signal from a valve drive device 80 controlled by the computer 60. The sampling rate in the pulse oximeter 50 is about 1/3 sec. The sampling rate in the CO2 meter 42, the sampling rate of the flow rate and the flow rate in the A / D converter 45, the integrator 46, the flow rate output meter 47 and the flow rate output meter 48 are as follows. It is about 1/20 sec.

  In the lung lesion evaluation apparatus configured as described above, the SpO2 sensor 51 is attached to the fingertip of the subject, the subject holds the mouthpiece 70 at one end of the flow sensor adapter 10 in the mouth, and performs nasal breathing. The measurement is performed with the nose blocked by a clip to stop.

  Before starting the measurement, the valve 35 is opened via the valve driving device 80 under the control of the computer 60, and a breathing gas of 15% N2 remaining amount of O2 from the cylinder 32 is stored in the reserve bag 31 for a predetermined time, for example. The valve 35 is closed.

  The computer of the lung lesion evaluation apparatus is provided with a measurement program corresponding to, for example, a flowchart as shown in FIG. 2 and is executed. The operation will be described based on this flowchart. In response to the measurement start instruction operation, the computer 60 controls the opening of the valve 28 via the valve driving device 80, and starts taking blood oxygen saturation information, carbon dioxide concentration, flow rate data, and flow rate data (S11). . As a result, the subject can suck the atmosphere (the breathing gas having the first oxygen concentration corresponding to the atmosphere) through the four-opening tube 20 and the flow sensor adapter 10, and breathe in the atmosphere. At this time, exhaled air is discharged from the opening 22 through the one-way valve 27 of the four-opening tube 20.

  At the time of the above breathing, the subject is instructed to breathe about 18 times per minute using a metronome, for example, and the measurement is performed under a quiet ventilation. The computer 60 uses the carbon dioxide concentration data sent from the CO2 meter 42, the flow rate data sent from the flow rate output meter 47, and the flow rate data sent from the flow rate output meter 48, and the end-tidal carbon dioxide partial pressure. Waiting for (PetCO2) to reach a steady-state of, for example, about 40 ± 2 Torr (S12). When the steady-state is reached, the valve 28 is closed and the valve 36 is opened. (S13).

  As a result, the subject breathes with the breathing gas of 15% O2 and the remaining amount of N2 in the same manner as when breathing in the atmosphere. During and after this, the blood oxygen saturation information, carbon dioxide concentration, flow rate data, and flow rate data are continuously taken in (S14). When breathing, the subject was instructed to be at rest ventilation, and was obtained in the first state where the subject breathed with a breathing gas having a first oxygen concentration corresponding to the atmosphere. The subject performed breathing with the breathing gas having the second oxygen concentration corresponding to the oxygen partial pressure within the steep range of the data SpO2 (a) relating to the blood oxygen saturation and the oxygen hemoglobin dissociation curve. Since the data SpO2 (b) relating to the blood oxygen saturation obtained in the second state is taken in, the blood oxygen saturation data SpO2 (a) in the first state and the data in the second state Based on the difference in blood oxygen saturation data SpO2 (b), a comparison is made with a threshold value (for example, 3%), and a lung lesion evaluation process is performed (S15).

  Thus, the computer 60 controls the switching means to realize a first state in which the subject performs breathing by the atmosphere and a second state in which breathing by the breathing gas is performed, Obtaining the blood oxygen saturation level of the first state acquired by the acquiring means in the first state and the blood oxygen saturation level of the second state acquired by the acquiring means in the second state Based on these relationships, an evaluation processing means for performing an evaluation process of lung lesions is configured.

  FIG. 3 and FIG. 4 show the measured data, which is displayed on the monitor such as the LCD by the computer 60. FIG. 3 shows the data of a 47-year-old male who is non-smoking, healthy and normal in a spirogram test, and FIG. 4 is a 62-year-old male who is non-smoking and usually asymptomatic. Although there is an asthma predisposition, spirogram testing shows normal subject data.

  3 and 4, f1 represents arterial oxygen saturation (SpO2) by the pulse oximeter 50, f2 represents the respiratory flow rate, f3 represents the tidal volume of breathing, and f4 represents end-tidal carbon dioxide. Partial pressure (PetCO2) is indicated. The horizontal axis is time (unit: second). In actuality, f1 to f4 are color-coded and displayed on the monitor.

  According to the above measurement results, the subject of FIG. 3 had only a 2% decrease in arterial oxygen saturation (SpO2) after rest ventilation after 15% oxygen breathing for 180 seconds, from 96% to 94%. It is evaluated that there is no early lung lesion. In contrast, in the subject of FIG. 4, the arterial oxygen saturation (SpO2) after rest ventilation after 15% oxygen breathing for 160 seconds was greatly reduced by 5% from 96% to 91%. It is evaluated that a lesion is seen.

  As described above, according to the embodiment of the present invention, by using a breathing gas having an oxygen concentration corresponding to an oxygen partial pressure in a range where the slope of the oxygen hemoglobin dissociation curve is steep in an oxygen concentration of 15% O2 and N2 remaining, It can be seen that the lesion can be properly evaluated and early lung lesions can be captured.

  The reason for using a breathing gas having an oxygen concentration corresponding to an oxygen partial pressure in the oxygen hemoglobin dissociation curve with a steep slope of O2 of 15% and N2 is as follows. This will be described with reference to the oxygen hemoglobin dissociation curve shown in FIG. FIG. 5 shows an oxygen hemoglobin dissociation curve diagram at the sea level. The horizontal axis represents oxygen partial pressure, and the unit is kPa (kilopascal) on the bottom and mmHg on the upper side. The vertical axis represents the oxygen saturation of hemoglobin (Hb). Although shown as three solid lines and one broken line, the healthy person is the second curve l1 from the right. The left solid line l2 corresponds to the transition when the pH is inclined to alkali, when the temperature of the blood is lowered, or 2,3DPG in the blood is decreased, and the right solid line l3 corresponds to the transition in the opposite case Represents. Dashed line l4 represents the neonatal oxygen hemoglobin dissociation curve.

  In an atmosphere of 1 atm (760 mmHg), the partial pressure of oxygen with an oxygen concentration of 21% is about 160 mmHg. Taking into account the saturated water vapor pressure (47 mmHg) at 37 ° C. and carbon dioxide excreted from the body into the alveoli, the alveolar oxygen partial pressure in healthy adults is about 100 mmHg. When the oxygen-hemoglobin dissociation curve of the previous healthy person is traced to the upper right, the oxygen saturation of hemoglobin reaches 98% when the oxygen partial pressure is near 100 mmHg, which means that almost 100% of hemoglobin is present in healthy adults. It means that oxygen is efficiently transported to the tissue in combination with oxygen.

  In addition, the entire curve is S-shaped, and is characterized by a particularly wide flat top part of the curve. In general, when the lungs are damaged, the oxygen content in the alveoli and lung capillaries is reduced. Although the pressure decreases, even if the alveolar oxygen partial pressure decreases by 20% (20 mmHg) due to lung injury, the oxygen saturation of hemoglobin is 97%. Indicates that Therefore, since there is no symptom such as shortness of breath due to lack of tissue oxygen in early lung disorders, the person cannot recognize lung disorders.

  On the other hand, if you change the atmosphere to 1 atmosphere and inhale the breathing gas with oxygen concentration of 15% O2 and N2 remaining, the oxygen partial pressure of the inhaled air will be about 114 mmHg, and the ventilation state will be maintained in the previous state As far as possible, the alveolar oxygen partial pressure in healthy individuals is 57 mmHg. However, in those with early lung injury, if the alveolar oxygen partial pressure is reduced by 20% (14 mmHg) as described above, the oxygen saturation is greatly reduced to 80%. This is because the oxygen hemoglobin dissociation curve is applied to the steep part (the middle steeper part of the curve).

  As described above, the oxygen concentration breathing gas with 15% O2 remaining amount of N2 is an example of a breathing gas with an oxygen concentration corresponding to the middle steeper part of the curve. is there. If a breathing gas having an oxygen concentration corresponding to a portion where the oxygen hemoglobin dissociation curve is steep is used, the breathing gas is not limited to a breathing gas having an oxygen concentration of 15% O2 remaining amount.

The block diagram of the Example of the lung lesion evaluation apparatus which concerns on this invention. The flowchart for demonstrating operation | movement of the Example of the lung lesion evaluation apparatus which concerns on this invention. Example of Display Displayed When Measuring Healthy Oxygen Saturation Information, Carbon Dioxide Concentration, Flow Rate Data, Flow Rate Data, etc. Using a Healthy Person as a Subject Using the Example of the Lung Lesions Evaluation Apparatus According to the Present Invention FIG. Displayed when blood oxygen saturation information, carbon dioxide concentration, flow rate data, flow rate data, and the like are measured using a person having a predisposition to asthma using the embodiment of the lung lesion evaluation apparatus according to the present invention as a subject. The figure which shows the example of a display. The figure which shows an oxygen hemoglobin dissociation curve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flow sensor adapter 11 Flow sensor 12 CO2 sensor 20 4 opening tube 31 Reserve bag 32 Cylinder 41 Amplifier 42 CO2 meter 45 A / D converter 46 Integrator 47 Flow velocity output meter 48 Flow rate output meter 50 Pulse oximeter 51 SpO2 sensor 52 Signal Converter 60 Computer 70 Mouthpiece 80 Valve drive device

Claims (6)

A breathing gas supply means for supplying a breathing gas having an oxygen concentration corresponding to an oxygen partial pressure in a range where the slope in the oxygen hemoglobin dissociation curve is steep;
Switching means for switching between the breathing gas supplied by the breathing gas supply means and the atmosphere to supply to the subject;
Obtaining means for obtaining data relating to blood oxygen saturation of the subject;
Control means for controlling the switching means to realize a first state in which the subject performs breathing by the atmosphere and a second state in which breathing by the breathing gas is performed;
A blood oxygen saturation level in the first state acquired by the acquisition means in the first state and a blood oxygen saturation level in the second state acquired by the acquisition means in the second state. And a lung lesion evaluation apparatus comprising: an evaluation processing means for performing a lung lesion evaluation process based on these relationships. A detection means for detecting a carbon dioxide concentration contained in the exhalation of the subject,
The evaluation processing means captures blood oxygen saturation information in the first state and the second state when a predetermined carbon dioxide concentration is stably detected by the detection means. The lung lesion evaluation apparatus described. The pulmonary lesion evaluation apparatus according to claim 1 or 2, wherein the respiratory gas supply means supplies a respiratory gas having an oxygen concentration of a predetermined concentration of 16% to 14%. The evaluation processing means compares the difference or ratio between the blood oxygen saturation level in the first state and the blood oxygen saturation level in the second state with a threshold value, and performs the evaluation processing. The lung lesion evaluation apparatus according to 1. Data relating to blood oxygen saturation obtained in the first state where the subject has breathed with a breathing gas having a first oxygen concentration corresponding to the atmosphere, and a range where the slope in the oxygen hemoglobin dissociation curve is steep The blood oxygen saturation data obtained in the second state in which the subject has performed breathing with the breathing gas having the second oxygen concentration corresponding to the oxygen partial pressure of
A lung lesion evaluation method, comprising: performing lung lesion evaluation processing based on a relationship between blood oxygen saturation data in the first state and blood oxygen saturation data in the second state. 6. The blood oxygen saturation data of the first state and the second state is captured when the carbon dioxide concentration contained in the exhalation of the subject is stabilized at a predetermined level. Of lung lesion evaluation.

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