JP2016036431A - Airway gas analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an airway gas analyzer capable of analyzing local airway gas by being inserted in an airway of a lung, etc.SOLUTION: An infrared light source 1 and a near-infrared laser light source 2 are combined by a beam splitter 3 and are made incident to a hollow optical fiber 4. The tip of the hollow optical fiber 4 is inserted in the inside of a lung through a catheter 5. A gas cell 6 is attached to the tip of the fiber, and gas to be measured flows into the inside through a gas introduction hole 8. Light reflected by a reflector 9 at a terminal of the gas cell 6 is discriminated into infrared light and near-infrared light by a wavelength selective beam splitter 10, and is detected by an infrared detector 11 and a Raman spectrometer 12. The infrared detector 11 can analyze mainly a concentration of carbon dioxide by an infrared absorption spectroscopic method, and the Raman spectrometer 12 can analyze mainly a concentration of oxygen by a Raman spectroscopic method. Thus, it is possible to analyze local airway gas in the inside of a lung.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an airway gas analyzer, and more particularly, to an airway gas analyzer for inserting into an airway via an endoscope or a catheter and measuring local oxygen and carbon dioxide concentrations in the airway. Regarding the device.

  Expiratory oxygen and carbon dioxide concentrations are important factors for pulmonary function monitoring, and the breath sampled from the oral cavity is usually measured by an electrical or optical sensor. Especially when these concentrations are monitored in real time, it is possible to observe changes in the concentration of each gas in response to breathing, and it is possible to know in detail the functions of the respiratory organs including the lungs. It becomes. In addition, since oxygen and carbon dioxide concentrations change in a targeted manner, it is possible to diagnose respiratory function with higher accuracy than when only one component is used as an index by processing these data in a complementary manner. It becomes.

Furthermore, by measuring the concentration of oxygen and carbon dioxide present locally in the respiratory tract using a bronchial endoscope, it is possible to identify dysfunctional sites in respiratory organs such as the lungs . Especially in the treatment under bronchoscope, by monitoring these gas concentrations in real time, it is possible to perform appropriate treatment in a short time, and the burden on the patient is greatly reduced.
JP 2009-284756 A JP 2002-345781 JP-A-6-242002

  However, measurement of exhaled breath under bronchoscopy is performed by collecting a small amount of local exhalation with a micropump connected to a catheter inserted into the endoscope and measuring it with an analyzer placed outside the body. Is normal. This is because various electric and optical gas sensors are relatively large and difficult to place at the tip of an endoscope, and it is difficult to maintain safety in the body due to the structure of the sensor. is there. Breath sampling using a catheter can measure a relatively small amount of gas, but a time lag occurs when the catheter is aspirated, so it is difficult to perform real-time monitoring at the catheter tip position.

  If a small gas cell is placed at the tip of the catheter and the gas concentration is analyzed optically, local gas concentration measurement in the airway will be possible. Since carbon dioxide concentration is generally highly absorbed by infrared light, it can be measured by measuring the absorbance when irradiated with infrared light that matches the absorption band of carbon dioxide molecules. On the other hand, oxygen that is inactive in infrared cannot be measured by the infrared absorption method, and detection by Raman scattering spectroscopy using near infrared light or visible light as excitation light is suitable. However, a general silica glass optical fiber is opaque to light around 4 microns, which is the absorption band of carbon dioxide, and cannot guide light to the gas cell placed at the tip of the catheter. For near-infrared light used for Raman scattering spectroscopy, quartz glass fiber is transparent, but strong Raman noise is generated from quartz glass, so an optical filter to remove this is placed at the fiber tip. It is difficult to place it at the tip of a small diameter catheter.

  The present invention has been devised to solve the above-mentioned problems of the conventional airway gas analyzer, and is inserted into the airway through an endoscope or a catheter, and local oxygen and The purpose is to realize an airway gas analyzer for measuring the concentration of carbon dioxide.

  In order to solve the above problems, a micro gas cell having a reflecting mirror, an optical fiber for transmitting excitation light to the gas cell and return light from the gas cell, a light source for generating the excitation light, and the micro gas cell An airway gas analyzer characterized by comprising an optical analyzer that detects and analyzes the return light of the air.

  The micro gas cell may have a length of 1 centimeter or less.

  In addition, a plurality of holes for allowing a gas to be measured to flow into the minute gas cell may be provided.

  The optical fiber may be a hollow optical fiber.

  The gas cell and the optical fiber may have a diameter of 2 millimeters or less.

  Further, the excitation light is visible or near infrared light, and the oxygen concentration in the airway is measured by detecting Raman scattered light of oxygen in the minute gas cell. Good.

  The excitation light may be infrared light, and the carbon dioxide concentration in the airway may be measured by detecting infrared absorption of carbon dioxide in the minute gas cell. .

  The optical fiber includes two light sources, a visible light or near-infrared light source, and an infrared light source, and the optical fiber can transmit these two light sources, and the Raman scattered light of oxygen in the minute gas cell and It may be characterized by measuring the oxygen concentration and carbon dioxide concentration in the airway by detecting both infrared absorption of carbon dioxide.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an airway gas analyzer showing an example of an embodiment of the present invention. The light from the infrared light source 1 is combined with the light from the near infrared laser light source 2 by the beam splitter 3 and enters the optical fiber 4. The tip of the optical fiber 4 is guided into the airway while being inserted into the catheter 5. A minute gas cell 6 is attached to the tip of the optical fiber 4 and the inside of the gas cell and the optical fiber are separated by a sealing window 7 attached to the tip of the fiber, so that the concentration of gas existing inside the minute gas cell 6 is measured. It is done. The minute gas cell 6 is provided with a plurality of perforations 8 so that gas can flow inside. A reflecting mirror 9 is attached to the tip of the minute gas cell 6, and the light reflected here returns to the optical fiber 4 and enters again as light. The return light is reflected by the beam splitter 3 and then guided to the infrared detector 11 and the Raman spectrometer 12 by the wavelength selective beam splitter 10.

  The infrared light source 1 is preferably a thermal light source having a wide power spectrum in the mid-infrared wavelength region. In that case, the infrared detector 11 may be one equipped with an optical filter that extracts only the vicinity of a wavelength of 4.2 microns, which is the absorption peak of carbon dioxide, or a spectroscope capable of measuring a spectrum in the infrared wavelength region. . In addition, if a laser light source such as a quantum cascade laser that oscillates at a wavelength of around 4.2 microns is used as the infrared light source 1, it is possible to measure the carbon dioxide concentration at a high S / N ratio because strong optical power is obtained. The near-infrared laser light source 2 is preferably a semiconductor laser light source that oscillates in the vicinity of a wavelength of 780 nanometers. If a combination of an optical filter that extracts only the Raman spectral wavelength of oxygen and a normal photodetector is used instead of a Raman spectrometer, a simpler measurement system can be constructed.

  The optical fiber 4 can transmit the mid-infrared light for measuring the carbon dioxide concentration and the near-infrared light for measuring the oxygen concentration with low loss, and the Raman when the near-infrared laser light is incident. It is desirable that noise is not generated as much as possible. A hollow optical fiber is suitable as the optical fiber 4 of the present invention in order to satisfy these conditions. In that case, a hollow optical fiber having a diameter of 1 mm or less and high flexibility is preferable, and a hollow optical fiber in which a silver thin film is formed on the inner surface of a glass capillary tube is suitable. The inner surface of the hollow optical fiber is more preferably coated with a dielectric coating that provides low loss for both mid-infrared and near-infrared light.

  Figure 2 shows an example of the appearance of a micro gas cell. A micro gas cell 6 is attached to the optical fiber 4, and gas flows into the gas cell from the perforations 8. In order to increase the inflow conductance to the inside, it is desirable that the diameter of the perforations is as large as possible and the number is as large as possible, as long as sufficient mechanical strength is maintained in the gas cell 6. The gas cell 6 may have a network structure instead of perforation. The reflecting mirror 9 desirably has a high reflectivity for both mid-infrared light and near-infrared light, and may have a concave mirror structure in order to improve the re-incidence efficiency to the fiber. The length of the minute gas cell 6 is preferably as small as possible within a range in which the gas can be detected with sufficient sensitivity, and if it is 1 cm or less, the local gas concentration inside the airway can be detected. The outer diameter of the micro gas cell should be less than 2 mm so that it can be inserted into an endoscope or catheter.

It is the block diagram of the gas analyzer in an airway which shows embodiment of this invention, and the expanded sectional view of a gas analyzer front-end | tip. It is an external view of the gas cell of the gas analyzer in the airway of the present invention.

DESCRIPTION OF SYMBOLS 1 Infrared light source 2 Near-infrared laser light source 3 Beam splitter 4 Optical fiber 5 Catheter 6 Gas cell 7 Fiber sealing window 8 Gas introduction hole 9 Reflector 10 Wavelength selective beam splitter 11 Infrared light detector 12 Raman spectrometer

Claims (9)

A micro gas cell with a reflecting mirror, an optical fiber for transmitting excitation light to the gas cell and return light from the gas cell,
An airway gas analyzer comprising: a light source that generates the excitation light; and an optical analyzer that detects and analyzes the return light from the micro gas cell;   The airway gas analyzer according to claim 1, wherein a length of the minute gas cell is 1 centimeter or less.   The airway gas analyzer according to claim 1, wherein a plurality of holes for allowing a gas to be measured to flow into the minute gas cell are provided.   The airway gas analyzer according to claim 1, wherein the optical fiber is a hollow optical fiber.   The airway gas analyzer according to claim 1, wherein the diameter of the gas cell and the optical fiber is 2 millimeters or less.   The airway according to claim 1, wherein the excitation light is visible or near-infrared light, and the oxygen concentration in the airway is measured by detecting Raman scattered light of oxygen in the minute gas cell. Internal gas analyzer.   2. The airway concentration according to claim 1, wherein the excitation light is infrared light, and the carbon dioxide concentration in the airway is measured by detecting infrared absorption of carbon dioxide in the minute gas cell. Gas analyzer. A visible light or near-infrared light source, and an infrared light source, and the optical fiber is an optical fiber capable of transmitting these two light sources, and the Raman scattered light of oxygen and carbon dioxide in the micro gas cell The airway gas analyzer according to claim 1, wherein the oxygen concentration and carbon dioxide concentration in the airway are measured by detecting both infrared absorptions of the airway.
  The airway gas analyzer according to claim 8, wherein the optical fiber is a hollow optical fiber.

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