AIRWAY ADAPTER

An airway adapter includes a measurement flow path through which at least one of expired air or inhaled air of a subject passes through. A water absorption member is provided in a lower portion of the measurement flow path in a state where the airway adapter is placed. The water absorption member is exposed to an outside, and is configured to discharge water to the outside.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2022-206466 filed on Dec. 23, 2022, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The presently disclosed subject matter relates to a sensor configured to detect a predetermined respiratory gas (carbon dioxide, oxygen, laughing gas, volatile anesthesia gas, or the like) contained in respiratory air of a living body, and an airway adapter detachably attached to the sensor and formed with a passage through which the respiratory air of the living body pass.

BACKGROUND ART

A measurement flow path through which a respiratory air of a subject pass is formed in the airway adapter, and a predetermined respiratory gas contained in the respiratory air is measured. For example, in an airway adapter for measuring a carbon dioxide concentration, an optical axis that connects a light emitting unit and a light receiving unit provided in a sensor is disposed so as to cross the measurement flow path. Infrared light emitted from the light emitting unit is received by the light receiving unit, and a signal corresponding to an intensity of the received light is output from the sensor. As the carbon dioxide concentration in the respiratory air increases, the infrared light is more strongly absorbed and the intensity of the received light decreases. Therefore, the carbon dioxide concentration contained in the respiratory air of the subject can be measured by monitoring an intensity of the signal output from the sensor. Examples of such airway adapter and sensor are disclosed in JP2015-163275A.

In the measurement flow path of the airway adapter, expired air containing moisture from a body of the subject and humidified inhaled air pass, but condensation occurs in the measurement flow path and in a vicinity thereof due to a decrease in temperature or the like. Further, when the condensation stays in the measurement flow path, the infrared light is refracted by water generated by the condensation, or the like, and accurate measurement is difficult.

SUMMARY OF INVENTION

According to an aspect of the present disclosure, there is provided an airway adapter including:a measurement flow path through which at least one of expired air or inhaled air of a subject passes through,in which a water absorption member is provided in a lower portion of the measurement flow path in a state where the airway adapter is placed, andthe water absorption member is exposed to an outside, and is configured to discharge water to the outside.

DESCRIPTION OF EMBODIMENTS

FIG.1is commonly used in a known embodiment and each embodiment.FIG.1schematically illustrates a state in which a respirator V is attached to a patient P lying on a bed B. The respirator V sends a gas for inhaled air containing a large amount of oxygen to the patient P, and discharges expired air of the patient P. An inhaled air circuit1is connected to an inhaled air side connection portion v1of the respirator V, and an expired air circuit2is connected to an expired air side connection portion v2. In the inhaled air circuit1, a breathing tube1ais connected to the inhaled air side connection portion v1of the respirator V, and a humidifier1bis connected to the breathing tube1a.A breathing tube1cis connected to the humidifier1b,and the breathing tube1cis connected to a Y-piece3a.Further, in the expired air circuit2, a breathing tube2ais connected to the expired air side connection portion v2of the respirator V, and a water trap2bis connected to the breathing tube2a.A breathing tube2cis connected to the water trap2b,and the Y-piece3ais connected to the breathing tube2c. The breathing tubes1cand2care connected to the Y-piece3a,and a flexible tube3bis connected to the remaining connection portion of the Y-piece3a.A connection tube3cis connected to an intubation tube3dvia an airway adapter4or the like. The intubation tube3dis inserted from a mouth of the patient P to a trachea.

An optical sensor5, which is a type of sensor, is attached to the airway adapter4or the like. The optical sensor5is configured to optically measure the respiratory gas passing through the airway adapter4or the like. In the optical sensor5, a received light value of the infrared light passing through the airway adapter4or the like is obtained, a carbon dioxide concentration is calculated from the received light value sent to a patient monitor M via wiring51, and a measured value is monitored.

As illustrated inFIG.1, the inhaled air supplied from the respirator V is humidified by the humidifier1b.Further, the expired air discharged from the patient P also contains water vapor. Therefore, condensation occurs around the airway adapter4or the like exposed to a temperature lower than a body temperature.

FIG.2andFIG.3illustrate a known airway adapter4.FIG.2is a side view of the airway adapter4.FIG.3is a cross-sectional view taken along plane A-A inFIG.2, and illustrates a state viewed from a direction of an arrow inFIG.2. The airway adapter4may include an adapter body42and window portions43. As illustrated inFIG.3, the adapter body42may include a sensor holding portion423projecting to both sides and locking projections424projecting upward. The sensor holding portion423is formed in a U-shape to hold the optical sensor5inside. The sensor holding portion423and the locking projections424are used to detachably fix the optical sensor5to the airway adapter4.

Further, as illustrated inFIG.3, a measurement flow path41through which the respiratory air passes is formed inside the airway adapter4. The measurement flow path41penetrates the adapter body42illustrated inFIG.2from a device side connection port421to a subject side connection port422, and passes between the opposed window portions43. The adapter body42may have openings on both sides of the measurement flow path41. A sheet-shaped infrared light transmission resin, which is a member through which the infrared light transmits, closes the openings to form the window portions43. The infrared light for measurement sent out from the optical sensor5fixed to the inside of the sensor holding portion423passes across the measurement flow path41from one window portion43to the other window portion43illustrated inFIG.3. Since the infrared light is absorbed by carbon dioxide in the measurement flow path41, the optical sensor5obtains a received light amount corresponding to a carbon dioxide concentration in the respiratory air passing through the measurement flow path41.

The airway adapter4is long in an extending direction of the measurement flow path41. The flexible tube3billustrated inFIG.1is connected to the device side connection port421, and the intubation tube3dis attached to the subject side connection port422via the connection tube3c.Further, as illustrated inFIG.3, the sensor holding portion423is expanded below the adapter body42, and the airway adapter4is unlikely to be horizontally oriented. With this configuration, the airway adapter4is placed and provided above the bed B substantially in a vertical direction provided inFIG.2andFIG.3.

Water generated by condensation inside and around the airway adapter4accumulates in a lower portion of the measurement flow path41illustrated inFIG.3, inside the airway adapter4. When the airway adapter4is turned in a lateral direction and is inclined, or when water is scattered in the measurement flow path41due to respiration, there is a possibility that water enters between the window portions43. When water enters between the window portions43, there is a concern that the infrared light for measurement is refracted by the water and the received light amount decreases. When the infrared light is refracted by the water and the received light amount decreases, it is difficult to accurately measure the carbon dioxide concentration.

FIG.4toFIG.6illustrate an airway adapter6according to Embodiment 1.FIG.4is a side view of the airway adapter6according to Embodiment 1.FIG.5andFIG.6are cross-sectional views taken along plane A-A inFIG.4, and illustrate a state viewed from a direction of an arrow inFIG.4.FIG.5illustrates the airway adapter6to which the optical sensor5is attached, andFIG.6illustrates the airway adapter6before an opening625is closed. The airway adapter6is placed and provided above the bed B substantially in a vertical direction illustrated inFIG.4toFIG.6during provision. The airway adapter6according to Embodiment 1 is connected and used as illustrated inFIG.1, same or similarly to the airway adapter4according to the known embodiment.

As illustrated inFIG.4toFIG.6, the airway adapter6according to Embodiment 1 may include an adapter body62, window portions63, and a water absorption member64. The adapter body62is made of resin. The window portions63are made of a resin that transmits the infrared light, and are provided on both sides of a measurement flow path61as illustrated inFIG.5andFIG.6. As illustrated inFIG.4toFIG.6, a U-shaped sensor holding portion623sticks out both sides of the adapter body62, and locking projections624project upward.

As illustrated inFIG.5andFIG.6, a measurement flow path61through which the respiratory air passes is formed inside the airway adapter6. The measurement flow path61penetrates the adapter body62from a device side connection port621to a subject side connection port622, and passes between the opposed window portions63. The adapter body62may have openings on both sides of the measurement flow path61. A sheet-shaped infrared light transmission resin, which is a member through which the infrared light transmits, closes the openings to form the window portions63.

As illustrated inFIG.1, the optical sensor5illustrated inFIG.5is connected to the patient monitor M via the wiring51. InFIG.5, in the optical sensor5, a light emitting unit52and a light receiving unit53which are internal configurations are conceptually described. The optical sensor5is held inside the U-shaped sensor holding portion623in a state of straddling the measurement flow path61. An upper portion of the optical sensor5is locked by the two locking projections624, and is detachably fixed to the airway adapter6.

In the optical sensor5attached to the airway adapter6, the light emitting unit52and the light receiving unit53are positioned straddling the two window portions63of the airway adapter6. The infrared light for measurement emitted from the light emitting unit52crosses the measurement flow path61from one window portion63of the airway adapter6to the other window portion63, and is received by the light receiving unit53. Since the infrared light is absorbed by carbon dioxide in the measurement flow path61, the light receiving unit53obtains a received light amount corresponding to a carbon dioxide concentration in the respiratory air passing through the measurement flow path61. Data of the received light amount is sent to the patient monitor M via the wiring51, the carbon dioxide concentration is calculated, and a measured value is monitored.

Unlike the airway adapter4according to the known embodiment, in the airway adapter6according to Embodiment 1, the opening625is provided at a lower portion of the measurement flow path61in a state where the airway adapter6is placed.FIG.6is a cross-sectional view of the airway adapter6before the opening625is closed. The water absorption member64is illustrated below the opening625. The water absorption member64is exposed to an outside, and is configured to discharge water to the outside. The water absorption member64is made of a porous member having fine spaces through which water permeates. This member allows water to permeate and pass therethrough, but hardly allows a gas such as the respiratory air to pass therethrough.

Further, in Embodiment 1, a groove-shaped storage portion641having a tapered structure including a tapered surface T is provided on an upper surface of the water absorption member64. The storage portion641is provided as a groove along an extending direction of the measurement flow path61. The storage portion641is configured to store water generated by condensation, and the stored water penetrates the water absorption member64.

As indicated by an arrow inFIG.6, the opening625is closed by the water absorption member64. In Embodiment 1, the water absorption member64is fixed in a vicinity of the opening625by adhesion, and the opening625is closed by the water absorption member64as illustrated inFIG.4andFIG.5.FIG.5illustrates a state in which water W is accumulated in the storage portion641. Water that cannot be immediately absorbed by the water absorption member64accumulates in the storage portion641. Since the water absorption member64may include the storage portion641and has the tapered structure, a water absorption surface can be enlarged.

The water condensed in the measurement flow path61of the airway adapter6or the tubes in a vicinity thereof penetrates the water absorption member64at the lower portion of the measurement flow path61in a state where the airway adapter6is placed. A part of the water absorption member64is exposed to an outside of the airway adapter6, and the permeated water is discharged from the water absorption member64to the outside. In a case in which a large amount of water is discharged, the water can be absorbed and evaporated by laying a gauze or the like under the water absorption member64. Further, in a case in which an amount of condensation is small, the water can also be directly evaporated from an outer portion of the water absorption member64by providing the airway adapter6in a state of floating from the bed B.

First Modification

FIG.7is a cross-sectional view of an airway adapter7according to a first modification of Embodiment 1.FIG.7is a cross-sectional view taken along a plane corresponding to plane A-A in Embodiment 1 orthogonal to an extending direction of a measurement flow path71. In the first modification, an uneven structure is provided in an outer portion of a water absorption member74attached to a lower portion of an adapter body72. As illustrated inFIG.7, grooves742are formed on a lower surface and a side surface of the outer portion of the water absorption member74, along the extending direction of the measurement flow path71. Other configurations are the same as those in Embodiment 1. The water absorption member74is exposed to the outside, and is configured to discharge water to the outside.

Since the outer portion of the water absorption member74has the uneven structure, a large surface area can be achieved, and a large evaporation amount from the water absorption member74can be achieved. The uneven structure is not limited to grooves along the extending direction of the measurement flow path71, and may be grooves orthogonal to the extending direction of the measurement flow path71, grooves obliquely intersecting the extending direction of the measurement flow path71, or a dot-shaped uneven structure.

Second Modification

FIG.8is a side view of an airway adapter8according to a second modification of Embodiment 1. The airway adapter8according to the second modification is provided with a plurality of openings, and each opening is closed by a water absorption member84. An adapter body82is provided with a window portion83and four openings below a sensor holding portion823. The water absorption member84is fixed by adhesion to the four openings below the sensor holding portion823. The water absorption member84is exposed to the outside, and is configured to discharge water to the outside. In the second modification, the four openings and the water absorption members84are arranged in an axial direction of the airway adapter8, and may be provided in another form. For example, the four openings and the water absorption members84May be arranged in a direction perpendicular to an axis, or may be arranged in a polka-dot pattern along the axis of the adapter body82and in a direction perpendicular to the axis.

FIG.9andFIG.10illustrate an airway adapter9according to Embodiment 2.FIG.9is a side view of the airway adapter9according to Embodiment 2.FIG.10is a cross-sectional view taken along plane A-A inFIG.9, and illustrates a state viewed from a direction of an arrow inFIG.9. The airway adapter9is placed above the bed B substantially in a vertical direction illustrated inFIG.9andFIG.10in a state where the airway adapter is placed. The airway adapter9according to Embodiment 2 is connected and used as illustrated inFIG.1, same or similarly to the airway adapter4according to the known embodiment and the airway adapter6according to Embodiment 1.

As illustrated inFIG.9andFIG.10, the airway adapter9according to Embodiment 2 may include an adapter body92and window portions93. As illustrated inFIG.10, a sensor holding portion923sticks out both sides of the adapter body92, and a measurement flow path91through which the respiratory air passes is formed inside the airway adapter9. The measurement flow path91penetrates the adapter body92from a device side connection port921to a subject side connection port922. Window portions93are provided on both sides of the measurement flow path91. The adapter body92May have openings on both sides of the measurement flow path91. A sheet-shaped infrared light transmission resin, which is a member through which the infrared light transmits, closes the openings to form the window portions93. An opening925is provided in a lower portion of the measurement flow path91and is closed by a water absorption member94. The water absorption member94is exposed to the outside, and is configured to discharge water to the outside. The above points are the same as those of the airway adapter6according to Embodiment 1.

FIG.10illustrates a state in which the water W is accumulated in a storage portion941including the tapered surface T. The water W is absorbed by the water absorption member94from the storage portion941. The absorbed water is discharged from an external exposed surface on a lateral side of the water absorption member94, and is evaporated.

On the other hand, unlike the airway adapter6according to Embodiment 1, in the airway adapter9according to Embodiment 2, a cover portion926is provided in a lower portion of the airway adapter9. As illustrated inFIG.9, the cover portion926may include leg portions926bat two positions in a lower portion of the adapter body92, and lower portions of the leg portions926bare connected by a plate-shaped portion926ato form a U-shape. The cover portion926and the opening925provided below the measurement flow path91are separated from each other, and the water absorption member94is fitted into a separated portion from a lateral side and is detachably fixed. Therefore, the water absorption member94can be easily fixed to the lower portion of the airway adapter9without using an adhesive.

Further, as illustrated inFIG.10, in the airway adapter9according to Embodiment 2, a lateral width of the cover portion926is larger than a lateral width of the water absorption member94. The cover portion926covers an entire lower surface of the water absorption member94with the plate-shaped portion926aat a lower portion of the water absorption member94. In the airway adapter9according to Embodiment 2, water is discharged by evaporation from a side surface of the water absorption member94. Since the lateral width of the cover portion926is larger than the lateral width of the water absorption member94, the fitted water absorption member94does not come into direct contact with the bed B, the sheet, or the like without laying a gauze or the like. By using the airway adapter9according to Embodiment 2, in a case where an amount of condensation inside the airway adapter9is small, the bed B or the like can be made difficult to get wet without laying a gauze or the like.

Third Modification

FIG.11is a cross-sectional view of an airway adapter10according to a third modification of Embodiment 2. Also in the airway adapter10according to the third modification, a plate-shaped portion1026aof a cover portion1026is separated from an opening1025provided below a measurement flow path101, and a water absorption member104is fitted from a lateral side. Further, same or similarly to Embodiment 2, the cover portion1026may include leg portions (not illustrated) at two positions in a lower portion of an adapter body102, and lower portions of the leg portions are connected by a plate-shaped portion1026ato form a U-shape. The water absorption member104is exposed to the outside, and is configured to discharge water to the outside.

FIG.11illustrates a state in which the water W is accumulated in a storage portion1041including the tapered surface T. The water is absorbed by the water absorption member104from the storage portion1041. The absorbed water is discharged from an external exposed surface on a lateral side or a lower side of the water absorption member104and is evaporated, or is absorbed by a gauze or the like laid under the airway adapter10. In the third modification, a lateral width of the cover portion1026is smaller than a lateral width of the water absorption member104. The cover portion1026covers a part of a lower surface of the water absorption member104with the plate-shaped portion1026aat a lower portion of the water absorption member104. The other points are the same as those in Embodiment 2. In the third modification, the external exposed surface of the water absorption member104is large, water is easily discharged to the outside, and the water absorption member104is easily attached and detached.

Fourth Modification

FIG.12is a cross-sectional view of an airway adapter11according to a fourth modification which is another modification of Embodiment 2. Also in the airway adapter11according to the fourth modification, a plate-shaped portion1126aof a cover portion1126is separated from an opening1125provided below a measurement flow path111, and a water absorption member114is fitted from a lateral side. Further, same or similarly to Embodiment 2, the cover portion1126may include leg portions (not illustrated) at two positions in a lower portion of an adapter body112, and lower portions of the leg portions are connected by the plate-shaped portion1126ato form a U-shape. The water absorption member114is exposed to the outside, and is configured to discharge water to the outside.

In the fourth modification, a replaceable evaporation sheet115is connected to the water absorption member114. The evaporation sheet115is formed of a filter paper-like paper, and has a water absorption property. A rectangular hole into which the water absorption member114is to be fitted is provided near a center of the evaporation sheet115. The water absorption member114according to the third modification is obtained by reducing a width of an upper portion of the water absorption member104of the airway adapter10according to the third modification illustrated inFIG.11, and has a shape illustrated inFIG.12. Further, the water absorption member114is covered with the evaporation sheet115having a hole from a lower side of the water absorption member114, passed through the hole, and connected as illustrated inFIG.12. Since the water absorption member114is in contact with the evaporation sheet115, the water absorbed by the water absorption member114inside the airway adapter11penetrates the evaporation sheet115. Then, the water permeated on a surface of the evaporation sheet115having a large surface area is evaporated.

FIG.13is a side view of an airway adapter12according to Embodiment 3. The airway adapter12according to Embodiment 3 is connected and used as illustrated inFIG.1, same or similarly to the airway adapter4according to the known embodiment, the airway adapter6and the airway adapter9according to Embodiment 1 and Embodiment 2, and the airway adapter7, the airway adapter8, the airway adapter10, and the airway adapter11according to the modifications.

In the airway adapter12according to Embodiment 3, an adapter body122is made of fired diatomaceous earth which is a porous member. A plastic sensor attachment portion124is fixed to the adapter body122. The sensor attachment portion124may include a sensor holding portion1241extending laterally and locking projections1242provided at two upper positions, and the optical sensor5can be detachably mounted. Same or similarly to other embodiments, a measurement flow path (not illustrated) from a device side connection port1221to a subject side connection port1222is formed inside the airway adapter12. The adapter body122, which is a water absorption member, may have openings on both sides of the measurement flow path, and forms window portions123by closing the openings with a sheet-shaped infrared light transmission resin, which is a member through which the infrared light transmits.

Since the adapter body122is made of fired diatomaceous earth which is a porous member, the adapter body122serves as a water absorption member as a whole, and the measurement flow path is provided inside the water absorption member. The water in the measurement flow path can be discharged by the condensation water penetrating the adapter body122from the measurement flow path inside the airway adapter12and the water evaporating from the entire outer surface of the adapter body122. The water absorption member formed as the adapter body122is exposed to the outside, and the water can be discharged to the outside.

In Embodiment 3, the plastic sensor attachment portion124is fixed to the water absorption adapter body122, and a periphery of the window portion123, the sensor attachment portion124, and the like are made of plastic. However, some or all of these may be formed as a water absorption member and integrated with the adapter body122.

In the above detailed description of the presently disclosed subject matter, it is assumed that the airway adapter is used for a patient. However, the airway adapter may be used for a subject other than a patient. As long as the optical sensor can be blocked such that the respiratory air does not leak, the window portion may be kept open without being blocked by a member through which the infrared light transmits. Further, the airway adapter may perform a measurement or the like other than the carbon dioxide concentration.

A groove forming the storage portion641and the like above the water absorption member64and the like in Embodiment 1 and Embodiment 2 and the modifications may extend over an entire width of the measurement flow path or may be formed in a part of the width. A shape of the groove may be a quadrangular prism having a trapezoidal side surface, such as the storage portion641, or may be a long quadrangular shape. Further, a plurality of grooves may be formed. A plurality of recesses may be formed in the water absorption member instead of the grooves such as the storage portion641. Further, the water absorption member may be a prism having no recess such as a groove on the upper surface.