JP3217833B2 - Airway resistance measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a respiratory airway from an oral cavity to a lung, and more particularly to an airway resistance measuring device for measuring airway resistance.

[0002]

2. Description of the Related Art When a gas flows through an airway, friction occurs between the gas molecules and the airway walls and between the gas molecules, that is, airway resistance occurs, and the energy of the gas becomes heat and disappears. The airway resistance varies from person to person, and various pathologically increasing diseases of the airway resistance are known. Measuring the airway resistance is important for understanding the pathology of these diseases.

In order to know the airway resistance Raw, it is necessary to determine the difference between the average intra-alveolar pressure Pal and the oral pressure Pm, that is, the airflow velocity Vf corresponding to the difference between the airway pressure inside and outside the airway. The following relational expression 1 holds between them.

## EQU1 ## Raw = (Pal-Pm) / Vf The airflow velocity Vf can be easily measured with a flow meter, but the alveolar pressure Pal cannot be directly measured.

[0004] As a conventional method for measuring airway resistance, an airflow blocking method (shutter method) such as von Neergaard et al. (1927) is known. Also Bavlis
(1939) proposed a different gas inhalation method, but the most reliable method is DuBois et al. (1939).
56), a body plethysmograph developed by Mead et al. (1960).
aphy). In addition, the needle retregrad
The e-catheter method is also known. Rohrer
(1915) aims to determine airway resistance, measures the size and number of airways from the nose to the alveoli by anatomical search of the lungs, and calculates these average alveolar pressure Pal and total airflow velocity Vf
The relationship

[Number 2] shown Pal-Pm = K1 Vf + K2 Vf 2 becomes a quadratic equation. Here, K1 and K2 are Rohre
r is a constant.

[0005] Therefore, the airway resistance Raw is expressed by Equations 1 and 2
The following relationship holds.

## EQU3 ## Raw = (K1 Vf + K2 Vf ² ) / Vf
= K1 + K2 Vf As shown by the equation 3, the airway resistance Raw is equal to the airflow velocity Vf.
It is expressed by a linear expression. That is, to know the airway resistance K1,
Finding K2 is more accurate.

[0006] Furthermore, it is thought that the increase in the value of K2 reflects an increase in the resistance of the peripheral airways, and it is more meaningful to measure the Rohrer constant than this.

[0007] Then, Mead et al. (1964) pushed this idea down to the entire airway system from the oral cavity to the chest, and determined K1 and K2 at this time based on data for the past 10 years.
= 2.7 and K2 = 0.3.

[0008]

However, in each of the conventional methods described above, the apparatus itself is large-scale, and it is difficult to easily perform measurement, and it is expected that accuracy is not so high. There were drawbacks that could not be done.

Although the above body plethysmograph method can measure the airway resistance relatively accurately, it requires an airtight box having a volume capable of accommodating the subject in a sitting position, and therefore the device becomes large. In addition, the operation was quite difficult.

[0010] The present invention has been made in view of the above-described conventional circumstances, and accordingly, an object of the present invention is to solve the above-described problems inherent in the conventional technology, and to achieve a simple configuration and operation.
It is an object of the present invention to provide a novel airway resistance measuring device capable of easily and highly accurately measuring airway resistance.

[0011]

In order to achieve the above object, an airway resistance measuring device according to the present invention is provided with a mouthpiece, an inner cylinder connecting portion communicating with the mouthpiece, and an inner cylinder connecting portion. A mouth side outer cylinder having a through-hole in the longitudinal direction having a pressure measuring portion provided therein, an air opening portion, an inner tube connecting portion communicating with the air opening portion, and a pressure measurement provided at the inner tube connecting portion. And an atmosphere-side outer cylinder having a through hole in the longitudinal direction, and a detachably and selectively inserted between the atmosphere-side outer cylinder and the mouth-side outer cylinder in the central longitudinal direction. A plurality of inner cylinders each having a through hole communicating with each through hole and having different inner diameters are provided.

Further, the airway resistance measuring device according to the present invention is used.
The method of measuring airway resistance using the following methods (1) to (1)
It has the procedure of 1).

(1) An airway resistance measuring device is assembled by selecting one of a plurality of inner cylinders having different inner diameters and inserting the inner cylinder between the mouth-side outer cylinder and the atmosphere-side outer cylinder.

(2) A constant flow generator is connected to the mouthpiece portion of the outer cylinder, and a constant flow of air flows into the measuring device.

(3) A pressure measuring device is connected to the pressure measuring section of the outer cylinder, and the pressure measuring section of the outer cylinder is closed.

(4) A certain amount of air is introduced into the inner cylinder, and the pressure and flow characteristics of the inner cylinder are measured.

(5) Another inner cylinder is selected and the above (2) to
The procedure of (4) is repeated to create a pressure / flow rate characteristic curve of each inner cylinder.

(6) Next, the state of (1) is reproduced, each of the pressure measuring sections is closed, and a flow meter is connected to the atmosphere opening section of the atmosphere side outer cylinder.

(7) The subject's nose is pinched, and the mouthpiece of the mouth-side outer cylinder is held in the mouth.

(8) The subject inhales deeply,
The breath is exhaled at once, and the flow rate is measured with a flow meter while confirming whether a constant flow rate is obtained at that time.

(9) The intraoral pressure Pm at this time is read from the pressure / flow rate characteristic curve of the inner cylinder used at that time.

(10) Another inner cylinder is selected and the above (7) is selected.
Repeat steps (9) to (9).

(11) Formula-Pm = K1Vf + K2V
f ² -Palmax (Pm:. intraoral pressure, Palmax maximum average alveolar pressure, K1
, K2: Laurel constant, Vf: flow rate), and Pm is obtained by the least squares method using Vm and Vf.
Calculate almax, K1 and K2.

[0024]

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[Measurement Apparatus] FIG. 1 is an exploded perspective view showing one embodiment of the present invention, FIG. 2 is a sectional view showing one embodiment of the present invention, and FIG. 3 is an equivalent circuit of one embodiment of the present invention. It is.

Referring to FIGS. 1 and 2, reference numeral 1 indicates an outer cylinder on the mouth side, 2 indicates an outer cylinder on the atmosphere side, and 3 indicates an inner cylinder (stenosis tube). The mouth outer tube 1, the atmosphere side outer tube 2, and the inner tube 3 constitute an airway resistance measuring device according to the present invention.
The mouth-side outer cylinder 1 and the atmosphere-side outer cylinder 2 may have substantially the same structure, and the same structure is more convenient in terms of manufacturing and use.

The mouth side outer cylinder 1 has a mouthpiece 11, an inner cylinder connecting part 12, a pressure measuring part 13, a screw insertion part 14 provided on the right side, and a screw hole 15 (not shown) provided on the left side. )
And the inner cylinder housing 17. 4 is a screw. On the other hand, the atmosphere side outer cylinder 2 has an atmosphere opening part 21, an inner cylinder connection part 22, a pressure measuring part 23, a screw insertion part 24 (not shown) provided on the right side, a screw hole 25 provided on the left side, and It is formed by the inner cylinder storage portion 27. The inner cylinder (stenosis tube) 3 is an object that is inserted into and interposed in a gap formed by the inner cylinder housing portions 17 and 27 between the outer cylinders 1 and 2.
A through hole 31 is formed in the longitudinal direction of the central portion, and an airtight packing 5 is interposed between these three elements. Although one packing 5 is used in this embodiment,
More than one may be provided. Through holes 16 and 26 are formed in the center portions of the outer cylinders 1 and 2, respectively.
The reference numerals 6 and 26 communicate with the through holes 31 of the inner cylinder 3.

In this embodiment, a screw 4 is used as a means for detachably connecting the outer cylinder 1, 2 and the inner cylinder 3, but an elastic body which can be detached with one touch is used instead of the screw. A hook mechanism can be used, which is more convenient for selectively attaching and detaching a plurality of inner cylinders.

FIGS. 4A and 4B are views showing a second embodiment of the inner cylinder according to the present invention, wherein FIG. 4A is an end view, and FIG.
FIG. 3A is a cross-sectional view taken along the line AA ′ of FIG.

Referring to FIGS. 4A and 4B, the inner cylinder 3
3, a through hole 331 is formed in the longitudinal direction of the center portion, and tapered portions 333 are provided at both end surfaces of the through hole 331.
Accordingly, the large-diameter portions 332 at both end surfaces of the through hole 331 are formed. By inserting the inner cylinder 33 between the outer cylinder 1 on the mouth side and the outer cylinder 2 on the atmosphere side, the flow of the fluid becomes smooth, and more accurate airway resistance can be measured.

In measuring the airway resistance, a plurality of inner cylinders 3 having different inner diameters of the through holes are prepared, and the measurement is performed by selectively using these inner cylinders. The following alternative is conceivable instead of preparing.

5A to 5C show a second embodiment according to the present invention, wherein FIG. 5A is a perspective view, FIG.
(C) is a left end view.

Referring to FIGS. 5A to 5C, reference numeral 6 indicates an airway resistance measuring device. The measuring device 6 includes a main body 6a having a hole 61 formed by a cylinder, and the main body 6a. A first cylinder 62 having a first communication hole communicating with the hole 61 of the second cylinder, a second cylinder 63 having a second communication hole communicating with the hole 61, and similarly, a third cylinder having a third communication hole. And a fourth cylinder 65 having a fourth communication hole. The inner diameter of each communication hole of the first to fourth cylinders 62 to 65 increases in the order of 62 <63 <64 <65. At the time of measurement, it is assumed that the end faces of only one of the cylinders 62 to 65 are opened, and the other cylinders are closed with a lid (not shown). In this embodiment, four cylinders are provided, but five or more cylinders can be provided. Reference numeral 6b denotes a mouthpiece portion to which the mouth comes in contact during measurement.

FIG. 6 shows a third embodiment according to the present invention.
It is a principal part principle diagram of the inside diameter free change mechanism used instead of the cylinder used in the 1st Example.

Referring to FIG. 6, reference numeral 7 denotes an inner diameter freely changing mechanism. The changing mechanism 7 comprises four plate members 71, 72, 7
The gap 75 can be made smaller by rotating each of the plate members 71 to 74 in the direction of the arrow in the figure.

FIG. 7 is a principal view showing the principle of a fourth embodiment according to the present invention.

The fourth embodiment shown in FIG. 7 is the same as the third embodiment shown in FIG. Plate member 8
1 to 85. The fourth embodiment has a structure similar to the aperture of a camera. Plate member 81
As in the third embodiment, the size of the center gap portion 86 can be changed by moving .about.85.

In both the third and fourth embodiments, the use of the cylinder shown in FIG. 1 makes it possible to measure the airway resistance while continuously changing the inner diameter through which the air flows.

Next , the airway resistance measuring device according to the present invention is used.
A method for measuring the airway resistance used will be described.

[Measurement Principle] When breathing while holding the mouthpiece 11 of the tube having the inner cylinder 3 having a variable inner diameter as shown in FIG. It is known that, when it is small, a constant flow of expiratory air can be obtained at the time of effortful exhalation to expel air with maximum force. The present inventor considers that as a result of earnest research, this phenomenon appears to occur because the muscle group that functions to exhale air, that is, the exhalation muscle group, has undergone maximum contraction, and therefore the average alveolar pressure Pal has become maximum. Was.

Then, it is considered that almost all the force obtained by the exhalation muscle group is converted to the average intra-alveolar pressure. Therefore, even if the inner diameter of the stenosis tube (inner cylinder) 3 changes, a constant exhalation flow can be obtained. Sometimes, it is considered that the mean intra-alveolar pressure always shows a constant maximum value Palmax.

At this time, Equation 2 is rewritten as Equation 4 below.

Equation 4] Palmax -Pm = K1 Vf + K2 Vf 2 further Palmax, K1, K2 is from considered to be constant in the same person, number 4 Palmax, K1, K
It is a ternary linear equation with 2 as the unknown. That is, by using three or more types of stenosis tubes (inner cylinders) 3 (in the case of four or more types, the least squares method), K1 and K2 can be obtained.

Here, the oral pressure Pm is obtained from the pressure measuring section 13 of the mouth side outer cylinder 1, and the air flow velocity Vf is obtained from the atmosphere opening section 2 of the atmosphere side outer cylinder 2.
1 can be easily measured by connecting it to the flow meter 10 (see FIG. 3).

[Measurement Method] [Method of Making FIGS. 8 and 9] One of a plurality (eight in this embodiment) of inner cylinders 3 having different inner diameters is selected and placed in outer cylinders 1 and 2. Insert
The airway measurement device according to the present invention is assembled.

In order to supply a constant flow of air from the mouthpiece 11, a steady-state generator (not shown) is connected to the mouthpiece 11.

The pressure measuring device 9 (see FIG. 3) is connected to the pressure measuring unit 13 to close the pressure measuring unit 23.

Then, various air flows are introduced into the inner cylinder 3, and the pressure / flow rate characteristics are measured, and graphs (FIGS. 8 and 9) are created.

Then, another inner cylinder 3 is selected and the above procedure is repeated.

[Measurement of actual airway resistance] One inner cylinder is selected and inserted into the outer cylinders 1 and 2 to assemble an airway measuring device.

Then, the pressure measuring units 13 and 23 are closed, and the flow meter 10 (see FIG. 3) is connected to the atmosphere opening unit 21.

The subject's nose is pinched, and the mouthpiece 11 is held in the oral cavity.

As in the case of measuring the vital capacity, a large amount of breath is inhaled, the breath is exhaled at a stretch, and the flow rate at that time is measured by the flow meter 10 (FIGS. 10 and 11).
The largest flat part).

The intraoral pressure Pm at this time is read from the pressure / flow rate characteristic graph (FIGS. 8 and 9) of the inner cylinder used at that time.

The above steps (1) to (4) are repeated using another inner cylinder 3.

The measured -Pm. FIG. 12 is created by plotting Vf on a graph.

Palmax, K1 and K2 are calculated by the least squares method using the equation (5) obtained by transforming the equation (4).

One embodiment of Equation 5] ^{-Pm = K1 Vf + K2 Vf 2} -Palmax above-described measurement method, FIG. 8, using the flow and pressure characteristics curves of the inner tube having different diameters as shown in FIG. 9 embodiment This is an example, and using this characteristic curve simplifies the subsequent actual measurement operation, but it can also be obtained directly without using these graphs. In that case, the operation is slightly complicated, but the measurement accuracy is further improved.

[0057]

As described above, according to the present invention,
With a simple configuration and operation, it is possible to measure airway resistance easily and with high accuracy, and it is expected to greatly contribute to early detection and treatment of lung disease at an early stage.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of an airway resistance measuring device according to the present invention.

FIG. 2 is a longitudinal sectional view showing a first embodiment of an airway resistance measuring device according to the present invention.

FIG. 3 is an equivalent circuit diagram showing a first embodiment of an airway resistance measuring device according to the present invention.

FIG. 4 shows a second embodiment of the inner cylinder used in the airway resistance measuring device according to the present invention, wherein (a) is an end view and (b) is a longitudinal sectional view.

5A and 5B show a second embodiment of an airway resistance measuring device according to the present invention, wherein FIG. 5A is a perspective view, FIG.
(C) is an end view thereof.

FIG. 6 is a principle view showing a first embodiment of a freely changing inner diameter mechanism used in place of the inner cylinder.

FIG. 7 is a principle view showing a second embodiment of the freely changing inner diameter mechanism according to the present invention.

FIG. 8 is a flow rate / pressure characteristic curve diagram of the inner cylinder.

FIG. 9 is a flow rate / pressure characteristic curve diagram of the inner cylinder.

FIG. 10 is a diagram showing flow rate characteristics (Flow-Volume characteristics) measured by a flow meter when exhaling using each inner cylinder.

FIG. 11 is a diagram showing flow rate characteristics (Flow-Volume characteristics) measured by a flow meter when exhaling using each inner cylinder.

FIG. 12 is an airway resistance characteristic curve diagram according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer side outer cylinder, 11 ... Mouthpiece part 12 ... Inner cylinder connection part 13 ... Pressure measurement part 14 ... Screw insertion part 15 ... Screw hole 16 ... Through hole 17 ... Inner cylinder storage part 2 ... Atmosphere side outer cylinder 21 ... Atmospheric release section 22 ... Inner cylinder connection section 23 ... Pressure measurement section 24 ... Screw insertion section 25 ... Screw hole 26 ... Through hole 27 ... Inner cylinder storage section 3 ... Inner cylinder (stenosis tube) 31 ... Through hole 4 ... Screw 5 ... Packing (concave ring) 6 Airway resistance measuring device 6a Main body 6b Mouthpiece 61 Hole 62-65 Cylindrical 7, 8 Inner diameter freely changing mechanism 71-74, 81-85 Plate members 75, 86 Air gap Part 9 Pressure measuring device 10 Flow meter 33 Inner cylinder 331 Through hole 332 Large diameter part 333 Tapered part

Continuation of the front page (56) References JP-A-1-145524 (JP, A) JP-A-53-16658 (JP, A) JP-A-1-311230 (JP, A) JP-A-61-26503 (JP, A) , U) Japanese Utility Model Showa 58-10705 (JP, U) Japanese Utility Model Showa 60-149607 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 5/08-5/085

Claims (5)

(57) [Claims] 1. A mouth-side outer cylinder having a mouthpiece portion, an inner cylinder connecting portion communicating with the mouthpiece portion, and a pressure measuring portion provided at the inner cylinder connecting portion and having a through hole in a longitudinal direction. An atmosphere-side outer cylinder having an atmosphere-opening portion, an inner cylinder connecting portion communicating with the atmosphere-opening portion, and a pressure measuring portion provided at the inner cylinder connecting portion and having a through hole in a longitudinal direction; A plurality of inner cylinders each having a through-hole that is detachably and selectively located between the outer cylinder and the mouth-side outer cylinder and that communicates with each of the through-holes in the longitudinal direction of the center and that have different inner diameters. An airway resistance measurement device comprising a tube. 2. A structure for connecting the inner cylinder between the mouth-side outer cylinder and the atmosphere-side outer cylinder, wherein the inner cylinder is housed in each of the through holes in the end faces of the outer cylinders that are joined to each other. A screw connection portion for forming a storage portion, joining the outer cylinders after the inner cylinder is stored in the storage portion, and removably fixing the outer cylinders is provided on each of the outer cylinder side surfaces. 2. The airway resistance measurement device according to 1. 3. The airway resistance measuring device according to claim 1, further comprising an airtight packing interposed between a joint portion between the mouth-side outer cylinder, the atmosphere-side outer cylinder, and the inner cylinder. 4. The airway resistance measuring device according to claim 1, further comprising a taper formed at both end portions of the through hole of the inner cylinder. 5. A cylindrical body whose one end is opened to form a mouthpiece portion and the other end of which is closed is formed as a main body, and is protruded along the longitudinal direction of the side surface of the main body, all of which have a different inner diameter. An airway resistance measurement device having a cylindrical body.