CA2134134A1 - Method of correcting componential concentration in expiration and expiration analyzer - Google Patents
Method of correcting componential concentration in expiration and expiration analyzerInfo
- Publication number
- CA2134134A1 CA2134134A1 CA002134134A CA2134134A CA2134134A1 CA 2134134 A1 CA2134134 A1 CA 2134134A1 CA 002134134 A CA002134134 A CA 002134134A CA 2134134 A CA2134134 A CA 2134134A CA 2134134 A1 CA2134134 A1 CA 2134134A1
- Authority
- CA
- Canada
- Prior art keywords
- expiration
- sample
- concentration
- measured value
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 16
- 238000012937 correction Methods 0.000 claims abstract description 19
- 239000003570 air Substances 0.000 claims description 45
- 239000012080 ambient air Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 description 58
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 8
- 210000000056 organ Anatomy 0.000 description 8
- 230000000241 respiratory effect Effects 0.000 description 8
- 238000012360 testing method Methods 0.000 description 5
- 238000007664 blowing Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 208000003443 Unconsciousness Diseases 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 201000010099 disease Diseases 0.000 description 2
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- -1 polytetrafluoroethylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
- A61B5/083—Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S436/00—Chemistry: analytical and immunological testing
- Y10S436/90—Breath testing
Abstract
ABSTRACT OF THE DISCLOSURE
A first sample measuring passage provided between a collection port and a suction pump has a sample gas measurer for measuring expiration components, while a second sample measuring passage which is provided in parallel with the first sample measuring passage has a standard gas measurer for measuring O2 gas. Assuming that [A] represents a measured value of a target component in an expiration sample and [b1] represents O2 concentration in the expiration sample, correction is made on the basis of:
[A'] = f1?(21-[a1])[A]/(21-[b1]) where [A'] represents the corrected measured value of the target component, [a1] represents O2 concentration in end-tidal air which is supplied as a constant such as 15.3, for example, and f1 represents an experimentally prescribed coefficient such as 1.67, for example.
A first sample measuring passage provided between a collection port and a suction pump has a sample gas measurer for measuring expiration components, while a second sample measuring passage which is provided in parallel with the first sample measuring passage has a standard gas measurer for measuring O2 gas. Assuming that [A] represents a measured value of a target component in an expiration sample and [b1] represents O2 concentration in the expiration sample, correction is made on the basis of:
[A'] = f1?(21-[a1])[A]/(21-[b1]) where [A'] represents the corrected measured value of the target component, [a1] represents O2 concentration in end-tidal air which is supplied as a constant such as 15.3, for example, and f1 represents an experimentally prescribed coefficient such as 1.67, for example.
Description
r~
-. - , .
TITLE OF THE INVENTION -~
Method of Correcting Componential Concentration in Expiration and Expiration Analyzer ' . .
BACKGROUND OF T~E INVENTION - ~
~ ",, Field of the Invention The present invention relates to a method of ~-correcting componential concentration which is measured for analyzing expiration of a subject with an analyzer such as a gas chromatograph, and an analyzer for implementing such a method.
: :, " :'.' ' `: ''. ,' :, Description of the Background Art -It has been recognized that expiration of a sick , person also contains information on his disease, and study is now being made on analysis of such expiration in ~r a clinical test which is made for diagnosing, curing or preventing the disease.
In expiration which is subjected to analysis, a part called end-tidal air"is1mos't suitably employed~as a sample for the analyzer. The end-tidal air is the remaining part of the explration from which an initial part containing air from a dead space is discarded.
Since the end-tidal air contains only alveolar air with ; ;~
:
,; :, 2 1 3 4 ~ 3 ~
-: .
homogeneous concentration of expiration components, it is excellent as a specimen. In an expiration test, therefore, the end-tidal air is measured as the most -~
reliable specimen expressing the state of the subject, -~
while a specific apparatus is required for collecting the end-tidal air.
On the other hand, it may be impossible or difficult ~ . ::
to test the end-tidal air, for some reason or other. For example, it is difficult to collect the end-tidal air from a sub~ect such as a baby, a child, a soporose patient or an unconscious patient. If the subject is -healthy but old, for example, it may also be difficult to test the end-tidal air in consideration of his physical strength.
In order to readily collect expiration in a painless ~ i . . , ., ~, : . .
manner, a collecting mask or hood is applied to the i~
:: ~ ~, .; , ,;,:
sub~ect for temporarily collecting his expiration in a baq or directly guiding the same to an analyzer. ;
However, the collecting mask, which can be prepared from ; ~
.: . :.... .
; ~.. ,; : ~:.,.
that for supplying oxygen to a patient, cannot be brought into close contact with thé sub~ect in an airtight manner~
but the mask itself has holes for communicating with ambient air. When the expiration is collected through such a collecting mask, ambient air is inevitably mixed into the expiration. While it is also possible to ' ~ ,' '.:,' "'' . "' ~:
: ~ ~
213ql3~ :`
.` :
collect the expiration by applying a mask or a hood to or covering the respiratory organ, ambient air is also inevitably mixed into the expiration since the respiratory organ cannot be sealed.
Thus, the expiration which is collected by a conventional method contains not only the alveolar air ~ ;~
but air from the dead space and ambient air, unless the ;;~
same is collected by a specific method.
' .' ~ i '. .
SUMMARY OF THE INVENTION ; ~;
' ..;.~,,; : .
A first object of the present invention is to provide a method of correctly calculating componential concentration of expiration also when an expiration sample collected from a subject contains air from a dead - ~
space and ambient air. i, ., ` , A second object of the present invention is to '~
provide an expiration analyzer comprising such correction The correction method according to the present invention has been proposed on the premise of such recognition that 02!co~centration and C02 concentration in end-tidal air are substantially constant regardless of the subject. Even if the expiration sample is diluted with ambient air and air exhaled from a dead space, 02 ~-concentration or C02 concentration in the expiration :~ .?
;-. ~..:, 213~13~ ~
sample is measured as standard gas concentration, to obtain the dilution of the expiration sample from the measured value of the standard gas concentration with reference to 02 concentration or C02 concentration in end-tidal air which is supplied as a constant, thereby correcting the measured value of the expiration componential concentration. -~-. , .
When 02 gas is employed as standard gas, correction is made as follows~
[A ) = fl (2l-~al~)[A)/(2l-~b assuming that [A~ represents a target componential measured value of the expiration sample, ~bl~ represents 02 concentration in the expiration sample, [A'~
represents the corrected target componential measured value, ~al~ represents 02 concentration in end-tidal air .: ~.. .;; :
which is supplied as a constant, and fl represents an experimentally prescribed coefficient. `~
When C02 gas is employed as standard gas, on the other hand, correction is made as follows~
~A'~ = f2~a2~ [A~/~b2~ (2) . ~.: ,~ ,, ~, assuming that tb2~ represents C02 concentration in the ! i expiration sample, ~a2~ represents C02 concentration in end-tidal air which is supplied as a constant, and f2 ;~ -represents an experimentally prescribed coefficient.
In order to implement this correction method, the ;~
' ' `'~' ''~'''`',''".,',, ~, ~'.:' " '' "'', . ,,`' . - .::;;.:: ::,:
~:~Zi ~ 213~13~
expiration analyzer according to the present invention ~;
comprises a first sample measuring passage, provided with a sample gas measurer for measuring at least one or two -~
, , . - , .
components in expiration, for receiving an expiration ~ '~
sample of alveolar air which is mixed with at least one , '' ' ~, ;: ';
of air from a dead space and ambient air, a second sample ;~
measuring passage, provided with a standard gas measurer for measuring at least one of 02 gas and C02 gas as standard gas, provided in parallel with the first sample measuring passage for receiving the same expiration sample as the first sample measuring passage, and a ;,";~
computing element for correcting a componential measured '~
value in the expiration sample measured by the sample gas measurer through standard gas concentration in the '~
expiration sample measured by the standard gas measurer ~!i',,".,,'~'~',;,;~,'",,,~
'' ' ` .: ' ' .. ';., '`,; ' ,''' ~' ., with reference to concentration of the standard gas in end-tidal air. The computing element is implemented by a ;
CPU(central processing unit).
In order to obtain the 02 concentration reference value ~al) and the C02 concentration reference value ~a2 ":, ,:, i,,:, ., ,: ,,~
of the standard gas,l'end-t~'dal'air samples were collected~ ,r~ "~
from 28 normals and 26 patients.
Table 1 shows the results of C02 concentration values in expiration, which were measured with respect to i-the normals and the patients. Referring to Table 1, ; .-,,- .;:.
~ ::, :. ': :
213gl3~
symbol n represents the numbers of the normals and the patients, symbol X represents mean C02 concentration values (vol. %), and symbol SD represents standard deviations of measured data distribution. The normals were 19 to 23 years of age and 21.1 years on the average, while the patients were 13 to 80 years of age and 52.7 .'!"' `"~',"''".'',"';',''''`~`'' years on the average.
(Table 1) Normal Patient n 28 26 ;~ ~,~,~, X 5.09 4.70 SD 0.48 0.45 ;~
Average Age 21.1 52.7 Oldest 23 80 Youngest 19 13 `~
~';i''`' ,'''`~. '', It is understood from Table 1 that the C02 concentration values in the end-tidal air are at similar levels with small individual differences between the normals and the patients. Similar results were obtained also as to 02 concentration values in the end-tidal air, ` -with small individual differences between the normals and the patients.
-:` ~. ~ ' ,~ .,'' ' Table 2 shows results of 02 concentration values ~Ç~
~al~ and C02 concentration values ~a2~ calculated from ,,, ,;, end-tidal air of 54 subjects including the normals and 2134134 ' the patients. As understood from Table 2, the average 02 : -concentration ~a1~ was 15.3 vol.%, the standard deviation ~-SD was 0.64, the average C02 concentration ~a2~ was 4.9 ~ -vol.%, and the standard deviation SD was 0.51.
(Table 2) 02 Concentration C02 Concentration ~al] ~a2~
Average Concentration 15.3 (%) 4.9 (%) Standard Deviation (SD) 0.64 0.51 ;;; ;.,~"
Number 54 54 , ~
" i~ """,.,,:, On the basis of the aforementioned results, the value 15.3 is employed as the 02 concentration ~al] in ` ', ~,: ,,~ , end-tidal air in the equation (1), and the value 4.9 is : .:.,, ", . .
employed as the CO2 concentration ~a2~ in end-tidal air in the equation (2). (21-~al~)/(21-~b1~) in the equations (1) and ~a2~/~b2~ in the equation (2) are ~`;
coefficients for correcting dilution of expiration "
samples with ambient air and gas from dead spaces. --~ ~
: ~ .
Referring to the equation (1), the value '~21" represents ! ~ . I ' , ! ' ~ , , 02 concentration (vol.%) in the air. ~`
:~, The concentration values tal~ and ~a2~, which may :: :-..:, ~, .
vary with ages, races and life styles of subjects, are preferably obtained for every control group. ~ : `
While a gas bag for colle-~ting expiration is -- :: ~ .::
.......
, prepared from a material causing neither adsorption nor decomposition of expiration componential gas and passages :
for feeding the expiration sample are heated to prevent the target component from reduction caused by condensation of moisture contained in the expiration, it has been discovered that the measured value is still reduced at a constant rate as compared with a value which ~ ` ; ;
is measured by directly introducing end-tidal air into a measurer. The values fl and f2 appearing in the -equations (1) and (2) respectively are adapted to correct the measured values reduced by the measuring method. In order to obtain the values fl and f~, respiratory organ portions of subjects were covered with masks or hoods and expiration samples from the masks or hoods containing end-~ -~ "~
tidal air and remaining expiration with contamination of ambient air were measured directly or collected in gas bags having no gas adsorptivity for thereafter measuring explration samples, while only end-tidal air samples were ; ~ :
directly guided to an analyzer for measuring true components, so that the results were compared with each -~
other. Table 3 shows tihe results. ! ' 2134134 "
. .
.` ..,. ~ .
(Table 3) Collection Measured Reference Corrected Value Method~Ac)ppm C02% 02% ppm ~Ac'~l ~Ac'~2 1. Hood 4.3 2.94 16.5 8.4 9.03 9.1 Collection (108) (108) : ~
2. Hood 4.9 2.91 16.5 10.1 10.4 I0.4 ~ ... c Collection (103) (103) 3. Nask 4.0 2.61 16.8 10.2 9.5 9.1 .
Collection (93) (92) 4. Mask 3.6 2.03 18.2 12.1 11.0 12.2 Collection (91) (101) 5. Hood 6.2 2.78 16.7 13.6 13.8 13.7 Collection (101) (101) ; -. '''.
The measurement was made by three types of collecting methods, including that of covering the respiratory organ portions of the subjects with hoods for -~
~ ~ -,., :,, temporarily collecting the expiration samples in gas bags (Hood Collection; No.l, 2), that of covering the respiratory organ portions of the subjects with masks for ~ . ~
temporarily collecting the expiration samples in gas bags - ~ .. `.
(Mask Collection; No,3, 4), and that of covering the :~
: ~ : .
respiratory organ portions of the subjects with hoods for directly incorporating the expiration samples in the analyzer (Hood Collection; No.5). As to the measured values, ~Ac~ represents acetone concentration values , .
(ppm) with respect to a target component of acetone.
Further, ~C02~ represents C02 concentration values [b ~ ~, ., . . ". "., 213~13~ '' " ~' ~vol.%) in the expiration samples, and 02' represents 02 concentration values [b1) (vol.X) in the expiration samples. The reference values (nReference~) were obtained by directly measuring acetone concentration values in the end-tidal air by another device.
The corrected values ~AC~1 were obtained by -prescribing a correction coefficient fl for correcting the five measured values ~Ac~ for most approaching the ;~
same to the reference values in the equation (l) with reference to 2 gas serving as standard gas. At this time, the correction coefficient fl was obtained as 1.67.
Similarly, the corrected values ~AC~2 were obtained `~
by prescribing a correction coefficient f2 for correcting ~
the five measured values ~Ac~ for most approaching the ~ ' ~ :, : ::,:;
same to the reference values in the equation (2) with .
reference to C02 gas serving as standard gas. At this time, the correction coefficient f2 was obtained as 1.26.
Referring to Table 3, parenthesized numerals such as (108) and (93) show ratios to reference values of lO0. ~ ' From the results, the values 1.67 and 1.26 are set in a CPU(computinlg element) as the'correction coefficients fl and f2 in the equations (l) and (2) respectively. The coeffic~ents fl and f2, which vary with measured gas components and the structure of the apparatus, are pr-Serably obtal=ed every apparatus eperifiration.
213~13~
According to the present invention, a measured value of target componential concentration is corrected with reference to 02 concentration or CO2 concentration in end- -tidal air also in an expiration sample which is collected in a diluted state, whereby it is possible to correctly obtain target componential concentration also from an ;
expiration sample of a subject whose end-tidal air is ~ ;
hard to test, in addition to an infant or an unconscious ;
patient. While collection of only end-tidal air leads to a burden on the subject and requirement for a specific collecting apparatus, it is possible to correctly analyze expiration with neither burden nor specific apparatus according to the present invention. ;`
The foregoing and other objects, features, aspects ~ , and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l~is a bldck diagram showing an embodiment of ! ' `~. '"'","d,~
.' ': " '," ' . ,''"'' /`" ' the present invention; and ;~
Figs. 2A and 2B illustrate functions of a CPU in the embodiment shown in Fig. 1 with respect to standard gas measurers 18 which are formed by an 02 measurer and a C02 `'~
~ ` 2 1 3 ~ 1 3 ~
measurer respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 schematically illustrates an expiration analyzer 2 according to an embodiment of the present invention. The expiration analyzer 2 has a collection port 4, which is connected with a gas bag of a material having no gas absorptivitY, so that an expiration sample of a subject collected in the gas bag is introduced into the analyzer 2 from the collection port 4. It is possible to connect the forward end of the collection `~
port 4 with an expiration blowing part 8 having an appliance 6 to be applied to a respiratory organ or for covering the same, in order to directly collect expiration of the subject. The appliance 6 for covering ~ ~
the respiratory organ is prepared from a mask, a hood or ~ c J~.
a mouthpiece. A passage of the blowing part 8 is ;.
pr-ferably formed by a heating pipe comprising a heater wound on a tube, which is prepared from an elastic material such as polytetrafluoroethylene to cause neither adsorption nor reaction of'gas contained in the ` ' expiration while facilitating handling. The heater is preferably temperature-controlled for heating the inner ~' wall temperature of the tube to 40 to 50 ~ so that .;~
moisture contained in the expiration is not condensed on ;~
- 12 - ;~
~,..,,",;",,~
, 2l34l3~ ' the inner wall of the tube.
A suction pump 10 is provided for sucking the ~ ~;
expiration from the gas bag or the expiration blowing part 8, while a sample gas measurer 14 i5 provided in a ; ;~ ~, first sample measuring passage 12 connecting the collection port 4 with the suction pump 10. The sample gas measurer 14, which is a detector capable of measuring expiratory components, can include a gas treatment unit at need. The components measured by the sample gas measurer 14 are acetone, CO, NH3, CH4 and the like. The .:,,:
: :. ',:
sample gas measurer 14 may be formed by a gas chromatograph. The flow rate of the suction pump 10 is ~ - ,.. . :, preferably about 200 to 1000 ml/min.
A second sample measuring passage 16 having a standard gas measurer 18 is provided between the collection port 4 and the suction pump 10 in parallel -with the first sample measuring passage 12. The standard ;; ~ X~
:. .,: ,.. ,~
gas measurer 18 is an 02 or C02 measurer. The 02 ^~
measurer, which may have any measurement principle, is of a system sub~ected to no interference with coexisting C02 gas, and suitably fd~méd by a magnetic or zirconia 02 measurer. On the other hand, an NDIR (nondispersive in~rared analyzer) type measurer is suitably employed as the C02 measurer for forming the standard gas measurer 18. ~' The first and second sample measuring passages 12 l3 -213~13~
and 16 receive the expiration sample simultaneously, so -~
that the gas measurers 14 and 18 can measure ;
concentration values of the target components. When the collection port 4 is connected with a gas bag, measuring times in the sample measuring passages 12 and 16 may deviate from each other since the expiration sample is homogenized in the gas bag. Therefore, switching valves may be provided on confluent points located upstream and downstream in the sample measuring passages 12 and 16 respectively, for switching the expiration sample to be introduced into the sample measuring passages 12 and 16.
The passages between the collection port 4 and the gas measurers 14 and 18 are heated to about 40 to 50 ~, to prevent condensation of the moisture contained in the expiration.
A CPU 20 receives detection signals from the gas measurers 14 and 18 respectively. An operation panel 22, which is provided with operation keys having functions of ,~,f~':;; ' .~
starting measurement and inputting an 02 concentration reference value ~al~, C02 coocentratlon reference value ;, ~a2~ and coefficient's fl add f2 for computing,lis ~ """,~
connected with the CPU 20. A recorder 24 records target componential concentration corrected by the CPU 20. ~ ', When the standard gas measurer 18 is formed by an 02 ~ ' -measurer, the CPU 20 functions as shown in Fig. 2A with - l4 - -2~3~134 .-.:. ~...,;,,.
the operational content expressed in the equation (1), to . `~
input the values 15.3 and 1.67 as the 2 concentration . ~;
reference value [a1~ and the coefficient fl respectively from the operation panel 22. The CPU 20 further incorporates the actually measured value [A] of the target component and the 02 concentration (vol.%) from the sample and standard gas measurers 14 and 18 respectively to carry out correction operation, and outputs the result to the recorder 24.
When the standard gas measurer 18 is formed by a C02 measurer, on the other hand, the CPU 20 functions as .
.: ~, ... ..
shown in Fig. 2B with the operational content expressed ;~
in the equation (2), to input the values 4.9 and 1.26 as i~
the C02 concentration reference value [a2~ and the coefficient f2 respectively from the operation panel 22.
The CPU 20 further incorporates the actually measured value ~A~ of the target component and the C02 i concentration (vol.%) from the sample and standard gas measurers 14 and 18 respectively to carry out correction operation, and outputs the result to the recorder 24.
! When thé standa!~digaslmeasurer 18 can measure both ! ' '~
02 and C02, it is possible to more correctly carry out the correction operation for calculating average values "~
of correction results through both of the equations (1) and (2), for example.
- l5 ~ .?-~:
213~13~ :
While the standard gas measurer 18 is independent of -the sample gas measurer 14 in the embodiment shown in ~;~
Fig. 1, the standard gas measurer 18 can be omitted if .,~
the sample gas measurer 14 can measure a plurality of components including 02 or C02. In this case, the sample measuring passage 16 can also be omitted, to simplify the structure.
Although the present invention has been described .. ',;
and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. ~.
', " '.
TITLE OF THE INVENTION -~
Method of Correcting Componential Concentration in Expiration and Expiration Analyzer ' . .
BACKGROUND OF T~E INVENTION - ~
~ ",, Field of the Invention The present invention relates to a method of ~-correcting componential concentration which is measured for analyzing expiration of a subject with an analyzer such as a gas chromatograph, and an analyzer for implementing such a method.
: :, " :'.' ' `: ''. ,' :, Description of the Background Art -It has been recognized that expiration of a sick , person also contains information on his disease, and study is now being made on analysis of such expiration in ~r a clinical test which is made for diagnosing, curing or preventing the disease.
In expiration which is subjected to analysis, a part called end-tidal air"is1mos't suitably employed~as a sample for the analyzer. The end-tidal air is the remaining part of the explration from which an initial part containing air from a dead space is discarded.
Since the end-tidal air contains only alveolar air with ; ;~
:
,; :, 2 1 3 4 ~ 3 ~
-: .
homogeneous concentration of expiration components, it is excellent as a specimen. In an expiration test, therefore, the end-tidal air is measured as the most -~
reliable specimen expressing the state of the subject, -~
while a specific apparatus is required for collecting the end-tidal air.
On the other hand, it may be impossible or difficult ~ . ::
to test the end-tidal air, for some reason or other. For example, it is difficult to collect the end-tidal air from a sub~ect such as a baby, a child, a soporose patient or an unconscious patient. If the subject is -healthy but old, for example, it may also be difficult to test the end-tidal air in consideration of his physical strength.
In order to readily collect expiration in a painless ~ i . . , ., ~, : . .
manner, a collecting mask or hood is applied to the i~
:: ~ ~, .; , ,;,:
sub~ect for temporarily collecting his expiration in a baq or directly guiding the same to an analyzer. ;
However, the collecting mask, which can be prepared from ; ~
.: . :.... .
; ~.. ,; : ~:.,.
that for supplying oxygen to a patient, cannot be brought into close contact with thé sub~ect in an airtight manner~
but the mask itself has holes for communicating with ambient air. When the expiration is collected through such a collecting mask, ambient air is inevitably mixed into the expiration. While it is also possible to ' ~ ,' '.:,' "'' . "' ~:
: ~ ~
213ql3~ :`
.` :
collect the expiration by applying a mask or a hood to or covering the respiratory organ, ambient air is also inevitably mixed into the expiration since the respiratory organ cannot be sealed.
Thus, the expiration which is collected by a conventional method contains not only the alveolar air ~ ;~
but air from the dead space and ambient air, unless the ;;~
same is collected by a specific method.
' .' ~ i '. .
SUMMARY OF THE INVENTION ; ~;
' ..;.~,,; : .
A first object of the present invention is to provide a method of correctly calculating componential concentration of expiration also when an expiration sample collected from a subject contains air from a dead - ~
space and ambient air. i, ., ` , A second object of the present invention is to '~
provide an expiration analyzer comprising such correction The correction method according to the present invention has been proposed on the premise of such recognition that 02!co~centration and C02 concentration in end-tidal air are substantially constant regardless of the subject. Even if the expiration sample is diluted with ambient air and air exhaled from a dead space, 02 ~-concentration or C02 concentration in the expiration :~ .?
;-. ~..:, 213~13~ ~
sample is measured as standard gas concentration, to obtain the dilution of the expiration sample from the measured value of the standard gas concentration with reference to 02 concentration or C02 concentration in end-tidal air which is supplied as a constant, thereby correcting the measured value of the expiration componential concentration. -~-. , .
When 02 gas is employed as standard gas, correction is made as follows~
[A ) = fl (2l-~al~)[A)/(2l-~b assuming that [A~ represents a target componential measured value of the expiration sample, ~bl~ represents 02 concentration in the expiration sample, [A'~
represents the corrected target componential measured value, ~al~ represents 02 concentration in end-tidal air .: ~.. .;; :
which is supplied as a constant, and fl represents an experimentally prescribed coefficient. `~
When C02 gas is employed as standard gas, on the other hand, correction is made as follows~
~A'~ = f2~a2~ [A~/~b2~ (2) . ~.: ,~ ,, ~, assuming that tb2~ represents C02 concentration in the ! i expiration sample, ~a2~ represents C02 concentration in end-tidal air which is supplied as a constant, and f2 ;~ -represents an experimentally prescribed coefficient.
In order to implement this correction method, the ;~
' ' `'~' ''~'''`',''".,',, ~, ~'.:' " '' "'', . ,,`' . - .::;;.:: ::,:
~:~Zi ~ 213~13~
expiration analyzer according to the present invention ~;
comprises a first sample measuring passage, provided with a sample gas measurer for measuring at least one or two -~
, , . - , .
components in expiration, for receiving an expiration ~ '~
sample of alveolar air which is mixed with at least one , '' ' ~, ;: ';
of air from a dead space and ambient air, a second sample ;~
measuring passage, provided with a standard gas measurer for measuring at least one of 02 gas and C02 gas as standard gas, provided in parallel with the first sample measuring passage for receiving the same expiration sample as the first sample measuring passage, and a ;,";~
computing element for correcting a componential measured '~
value in the expiration sample measured by the sample gas measurer through standard gas concentration in the '~
expiration sample measured by the standard gas measurer ~!i',,".,,'~'~',;,;~,'",,,~
'' ' ` .: ' ' .. ';., '`,; ' ,''' ~' ., with reference to concentration of the standard gas in end-tidal air. The computing element is implemented by a ;
CPU(central processing unit).
In order to obtain the 02 concentration reference value ~al) and the C02 concentration reference value ~a2 ":, ,:, i,,:, ., ,: ,,~
of the standard gas,l'end-t~'dal'air samples were collected~ ,r~ "~
from 28 normals and 26 patients.
Table 1 shows the results of C02 concentration values in expiration, which were measured with respect to i-the normals and the patients. Referring to Table 1, ; .-,,- .;:.
~ ::, :. ': :
213gl3~
symbol n represents the numbers of the normals and the patients, symbol X represents mean C02 concentration values (vol. %), and symbol SD represents standard deviations of measured data distribution. The normals were 19 to 23 years of age and 21.1 years on the average, while the patients were 13 to 80 years of age and 52.7 .'!"' `"~',"''".'',"';',''''`~`'' years on the average.
(Table 1) Normal Patient n 28 26 ;~ ~,~,~, X 5.09 4.70 SD 0.48 0.45 ;~
Average Age 21.1 52.7 Oldest 23 80 Youngest 19 13 `~
~';i''`' ,'''`~. '', It is understood from Table 1 that the C02 concentration values in the end-tidal air are at similar levels with small individual differences between the normals and the patients. Similar results were obtained also as to 02 concentration values in the end-tidal air, ` -with small individual differences between the normals and the patients.
-:` ~. ~ ' ,~ .,'' ' Table 2 shows results of 02 concentration values ~Ç~
~al~ and C02 concentration values ~a2~ calculated from ,,, ,;, end-tidal air of 54 subjects including the normals and 2134134 ' the patients. As understood from Table 2, the average 02 : -concentration ~a1~ was 15.3 vol.%, the standard deviation ~-SD was 0.64, the average C02 concentration ~a2~ was 4.9 ~ -vol.%, and the standard deviation SD was 0.51.
(Table 2) 02 Concentration C02 Concentration ~al] ~a2~
Average Concentration 15.3 (%) 4.9 (%) Standard Deviation (SD) 0.64 0.51 ;;; ;.,~"
Number 54 54 , ~
" i~ """,.,,:, On the basis of the aforementioned results, the value 15.3 is employed as the 02 concentration ~al] in ` ', ~,: ,,~ , end-tidal air in the equation (1), and the value 4.9 is : .:.,, ", . .
employed as the CO2 concentration ~a2~ in end-tidal air in the equation (2). (21-~al~)/(21-~b1~) in the equations (1) and ~a2~/~b2~ in the equation (2) are ~`;
coefficients for correcting dilution of expiration "
samples with ambient air and gas from dead spaces. --~ ~
: ~ .
Referring to the equation (1), the value '~21" represents ! ~ . I ' , ! ' ~ , , 02 concentration (vol.%) in the air. ~`
:~, The concentration values tal~ and ~a2~, which may :: :-..:, ~, .
vary with ages, races and life styles of subjects, are preferably obtained for every control group. ~ : `
While a gas bag for colle-~ting expiration is -- :: ~ .::
.......
, prepared from a material causing neither adsorption nor decomposition of expiration componential gas and passages :
for feeding the expiration sample are heated to prevent the target component from reduction caused by condensation of moisture contained in the expiration, it has been discovered that the measured value is still reduced at a constant rate as compared with a value which ~ ` ; ;
is measured by directly introducing end-tidal air into a measurer. The values fl and f2 appearing in the -equations (1) and (2) respectively are adapted to correct the measured values reduced by the measuring method. In order to obtain the values fl and f~, respiratory organ portions of subjects were covered with masks or hoods and expiration samples from the masks or hoods containing end-~ -~ "~
tidal air and remaining expiration with contamination of ambient air were measured directly or collected in gas bags having no gas adsorptivity for thereafter measuring explration samples, while only end-tidal air samples were ; ~ :
directly guided to an analyzer for measuring true components, so that the results were compared with each -~
other. Table 3 shows tihe results. ! ' 2134134 "
. .
.` ..,. ~ .
(Table 3) Collection Measured Reference Corrected Value Method~Ac)ppm C02% 02% ppm ~Ac'~l ~Ac'~2 1. Hood 4.3 2.94 16.5 8.4 9.03 9.1 Collection (108) (108) : ~
2. Hood 4.9 2.91 16.5 10.1 10.4 I0.4 ~ ... c Collection (103) (103) 3. Nask 4.0 2.61 16.8 10.2 9.5 9.1 .
Collection (93) (92) 4. Mask 3.6 2.03 18.2 12.1 11.0 12.2 Collection (91) (101) 5. Hood 6.2 2.78 16.7 13.6 13.8 13.7 Collection (101) (101) ; -. '''.
The measurement was made by three types of collecting methods, including that of covering the respiratory organ portions of the subjects with hoods for -~
~ ~ -,., :,, temporarily collecting the expiration samples in gas bags (Hood Collection; No.l, 2), that of covering the respiratory organ portions of the subjects with masks for ~ . ~
temporarily collecting the expiration samples in gas bags - ~ .. `.
(Mask Collection; No,3, 4), and that of covering the :~
: ~ : .
respiratory organ portions of the subjects with hoods for directly incorporating the expiration samples in the analyzer (Hood Collection; No.5). As to the measured values, ~Ac~ represents acetone concentration values , .
(ppm) with respect to a target component of acetone.
Further, ~C02~ represents C02 concentration values [b ~ ~, ., . . ". "., 213~13~ '' " ~' ~vol.%) in the expiration samples, and 02' represents 02 concentration values [b1) (vol.X) in the expiration samples. The reference values (nReference~) were obtained by directly measuring acetone concentration values in the end-tidal air by another device.
The corrected values ~AC~1 were obtained by -prescribing a correction coefficient fl for correcting the five measured values ~Ac~ for most approaching the ;~
same to the reference values in the equation (l) with reference to 2 gas serving as standard gas. At this time, the correction coefficient fl was obtained as 1.67.
Similarly, the corrected values ~AC~2 were obtained `~
by prescribing a correction coefficient f2 for correcting ~
the five measured values ~Ac~ for most approaching the ~ ' ~ :, : ::,:;
same to the reference values in the equation (2) with .
reference to C02 gas serving as standard gas. At this time, the correction coefficient f2 was obtained as 1.26.
Referring to Table 3, parenthesized numerals such as (108) and (93) show ratios to reference values of lO0. ~ ' From the results, the values 1.67 and 1.26 are set in a CPU(computinlg element) as the'correction coefficients fl and f2 in the equations (l) and (2) respectively. The coeffic~ents fl and f2, which vary with measured gas components and the structure of the apparatus, are pr-Serably obtal=ed every apparatus eperifiration.
213~13~
According to the present invention, a measured value of target componential concentration is corrected with reference to 02 concentration or CO2 concentration in end- -tidal air also in an expiration sample which is collected in a diluted state, whereby it is possible to correctly obtain target componential concentration also from an ;
expiration sample of a subject whose end-tidal air is ~ ;
hard to test, in addition to an infant or an unconscious ;
patient. While collection of only end-tidal air leads to a burden on the subject and requirement for a specific collecting apparatus, it is possible to correctly analyze expiration with neither burden nor specific apparatus according to the present invention. ;`
The foregoing and other objects, features, aspects ~ , and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l~is a bldck diagram showing an embodiment of ! ' `~. '"'","d,~
.' ': " '," ' . ,''"'' /`" ' the present invention; and ;~
Figs. 2A and 2B illustrate functions of a CPU in the embodiment shown in Fig. 1 with respect to standard gas measurers 18 which are formed by an 02 measurer and a C02 `'~
~ ` 2 1 3 ~ 1 3 ~
measurer respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 schematically illustrates an expiration analyzer 2 according to an embodiment of the present invention. The expiration analyzer 2 has a collection port 4, which is connected with a gas bag of a material having no gas absorptivitY, so that an expiration sample of a subject collected in the gas bag is introduced into the analyzer 2 from the collection port 4. It is possible to connect the forward end of the collection `~
port 4 with an expiration blowing part 8 having an appliance 6 to be applied to a respiratory organ or for covering the same, in order to directly collect expiration of the subject. The appliance 6 for covering ~ ~
the respiratory organ is prepared from a mask, a hood or ~ c J~.
a mouthpiece. A passage of the blowing part 8 is ;.
pr-ferably formed by a heating pipe comprising a heater wound on a tube, which is prepared from an elastic material such as polytetrafluoroethylene to cause neither adsorption nor reaction of'gas contained in the ` ' expiration while facilitating handling. The heater is preferably temperature-controlled for heating the inner ~' wall temperature of the tube to 40 to 50 ~ so that .;~
moisture contained in the expiration is not condensed on ;~
- 12 - ;~
~,..,,",;",,~
, 2l34l3~ ' the inner wall of the tube.
A suction pump 10 is provided for sucking the ~ ~;
expiration from the gas bag or the expiration blowing part 8, while a sample gas measurer 14 i5 provided in a ; ;~ ~, first sample measuring passage 12 connecting the collection port 4 with the suction pump 10. The sample gas measurer 14, which is a detector capable of measuring expiratory components, can include a gas treatment unit at need. The components measured by the sample gas measurer 14 are acetone, CO, NH3, CH4 and the like. The .:,,:
: :. ',:
sample gas measurer 14 may be formed by a gas chromatograph. The flow rate of the suction pump 10 is ~ - ,.. . :, preferably about 200 to 1000 ml/min.
A second sample measuring passage 16 having a standard gas measurer 18 is provided between the collection port 4 and the suction pump 10 in parallel -with the first sample measuring passage 12. The standard ;; ~ X~
:. .,: ,.. ,~
gas measurer 18 is an 02 or C02 measurer. The 02 ^~
measurer, which may have any measurement principle, is of a system sub~ected to no interference with coexisting C02 gas, and suitably fd~méd by a magnetic or zirconia 02 measurer. On the other hand, an NDIR (nondispersive in~rared analyzer) type measurer is suitably employed as the C02 measurer for forming the standard gas measurer 18. ~' The first and second sample measuring passages 12 l3 -213~13~
and 16 receive the expiration sample simultaneously, so -~
that the gas measurers 14 and 18 can measure ;
concentration values of the target components. When the collection port 4 is connected with a gas bag, measuring times in the sample measuring passages 12 and 16 may deviate from each other since the expiration sample is homogenized in the gas bag. Therefore, switching valves may be provided on confluent points located upstream and downstream in the sample measuring passages 12 and 16 respectively, for switching the expiration sample to be introduced into the sample measuring passages 12 and 16.
The passages between the collection port 4 and the gas measurers 14 and 18 are heated to about 40 to 50 ~, to prevent condensation of the moisture contained in the expiration.
A CPU 20 receives detection signals from the gas measurers 14 and 18 respectively. An operation panel 22, which is provided with operation keys having functions of ,~,f~':;; ' .~
starting measurement and inputting an 02 concentration reference value ~al~, C02 coocentratlon reference value ;, ~a2~ and coefficient's fl add f2 for computing,lis ~ """,~
connected with the CPU 20. A recorder 24 records target componential concentration corrected by the CPU 20. ~ ', When the standard gas measurer 18 is formed by an 02 ~ ' -measurer, the CPU 20 functions as shown in Fig. 2A with - l4 - -2~3~134 .-.:. ~...,;,,.
the operational content expressed in the equation (1), to . `~
input the values 15.3 and 1.67 as the 2 concentration . ~;
reference value [a1~ and the coefficient fl respectively from the operation panel 22. The CPU 20 further incorporates the actually measured value [A] of the target component and the 02 concentration (vol.%) from the sample and standard gas measurers 14 and 18 respectively to carry out correction operation, and outputs the result to the recorder 24.
When the standard gas measurer 18 is formed by a C02 measurer, on the other hand, the CPU 20 functions as .
.: ~, ... ..
shown in Fig. 2B with the operational content expressed ;~
in the equation (2), to input the values 4.9 and 1.26 as i~
the C02 concentration reference value [a2~ and the coefficient f2 respectively from the operation panel 22.
The CPU 20 further incorporates the actually measured value ~A~ of the target component and the C02 i concentration (vol.%) from the sample and standard gas measurers 14 and 18 respectively to carry out correction operation, and outputs the result to the recorder 24.
! When thé standa!~digaslmeasurer 18 can measure both ! ' '~
02 and C02, it is possible to more correctly carry out the correction operation for calculating average values "~
of correction results through both of the equations (1) and (2), for example.
- l5 ~ .?-~:
213~13~ :
While the standard gas measurer 18 is independent of -the sample gas measurer 14 in the embodiment shown in ~;~
Fig. 1, the standard gas measurer 18 can be omitted if .,~
the sample gas measurer 14 can measure a plurality of components including 02 or C02. In this case, the sample measuring passage 16 can also be omitted, to simplify the structure.
Although the present invention has been described .. ',;
and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. ~.
', " '.
Claims (10)
1. A method of correcting componential concentration in expiration, comprising the steps of:
analyzing an expiration sample of alveolar air being mixed with at least one of air from a dead space and ambient air for obtaining a measured value of a target component;
measuring at least one of O2 gas concentration and CO2 gas concentration as standard gas concentration in said expiration sample; and correcting said measured value of said target component by a measured value of standard gas concentration in said expiration sample with reference to said standard gas concentration in end-tidal air.
analyzing an expiration sample of alveolar air being mixed with at least one of air from a dead space and ambient air for obtaining a measured value of a target component;
measuring at least one of O2 gas concentration and CO2 gas concentration as standard gas concentration in said expiration sample; and correcting said measured value of said target component by a measured value of standard gas concentration in said expiration sample with reference to said standard gas concentration in end-tidal air.
2. A method of correcting componential concentration in expiration in accordance with claim 1, wherein said steps of obtaining said measured value of said target component and measuring said standard gas concentration are carried out by measuring means being different from each other.
3. A method of correcting componential concentration in expiration in accordance with claim 1, wherein said steps of obtaining said measured value of said target component and measuring said standard gas concentration are simultaneously carried out by the same measuring means.
4. A method of correcting componential concentration in expiration in accordance with claim 1, wherein said correction is made on the basis of:
[A'] = f1?(21-[a1])[A]/(21-[b1]) assuming that [A] represents said measured value of said target component in said expiration sample, [b1]
represents said O2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a1] represents O2 concentration in end-tidal air, being a constant, and f1 represents an experimentally prescribed coefficient.
[A'] = f1?(21-[a1])[A]/(21-[b1]) assuming that [A] represents said measured value of said target component in said expiration sample, [b1]
represents said O2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a1] represents O2 concentration in end-tidal air, being a constant, and f1 represents an experimentally prescribed coefficient.
5. A method of correcting componential concentration in expiration in accordance with claim 1, wherein said correction is made on the basis of:
[A'] = f2?[a2][A]/[b2]
assuming that [A] represents said measured value of said target component in said expiration sample, [b2]
represents said CO2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a2] represents CO2 concentration in end-tidal air, being a constant, and f2 represents an experimentally prescribed coefficient.
[A'] = f2?[a2][A]/[b2]
assuming that [A] represents said measured value of said target component in said expiration sample, [b2]
represents said CO2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a2] represents CO2 concentration in end-tidal air, being a constant, and f2 represents an experimentally prescribed coefficient.
6. An expiration analyzer comprising:
a first sample measuring passage, having a sample gas measurer for measuring at least one or two components in expiration, for receiving from a collection port an expiration sample of alveolar air being mixed with at least one of air from a dead space and ambient air;
a second sample measuring passage, having a standard gas measurer for measuring at least one of O2 gas and CO2 gas as standard gas, being provided in parallel with said first sample measuring passage for receiving from a collection port said expiration sample being identical to that guided in said first sample measuring passage;
a heating means for heating passages between said collection port and said sample and standard gas measurers; and a computing element for correcting a componential measured value in said expiration sample, being measured by said sample gas measurer, by a measured value of standard gas concentration in said expiration sample, being measured by said standard gas measurer, with reference to concentration of said standard gas in end-tidal air.
a first sample measuring passage, having a sample gas measurer for measuring at least one or two components in expiration, for receiving from a collection port an expiration sample of alveolar air being mixed with at least one of air from a dead space and ambient air;
a second sample measuring passage, having a standard gas measurer for measuring at least one of O2 gas and CO2 gas as standard gas, being provided in parallel with said first sample measuring passage for receiving from a collection port said expiration sample being identical to that guided in said first sample measuring passage;
a heating means for heating passages between said collection port and said sample and standard gas measurers; and a computing element for correcting a componential measured value in said expiration sample, being measured by said sample gas measurer, by a measured value of standard gas concentration in said expiration sample, being measured by said standard gas measurer, with reference to concentration of said standard gas in end-tidal air.
7. An expiration analyzer in accordance with claim 6, further comprising a suction pump for sucking the expiration sample into said first and second sample measuring passages through said collection port.
8. An expiration analyzer in accordance with claim 6, further comprising a switching valve being provided on a confluent point located upstream in said first and second sample measuring passages, for switching the expiration sample to be introduced into said first and second sample measuring passages.
9. An expiration analyzer in accordance with claim 6, wherein said computing element makes said correction on the basis of:
[A'] = f1?(21-[a1])[A]/(21-[b1]) assuming that [A] represents said measured value of said target component in said expiration sample, [b1]
represents said O2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a1] represents O2 concentration in end-tidal air, being a constant, and f1 represents an experimentally prescribed coefficient.
[A'] = f1?(21-[a1])[A]/(21-[b1]) assuming that [A] represents said measured value of said target component in said expiration sample, [b1]
represents said O2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a1] represents O2 concentration in end-tidal air, being a constant, and f1 represents an experimentally prescribed coefficient.
10. An expiration analyzer in accordance with claim 6, wherein said computing element makes said correction on the basis of:
[A'] = f2?[a2][A]/[b2]
assuming that [A] represents said measured value of said target component in said expiration sample, [b2]
represents said CO2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a2] represents CO2 concentration in end-tidal air, being a constant, and f2 represents an experimentally prescribed coefficient.
[A'] = f2?[a2][A]/[b2]
assuming that [A] represents said measured value of said target component in said expiration sample, [b2]
represents said CO2 concentration in said expiration sample, [A'] represents corrected said measured value of said target component, [a2] represents CO2 concentration in end-tidal air, being a constant, and f2 represents an experimentally prescribed coefficient.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29013193A JP3325673B2 (en) | 1993-10-25 | 1993-10-25 | Method for correcting component concentration in breath and breath analyzer |
| JP5-290131 | 1993-10-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2134134A1 true CA2134134A1 (en) | 1995-04-26 |
Family
ID=17752202
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002134134A Abandoned CA2134134A1 (en) | 1993-10-25 | 1994-10-24 | Method of correcting componential concentration in expiration and expiration analyzer |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5495744A (en) |
| EP (1) | EP0653186B1 (en) |
| JP (1) | JP3325673B2 (en) |
| CA (1) | CA2134134A1 (en) |
| DE (1) | DE69420513T2 (en) |
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| JPH0810216B2 (en) * | 1990-07-17 | 1996-01-31 | 株式会社堀場製作所 | Gas analyzer |
| DE69131836T2 (en) * | 1990-09-19 | 2000-07-27 | Univ Melbourne Parkville | CONTROL CIRCUIT FOR MONITORING THE ARTERIAL CO 2 CONTENT |
| JP2541051B2 (en) * | 1991-09-27 | 1996-10-09 | 株式会社島津製作所 | Limiting current type oxygen concentration measuring device |
| US5361771A (en) * | 1993-03-05 | 1994-11-08 | Western Research Company, Inc. | Portable pulmonary function testing device and method |
-
1993
- 1993-10-25 JP JP29013193A patent/JP3325673B2/en not_active Expired - Lifetime
-
1994
- 1994-10-24 US US08/327,909 patent/US5495744A/en not_active Expired - Lifetime
- 1994-10-24 EP EP94116761A patent/EP0653186B1/en not_active Expired - Lifetime
- 1994-10-24 DE DE69420513T patent/DE69420513T2/en not_active Expired - Lifetime
- 1994-10-24 CA CA002134134A patent/CA2134134A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07120463A (en) | 1995-05-12 |
| DE69420513D1 (en) | 1999-10-14 |
| JP3325673B2 (en) | 2002-09-17 |
| US5495744A (en) | 1996-03-05 |
| EP0653186B1 (en) | 1999-09-08 |
| EP0653186A1 (en) | 1995-05-17 |
| DE69420513T2 (en) | 2000-04-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |