METHOD AND APPARATUS FOR PRIMARILY AMBULATORY GASTROINTESTINAL REGISTRATION

Abstract: A method for the determination of at least one of the parameters pH, PO2, PCO2 in a fluid by means of a metal monocrystal electrode (1). The method is characterized especially in that the determination is supplemented by a determination of at least one further parameter influencing the determination of the measuring parameter, the measuring parameter being corrected on the basis of the determination of said further parameter. The invention relates also to a system to perform said method.

Description: Method and apparatus for primarily ambulatory gastrointestinal registration The present invention relates to a method for a primarily ambulatory parameter registeration related to the presence of bilirubin in the gastrointestinal tract. The invention also relates to a system for performing said method. According to the state of art of essentially said type a fibreoptic means in the gastrointestinal tract and the light absorption at a wave length of about 460nm is mea¬ sured by means of spectrophotography, the wave length being indicated to correspond the maximum bilirubin absorption. Also, the light absorption is measured at a wave length of 600 nm, being a reference length with a minimal bilirubin related absorption. This technology has by means of a checking be found to possibly provide absorption values for bilirubin containing more than a 10 precent error level or more. Errors in this magnitude are sufficient to make it impossible to distinguish patients with a normal bilirubin exposure in the measuring region of the gastrointestinal tract from patients with an abnormal exposure. The present invention relates to a method and a system, with which reliable bili¬ rubin related exposure measurements can be achieved. Thus, the present invention relates to a method according to the preambles of the attached claim 1. The method is especially characterized by the contents of the cha¬ racterizing part of said claim. The present invention also relates to a system according to the preambles of the attached claim 10. The system is especially characterized by the contents of the cha¬ racterizing part of said claim. The invention is described here below more in detail with reference to an execu¬ tion example and the attached drawings, wherein - Figure 1 illustrates schematically a first embodiment of a system according to the present invention for an ambulatory registration of i.a. the presence of bilirubin in the gastrointestinal tract, - Figure 2 shows schematically and in more detail a part of the system in figure 1, and - Figure 3 shows schematically the maximum absorption in relation to the pH-value. In the preferred embodiment of the system shown i figure 1 and 2 with 1 is designated a registration unit for the ambulatory measurement and registration adapted to be carried by the patient together with the actual detecting means. Units of this kind are already known. According to a preferred embodiment the registration unit 1 thus comprises a Synectics MicroDigitrapper 2 being descbribed in the european patent No 0,356,603, by which means a plurality of measurement items, i.e. parameters such as a pH-value, can be registered. The system includes means for the determination of at least one parameter depending on the presence of bilirubin in a measuring region 3 in the gastrointestinal tract 4 of a patient 5. The region is here shown schematically as a container 7 filled with a fluid 6. For the determination of i.a. the light absoφtion in the measuring region a cat¬ heter 8 is provided adapted to run from the outside of the patient to the measuring region and including fibreoptical conducting means 9 adapted to conduct light by means of at least one light diode 10 or a similarly created light, the present light diodes 10 consisting of measuring and control means 11, here illustrated separated from the unit 2, but which preferably are included in the registration unit as schematically il¬ lustrated in figures 1 and 2. According to preferred embodiments means are provided in the form of light emitting diodes, fibreoptical conductors, sensor elements 12, etc., principally according to US-A-4,976,265 to determine the amount of light absoφtion in the measuring region, this light being of a generally certain first wave length U cor¬ responding to the maximum bilirubin light absoφtion in the measuring region and as a reference to determine the amount of light absoφtion in the measuring region, this light being of a generally certain second wave length 1Q corresponding to the minimum bili¬ rubin light absoφtion, schematically shown spectrophotographical means 11 prefe¬ rably being provided in the measuring and control means to analyze the light from the measuring region. Furthermore, there are, according to the invention, provided means, e.g. compri¬ sing an antimony crystal sensor 13 for measuring the pH-value in the measuring region, the pH-value related measuring values being adapted to be carried to the mea¬ suring and control means 11, said means according to an embodiment being adapted to control the absoφtion determination in relation to the pH- value. According to a first embodiment said first wave length is however provided to be by means of the measuring and control means 11 chosen on the basis of an actual pH-value, as the wave length 1-. corresponding to the the maximum absoφtion A, figure 3, is changed in relation to the pH-value. For a pH-value over 3.5, for example, is chosen to have a value of e.g. 460 nm and for a pH-value below 3.5 L is chosen to have another, from said first value diverging value. This can be achieved by using alternative light emitting diodes 10 or similar. It is also possible that at least L acccor- ding to this embodiment essentially varies continuously with the pH-value by means of a convenient light emitting diode. Combinations of gradual and continuous changes are also possible of the L with the pH-value. The changes in the maximum absoφtion A is shown schematically in figure 3, the relation between the absoφtion a., and a Q for 1, and 1 , respectively, shown as a function of L and both curves representing different pH-values, with 1Q e.g. being 600 nm. According to a second embodiment, the measuring and control means are prefe¬ rably adapted to form the basis for a correction, preferably basing on previous measu¬ rements, of at least said first wave length . An example of such a correction is given here below: b cor = b read x K where b » corrected absoφtion b j = measured absoφtion, and K = a corection factor, related to the pH-value According to this example, there is K = 1 for a pH-value over 3.5 and K = 1.2 for a pH-value below 3.5. The quoted formula is an example and can naturally be improved to achieve a finer correction. Said correction is not necessarily performed by means of the measuring and control unit , but can also be preformed later on in the registrating unit 2 or during an analysis of the measuring values by means of an exter¬ nal unit, see figure 1, to which the information from the registration unit 1 is adapted to be transmitted. During the absoφtion measuring also the light intensity can be varied in a com¬ pensating and finely adjusting way. The performance and the function of the system according to the invention has been generally presented her above. According to the all comprising function the determination of the bilirubin presence is thus related to the pH-value, and preferably essentially all pH-value and all actual parameters are used. Especially during a light absoφtion measuring the measurings are adapted to the pH-value by means of the wave length or the measuring values are corrected basing on the pH-value by means of a preferably empirically defined correction relation. As to be seen from above the invention provides the possibility to most essenti¬ ally and even decisively increase the reliability of the measured presence of bilirubin in the gastrointestinal tract. The invention has been described in connection to an execution example. Of course, further embodiments and minor changes and can therefore be imagined without departing from the scope of the invention. The invention primarily relates to bilirubin, but can even be used for several other substances being present in the gastrointestinal tract. The description and the claims are therefore to be inteφreted so that in any case bilirubin possibly can be substituted by any other substance. According to an embodiment being preferred in many cases said first wave length is set to about 450 nm at a pH-value of 3.5 and to about 400 nm at a pH- value < 3.5. It is then preferred that also the other wave length is about 565 nm. Thus, the invention is supposed not to be restricted to the embodiments stated above, but can be varied wthin the scope of the attached claims.

Claims: C L A I M S 1. A method, preferably ambulatory, for measuring and registration of at least one parameter related to the presence of bilirubin in a measuring region in the gastro¬ intestinal tract to determine the presence of bilirubin in the region, characterized by that the determination of the bilirubin presence is made by means of the pH-value. 2. A method according to claim 1, characterized in that generally all pH-values and said parameter values in the measuring region are registered and form the basis for said determination. 3. A method according to claim 1 or 2, characterized in that said parameter comprises the light absoφtion level in the measuring region, the light having a gene¬ rally defined first wave length (L) corresponding to the maximal absoφtion value (A) for bilirubin said parameters preferably also providing a reference including the light absoφtion level in the measuring region,, which light has a generally defined second wave length (1^) corresponding to a minimum bilirubin absoφtion and said light pre¬ ferably being fed to the measuring region by fibreoptical means and said absoφtion preferably being analyzed by means of spectrophotography. 4. A method according to claim 3, characterized in that the pH-value forms the basis for at least said first wave length. 5. A method according to claim 4, characterized in that said first wave length has a value, such as 460 nm, at a pH-value of more than 3,5 and another value at a pH-value of less than 3,5. 6. A method according to claim 4 or 5, characterized in that said first wave length is generally varied continuously with said pH-value. 7. A method according to claim 3, 4, 5 or 6, characterized in that said pH-value forms the basis for a preferably measure based correction of the determined absoφtion level at least with respect to said first wave length. 8. A method according to any one of the preceding claims, characterized in that said pH-value is determined by means of an antimony crystal sensor. 9. A method according to any one of the preceding claims, characterized in that said certain values related to the bilirubin presence and preferably the pH-value are registered in an ambulatory way. 10. A system for the preferably ambulatory measuring and registration of at least one bilirubin related parameter in a measuring region of the gastrointestinal tract to determine the presence of bilirubin, where means (1, 8, 9, 11, 11 , 12, 13) are proovi- ded to determine said parameter or parameters and to determine the pH-value, and means (11) for controlling the determination of said parameter or parameters in relation to the pH-value. 11. A system according to claim 10, characterized in that means (1, 8, 9, 11, 1 11 , 12) are provided to determine the light absoφtion level in the measuring region, the light being of generally a first light wave length (L ) corresponding to the maximum ι * ■ bilirubin absoφtion (A), and means (8, 9, 11, 11 , 12) preferably being provided to determine the light absoφtion level as a reference in the measuring region, the light being of generally a second wave length corresponding to the minimum bilirubin ab¬ soφtion, and fibreoptical means (9) are preferably provided to conduct said light in the measuring region and preferably spectrophotographical means (11 ) for an analysis of said absoφtion. 12. A system according to claim 11, characterized in that means (10, 11) are provided to choose at least said first wave length on the basis of the pH-value. 13. A system according to claim 11 or 12, characterized in that said means are arranged in such a way as to provide said first wave length with a value, such as 460 nm, at a pH-value over 3.5 and wirh another value at a pH-value of less than 3,5. 14. A system according to claim 12 or 13, characterized in that said means are provided in such a way that at least said first wave length i generally varying with the pH-value. 15. A system according to claim 11, 12, 13 or 14, characterized in that means (1, 11, 14) are provided to let the pH-value form the basis for a preferably measure¬ ment based correction of a certain absoφtion level, at least in relation to said first wave length. 16. A system according to claim 10, 11, 12, 13, 14 or 15, characterized in that an antimony crystal sensor (13) is provided to determine the pH-value. 17. A system according to claim 10, 11, 12, 13, 14, 15 or 16, characterized by that an ambulatory registration unit (1, 2) is provided for the registration of the pH- value. 18. A system according to claim 3, 4, 5, 6, 7, 8 or 9, characterized in that said first wave length has a level of about 450 nm at a pH-value > 3.5 and a value of about 400 nm at a pH-value < 3.5. 19. A system according to claim 11, 12, 13, 14, 15, 16 or 17, characterized by that said first wave length has a level of about 450 nm at a pH-value > 3.5 and a value of about 400 nm at a pH- value < 3.5.

Inventors: ESSEN-MOELLER ANDERS, ESSEN-MOELLER, ANDERS
Applicants: ESSEN MOELLER ANDERS, SYNECTICS MEDICAL AB, ESSEN-MOELLER, ANDERS
Application year: 1995
Main classification: G01N21
IPC codes: A61B5, G01N21