RU2063697C1 - Device for measurement of ph-value in hollow organs - Google Patents

Abstract

FIELD: medical equipment, used for measurement of pH-value in hollow organs (gastroenteric tract, tracheae and bronchi, etc). SUBSTANCE: by reference to the scale of the pH meter or with the aid of an acoustic adapter the device provides for a quick determination of the projection of measuring pH electrode in three planes at once due to summary interaction of the used position pickup-contacts of hermetically sealed reed relay (hermetically sealed ferreed contact) with the field of solenoid coil, in whose space the hermetically sealed reed relay is installed in the immediate proximity to the measuring electrode, and the body surface in the zone of the supposed projection of the pickup onto the skin. The device uses pH probes with measuring and reference electrodes in the end portion of the tubular casing and a position pickup in the form of a solenoid coil fixed in the immediate proximity to the measuring electrode and connected to the circuit of external magnetic biasing, and an external interacting unit in the form of a permanent magnet; a hermetically sealed reed relay is installed in the space of the solenoid coil in a casing of non-magnetic material, and the reed relay contacts are connected to the measuring and reference electrodes, respectively. EFFECT: facilitated procedure of measurement of pH-value. 3 dwg

Description

 The invention relates to medical equipment, in particular to devices for pH measurements in the hollow organs, for example at various levels (when performing "floor" pH metering) of the digestive canal, trachea and bronchi, uterus, etc. with an indication of the position of the pH- measuring electrodes probe relative to the skin.

 Known devices for pH measurements in hollow organs according to the magnitude of the electromotive force arising between the electrodes of the pH probe mounted in a tubular body and connected to a measuring device (M.C. A 61 V 5/00, a.s. USSR No. 178028, Bull. N2, 1966).

 The detection and verification of the position of the pH probe in the body of the subject is monitored radiologically and using special indicators, which are expensive, technically complex devices (MKI A 61 B 5/06, M 16/04, G 01 D 5/12, French application N 2617395, 1989).

 Closest to the claimed of known structures is a probe a. from. USSR N 824981 (M. Cl. A 61 B 5/00, M 25/00, bull. N 16, 1981), equipped with a device for indicating its position in the form of a position sensor, consisting of two parts: fixed in the end section of the tubular body a probe of an electromagnetic coil included in the circuit of an external low-frequency generator to act as an emitter of an electromagnetic field and a moving interacting part in the form of an electronic level detector mounted on the body surface of the subject with the possibility of movement relative to the emitter and combined with the recording device in the form of a dial indicator.

 The position of the probe is indicated by the prototype in several stages: first, by moving the level detector on the surface of the body of the subject, they find the area in which the received signal is of the maximum value, and rotate the detector around its axis, determining the position with the minimum signal level. Then, partially extending the probe, repeat the measurements and, combining two places marked on the surface of the body, evaluate the position of the probe.

 Due to the multi-stage search methodology, the duration of the examination increases significantly. The need for partial removal of the probe at the time of indication does not allow us to fix the direction of the probe axis during dynamic observation (in the case of pH-level metering). In this case, the initial position of the end section of the probe changes and the mucous membrane of the organ under investigation is additionally injured. In addition, the prototype does not allow to indicate the position of the sensors relative to the skin, i.e. the depth of their location, when indicating the position of the probe.

 The objective of the invention is the provision of quick determination of the position of the measuring (measuring, if several) electrode of the pH probe in a hollow organ simultaneously in three planes.

 This object is achieved in that the claimed device for pH measurements in the hollow organs is made in the form of a pH probe with measuring (or measuring if there are several) and standard electrodes in the end of its tubular body and contains a position sensor made of two parts: a sensor in the form of an electromagnetic coil (magnetization coil), fixedly mounted in a tubular housing in the immediate vicinity of the measuring electrode, included in the external magnetization circuit and containing reed switch (contact magnetically sealed) mounted in a cavity of the electromagnetic coil in a protective casing of non-magnetic material, and an external unit in the form of cooperating permanent magnet mounted for movement and fixation on the body surface.

 The magnetization coil is included in the circuit of a stabilized DC source with adjustable parameters (magnetization block). The contacts of the reed switch are connected to the input of the contact position analyzer (closed-open), for example, to the input of the measuring pH meter used, and to simplify the design, they are connected to the measuring and auxiliary pH electrodes of the probe.

 In order to facilitate obtaining information about the position and depth of the measuring pH electrode, the permanent magnet is used with the direction of the power lines indicated on its housing, and the magnetization unit is equipped with an output current indicator and a current regulator (roughly, accurately).

 If the pH probe of the inventive device for pH measurements in the hollow organs has several measuring pH electrodes, each of them is equipped with a reed switch with its own magnetizing coil and a protective casing of non-magnetic material, each of which is connected to an individual source of stabilized direct current with adjustable parameters, and Reed contacts are connected to a multi-channel analyzer of their position.

 As an analyzer of the position of the contacts of the reed switch in a simple technical version, a pointer device of a measuring pH meter of the type EV-74, pH-121, etc., which is in the millivoltmeter mode, is used. Various designs of existing pH meters are described in detail in the manual of Yu.Ya. Leia // pH-measurement of the stomach. L. "Honey.", 1987, 126 S. When the contacts of the reed switch are shorted, the gauge readings are absent as a result of the input short circuit.

 To simplify the indication of the moment of changing the position of the contacts of the reed switch, a writing unit, a sound or other signaling device of a standard design is connected to the output of the pH meter. Similar devices are described in the manual of M.G.Shuvalov // Fundamentals of Fire, M. "Stroyizdat", 1979, 249 p.

 The stabilized direct current source was used in a well-known design (G.P. Veresov, Yu.L. Smuryakov // Stabilized power sources for radio equipment. M. "Energy", 1978, 192 p.). You can apply, for example, a power supply with an adjustable output voltage, described in the 84th edition of "To help the radio amateur", DOSAAF USSR Publishing House, 1983, pp. 70-72 or pp. 74-78 (two-channel).

 The design features of the reed switches used are described in detail in TSB, ed. 3, publishing house "Soviet Encyclopedia", 1971 t.6, p. 357, article "Reed switch". Moreover, the method of using the inventive pH probe will depend on the type of reed switch used: normally-closed, normally-open, or switching.

 So, when using a normally open reed switch, before research, the constant voltage (magnetization voltage) supplied to the electromagnetic coil is gradually increased until a further increase leads to the operation of the contacts of the reed switch in the absence of a magnet. In this state, the reed switch of the pH probe position sensor inserted into the hollow organs (esophagus, stomach, etc.) of a human or animal body (in the experiment) is a sensitive element for interaction with magnetic field lines of a magnetic field mounted on the surface of the body of the subject in close proximity from the position sensor.

 The operation of the reed contacts at the minimum bias current occurs only if the installed magnet is located directly above the magnetization coil and the lines of force of the interacting fields (magnet and coil) coincide in direction.

 This property of the developed sensor was used by the authors in the inventive device to indicate the position of the measuring electrodes of the pH probe simultaneously in three planes when performing the floor pH meter.

 In this case, the magnet located on the surface of the body triggers the contacts of the reed switch and is also a marker of the projection onto the skin of the position sensor: its location, the longitudinal axis of the sensor on the body surface and the direction of insertion of the probe. In this case, it becomes possible to determine the depth of the position sensor under study by the magnitude of the minimum current in the magnetization coil, which can cause the contacts of the reed switch to be activated, when the magnet is placed directly on the skin at the time of indication.

 If a normally-open reed switch is used, then no pH measurement occurs at the time of the indication, since the pH electrodes of the probe turn out to be closed to each other, and the measuring pH meter is included in the millivoltmeter mode and acts as an analyzer of the position of the reed contacts. The sound indicator, which gives an audio signal when the contacts of the reed switch is closed, are connected for convenience in operation.

 The authors tested two options as a movable magnet: a permanent horseshoe-shaped magnet with lines of force extended toward the position sensor, and an electromagnet.

 The authors tested three ways of fixing the reed switch with a magnetizing coil in a tubular body due to fast-hardening medical plastics such as Protacryl-M in the cavity of the measuring electrode, behind the measuring electrode and between the auxiliary and measuring electrodes.

 It was found that fixing the position sensor closer than 10 mm from the measuring electrode reduces the flexibility of the probe and makes it difficult to insert. Fixing the position sensor in the cavity of the measuring probe in the case of its ring design additionally protects the glass housing of the reed switch from possible damage and is preferable.

 The introduction of the developed pH probe of the inventive device for pH measurements in the hollow organs with a position sensor in any medical probe of suitable diameter (endotracheal tube, rectal probe, etc.) as a mandrin allows it to be used as a universal position indicator.

 The equipment of the pH probe of the inventive device for pH measurements in the hollow organs with additional position sensors allows us to judge by the magnitude of the distance from the skin to the sensors and the gap between them on the projection line about the location of the longitudinal axis of the tube body of the probe along the front wall and thus quickly obtain the coordinates spatial position of the sensors when carrying out the technique of "floor pH-meter" simultaneously in three planes.

 All this determines the significance of the differences of the claimed device from existing ones.

 The essence of the alleged invention is illustrated by drawings: FIG. 1, which shows a diagram of the application of the inventive device for pH measurements in hollow organs when performing "floor" pH meter; FIG. 2, which shows the structure of the end section of the developed pH probe with a position sensor fixed behind the measuring pH electrode in the case of a reed switch with normally open contacts.

 The inventive device for pH measurements in the hollow organs contains a pH probe 1 (Fig. 1), which in the end section 2 of the tubular body 3 contains a magnetization coil 11 with a small reed switch 4 installed in its cavity, fixed with a sealant 5 in a protective casing 6, made from non-magnetic material. A sealant (not shown in the diagram) fixes the protective casing 6 of the position sensor in the cavity of the tubular body 3 in the immediate vicinity of the measuring pH electrode (or alternatively in the cavity of the measuring electrode in the case of its ring-shaped design or between the measuring and auxiliary pH electrodes in the diagram shown). Normally open contacts 7 of the reed switch 4 are connected to the measuring 8 and auxiliary 9 pH electrodes of the sensors by flexible wires (A and B, respectively) and to the input of the measuring reed meter used as an analyzer of the contact position of the contacts of the pH meter 12. In this case, the pointer device 15 is pH meter 12 in the measurement mode, pH is used to record the pH values of the investigated part of the hollow organs, and in the millivoltmeter mode (voltage measurement) as an analyzer of the position of the contacts of the reed switch to indicate the position of the probe. To simplify the design of the probe, the connection of the contacts of the reed switch with pH electrodes can be performed in their immediate vicinity (this option is not shown in the diagram).

 Conductors C from the bias coil 11 are connected to the bias unit 10, manufactured as a stabilized direct current source with adjustable (roughly and precisely) parameters. The bias unit 10 has a scale for the current regulator or an indicator of the output current (not shown in the diagram) for quick decoding of the depth parameters of the position sensor in a hollow organ relative to the surface of the skin of the subject. For convenience in use, the pH meter 12 is equipped with an audio indicator 13, which gives a signal in the absence of indications on the scale of the measuring device 15. If necessary, in the graphical recording of pH indicators and "floors" of their measurement, the output of the pH meter 12 is connected to a recording device 14 (directly or using the remote control 16).

 When working with the inventive device for pH measurements in the hollow organs in the mode of indicating the position of the measuring electrodes or the end section of the developed pH probe on the skin of the subject 17 (Fig. 2), in the region above the proposed location of the projection of the position sensor. a bipolar magnet 18 is installed so that the power lines 19 of the magnet 18, penetrating through the soft tissue 20, interact with the magnetically sensitive contacts of the reed switch 4, previously magnetized due to the electromagnetic field of the magnetization coil 11.

 In the absence of a magnet on the skin of the patient, the used probe of the inventive device for pH measurements in the hollow organs works like a normal pH probe.

 The inventive device for pH measurements in hollow organs works as follows: before preparing for administration and calibration in buffer solutions according to generally accepted methods, the position sensor of the pH probe is calibrated by magnetic sensitivity. To do this, gradually increase the current in the magnetization coil (1 until the contact of the reed contact is triggered, using the control knob of the magnetization block 10 in the rough and accurate mode) (the response time of the contacts of the reed switch is fixed on the scale of the measuring pH meter in millivoltmeter mode (no readings, since the device this moment is short-circuited) or by the appearance of a sound indication.

 When the indication appears, the bias current is gradually reduced until the contacts of the reed switch are not triggered. The value of the set bias current at this moment and the position of the control knob are fixed.

 The measuring and auxiliary electrodes of the calibrated pH probe are introduced into a test tube with a buffer solution of known pH, for example, 1.69 at 37 ° C (in a water bath), having the longitudinal axis of the probe strictly vertical. The sensor is heated to a thermostable state and finally regulate the bias current. After that, the pH electrodes are calibrated using standard sets of buffer solutions, having previously connected a writing device for graphically recording the pH-gram and switching the pH meter to measurement mode.

 Calibration of the magnetosensitive sensor (reed switch with an electromagnetic coil) to determine the depth of its location is carried out by determining the distance from the magnet to the sensor at the time of indication for different values of the bias current, provided that the arrow indicating the direction of the lines of force of the magnet used coincides with the longitudinal axis pH probe and is directed towards its end department.

 The prepared probe is allowed to swallow the patient. Under these conditions, the position sensor has maximum magnetic sensitivity.

 The authors have developed the following methods of working with the claimed device for pH measurements in hollow organs.

 The indication mode involves the introduction of a pH probe into the hollow organs under study when the magnet is fixed at known points on the surface of the body, taking into account topographic and anatomical diagrams (Fig. 3) of the location of the organs, their projection onto the skeleton (skeletonotopy) and skin (holotopia). In this case, the longitudinal axis of the magnet is oriented deliberately to the estimated location of the longitudinal axis of the organ under study. So when indicating the passage of the lower third of the esophagus with a pH sensor, the axis of the magnet is positioned vertically with a downward direction, between the X and XII thoracic vertebrae when the magnet is located at the back, or at the point of attachment of the VI-VII costal cartilage to the left when the magnet is located in front or at level VII -VIII ribs along the axillary line when the magnet is located on the lateral surface of the chest.

 With the introduction of the probe along linear marks on the tubular body, the doctor is guided by the translational movement of the end section along the gastrointestinal tract. So along the length of the probe, the lower third of the esophagus is in the range of 35-45 cm, depending on the age of the patient, his physique and topographic and anatomical features of the organs under investigation.

 In the indication mode, a sound signal appears when the probe position sensor approaches the zone of penetration from the soft tissue of the lines of force of the magnet mounted on the skin.

 When working in this mode, you can measure the pH in this section of the housing complex. and at the moment the contacts of the reed contact are triggered with a minimum bias current, write on the tape of the recorder or in the computer's memory the marking (coding) of the "floor" currently being studied.

 When using this technique, in some cases it is necessary to apply special techniques when introducing the probe, allowing the end section to reach the planned section of the digestive canal under the influence of gravity and directed peristalsis of the organ wall. The pH probe is moved to the next display point after a stable indication of the moment when the end section of the probe passes the previous projection zone and obtain stable pH values.

 The depth of the probe is calculated taking into account the calibration data for magnetic sensitivity: according to the magnitude of the bias current, which causes the contacts of the reed switch to operate, provided that the magnet is located on the skin, directly above the measuring electrode, along its longitudinal axis, in the direction of introduction.

 Clinical testing of this technique has shown the ability to obtain pH values from the same departments of patients in the dynamics of the examination and treatment. In this case, the sounding is accelerated, especially when examining the sections of the 12-g colon, the reliability and reproducibility of the obtained data increases, paper is saved when recording pH-grams, and their decoding is facilitated.

 In the display mode, the magnet is a position marker, as it remains fixed on the skin until the contacts of the reed switch. In this case, the end section of the probe is a movable element, since it tends to approach each other and to a given orientation with respect to the magnet.

 Another recommended operating mode is search mode. In this case, the patient swallows the prepared probe to an individual mark on the tubular body (for example, when examining the stomach, the patient’s height is in cm minus 100 cm), and using a magnet, moving it along the spine and around its axis, focusing on sound indication or pH meter scale readings, find the projection of a magnetically sensitive sensor on the surface of the body, evaluate the location and direction of its axis and measure the depth.

 This technique makes it possible to clarify and correct the position of the probe, to carry out the marking of the studied organ department in a particular patient.

 When introducing a probe tuned for maximum magnetic sensitivity, the authors discovered the effect of the appearance of an indication when the longitudinal axis of the sensor deviated from the vertical plane by an angle of 5-10 degrees in the absence of a marker magnet due to interaction with the lines of force of the Earth’s magnetic field. This property was used for dynamic monitoring of the progress of the sensor along the bends of the esophagus, respiratory movements of the stomach wall due to the movements of the diaphragm. When a gastric tube was introduced to a seriously ill patient for drainage with a position sensor, the indicating device allowed monitoring the function of external respiration.

 Methods have been developed for using the inventive device for pH measurements in the hollow organs, which allow the doctor-researcher to evaluate the topographic and anatomical features of the hollow organs in the patient being examined, depending on the constitution, body position at the time of examination, phase of the act of breathing, the nature of the revealed pathology; to assess the degree of development of the anterior wall, difficulties with surgical access during surgery, to study the magnetic permeability of various tissues in the norm and with the appearance of pathological formations (tumors, cysts, etc.).

 During bench tests of prototypes of the inventive device for pH measurements in hollow organs, the need to use small-sized reed switches of the MKA 10103 type with normally open contacts and to protect the glass housing of the reed switch with a casing of non-magnetic material with an additional output of flexible connecting conductors was confirmed.

 It is recommended to use a battery isolated from a household network as a reference voltage for a stabilized direct current source of a bias coil to prevent electric shock when working with the device. The need for a coarse and accurate installation of the bias current in the electromagnetic coil of the position sensor is revealed.

 It has been established that when using reed switches with normally closed contacts, the developed pH probe of the inventive device for pH measurements in hollow organs cannot be used as a conventional pH probe if there is no need to indicate its location, since without a magnet or additional electronic transitional devices, the pH electrodes are constantly in a closed state and the measurement of pH becomes technically impossible.

 The authors tested the method of indicating the location of the end section of the probe, when the bias current was gradually increased until the contacts of the reed switch were closed, and then, changing the position of the magnet, they tried to find its place and such an orientation on the surface of the body to cause the contacts to open, orienting the lines of force of the magnet against the lines of the coil bias. This method did not pass the tests, since it simulated the use of a reed switch with normally-closed contacts.

 It is concluded that the use of a sealant to fill the gap between the reed switch housing with a magnetizing coil, a protective casing and terminal leads, as well as the fastening of Protakril-M plastic with a position sensor in the immediate vicinity, but not closer than 10 mm from the measuring pH electrodes or their cavities (with a ring-shaped structure) provides the necessary flexibility and mechanical strength of the structure with the introduction of the developed pH probe into the hollow organs.

 The invention is confirmed by clinical testing of the inventive device for pH measurements in the hollow organs in the digestive laboratory of MSCh N 10 (846 patients) and children's clinic N2 (248 children) in Omsk.

 The acceleration of the survey methodology, an increase in the objectivity and reliability of the information received, its reproducibility (with floor pH-metering) were established. Revealed new positive properties of the claimed device: the ability to determine the depth of the position sensor relative to the skin; a position marker (bipolar magnet), in addition to the projection of the position sensor on the skin, allows you to assess the location and direction of the axis of the inserted probe; there is the possibility of telemetric control of the writing device and the formation of easily decrypted pH-grams in the "floor" study.

 A study of the dynamics of the movement of the end section of the probe and its interaction with the wall of the hollow organs allows an intravital study of the topography of the floors. ct architectonics of the bronchial tree, etc. to identify functional disorders and the initial stages of organic diseases (gastroptosis, stenosis of exit from the stomach, etc.), for the diagnosis of which it is usually necessary to use special research methods.

 The scope of application of the developed device is determined: gastroenterological diagnostic and treatment departments, experimental laboratories (in animals) and departments of medical universities of topographic anatomy (on biomanekens). The inventive device can be a universal indicator of the position, if the pH probe before the study (drainage) of the hollow organs (trachea, bladder, uterus, rectum, etc.) is introduced into the medical probe of the appropriate diameter as a mandrin. YYY2

Claims (1)

 A device for pH measurements in hollow organs, containing a pH probe with measuring and standard electrodes at the end of its tubular body and a position sensor made in the form of an electromagnetic coil mounted motionless in the tubular body, in the immediate vicinity of the measuring electrode included in the circuit external magnetization, and an external interacting node installed with the ability to move and fix on the human body, characterized in that the reed switch is additionally introduced into the position sensor in a protective casing of non-magnetic material, mounted in the cavity of the electromagnetic coil, and a permanent magnet is used as an external interacting node, while the contacts of the reed switch are connected respectively to the measuring and standard electrodes.

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