WO2002003859A1 - Transcutaneous calibration of an implanted pressure sensor - Google Patents

Transcutaneous calibration of an implanted pressure sensor Download PDF

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Publication number
WO2002003859A1
WO2002003859A1 PCT/EP2001/007302 EP0107302W WO0203859A1 WO 2002003859 A1 WO2002003859 A1 WO 2002003859A1 EP 0107302 W EP0107302 W EP 0107302W WO 0203859 A1 WO0203859 A1 WO 0203859A1
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Prior art keywords
pressure sensor
calibration
pressure
flow resistance
implanted
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PCT/EP2001/007302
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German (de)
French (fr)
Inventor
Wolfgang Barnikol
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Glukomeditech Ag
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Priority to AU2001281896A priority Critical patent/AU2001281896A1/en
Publication of WO2002003859A1 publication Critical patent/WO2002003859A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/021—Measuring pressure in heart or blood vessels
    • A61B5/0215—Measuring pressure in heart or blood vessels by means inserted into the body
    • A61B5/02156—Calibration means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/03—Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs
    • A61B5/031—Intracranial pressure

Definitions

  • the invention relates to a method with the features of claim 1 and a device for carrying out this method with the features of claim 3. It is thus possible, in particular, an intracranial, for example intraventricular pressure sensor, which is part of a fully implanted drainage system for the cerebrospinal fluid is to calibrate in a bloodless way.
  • an intracranial for example intraventricular pressure sensor, which is part of a fully implanted drainage system for the cerebrospinal fluid is to calibrate in a bloodless way.
  • the liquor is in the pair, so-called.
  • the choroid plexus of the 1st and 2nd ventricles is formed and flows into the venous blood in various ways: via the arachnoid granulation and the interventricular foramina in the 3rd ventricle and further via the cerebral aqueduct in the 4th brain ventricle.
  • the formation and drainage of the brain water are usually coordinated so that a proper one in the brain water
  • intracranial intracranial pressure also depends on the position and is physiologically 10 ⁇ 5mmHg in the lying adult.
  • the cerebrospinal fluid pressure also increases due to a decrease in cerebrospinal fluid absorption (Hydrocephalus aresorptivus) after meningitis or encephalitis; the Increases also result from an increase in the resistance to outflow (hydrocephalus occlucus) in the event of malformations and from tumors. Finally, the intracranial pressure increases with increased cerebrospinal fluid production (Hydrocephalus hypersecretorius), for example due to toxic influences on the brain. Further detailed explanations on pathophysiology, the clinic but also measurement technology and their problems can be found in S. Schwab, D. Krieger, W. Müllgas, G. Haman, W. hacke (ed.), "Neurological Intensive Care Medicine", chap. 14, P. 271 f., Springer-Verlag, 1999.ISBN 3-54065412-7.
  • a thin tube with an outer diameter of approximately 2.5 mm is used a CSF drainage (so-called, cerebral "shunt").
  • the tube is located at one end in one of the two lateral and paired intracerebral CSF spaces (so-called brain ventricles) and leads out through the skull cap; it usually runs under the skin to the abdomen.
  • a measuring and calibration device for calibrating pressure sensors for measuring the pressure in the brain in the non-implanted or implanted state is known.
  • a reference pressure is applied via a reference pressure channel with the aid of a pressure transmitter, this is measured via a reference pressure sensor, and the pressure sensor is therefore calibrated and calibrated using electronics.
  • a transcutaneously implanted pressure sensor is known in which the intracranial pressure is determined with the aid of a pressure reservoir on the skin and an audio signal resulting from the pressure difference between the internal pressure and the pressure on the skin surface due to mechanical contact.
  • the resistance is set according to clinical experience, taking into account the above symptoms. There is currently no way for clinical routine to measure the intracranial pressure without a transcutaneous probe and even to record a long-term profile of this pressure (diagnostic working mode), which would be of the greatest diagnostic and consequently therapeutic interest for the patient concerned. Likewise, it would be of great advantage if (with stabilized pressure,
  • the desired system for stabilizing the intracranial pressure is to be integrated into a cerebrospinal fluid drainage
  • only a micro pressure sensor can be used for pressure measurement, which is best integrated at the tip of the implanted catheter of the cerebrospinal fluid drainage so that its pressure-sensitive area is facing the cerebral cerebrospinal fluid space.
  • Stabilization in the form of a negative feedback with the help of a controllable flow resistance in the working hose of the drainage should function properly for years; for this it is particularly important that the sensitivity and in particular the zero point of the fully integrated and implanted pressure sensor remain stable for years - a problem that cannot be solved practically, even if the pressure sensors are designed to be as stable as possible. Therefore, the fully implanted system must have a device with which the calibration of the
  • Pressure sensor can be checked at any time and corrected if necessary. At the moment there is no possibility for the clinical routine to adjust such a pressure microsensor implanted in situ, either bloody and certainly not bloodless.
  • the reliable display of the pressure over a long period of time by the (intraventricularly lying) sensor is so important because, for example, an incorrectly too low pressure signal would cause the negative feedback mechanism to set a much too high intracranial one and thus damage the brain. Under certain circumstances it would be less harmful not to take any iatrogenic measures. So if you get involved in a technical stabilization of the cerebrospinal fluid pressure, the permanently correct pressure detection is extremely important. This emphatically underlines the demand for the pressure signal to be checked at all times.
  • a control can be achieved with the help of a subcutaneous puncture system integrated in the drainage.
  • a skin area can only be punctured to a limited extent, apart from the risk of infection and apart from the discomfort for the patient concerned.
  • Optimal would be the possibility of a bloodless calibration, which could be repeated as often as desired and practically without risk.
  • the problem is solved according to the invention by a calibration, measuring and control device which is switched on in the working tube of the liquor and under the skin lies.
  • the fully implanted part of the device can equally serve to control the CSF flow for the purpose of stabilizing the intracranial pressure and to measure this flow as well as a bloody calibration - as an alternative to the bloodless one.
  • Both devices enable a method of a bloodless calibration of an implanted pressure sensor, such as a micro pressure sensor located in the brain ventricle.
  • FIG. 1 and 2 show the device schematically for the case of use in intracranial pressure measurement: FIG. 1 shows a longitudinal section through the entire structure and FIG. 2 shows a top view of the calibration, measurement and control device ,
  • the measuring and control device (1) is located directly below the
  • CSF tube usually runs.
  • Your capsule (1.2) has the shape of a thin disc, which has a hose attachment for the CSF supply (1.3) and another one for the drain (1.4).
  • the end of the supply tube (3) lies in the brain ventricle, at the end of which is the pressure microsensor; the drain hose (4) ends in the abdominal cavity.
  • the two hose attachments go into the inner tube (1.5) of the measuring and control device (1).
  • This tube - seen from the side of the CSF inflow - is initially a subcutaneous one
  • Another element is a differential pressure sensor (1.9) which, with sufficient sensitivity, is a pressure difference between the interior of the device 1 and the Can signal inside the calibration hood (2).
  • the sensor membrane of this differential pressure sensor (1.9) lies directly against the inside of the skin (5).
  • a flow sensor (1.10) is installed in the pipe behind the second flow resistance. This is followed by the drainage approach (1.4), the attached tube of which opens into the abdomen.
  • Both flow resistances can be operated externally; the signals from the differential pressure sensor (1.2) and from the flow sensor (1.10) can be received telemetrically outside the organism.
  • the calibration hood (2) is used for bloodless calibration of the intracranial pressure microsensor. It preferably has a circular base (2.1) which fits exactly on the circular edge of the measuring and control device (1). The seal between the two devices is ensured by the skin under pressure.
  • the calibration hood (2) has a manometer (2.2) with which the internal pressure of the hood can be determined; it also has a pump device (2.3), with the aid of which a certain positive or negative pressure can be set inside the calibration hood, which in turn can be measured with the manometer (2.2).
  • the pump device is connected to the hood via a hose (2.4). This has a compensation flap (2.5) for pressure compensation with the surroundings.
  • the calibration hood (2) is placed on the device (1) and pressed there; In the calibration hood there is initially a balance with the air pressure, which can be achieved by opening the compensation flap (2.5). Then the flow resistance (1.8.1) is closed and the pressure range of the intracranial pressure sensor is decoupled from the pressure differential sensor. Therefore the differential pressure sensor (1.9) now shows its zero signal, which can be set to zero, but does not have to. The flow sensor (1.10) also indicates its zero signal. Then the river Resistor (1.8.2) also closed; the zero signal from the differential pressure sensor (1.9) should be retained, as should the signal from the flow sensor (1.10). After opening the flow resistance (1.8.1), the pressure of the brain ventricle acts on the differential pressure sensor (1.9): Its display then changes accordingly.
  • the compensating flap (2.5) is closed and the pump device (2.3) inside the calibration hood generates a pressure such that the differential pressure sensor 1.9 again displays the zero signal.
  • the pressure required inside the hood which can be determined directly with the calibrated manometer (2.2), is equal to the pressure in the brain ventricle.

Abstract

The invention relates to a method for transcutaneously calibrating an implanted pressure sensor according to which a calibration cap (2), which has a manometer (2.2) and a pump device (2.3) with a compensating flap (2.5) arranged inside the feed tube (2.4), is placed on the skin (5) above an implanted measuring and control device (1) provided with a first flow restrictor (1.8.1), a differential pressure sensor (1.9), a second flow restrictor (1.8.2) and with a flow sensor (1.10). By opening the compensating flap (2.5) in the calibration cap (2), the outside air pressure is adjusted, the flow restrictor (1.8.1) is closed, the second flow restrictor (1.8.2) is closed as well, and the first flow restrictor (1.8.1) is re-opened. The pump device (2.3) is used to generate a pressure inside the calibration cap (2) in such a manner that the differential pressure sensor (1.9) indicates the signal once again before opening the first flow restrictor (1.8.1), and the pressure inside the calibration cap (2) is determined by the manometer (2). The invention also relates to a device for carrying out said method.

Description

TRANSKUTANE EICHUNG EINES IMPLANTIERTEN DRUCKSENSORS TRANSCUTANE CALIBRATION OF AN IMPLANTED PRESSURE SENSOR
Die Erfindung betrifft ein Verfahren mit den Merkmalen des Anspruchs 1 sowie eine Vorrichtung zur Durchführung dieses Verfahrens mit den Merkmalen des Anspruchs 3. Damit ist es insbesondere möglich, einen intrakraniell , beispielsweise intraventrikuiär liegenden Drucksensor, der Teil eines vollimplantierten Drainage-Systems für den Liquor cerebrospinalis ist, auf unblutige Weise zu eichen.The invention relates to a method with the features of claim 1 and a device for carrying out this method with the features of claim 3. It is thus possible, in particular, an intracranial, for example intraventricular pressure sensor, which is part of a fully implanted drainage system for the cerebrospinal fluid is to calibrate in a bloodless way.
Zu seinem Schutz schwimmt das sehr weiche Gehirn des Menschen gleichsam im Hirnwasser, dem sogenannten Liquor cerebrospinalis (Hirnwasser). Der Liquor wird in den paarigen, sogen. Plexus choroidei des 1. und 2. Ventrikels gebildet und fließt über verschiedene Wege in das venöse Blut: über die Granulationes arachnoidales und über die Foramina interventricularia in den 3. Ventrikel und weiter über den Aquaeductus cerebri in den 4. Hirnventrikel. Bildung und Abfluss des Hirnwassers sind normalerweise so aufeinander abgestimmt, dass im Hirnwasser ein regelrechterTo protect it, the very soft brain of the human being swims, as it were, in the cerebrospinal fluid (cerebrospinal fluid). The liquor is in the pair, so-called. The choroid plexus of the 1st and 2nd ventricles is formed and flows into the venous blood in various ways: via the arachnoid granulation and the interventricular foramina in the 3rd ventricle and further via the cerebral aqueduct in the 4th brain ventricle. The formation and drainage of the brain water are usually coordinated so that a proper one in the brain water
Überdruck herrscht. Dieser sogen, intrakranielle Hirndruck ist auch lageabhängig und beträgt physiologischerweise beim liegenden Erwachsenen 10±5mmHg.There is overpressure. This so-called intracranial intracranial pressure also depends on the position and is physiologically 10 ± 5mmHg in the lying adult.
Durch verschiedenartige Störungen kann es zu Abweichungen des Druckes von der Norm kommen, insbesondere zu Erhöhungen, welche nicht nur erheblicheVarious types of disturbances can lead to pressure deviations from the norm, in particular to increases which are not only significant
Beschwerden, sondern auch (zerebrale) Störungen und Schädigungen des Gehirns für den Träger bedingen können, nämlich in Form des irreversiblen Untergang von Nervenzellen, insbesondere in der Hirnrinde, d.h. zu einer Entrindung der betreffenden Person führen. Ursache hierfür ist unter anderem, dass der Zerebrale Perfusionsdruck (ZPD) sich vermindert, da dieser die Differenz des Blutdruckes und des Hirndruckes ist. Der zerebrale Perfusionsdruck wiederum stellt die entscheidende treibende Kraft für die Durchblutung des Gehirns und damit für dessen Sauerstoff-Versorgung aber auch für die Entsorgung des Gehirns von Stoffwechselprodukten dar.Discomfort, but also (cerebral) disorders and brain damage for the wearer, namely in the form of irreversible loss of nerve cells, especially in the cerebral cortex, i.e. lead to debarking of the person concerned. One of the reasons for this is that the cerebral perfusion pressure (ZPD) decreases because it is the difference between the blood pressure and the cerebral pressure. The cerebral perfusion pressure in turn is the decisive driving force for the blood circulation in the brain and thus for its oxygen supply but also for the disposal of the brain of metabolic products.
Der Liquordruck erhöht sich ebenfalls durch Verminderung der Liquorresorption (Hydrocephalus aresorptivus) nach Meningitiden oder Encephalitiden; die Steigerungen entstehen ferner durch eine Vergrößerung des Abfiusswiderstandes (Hydrocephalus occlucus) bei Missbildungen sowie durch Tumore. Schließlich steigert sich der intrakranielle Druck unter vermehrter Liquorproduktion (Hydrocephalus hypersecretorius) bespielsweise durch toxische Einflüsse auf das Gehirn. Weitere ausführliche Darlegung zur Pathophysiologie, zur Klinik aber auch Messtechnik und ihrer Probleme findet man bei S. Schwab, D. Krieger, W. Müllgas, G. Haman, W. Hacke (Hrsg.), „Neurologische Intensivmedizin", Kap. 14, S. 271 f., Springer-Verlag, 1999.ISBN 3-54065412-7.The cerebrospinal fluid pressure also increases due to a decrease in cerebrospinal fluid absorption (Hydrocephalus aresorptivus) after meningitis or encephalitis; the Increases also result from an increase in the resistance to outflow (hydrocephalus occlucus) in the event of malformations and from tumors. Finally, the intracranial pressure increases with increased cerebrospinal fluid production (Hydrocephalus hypersecretorius), for example due to toxic influences on the brain. Further detailed explanations on pathophysiology, the clinic but also measurement technology and their problems can be found in S. Schwab, D. Krieger, W. Müllgas, G. Haman, W. Hacke (ed.), "Neurological Intensive Care Medicine", chap. 14, P. 271 f., Springer-Verlag, 1999.ISBN 3-54065412-7.
Um in Fällen entsprechender klinischer zerebraler Symptome, wie Ausfall des Kurzzeit- Gedächtnisses und/oder imperativer Harndrang und/oder Gehstörungen (unsicherer Gang) einen weiteren irreversiblen Untergang von Gehirnzellen zu vermeiden, legt man mit Hilfe eines dünnen Schlauchs von etwa 2,5 mm Außendurchmesser eine Liquor-Drainage (sogen, zerebraler „shunt"). Der Schlauch befindet sich mit einem Ende in einem der beiden seitlichen und paarigen intrazerebralen Liquorräume (sogen. Hirnventrikel) und führt durch die Schädeldecke nach außen; er verläuft unter der Haut in der Regel bis in den Bauchraum.In order to prevent further irreversible destruction of brain cells in cases of corresponding clinical cerebral symptoms, such as short-term memory loss and / or imperative urge to urinate and / or walking disorders (unsafe walking), a thin tube with an outer diameter of approximately 2.5 mm is used a CSF drainage (so-called, cerebral "shunt"). The tube is located at one end in one of the two lateral and paired intracerebral CSF spaces (so-called brain ventricles) and leads out through the skull cap; it usually runs under the skin to the abdomen.
Derzeitiger Stand der Technik ist, dass man - um einen physiologischen Liquordruck einstellen zu können - meist unterhalb des Schlüsselbeins einen künstlichen Widerstand in den Ableitschlauch der Liquor-Drainage bringt; die Größe des Widerstandes ist mit Hilfe eines Magneten transkutan in einigen diskreten Stufen einstellbar ist. Eine Problematik dieser fest eingestellten Abflusswiderstände ist auch die Lageabhängigkeit des Liquordruckes. Eine kritische Übersicht der zur Zeit verfügbaren einstellbaren Abflusswiderstände dieser Art findet man bei A. Aschoff, „In vitro-Testung von Hydrocephalus-Ventilen", Habil.-Schrift, Heidelberg, 1994 (www.med.uni-heidelberg.de/nch/literat/buch002/aschoff-habil-t1.rtf, S. 12 f.).The current state of the art is that - in order to be able to set a physiological CSF pressure - an artificial resistance is usually placed in the drainage tube of the CSF drainage below the clavicle; the size of the resistance can be set transcutaneously in a few discrete steps with the help of a magnet. One problem with these fixed discharge resistances is the positional dependence of the CSF pressure. A critical overview of the adjustable discharge resistances of this type currently available can be found in A. Aschoff, "In Vitro Testing of Hydrocephalus Valves", Habil.-Schrift, Heidelberg, 1994 (www.med.uni-heidelberg.de/nch/ literat / buch002 / aschoff-habil-t1.rtf, p. 12 f.).
Aus DE 91 05 742 U1 ist eine Meß- und Kalibriereinrichtung zur Kalibrierung von Drucksensoren für Himdruckmessungen im nicht implantierten oder implantierten Zustand bekannt. Dabei wird über einen Referenzdruckkanal mit Hilfe eines Druckgebers ein Referenzdruck beaufschlagt, dieser über einen Referenzdrucksensor gemessen und damit der Drucksensor mit Hilfe einer elektronik abgeglichen und geeicht. Dabei ist es jedoch erforderlich, zwischen dem Referenzkanal und dem Drucksensor eine Verbindung herzustellen. Aus US 4 378 809 ist ein transkutan implantierter Drucksensor bekannt, bei dem mit Hilfe eines Druckreservoirs auf der Haut und eines durch die Druckdifferenz zwischen dem internen Druck und dem Druck an der Hautoberfläche durch mechanischen Kontakt entstehenden Audio-Signals der intrakranielle Druck ermittelt wird.From DE 91 05 742 U1, a measuring and calibration device for calibrating pressure sensors for measuring the pressure in the brain in the non-implanted or implanted state is known. A reference pressure is applied via a reference pressure channel with the aid of a pressure transmitter, this is measured via a reference pressure sensor, and the pressure sensor is therefore calibrated and calibrated using electronics. However, it is necessary to establish a connection between the reference channel and the pressure sensor. From US 4,378,809 a transcutaneously implanted pressure sensor is known in which the intracranial pressure is determined with the aid of a pressure reservoir on the skin and an audio signal resulting from the pressure difference between the internal pressure and the pressure on the skin surface due to mechanical contact.
Die Einstellung des Widerstandes erfolgt gemäß klinischer Erfahrung unter Berücksichtigung oben genannter Symptomatik. Es gibt derzeit für die klinische Routine keine Möglichkeit, den intrakraniellen Druck ohne transkutane Sonde zu messen und gar ein Langzeit-Profil diese Druckes zu erfassen (diagnostischer Arbeitsmodus), was aber von größtem diagnostischem und folglich auch therapeutischem Interesse für den betreffenden Patienten wäre. Gleichermaßen wäre es von großem Vorteil, könnte (bei stabilisiertem Druck, The resistance is set according to clinical experience, taking into account the above symptoms. There is currently no way for clinical routine to measure the intracranial pressure without a transcutaneous probe and even to record a long-term profile of this pressure (diagnostic working mode), which would be of the greatest diagnostic and consequently therapeutic interest for the patient concerned. Likewise, it would be of great advantage if (with stabilized pressure,
therapeutischer Arbeitsmodus) auch der Liquorfluß gemessen werden. Gar nicht möglich ist es bisher, den intrakraniellen Druck auf einem gewünschten Wert stabil zu halten.therapeutic working mode) also the CSF flow can be measured. So far it has not been possible to keep the intracranial pressure stable at a desired value.
Da das gewünschte System zur Stabilisierung des intrakraniellen Druckes in eine Liquor-Drainage integriert werden soll, kommt zur Druckmessung nur ein Mikro- Drucksensor in Frage, der am besten an der Spitze des implantierten Katheters der Liquor-Drainage so integriert ist, daß seine druckempfindliche Fläche dem zerebralen Liquorraum frei zugewandt ist. Die Stabilisierung in Form einer Gegenkopplung mit Hilfe eines steuerbaren Fluss-Widerstandes im Arbeitsschlauch der Drainage soll jahrelang regelrecht funktionieren; hierfür ist es insbesondere wichtig, dass die Empfindlichkeit und insbesondere der Nullpunkt des voll integrierten und implantierten Drucksensors über Jahre stabil bleibt - ein praktisch nicht lösbares Problem, auch wenn die Drucksensoren so stabil wie möglich konstruiert sind. Deshalb muß das voll implantierte System eine Vorrichtung besitzen, mit deren Hilfe die Eichung desSince the desired system for stabilizing the intracranial pressure is to be integrated into a cerebrospinal fluid drainage, only a micro pressure sensor can be used for pressure measurement, which is best integrated at the tip of the implanted catheter of the cerebrospinal fluid drainage so that its pressure-sensitive area is facing the cerebral cerebrospinal fluid space. Stabilization in the form of a negative feedback with the help of a controllable flow resistance in the working hose of the drainage should function properly for years; for this it is particularly important that the sensitivity and in particular the zero point of the fully integrated and implanted pressure sensor remain stable for years - a problem that cannot be solved practically, even if the pressure sensors are designed to be as stable as possible. Therefore, the fully implanted system must have a device with which the calibration of the
Drucksensors jederzeit überprüft und gegebenenfalls korrigiert werden kann. Derzeit gibt es keine Möglichkeit für die Klinikroutine, um einen so implantierten Druck- Mikrosensor in situ einzujustieren, weder blutig und schon gar nicht unblutig.Pressure sensor can be checked at any time and corrected if necessary. At the moment there is no possibility for the clinical routine to adjust such a pressure microsensor implanted in situ, either bloody and certainly not bloodless.
Die verläßliche Anzeige des Druckes über lange Zeit des (intraventrikulär liegenden) Sensors ist deshalb so wichtig, weil beispielsweise ein falsch zu niedriges Drucksignal den Gegenkopplungs-Mechanismus einen viel zu hohen intrakraniellen einstellen ließe und somit das Gehirn schädigte. Weniger schädlich wäre unter Umständen, gar keine iatrogene Maßnahme zu ergreifen. Läßt man sich also auf eine technische Stabilisation des Liquordruckes ein, so kommt der dauerhaft richtigen Druck-Detektion eine extrem große Bedeutung zu. Dies unterstreicht nachdrücklich die Forderung nach einer jederzeitigen Kontrolle des Drucksignals.The reliable display of the pressure over a long period of time by the (intraventricularly lying) sensor is so important because, for example, an incorrectly too low pressure signal would cause the negative feedback mechanism to set a much too high intracranial one and thus damage the brain. Under certain circumstances it would be less harmful not to take any iatrogenic measures. So if you get involved in a technical stabilization of the cerebrospinal fluid pressure, the permanently correct pressure detection is extremely important. This emphatically underlines the demand for the pressure signal to be checked at all times.
Eine Kontrolle läßt sich mit Hilfe eines in der Drainage integrierten subkutanen Punktionssystems erreichen. Jedoch ist ein Hautbereich nur begrenzt oft punktierbar, abgesehen von der Gefahr der Infektion und abgesehen von der Unannehmlichkeit für den betreffenden Patienten. Optimal wäre hierbei die Möglichkeit einer unblutigen Eichung, welche gleichsam beliebig oft wiederholbar und praktisch risikolos wäre.A control can be achieved with the help of a subcutaneous puncture system integrated in the drainage. However, a skin area can only be punctured to a limited extent, apart from the risk of infection and apart from the discomfort for the patient concerned. Optimal would be the possibility of a bloodless calibration, which could be repeated as often as desired and practically without risk.
Das Problem wird erfindungsgemäß durch eine Eich-, Mess- und Steuer- Vorrichtung gelöst, welche in den Arbeitsschlauch es Liquors eingeschaltet ist und unter der Haut liegt. Die vollimplantierte Teil der Vorrichtung kann gleichermaßen der Steuerung des Liquorstromes zwecks Stabilisation des Hirndruckes dienen und der messenden Überwachung dieses Stromes wie auch einer blutigen Eichung - als Alternative zur unblutigen - dienen.The problem is solved according to the invention by a calibration, measuring and control device which is switched on in the working tube of the liquor and under the skin lies. The fully implanted part of the device can equally serve to control the CSF flow for the purpose of stabilizing the intracranial pressure and to measure this flow as well as a bloody calibration - as an alternative to the bloodless one.
Dazu kommt ein zweiter Vorrichtungsteil, die sogenannte Eichhaube, welche sich über der Haut befindet.There is also a second device part, the so-called calibration hood, which is located above the skin.
Beide Vorrichtungen ermöglichen ein Verfahren einer unblutigen Eichung eines implantierten Drucksensors, wie beispielsweise eines im Hirnventrikel liegenden Mikro- Drucksensors.Both devices enable a method of a bloodless calibration of an implanted pressure sensor, such as a micro pressure sensor located in the brain ventricle.
Fig. 1 und Fig. 2 geben die Vorrichtung schematisch für den Fall der Anwendung bei der Hirndruck-Messung wieder: Fig. 1 stellt einen Längsschnitt durch den gesamten Aufbau dar und Fig. 2 eine Aufsicht der Eich-, Mess- und Steuer-Vorrichtung.1 and 2 show the device schematically for the case of use in intracranial pressure measurement: FIG. 1 shows a longitudinal section through the entire structure and FIG. 2 shows a top view of the calibration, measurement and control device ,
Die Mess- und Steuer-Einrichtung (1) befindet sich direkt unter derThe measuring and control device (1) is located directly below the
Haut (5), beispielsweise unmittelbar unterhalb des Schlüsselbeines, wo derSkin (5), for example immediately below the clavicle, where the
Liquorabieitschlauch üblicherweise verläuft. Ihre Kapsel (1.2) hat die Form einer dünnen Scheibe, welche einen Schlauchansatz für die Liquor-Zufuhr (1.3) und einen weiteren für den Abfluss (1.4) besitzt. Das Ende des Zufuhr-Schlauches (3) liegt im Hirnventrikel, an dessen Ende sich der Druck-Mikrosensor befindet; der Abfluss- Schlauch (4) endet im Bauchraum. Die beiden Schlauchansätze gehen in das innere Rohr (1.5) der Mess- und Steuer-Einrichtung (1) über. An diesem Rohr - von der Seite des Liquor-Zuflusses gesehen - befindet sich zunächst ein subkutanesCSF tube usually runs. Your capsule (1.2) has the shape of a thin disc, which has a hose attachment for the CSF supply (1.3) and another one for the drain (1.4). The end of the supply tube (3) lies in the brain ventricle, at the end of which is the pressure microsensor; the drain hose (4) ends in the abdominal cavity. The two hose attachments go into the inner tube (1.5) of the measuring and control device (1). This tube - seen from the side of the CSF inflow - is initially a subcutaneous one
Punktionssystem (1.6) mit einer Membran (1.7), durch die man mit der Spitze einer Kanüle unter Durchstechen der Haut (5), allerdings ohne Eichhaube (2), in die Liquorflüssigkeit gelangen kann; das Punktionssystem dient einer blutigen Eichung des intrakranial liegenden Druck-Mikrosensors.Puncture system (1.6) with a membrane (1.7), through which one can get into the CSF fluid with the tip of a cannula while piercing the skin (5), but without a calibration cap (2); the puncture system is used for bloody calibration of the intracranial pressure microsensor.
Als Nächstes folgt ein von außen (telemetrisch) steuerbarer Flusswiderstand (1.8.1), mit dem der Liquorfluss einstellbar ist, bis hin zum unendlich großen Widerstand, d. h. zum vollständigen Verschluss des Liquorschlauches.Next comes an externally (telemetrically) controllable flow resistance (1.8.1), with which the CSF flow can be adjusted, up to the infinitely large resistance, i.e. H. for the complete closure of the CSF tube.
Als weiteres Element folgt ein Differenz-Drucksensor (1.9), der mit ausreichender Empfindlichkeit eine Druckdifferenz zwischen dem Inneren der Einrichtung 1 und dem Inneren der Eichhaube (2)zu signalisieren vermag. Die Sensor-Membran dieses Differenz-Drucksensors (1.9) liegt unmittelbar an der Haut (5) innen an.Another element is a differential pressure sensor (1.9) which, with sufficient sensitivity, is a pressure difference between the interior of the device 1 and the Can signal inside the calibration hood (2). The sensor membrane of this differential pressure sensor (1.9) lies directly against the inside of the skin (5).
Hinter dem Differenz-Drucksensor (1.9) findet sich ein zweiter Flusswiderstand (1.8.2) vom Typ des ersten.Behind the differential pressure sensor (1.9) there is a second flow resistance (1.8.2) of the first type.
Hinter dem zweiten Flusswiderstand ist in das Rohr ein Fluss-Sensor (1.10) angebracht. Danach folgt der Abfluss-Ansatz (1.4), dessen angesetzter Schlauch in den Bauchraum mündet.A flow sensor (1.10) is installed in the pipe behind the second flow resistance. This is followed by the drainage approach (1.4), the attached tube of which opens into the abdomen.
Beide Flusswiderstände können telemetrisch von außen betätigt werden; die Signale des Differenz-Drucksensors (1.2) wie auch des Fluss-Sensors (1.10) lassen sich telemetrisch außerhalb des Organismus empfangen.Both flow resistances can be operated externally; the signals from the differential pressure sensor (1.2) and from the flow sensor (1.10) can be received telemetrically outside the organism.
Zur unblutigen Eichung des intrakraniellen Druck-Mikrosensors wird die Eichhaube (2) verwendet. Sie besitzt vorzugsweise einen kreisförmigen Fuß (2.1), der genau auf den kreisförmigen Rand der Mess- und Steuer-Einrichtung (1) paßt. Die Abdichtung zwischen beiden Vorrichtungen wird durch die Haut unter Andrücken gewährleistet. Die Eichhaube (2) hat ein Manometer (2.2), mit dem der Innendruck der Haube bestimmt werden kann; sie besitzt außerdem eine Pumpeinrichtung (2.3), mit deren Hilfe sich ein bestimmter Über- oder Unterdruck im Inneren der Eichhaube einstellen läßt, der wiederum mit dem Manometer (2.2) meßbar ist. Die Pumpeinrichtung ist mit der Haube über einen Schlauch (2.4) verbunden. Dieser besitzt eine Ausgleichsklappe (2.5) für den Druckausgleich mit der Umgebung.The calibration hood (2) is used for bloodless calibration of the intracranial pressure microsensor. It preferably has a circular base (2.1) which fits exactly on the circular edge of the measuring and control device (1). The seal between the two devices is ensured by the skin under pressure. The calibration hood (2) has a manometer (2.2) with which the internal pressure of the hood can be determined; it also has a pump device (2.3), with the aid of which a certain positive or negative pressure can be set inside the calibration hood, which in turn can be measured with the manometer (2.2). The pump device is connected to the hood via a hose (2.4). This has a compensation flap (2.5) for pressure compensation with the surroundings.
Unter Zuhilfenahme der beschriebenen kann nun mit folgendem Verfahren eine unblutige Eichung des im Gehirn befindlichen Druck-Mikrosensors am liegenden Patienten vorgenommen werden:With the help of the described one, the following procedure can now be used to perform a bloodless calibration of the pressure microsensor in the brain on the patient lying down:
Die Eichhaube (2) wird auf die Einrichtung (1) gesetzt und dort angedrückt; in der Eichhaube herrscht zunächst Ausgleich mit dem Luftdruck, was durch Öffnen der Ausgleichsklappe (2.5) erreicht werden kann. Dann wird der Flusswiderstand (1.8.1) geschlossen, und damit der Druckbereich des intrakranialen Drucksensors von Druck- Differenzsensor Theologisch abgekoppelt. Deshalb zeigt jetzt der Differenz- Drucksensor (1.9) sein Nullsignal an, welches auf null gesetzt werden kann, aber nicht muß. Auch der Fluss-Sensor (1.10) indiziert sein Nullsignal. Danach wird der Fluss- Widerstand (1.8.2) ebenfalls geschlossen; dabei sollte das Nullsignal des Differenz- Drucksensors (1.9) erhalten bleiben, genauso das Signal des Fluss-Sensors (1.10). Nach Öffnen des Fluss-Widerstandes (1.8.1) wirkt der Druck des Hirnventrikels auf den Differenz-Drucksensor (1.9): Dessen Anzeige ändert sich dann entsprechend. Die Ausgleichsklappe (2.5) schließt man und erzeugt nun mit der Pumpvorrichtung (2.3) im Inneren der Eichhaube einen derartigen Druck, dass der Differenz-Drucksensor 1.9 wieder das Nullsignal anzeigt. Der dazu erforderliche Druck im Hauben-Inneren der mit dem geeichten Manometer (2.2) direkt bestimmt werden kann, ist gleich dem Druck im Hirnventrikel. The calibration hood (2) is placed on the device (1) and pressed there; In the calibration hood there is initially a balance with the air pressure, which can be achieved by opening the compensation flap (2.5). Then the flow resistance (1.8.1) is closed and the pressure range of the intracranial pressure sensor is decoupled from the pressure differential sensor. Therefore the differential pressure sensor (1.9) now shows its zero signal, which can be set to zero, but does not have to. The flow sensor (1.10) also indicates its zero signal. Then the river Resistor (1.8.2) also closed; the zero signal from the differential pressure sensor (1.9) should be retained, as should the signal from the flow sensor (1.10). After opening the flow resistance (1.8.1), the pressure of the brain ventricle acts on the differential pressure sensor (1.9): Its display then changes accordingly. The compensating flap (2.5) is closed and the pump device (2.3) inside the calibration hood generates a pressure such that the differential pressure sensor 1.9 again displays the zero signal. The pressure required inside the hood, which can be determined directly with the calibrated manometer (2.2), is equal to the pressure in the brain ventricle.

Claims

Patentansprüche claims
1. Verfahren zur transkutanen Eichung eines implantierten Drucksensors, dadurch gekennzeichnet, daß man auf eine implantierte Mess- und Steuereinrichtung (1 ) mit einem ersten Flusswiderstand (1.8.1 ), einem Differenz-Drucksensor (1.9), einem zweiten Flusswiderstand (1.8.2) und einem Fluss-Sensor (1.10) eine Eichhaube (2) mit einem Manometer (2.2) und einer Pumpeinrichtung (2.3) mit im Zuleitungsschlauch (2.4) angeordneter Ausgleichsklappe (2.5) auf die Haut (5) aufsetzt, durch Öffnen der Ausgleichsklappe (2.5) in der Eichhaube (2) den1. A method for transcutaneous calibration of an implanted pressure sensor, characterized in that an implanted measuring and control device (1) with a first flow resistance (1.8.1), a differential pressure sensor (1.9), a second flow resistance (1.8.2 ) and a flow sensor (1.10) places a calibration hood (2) with a manometer (2.2) and a pump device (2.3) with a compensating flap (2.5) arranged in the supply hose (2.4) on the skin (5) by opening the compensating flap ( 2.5) in the calibration hood (2)
Außenluftdruck einstellt, den Flusswiderstand (1.8.1 ) schließt, den zweiten Fluss- Widerstand (1.8.2) ebenfalls schließt; den ersten Fluss-Widerstandes (1.8.1 ) wieder öffnet, mit der Pumpvorrichtung (2.3) im Inneren der Eichhaube (2) einen derartigen Druck erzeugt, dass der Differenz-Drucksensor (1.9) wieder das Signal vor Öffnen des ersten Fluss-Widerstandes (1.8.1) anzeigt, und den Druck in der Eichhaube (2) mit dem Manometer (2.2) bestimmt.Sets outside air pressure, the flow resistance (1.8.1) closes, the second flow resistance (1.8.2) also closes; opens the first flow resistance (1.8.1) again, with the pump device (2.3) inside the calibration hood (2) generates such a pressure that the differential pressure sensor (1.9) again the signal before opening the first flow resistance ( 1.8.1) is displayed and the pressure in the calibration hood (2) is determined using the manometer (2.2).
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß das Signal des Differenz-Drucksensors (1.9) nach Schliessen des ersten Flusswiderstandes (1.8.1 ) auf null gesetzt wird.2. The method according to claim 1, characterized in that the signal of the differential pressure sensor (1.9) after closing the first flow resistance (1.8.1) is set to zero.
3. Vorrichtung zur transkutanen Eichung eines implantierten Drucksensors, bestehend aus a) einer Mess- und Steuereinrichtung (1 ), mit deren in einer Kapsel (1.2) angeordneten inneren Rohr (1.5) ein Zufuhrschlauch (3) und ein3. Device for transcutaneous calibration of an implanted pressure sensor, consisting of a) a measuring and control device (1), with its inner tube (1.5) arranged in a capsule (1.2), a supply hose (3) and a
Abflussschlauch (4) verbunden sind, wobei am anderen Ende des Zufuhrschlauchs (3) der Drucksensor angebracht ist, und das innere Rohr (1.5) in der Flußrichtung hintereinander mit einem subkutanen Punktionssystem (1.6) mit einer Membran (1.7), einem ersten telemetrisch von außen steuerbaren Flusswiderstand (1.8.1), einem Differenz-Drain hose (4) are connected, the pressure sensor being attached to the other end of the supply hose (3), and the inner tube (1.5) one behind the other in the flow direction with a subcutaneous puncture system (1.6) with a membrane (1.7), a first telemetric of externally controllable flow resistance (1.8.1), a differential
Drucksensor (1.9), einem zweiten Flusswiderstand (1.8.2) und einem Fluss- Sensor (1.10) versehen ist, und b) einer Eichhaube (2) mit Fuß (2.1), die mit einem Manometer (2.2) sowie einer über einen Schlauch (2.4) mit Ausgleichsklappe (2.4) mit ihr verbundenen Pumpeinrichtung (2.3) versehen ist. Pressure sensor (1.9), a second flow resistance (1.8.2) and a flow sensor (1.10) is provided, and b) a calibration hood (2) with foot (2.1) with a pressure gauge (2.2) and one via a hose (2.4) is provided with a compensating flap (2.4) with its connected pump device (2.3).
4. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß die Kapsel (1.2) einen kreisförmigen Rand aufweist und der Fuß (2.1) der Eichhaube (2) ebenfalls kreisförmig mit einem dem Kapselrand entsprechenden Durchmesser ist.4. The device according to claim 3, characterized in that the capsule (1.2) has a circular edge and the foot (2.1) of the calibration hood (2) is also circular with a diameter corresponding to the capsule edge.
5. Vorrichtung nach einem der Ansprüche 3 oder 4, dadurch gekennzeichnet, daß sich der Drucksensor in einer implantierten Liquor-Drainage befindet. 5. Device according to one of claims 3 or 4, characterized in that the pressure sensor is located in an implanted CSF drainage.
PCT/EP2001/007302 2000-07-07 2001-06-26 Transcutaneous calibration of an implanted pressure sensor WO2002003859A1 (en)

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US9668663B2 (en) 2014-03-24 2017-06-06 Arkis Biosciences Implantable dual sensor bio-pressure transponder and method of calibration

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US4378809A (en) 1978-04-13 1983-04-05 Cosman Eric R Audio-telemetric pressure sensing systems and methods
DE9105742U1 (en) 1991-05-08 1991-07-04 Keller Ag Fuer Druckmesstechnik, Winterthur, Ch
DE4115134A1 (en) * 1990-05-10 1991-11-14 Nippon Mdm Kk METHOD FOR MEASURING THE INTRACRANIAL PRESSURE AND DEVICE FOR CARRYING OUT THIS METHOD

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378809A (en) 1978-04-13 1983-04-05 Cosman Eric R Audio-telemetric pressure sensing systems and methods
DE4115134A1 (en) * 1990-05-10 1991-11-14 Nippon Mdm Kk METHOD FOR MEASURING THE INTRACRANIAL PRESSURE AND DEVICE FOR CARRYING OUT THIS METHOD
DE9105742U1 (en) 1991-05-08 1991-07-04 Keller Ag Fuer Druckmesstechnik, Winterthur, Ch

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9668663B2 (en) 2014-03-24 2017-06-06 Arkis Biosciences Implantable dual sensor bio-pressure transponder and method of calibration
US10791944B2 (en) 2014-03-24 2020-10-06 Arkis Biosciences Inc. Implantable dual sensor bio-pressure transponder and method of calibration

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