Electrode array adapted to a measuring transducer.

p0001The invention relates to an electrode arrangement for measuring sensor for combined measurement of various physiological variables with a measuring head for receiving a first physiological quantity and means for measuring a second physiological variable, which measuring electrode located in a first, on a side facing the measuring head side of an annular body and a second, the measuring head facing away from the counter electrode made.

p0002Such an electrode arrangement for a transducer is known from EP-A 0,077,054th In this transducer, a further electrode arrangement is provided on a Meßkopfkörper next to the electrode arrangement for receiving a first physiological measurement variable, having a first electrode on the contact surface of the facing side of the Meßkopfkörpers and a second electrode on the back of Meßkopfkörpers. With such a transducer, a second physiological size, such as the heart action voltage (ECG) be measured, for example, over the first electrode assembly of transcutaneous partial pressure of oxygen and the other electrode assembly. Here, the first electrode serves on the contact surface side facing the Meßkopfkörpers as measuring electrode and the second electrode on the back of Meßkopfkörpers as a counter electrode.

p0003In the known electrode assembly, the adhesive is applied to the dedicated contact surface of the Meßkopfkörpers, wherein the Meßlektrode is surrounded by this adhesive agent. Such adhesive bonding is to establish the electrical insulation of the sensing electrode relative to the counter electrode. However, only a small area of ​​the entire outer surface for the adhesive bond is available, so that their shelf life is limited. This is further reduced by that in the adhesive layer in, for example, can penetrate body fluids from the outside and so reduce the adhesiveness of the adhesive layer.

p0004In the arrangement of adhesive surfaces alongside the to be connected with the skin electrode faces two apparently contradictory requirements have to be met: the surfaces of the electrodes should be as large as possible on the one hand, so that they have a very low impedance towards the body and are thus immune to interference, and also to the bonding surfaces of the transducer as large as possible, so that they in their practical application also under greater shear and tension loads can not move away from the contact surface; secondly, the total area of ​​the adhesive surface and electrode surface should be as small as possible, so that the sensors can be attached also to small-area body parts of people, even from the baby's head Unqeborenen. Generally, electrodes for recording physiological parameters with an ion-conducting gel for contact are provided with the skin. However, its adhesive force is insufficient for larger loads, so that the use at the comparatively bulky and heavy transducers for transcutaneous oxygen measurement ensures no reliable prison conditions on the contact surface with the occurring in practice, difficult conditions.

p0005The adhesive force is further reduced when a measuring sensor suitable for measuring physiological variables, as a recess for the correspondingly necessary electrode assemblies in the bonding surface is necessary.

p0006The object of the present invention is therefore seen to train the contact adhesive surface of a transducer for the combined measurement of multiple physiological parameters so and to find an appropriate fastening to the skin that the electrode for receiving the second physiological variable and the adhesive surface for Besfestigung the transducer mutually not interfere and have a tolerable in practice overall size.

p0007This object is achieved in that the annular body with the skin can be connected on its side facing the measuring head facing side by an adhesive surface having a to an outer, consisting of electrically insulating material edge piece reaching doping zone which is electrolytically or electrically conductive, through which the measuring electrode is in electrical contact with the skin.

p0008In forming the adhesive layer according to the invention it is ensured that the electrode for measuring a bioelectrical size, as separated, for example of the electrocardiogram from its counter electrode by an insulating region of the adhesive surface, so that neither body fluids under in the application of the transducer in the fetus might arise birth in the form of amniotic fluid, or other zoom passing externally liquids neither a short circuit between the measuring and counter-electrode can still cause a reduction in the potential difference between two electrodes. The large-area gluing the transducer ensures reliable mounting even under increased tensile and shear forces along the adhesive surface. The area of ​​the adhesive surface of electrically insulating material increases advantageously the electrical insulation of conducting doping zone from its surroundings.

p0009The electrode assembly according to the invention can expediently be designed such that the annular body has a central recess with a threaded inlet which serves for its fastening to the known transducers for the transcutaneous measurement of oxygen.

p0010In a further advantageous embodiment of the invention, to arrange the counter electrode on the back of the ring body. This makes it possible, the ring body with its sensing and counter electrode in case of need merely for measuring a physiological quantity, such as the cardiac action voltage to use. For this purpose, the measuring head for the transcutaneous measurement by an appropriate dummy plug is replaced.

p0011Based on the figure given in the drawing, an embodiment of the invention is explained in more detail.

p0012The transducer depicted shows a measuring head 1 for measuring a first physiological quantity, for example of the transcutaneous oxygen partial pressure. Him surrounds an annular body 2, which in its central recess receiving the measuring head 1 with a threaded portion 11th On the ring body 2 is an electrode arrangement for measuring a second physiological quantity, such as the cardiac action tension mounted. This contains a measuring electrode 4, which is recessed in an annular recess of the annular body second In the measuring electrode 4 opposite side of the annular body 2, a counter electrode 3 is attached. Both electrodes 3, 4 are connected via connection lines to an evaluation unit 9 is not shown. The annular body 2 with the measuring head 1 contained therein is mounted on an adhesive surface 10 to the skin 7 for receiving the measured variables. The adhesive surface 10 is bounded by an adhesive, electrically insulating edge piece. 5 Between edge piece 5 and measuring head 1 to a doping zone 6 connects containing a known electrolytic or electrically conductive adhesive; this provides the electrical_Vachieved connection between skin and measuring electrode 7 4 forth.