BRPI0704408B1 - electrode band for electrical impedance tomography - Google Patents

Abstract

electrode strap for electrical impedance tomography. electrically impedance tomography electrode strap comprising a plurality of electrode subsets (20, 20 ') for injecting and capturing electrical signals in the patient, each subset comprising three basic elements formed from an electrically conductive lamina, namely, a contact zone (22, 52) attached to the patient's skin and accompanying its movement electrically connected by flexible conductive means (24, 53) to a terminal area (27, 54), the latter being affixed to a contact island ( 12) provided with a flexible and longitudinally undeformable support strip (10), with means of connection to each contact island for connecting the cables electrically interfacing said strap with the monitoring apparatus. the conductive elements forming said sub-assemblies use as a common base a porous, deformable insulating material, which may be a non-woven fabric or a rubber foam or porous synthetic material. Due to the deformability of the base material, the contact zones accompany the movement of the patient's skin reducing its discomfort, while the terminal areas remain in fixed and known positions coincident with the said contact islands, providing the accurate reconstitution of the skin. tomographic image. The porosity of the base material has the additional advantage of allowing the patient's skin to breathe, avoiding occlusion and accumulation of sweat.

Description

(54) Title: ELECTRODES BELT FOR ELECTRIC IMPEDANCE TOMOGRAPHY (73) Holder: TIMPEL SA CGC / CPF: 06370174000122. Address: RUA SIMÃO ALVARES, 356 - CJ 51, PINHEIROS, SP, SP, BRAZIL (BR), 05417 -020 (72) Inventor: ALBERT HOLZHACKER.

Validity Term: 10 (ten) years from 12/04/2018, subject to legal conditions

Issued on: 12/04/2018

Digitally signed by:

Liane Elizabeth Caldeira Lage

Director of Patents, Computer Programs and Topographies of Integrated Circuits

ELECTRODES BELT FOR ELECTRIC IMPEDANCE TOMOGRAPHY ”

Field of invention

The present invention refers to the provision of sets of 5 electrodes used in Electrical Impedance Tomography and, more particularly, to modular straps provided with a plurality of electrodes, which allow the application around a segment of a patient's body or even an animal.

Description of the state of the art

Electrical impedance tomography - generally known by the acronym EIT: Electrical Impedance Tomography - is a well-known technique that consists of placing a plurality of electrodes in contact with the patient's skin in a given region, and executing a sequence of steps that comprises the injection of a current between the electrodes of a pair, measuring the electrical potentials of the remaining electrodes, repeating this step for all electrodes in the set. The measured values are sent to a data processing equipment and subjected to a treatment that results in an image that shows the electrical impedance within the region of interest.

The number of electrodes used determines, within certain limits, the resolution of the image obtained, with systems using 8, 16 or 32 electrodes being more common. One of the most frequent applications of the EIT consists of monitoring the patients' rib cage, in which the electrodes are distributed so as to form a plane, normally perpendicular to the axis that defines the length of the part of the organism that is to be monitored.

When it comes to monitoring the rib cage, it is also necessary to take into account the fact that the circumference varies due to the patient's breathing and / or movement. Thus, during its use, the distance between the points of the skin that make contact with the electrodes will change, as occurs, for example, due to breathing; if these are permanently attached to an unformable carrier belt, it may become loose during expiration, compromising the integrity of the electrode contact with the skin.

A possible solution to this problem is presented in patent application US 2006/0058600, in which the electrodes are mounted on modular straps that are longitudinally coupled by means of fittings that allow to obtain sets with different quantities of electrodes. In the illustrative embodiment that instructs that order, each modular belt comprises four electrodes; thus, joining four of these straps in order to surround the patient's chest, a set with 16 electrodes is obtained. Given the fact that there are variations in the physical size of the patients, the straps described are made of plastically deformable material. This allows the attendant to lengthen the brace in order to adapt it to the patient's chest circumference. Evidently, said deformation will alter the distance between electrodes and, therefore, their positioning. According to the description of the invention, the material of each strap is substantially uniformly deformable, so that the spacing between the electrodes, although increased, could continue to be considered uniform. However, considering that several straps are necessary to surround the patient's body, it may happen that they will be stretched to varying degrees. Consequently, the spacing of the electrodes, although possibly uniform within the same modular belt, will not be so throughout the entire set of electrodes, which, certainly, will compromise the reliability of the reconstitution of the tomographic image.

In addition, the electrodes conventionally employed do not allow the skin to breathe, which can create problems during prolonged treatments. This is the case for the electrodes described in the patents

US 4,722,354 and US 4,736,752. In the first of these documents, a conductive fabric of deformable mesh is impregnated with a conductive adhesive that adheres to the patient's skin. The electrical contact is provided by a flexible multi-conductor cable, the insulation of the end of the cable being removed to allow these conductors to be separated on the surface of said fabric, forming a fan. An insulating plastic sheet is glued over this set to prevent accidental electrical contact with the conductive portions of the electrode. This system of contact between the conductor and the electrode is precarious and sensitive. In the case of US 4,736,752 the conductive portion of the electrode consists of a plurality of strokes in conductive paint applied on a flexible insulating base, such as a polyethylene sheet with a thickness of approximately 0.075mm. In both cases, said plastic sheets cause the skin to occlude, creating long-term problems.

Objectives of the invention

In view of the above, it is a first objective of the invention to provide a set of electrodes in which the distances between them are known and kept substantially constant.

Another objective is the provision of a set of 20 electrodes that do not cause occlusion of the patient's skin.

Another objective is the provision of a set of electrodes to monitor the movement of the skin due to body movements and / or breathing.

Another objective is the provision of a system in which the contact of the electrodes with the conductors is easy to perform and has high reliability.

Another objective is the provision of a set of electrodes with a low profile, so as not to cause discomfort to the patient.

Brief description of the invention

The invention comprises a plurality of electrode subsets for injection and capture of electrical signals in the patient, each subset consisting of three basic elements, namely, a contact zone fixed to the patient's skin and following its movement, electrically connected by conductive means flexible to a terminal area whose position is fixed and known. Such subsets have the double advantage of allowing a more accurate reconstitution of the tomographic image because they are located in fixed positions, without, however, causing excessive discomfort to the patient, since the mechanical coupling between the fixed terminal areas and the zones is deformable. of contact, allowing the latter to follow the movement of the skin that occurs naturally due to their body movements. As an additional advantage, the proposed arrangement allows the patient's skin to breathe, preventing its occlusion and the accumulation of sweat.

In a preferred embodiment of the invention, each electrode subset consists of a strip of textile material, flexible and non-conductive, folded over itself, resulting in a flap facing the patient and a flap facing in the opposite direction. A layer of electrically conductive material is selectively deposited on the flap facing the patient, forming a first circular or oblong zone, extending towards the fold, forming it and extending over the other flap where it forms a second zone, approximately coincident with said first zone. This first zone constitutes the zone of contact with the patient's skin while said second zone constitutes the terminal area.

Also according to the invention, the electrode strip comprises a support strip, made of insulating material, flexible and longitudinally deformable, along which, in known positions, are provided fixing islands for the said terminal areas of said electrode subsets, being associated to these islands the means of connection of the cables that interconnect said belt to the monitoring apparatus.

According to another feature of the invention, said fixing is done by removable means.

According to another feature of the invention, said removable means comprise an electrically conductive adhesive gel.

According to another characteristic of the invention, said flexible base consists of a non-conductive textile base material.

According to another feature of the invention, said textile material is porous.

Advantageously, said textile material consists of a non-woven fabric (“non-woven fabric”).

According to another characteristic of the invention, said flexible base consists of a porous and non-conductive foam.

Description of the figures

The other advantages and characteristics of the invention will become more evident through the description of preferred embodiments, given by way of example and not limitation, and the figures to which they refer, in which:

Figure 1 illustrates in a simplified way, through a perspective view, the basic elements of the invention.

Figure 2 illustrates, from a perspective view, a practical embodiment of an insulated electrode subset.

Figure 3 illustrates, by means of a plan view, an embodiment of the invention using the same strip of base material for a plurality of electrode subsets arranged in sequence.

Figure 4 illustrates, through a perspective view, the strip of base material of the previous figure after folding along its central axis and its position in relation to the material support strip

insulating and longitudinally deformable.

Figure 5 illustrates, by means of a plan view, a preferred embodiment of the invention in which cutouts are provided in the strip of base material.

Figure 6 illustrates, in perspective view, an intermediate phase in the folding of the strip of base material of the previous figure.

Figure 7 illustrates, through a perspective view, the assembled electrode belt, in accordance with the embodiment of figures 5 and

6.

Figure 8 illustrates, by means of a plan view, a more preferred embodiment of the invention, showing changes in the cutouts of the strip of base material.

Figure 9 illustrates, through a perspective view, an intermediate phase in the folding of the strip of base material of Figure 8, detailing its spatial relationship with the support strip, as well as the elements of mutual positioning.

Figure 10 illustrates, through a perspective view, the assembled electrode strip, according to the embodiment corresponding to figures 8 and 9.

Figure 11 shows a cross-sectional view of the most preferred embodiment of the electrode belt illustrated in Figure 10.

Figure 12 shows, through a sectional view, a first alternative arrangement of the electrode belt.

Figure 13 shows, through a sectional view, a second alternative arrangement of the electrode belt.

Figure 14 shows, through a sectional view, a third alternative arrangement of the electrode belt.

Figure 15 shows, through a sectional view, a fourth alternative arrangement of the electrode belt.

Detailed description of the invention

Referring now to Fig. 1, the main elements that make up the invention comprise the support strip 10 of flexible and longitudinally non-deformable insulating material, presenting an internal face 11 and an external face, not referenced in the figure. In said inner face, which is facing the patient, contact islands 12 are provided arranged in fixed positions along said face, which are of electrically conductive material and may, in a preferred embodiment, consist of metals such as copper, brass and equivalent, without, however, excluding the possibility of using other conductive materials, such as conductive polymers or equivalent. The positions of these islands are preset for each support strip, in order to allow the software of the monitoring apparatus to reconstruct the tomographic image. These positions can be informed to the operator by known means, such as labels, bar codes, etc., or even be electronically signaled to the monitoring apparatus when interrogated by the latter, as in the case of known techniques already used for identification of cartridges in inkjet printers.

In the simplified representation of Fig. 1, each contact island

12 corresponds to a subset of electrode 20, consisting of a base of flexible and insulating material 21, which serves as physical support for the conductive element hereinafter referred to as the "contact zone" that is in electrical contact with the patient's skin and for the "terminal area" ”Conductive, mechanically and electrically linked to said contact island, through which electrical signals are transmitted between the monitoring apparatus and the patient. According to the principles of the invention, the conductor that joins the terminal area to the contact area is flexible, allowing it to move in order to follow the patient's movement, the position of the terminal area remaining fixed.

Specifically, as shown in Fig. 1, on the face of the flexible and insulating material 21 facing the patient (bottom face in the figure), a layer of conductive material is applied, forming the contact zone 22 with the patient's skin, ie , the electrode itself. As illustrated, the layer of conductive material extends along the extension 25 of the base 21, which extends 180 ° towards the strip 10, folding over itself to form a section 26, substantially parallel to the contact zone 22 and whose length is approximately equal to the width of said support strip 10. The layer of conductive material forms a track 24 which, starting in said contact zone 22, extends to a widening 27, located approximately at center of section 26, also covered with conductive material, which constitutes the terminal area which, when the sub-assembly is assembled, is juxtaposed to the contact island 12, in order to provide electrical continuity with it. In the embodiment illustrated in Fig. 1, the base material extends beyond the widening 27, presenting a second curve 28 also 180 ° and joining with the base material of the contact zone 22 in order to form a closed ring of base material.

According to the principles of the invention, each electrode subset 20 corresponds to a contact island 12. The fixation of each said terminal of the subset to the respective contact island can be done by known means such as, for example, eyelets, rivet, clamp or, preferably, through a layer of conductive gel that will provide, in addition to the electrical contact, the mechanical fixation of the electrode subset to the support strip 10. Thus, the fillet 24 functions as a flexible conductor that electrically connects each contact zone 22 to the respective terminal area 27 and this to the contact island 12 in the support strip.

Fig. 2 illustrates a practical way of making the electrode subset presented ideally in the previous figure. Indeed, the coating of the base material with the conductive layer is

more easily accomplished when said base material is developed on a plane, as illustrated in Fig. 2-a. As illustrated, the strip of base material has a portion coated with conductive material, which forms the contact zone 22, the end area 27 and the flexible conductor, or fillet, 24 between them. In addition to said coated portion, said strip of base material is provided with two extensions 21a and 21b extending to its ends 29a and 29b.

Once said coating is made, the strip is folded on itself as shown in Fig. 2-b, so that said ends 29a and 29b are juxtaposed, whose ends are then joined by any known means, such as, for example , ultrasound, heat or adhesive. Thus, according to the figure, after said folding, the contact zone 22 and the terminal area 27 are approximately juxtaposed, in mutual opposition. It is noted that, due to the fact that the mechanical fixation of the electrode subset to the strip of support 10 be made only between the terminal area 27 and the contact island 12, the contact zone 22 can move freely, as indicated by the arrows in Fig. 2b, within certain limits that depend on the properties of the base material 21 (such as its deformability) and the configuration of the electrode subset 20. Such mobility allows the contact zones to follow the displacement of the skin due to the patient's breathing or movement, maintaining, however, the position reference that is given by the islands contact 12.

Figures 3 and 4 illustrate a practical industrial embodiment of the invention, in which a strip 23 of base material serves as support for a strip 30 containing at least one and, preferably, two or more electrode subsets 20 '. The length of this strip is not critical to the realization of the invention, it can be equal to the length of the support strip or a sub-multiple thereof, such as for example, half, quarter, etc.

As shown in Fig. 3, a longitudinal imaginary axis 44, centrally located, divides this band 30 into two bands, the first band 31 containing the contact zones 22 and the second band 38 containing the terminal areas 27, both formed by the application of a layer of electrically conductive material and interconnected by the loops 24, preferably formed by the same material as said zones or said end areas. Thus, each electrode subset 20 'comprises, in the described embodiment, a continuous layer of conductive material that extends perpendicularly to said axis 44, with its first end constituting the contact zone 22 located in said first band and with its second end, constituting the terminal area 27 located in said second band and whose interconnecting thread 24 crosses said imaginary axis 44.

Fig. 4 illustrates the position of the strip 30 after folding along the axis 44, resulting in the overlapping of the bands 38 and 31, facing the strip 38 on the support strip 10, while the strip 31, carrying the contact zones 22, is facing the patient (not shown). As already mentioned, the distribution of the electrode subsets along said strip coincides with the distribution of the contact islands 12 along the support strip 10, making it possible to fix said strip to said strip by juxtaposing the terminal areas of the first to the islands contact details of the second, complemented by the use of mutual retention means as detailed below.

In the embodiment of the invention corresponding to figures 3 and 4, it is observed that the mobility of the contact zones 22 is quite restricted when the patient moves. One way to increase this mobility is to introduce cutouts in the strip of base material, as shown in Fig. 5. As shown, two series of rectangular cutouts are provided extending from the outer edges of said strip towards the center, the first series of cutouts 36 configuring the flaps 34 that contain the contact zones 22 and the second cutouts 37 defining the flaps 35 that contain the terminal areas 27. To increase the mobility of the set, the cutouts 33 along the axis are also provided central imaginary 44.

Fig. 6 illustrates the folding of the support strip shown in the previous figure, observing that the strips of material in the central area work as a “hinge” around which the two bands that constitute, in the directions indicated by the arrows, rotate said support strip. As indicated, when carrying out such folding, surfaces coated with conductive material are exposed. At the end of this operation, the internal faces of said bands will be juxtaposed, as well as the tabs 29a and 29b located on the outer edges of said bands, which are joined by means of ultrasound, heat, adhesive or other known process.

Fig. 7 shows the strap when the assembly is completed by fixing said terminal areas 27 to the contact islands 12 on the support strip 10. In the illustrated embodiment, the contact islands are connected by means of conductive tracks 39, embedded in the support strip, to a connector 42, of known type, which has means of contact with the wiring that interconnects said strap to the monitoring apparatus.

The arrangement illustrated in Fig. 8 provides greater mobility for the flaps that carry the contact zones 22 while facilitating the separation of the strip 30 from the support strip, which results from the fact that the strip 38 is continuous in the region containing the terminal areas 27. In addition to configuring the flaps 34, the cutouts 36 extend beyond the central line 44 in order to configure most of the joining strips on which the conductive threads 24 are applied, which gives even greater mobility to the said flaps . As shown in the figure, these flaps may be interconnected by means of narrow strips 26 of non-extensible material that extend between the lateral edges of said flaps. Strips 26 are extended when the strap is / 4

L12 applied to the patient on inspiration, a condition in which the thoracic perimeter is maximum. When this perimeter is reduced during expiration, said strips flex, allowing the mutual contact zones that are attached to the patient's skin to be approached.

Since the electrode belt consists of the union of the support strip 10 and the strip 30 containing the electrode subsets, means can be used to facilitate the relative positioning of these two parts, in order to ensure an adequate correspondence between the areas terminals and contact islands. Such positioning means may consist of complementary elements in high / low relief in the referred parts to be joined. An example of these elements is illustrated in figure 9, consisting of cylindrical protuberances 45 affixed to the surface of the band 38 that fit with little clearance in holes provided in the support strip 10. Other positioning arrangements can be used, therefore the invention is not limited to the elements illustrated by way of example.

Fig. 9 shows an optional feature that can be used to reduce the deformation of the strip 30 during its assembly and disassembly on the support strip 10. It is a strip of little deformable material 47 glued to the inner face of the strip 38. When pull the strip 30 to separate it from the support strip, this material 47 absorbs the effort and facilitates the detachment of the terminal areas of the contact islands.

As appropriate, it should be noted that the occlusion of the skin can be minimized using a porous base material, thus allowing the skin to breathe. In any of the described embodiments, the entire strip 30 can be made from a strip of porous material 35, preferably using a non-woven fabric for this purpose. In another embodiment of the invention, said strip may consist of a foam sheet permeable to water vapor, a material known and used in several applications, such as

such as shoe soles and insoles. Thus, the moisture of the skin in the region of application of the belt moves through the screen or porous lamina and from there to the atmosphere, through the holes 49, optionally provided in the support strip U as illustrated in figures 6 and 7.

Furthermore, the surface of the contact zones 22 is coated with conductive gel, which, in addition to providing a better transmission of electrical signals, allows its attachment to the skin, which are protected by an impermeable sheet that will be removed when applied to the patient. .

Similarly, a conductive gel can be used to affix 10 of the terminal areas 27 to the contact islands 12. In Fig. 11, which is a cross-sectional view of the electrode belt illustrated through figures 8, 9 and 10, the said fixation is provided by the conductive gel layer 13, which, furthermore, forms a low resistance path between the contact island 12 and the conductive layer 27 of the terminal area. Still in this figure, it is possible to observe the layer of conductive gel 14 applied over the region 22 that constitutes the zone of contact with the patient's skin. This preferred form of the invention has the advantage of not having protrusions or projections that could cause discomfort to the patient when a portion of the electrode belt is interposed between the patient's body and the mattress.

In alternative embodiments of the invention, the attachment of the terminal areas to the contact islands can be achieved by other known means, such as rivets, eyelets, loops or the like. The fixation by means of clips is illustrated in the sectional view of Fig. 12, observing that, in this example, external contact means - clip - 41, preferably of conductive metal, are provided, which allow the fitting of a spring connector provided in the end of the cable that conducts signals between the electrode and the monitoring unit. In an alternative form of this fitting, the cable connector can be provided with a permanent magnet in the shape of a washer, dispensing with the bulging at the end of the pin of said clip, which, for this purpose, must be constituted, at least in part, of ferromagnetic material like steel. In the arrangement shown in this figure, a layer of conductive material 27 'can be provided on the inner face of the band 38 in the region opposite the terminal area 27, said layer being juxtaposed to the inner disk 41a of said clip, thereby improving the electrical contact between these elements . Furthermore, the upper washer 41b that locks this clip may be a removable elastic washer or equivalent, which, when removed, will allow to separate the strip containing the electrodes of the support strip 10.

In order to better illustrate the structure of the electrode subset 10 object of the present invention, the thicknesses of the various elements shown in the sectional representations of figures 11 and 12 are considerably increased.

As previously mentioned, in a preferred embodiment of the invention, strip 30 consists of a porous non-woven fabric and the conductive material is a conductive paint applied to this fabric. Advantageously, the electrodes produced as described have a low cost, allowing their disposal after use in a patient. This avoids the cost of sterilizing the electrodes, since they are replaced with each new use of the equipment.

In order to preserve the properties of the conductive gel, especially avoiding its drying out, it is customary to store the straps with contact zones 23 and terminal areas 27 protected by one or more impermeable sheets, based on materials such as silicone or teflon, these blades being removed when using the strap.

Figures 13 and 14 illustrate alternative versions of the invention, in which a pad 41 is interposed between bands 31 and 38 of the base material band. This pillow, made of elastic and soft material, preferably porous and therefore permeable to the passage of water or gases, such as air or water vapor, allows the electrodes to be accommodated to irregularities on the patient's body surface, as occurs , for example, in the central depression in the back along the spine · Said cushion may consist of a single piece, with the approximate length of strip 30 or may comprise a plurality of pieces individually positioned in coincidence with some or all of said sets electrode.

In the embodiment of the invention illustrated in Fig. 14, said pads are additionally used as means for positioning and fixing the electrodes. In this arrangement, the pad 41 'has its upper face affixed, by means of adhesive 43, to the inner face of the band 38, the lower face of the same pad having an adhesive layer 43', in order to retain the inner face of the band. 31 which contains the contact zones 22 ”on its external face. In this case, it is not necessary to extend the distal ends of the bands 31 and 38 without also releasing the tabs 29a and 29b.

In addition, this arrangement makes it possible to use, instead of strip 30 containing a plurality of electrode sets, the individual sets similar to those illustrated in figure 2-b, in which case extensions 21a and 21b are dispensed with.

A particularly advantageous variant of the constructive arrangement shown in Fig. 14 consists of the arrangement 50, shown in Fig. 15, which allows the use of the strip of base material to be dispensed with. As illustrated, the pad 51 itself is coated with the conductive material configured according to the shape of the electrode, constituting the contact zone 52, the terminal area 54 and the interconnection thread 53. This coating can be done by applying a layer of conductive material, for example, by screen printing - or, more advantageously, using a metallized adhesive label with the appropriate shape. The connection between the set of electrodes and the support strip 10 is made using a layer of gel 13, as already exposed together with figures 13 or 14.

Although the invention has been described on the basis of some preferred embodiments, it is understood that modifications can be made, remaining within the spirit and scope of the inventive idea.

Thus, for example, at the junction between the distal edges of bands 31 and 38, means other than tabs 29a and 29b, such as, for example, clamps, brackets, clips or the like, may be used. Furthermore, the use of metallized adhesive labels to provide the conductive elements (22-24-27 and 52-53-54) can be extended to the embodiments that use a nonwoven and porous fabric (“nonwoven fabric”) as a base.

Accordingly, the invention is defined and delimited by the following set of claims.

Claims (4)

1. Electrode belt for electrical impedance tomography, comprising a support strip (10) formed of flexible and longitudinally non-deformable material, equipped with contact islands (12) in positions 5 fixed and known, with a corresponding electrode subset (20, 20 ', 50) attached to each contact island that makes contact with the patient's skin, characterized by the fact that each electrode subset comprises a conductive zone of contact (22, 52) with the patient's skin, linked by a deformable material to a terminal conductive area (27, 10 54), to which it is electrically connected by means of a flexible conductor (24, 53), said contact zone being facing the patient and oriented approximately in opposition to said terminal area (27, 54) facing the support strip (10), to whose fixed contact islands (12) is linked by mechanical retention means and electrical contact. 2. Electrode strap according to claim 1, characterized by the fact that said deformable material serves as a mechanical support for the conductive materials that constitute the said contact zone and the said terminal area. 3. Electrode strap according to claim 1 or 2, 20 characterized by the fact that it consists of at least a subset of electrode (50) comprising a contact zone (52), facing the patient's skin, formed by a sheet of conductive material applied directly on a first face of a cushion (51 ) of elastic, soft material and a terminal area (54), facing the contact islands (12) of the 25 support (10), consisting of a sheet of conductive material applied directly on a second face of said cushion, interconnected by a flexible sheet (53). 4. Electrode strap according to claim 1 or 2, characterized in that each said electrode subset comprises a base sheet in deformable and non-conductive material (21, 23) having applied at least on one of its faces a conductive material layer configured to form a contact zone (22) located on a first portion of said base blade, said contact zone being 5 interconnected by means of a flexible conductor (24) to a terminal area (27) located in a second portion of said base sheet, said first and second portions being superimposed by providing a fold of said base sheet in an intermediate position between said contact zone and said terminal area in order to leave them exposed and in mutual opposition. Electrode strap according to claim 1, 2, 3 or 4, characterized by the fact that said mechanical retention means are detachable. 6. Electrode strap according to claim 5, characterized in that said retention means are provided by a gel 15 conductor. 7. Electrode belt according to claims 1, 2, 3 or 4, characterized by the fact that a layer of conductive gel is applied to said contact zone (22, 52). 8. Electrode strap according to claim 4, 20 characterized in that said base blade (21, 23) consists of a non-woven and non-conductive mesh. 9. Electrode strap according to claim 4, characterized in that said base sheet (21,23) consists of a non-conductive foam sheet. 10. Electrode strap according to claim 4, 8 or 9, characterized by the fact that said base sheet (21, 23) is porous. 11. Electrode strap according to claims 1, 2, 4, 5, 6, 7, 8, 9 or 10, characterized by the fact that it comprises a plurality of electrode subsets (20 '), each subset comprising a contact zone (22), a terminal area (27) and a fillet (24 ) of interconnection between both, said electrode subsets being formed by sheets of conductive material applied along the same strip of base material, which comprises a first (31) and a second (38) bands 5 contiguous longitudinals with substantially equal widths, said bands being superimposed by folding said bands on themselves along the boundary line (44) between them, the direction of said folding leaving exposed the sheets of conductive material that constitute said sets of electrode. 12. Electrode strap according to claim 11, characterized by the fact that said contact zones (22) are contained in tabs (34) that extend in a substantially perpendicular direction to said imaginary axis (44), said tabs being delimited by cutouts (36, 37) made in the base material range (30). 13. Electrode strap according to claim 12, characterized in that narrow strips of deformable material (26) are provided interconnecting said adjacent flaps (34) containing said contact zones (22). 14. Electrode strap according to claim 11, 20 characterized by the fact that reciprocal mechanical positioning means (45, 46) are provided between said second band (38) and said support strip (10). 15. Electrode strap according to claim 14, characterized by the fact that said means of positioning consist of relief elements, of complementary shapes (45, 46), located in said 25 second band (38) and said support strip (10). 16. Electrode strap according to claims 4 or 11, 12, 13, 14 or 15, characterized by the fact that a pad (41) of elastic and soft material is interposed between the inner face of said second band (38) which it contains the terminal areas on its external face and the internal face of said first band (31) which contains on its external face the contact zones. 17. Electrode strap according to claim 16, characterized in that said pad (41) is permeable to the passage of water and gases. 18. Electrode strap according to claim 17, characterized in that said pad comprises one or more pieces individually positioned in coincidence with one or more electrode sets. 19. Electrode strap according to claims 1 to 18, characterized in that said subsets of sheets of conductive material (22-24-27, 52-53-54) are conductive labels. 20. Electrode strap according to any one of the preceding claims, characterized by the fact that each said contact island (12) is associated with means of electrical connection with the monitoring apparatus and its position is informed to the operator through labels, codes bars, electronic signals or equivalent means. 1/6 2/(, F / g.5 3/6 4/6 29th