the present invention relates to a method for placement of certain medical devices , and in particular , to the placement of electrodes in the field biopotential monitoring . more particularly , it provides a new method for marking the skin of a subject where medical electrodes are to be placed including the placement of an electrode harness containing these electrodes . these medical devices include but are not limited to ecg , eeg , emg , electrodes and the like . the method of the present invention comprises a number of steps and the various embodiments encompass variations of those steps . in the present invention , preferably some person locates an area on a subject on which to place an electrode , multiple electrodes , an electrode array or some combination thereof . the subject to be monitored can be any animal but preferably is a human . generally , the area is determined by means known to those skilled in the art . some factors affecting location selection include the end - use application or testing method which will preferably determine not only the intended anatomical location where the electrodes will be placed , but also the number and placement on the body of the subject . for example , cardiac electrophysiology protocols ( ecgs ) may simply require two electrodes for a low - resolution projection of cardiac electrical activity on the body surface . on the other hand , high - resolution studies may make use of more than 224 electrodes simultaneously . each electrode placement configuration will have optimal anatomical location on the surface of the body for the most accurate readings , and the interelectrode distance will vary according to the number of electrodes used . there are a number of different types of electrodes available today . the major types of existing electrodes include the wet surface electrodes , dry surface electrodes , invasive electrodes , and the like . the wet surface electrodes are the most commonly used electrodes today . these electrodes require a wet electrolyte gel or conductive hydrogel solution to enhance signal performance . the most commonly materials used for these electrodes include solid silver , gold , sintered silver and silver chloride , carbon , and sponge saturated with conductive gel or also called pre - gelled electrodes . the dry electrodes on the other hand do not make use of conductive gel and include non - polarizable dry electrodes ( e . g . nasicon - type ceramic ); active dry electrodes with built - in amplifiers , capacitively coupled electrodes coated with dielectric substances , micropenetrators or spiked based dry electrodes , etc . the invasive electrodes include the needle type electrodes designed to fully penetrate the skin of the subject to form a direct interface with bodily fluids . preferably the wet surface electrodes and the dry surface electrodes are used in the method of the present invention . electrode arrays are flexible and conformable substrates which allow many individual electrodes to be placed together as a single assembly , while conforming to the shape of the anatomical geometry under the electrodes ( e . g . chest , scalp , back , legs , etc ). electrode arrays are convenient devices that allow fast and accurate placement of multiple electrodes for multi - array recordings . electrode arrays may contain built - on or preassembled electrodes , or appropriate connections for the attachment of electrodes . in addition , the electrode arrays may contain built - on circuitry and connection pads that independently connect the electrodes to a single and non - intrusive cable that connects to the signal receiver equipment . a reference point system may be included on the arrays to facilitate the identification of the appropriate anatomical regions to enhance the accurate placement of all electrodes . overall the electrode arrays provide the opportunity for enhanced patient comfort and may reduce the risk of cross contamination as a result of minimizing or eliminating the potential for the overlapping of two or more electrodes and / or for signal interference as a result of two or more wires contacting each other . in addition it facilitates patient mobility and ambulation by minimizing or eliminating the number of cables required for connecting all electrodes to monitoring equipment . the electrodes and / or electrode arrays used in the present invention preferably also have distinct reference points , areas or locations that are used in the placement , respectively of the electrodes and / or arrays based on markings placed on and / or anatomical features of the subject . these reference points , areas or locations could include various markings on either the electrode or electrode array , voids or cutouts , and the like . one embodiment would be to line up these reference points , areas or locations on the electrode and / or electrode array with the marking ( s ) and / or anatomical features on the subject . another step used in various embodiments of the present invention includes applying a marking under or over the subject &# 39 ; s outer layer of skin . this marking can be any marking to those skilled in the art . the marking can include but is not limited to a tattoo both permanent and henna tattoos / semi - permanent tattoos ( including but not limited to various types of tattoo inks ), other types of permanent and semi - permanent inks , small marks with adhesive backing that can be placed on the subject &# 39 ; s skin , small objects placed below the skin , a burn or branding , and the like . preferably , the marking is either small or can be removed so when the subject is finished with the monitoring program there is little or no visibility of the markings . one preferred embodiment of the marking is a tattoo created with inks that are of a color so that they are not very noticeable under normal lighting conditions of a subject &# 39 ; s skin , but can be seen distinctly under another type of light such as a “ black light ”. more preferably , these markings match or nearly match the color of the subject &# 39 ; s skin . another preferred embodiment of the marking is a small plastic disk with a permanent adhesive backing , which can be positioned as a marking on a subject , and can be removed with an appropriate solvent when the monitoring period is over . still another preferred embodiment of the marking is a semi - permanent tattoo or inks that wear off after a given period of time , preferably several months . for purposes of this application , by semi - permanent it is meant that the marking will remain visible under the appropriate conditions on the subject over a reasonable period of time even after the subject washes or bathes . this reasonable period of time is preferably at least 2 days , more preferably is at least 7 days , even more preferably is at least 2 weeks , still even more preferably at least 1 month , still even more preferably is at least 3 months and most preferably is at least 6 months . preferably , also the marking can fade or disappear , can be removed or covered in some fashion after the monitoring period is over [ dk2 ] . preferably , the marking is large enough to be seen by the person including the subject applying the electrodes but is small enough not to be highly visible to other individuals . preferably , each marking has a surface area of between 0 . 001 and 2000 mm 2 , more preferably between 0 . 01 and 500 mm 2 , even more preferably between 0 . 25 and 100 mm 2 , still even more preferably between 0 . 25 and 50 m m2 , and most preferably between 0 . 25 and 5 mm 2 . the system of marking can be used for the present invention to place individual electrodes or to place a harness with multiple electrodes . an individual marking can be used by itself or with some other anatomical feature of the subject to place the one or more electrodes or the harness containing the electrodes . one example is a marker could be used along with the sternum ( or breast bone ) of the subject to place an electrode harness . multiple markings allow for an even more accurate placement of the electrode ( s ) or electrode harness . preferably , at least 2 markings are used for placement of electrodes or an electrode harness , more preferably at least 4 markings are used , even more preferably at least 6 markings are used , still even more preferably at least 8 markings are used , still even more preferably at least 10 markings are used and most preferably at least 12 markings are used [ dk3 ] . another step used in various embodiments of the present invention involves applying an electrode ( s ) ( or the electrode harness containing an electrode ) to the subject &# 39 ; s outer layer of skin in reference to the marking . this can be done by the subject , a friend , a family member , a home healthcare provider or a medical professional . the markings , however , make it simpler for an unskilled individual to accurately apply the monitoring electrode ( s ) or electrode harness . the markings also make it quicker for a healthcare provider or medical professional to make the application . fig1 - 3 demonstrate the use of this marking system on a human subject . fig1 is a schematic diagram showing one embodiment of the step of marking a subject under the method of the present invention . in fig1 the subject 2 is 25 marked under or over the subject &# 39 ; s outer layer of skin 6 using a device to create a permanent or semi - permanent mark . in this particular embodiment , the subject 2 actually has five marks 4 , 5 , 7 , 8 and 9 , which are placed on the subject &# 39 ; s thorax . fig2 is a schematic diagram showing an electrode array 12 with reference marks for alignment on the subject 2 shown in fig1 . in the particular embodiment of the electrode array 12 in fig2 , the electrode array 12 contains five reference marks 14 to be aligned with the permanent or semi - permanent marks 4 , 5 , 7 , 8 and 9 shown in fig1 under or over the subject &# 39 ; s 2 outer layer of skin 6 . the electrode array 12 , in this embodiment , further includes a connector 18 for connecting the electrode array to a processing or monitoring device ( not shown ), and flexible arms 16 to allow for positioning of the array 12 . the call - out 20 shows both a planar and a side view of one of the electrodes and corresponding reference mark of the electrode array 12 . fig3 is a schematic diagram showing the electrode array 12 in fig2 aligned to the markings 4 , 5 , 7 , 8 , and 9 on the subject 2 shown in fig1 . it will be noted that the electrode array in fig3 is aligned to the markings by being placed so as to cover ( or be aligned over ), to overlap or to touch the markings . in addition , in this embodiment the connector 18 for the electrode array 12 connects the electrode array 12 with a wireless monitoring and / or transmission device 32 for relaying the biopotential signal picked up from the subject 2 . it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention . thus , it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents .
the currently claimed invention is for a method of placement of certain medical devices , and in particular , to the placement of electrodes in the field biopotential or electrophysiological monitoring . more particularly , it provides a new method for marking the skin of a subject where medical electrodes are to be placed including the placement of an electrode harness containing these electrodes . the method for accurate placement of electrodes of the currently claimed invention provides a quick , efficient method of electrode placement and replacement . this method further allows homecare providers or even the patient themself to accurately place and replace electrodes for home health care or outpatient monitoring .