U.S. patent number 3,677,268 [Application Number 04/880,767] was granted by the patent office on 1972-07-18 for iontophoresis electrode.
This patent grant is currently assigned to Sherwood Medical Industries Inc.. Invention is credited to Richard A. Reeves.
United States Patent |
3,677,268 |
Reeves |
July 18, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
IONTOPHORESIS ELECTRODE
Abstract
A self-contained iontophoresis electrode, disposable after use
on a patient, is prefilled with an inducing iontophoresis liquid
completely contained within a chamber covered by a filter cover. A
protective cover, impenetrable to liquids and to light energy,
seals the filter cover and is removable when the electrode is to be
used.
Inventors: |
Reeves; Richard A. (Creve
Coeur, MO) |
Assignee: |
Sherwood Medical Industries
Inc. (N/A)
|
Family
ID: |
25377028 |
Appl.
No.: |
04/880,767 |
Filed: |
November 28, 1969 |
Current U.S.
Class: |
604/20;
607/153 |
Current CPC
Class: |
A61N
1/044 (20130101); A61B 5/4266 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); A61N 1/30 (20060101); A61N
1/04 (20060101); A61n 003/06 () |
Field of
Search: |
;128/172.1,405,406,411,417,418,2.6E,2.1E,DIG.4,404,416 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Assistant Examiner: Dunne; G. F.
Claims
I claim:
1. A prefilled, disposable iontophoresis electrode, comprising:
housing means including a hollow neck portion and a partial chamber
portion spaced radially surrounding said hollow neck portion;
electrically conductive means extending through said hollow neck
portion and into the partial chamber portion to allow external
electrical connection to the partial chamber portion, said partial
chamber portion and said conductive means forming a fluid
impenetrable chamber with a fluid opening being the sole fluid
passageway for said chamber;
first cover means completely enclosing said fluid impenetrable
chamber along said fluid opening to completely contain therein an
iontophoresis fluid for inducing iontophoresis on the skin of a
patient, said first cover means being absorbent to said
iontophoresis fluid to allow iontophoresis when said first cover
means is placed against the skin of the patient and electrical
connection is made to said electrically conductive means; and
second cover means impenetrable by said iontophoresis fluid for
sealing said first cover means, including means attaching said
second cover means to said housing for removal therefrom without
disrupting said first cover means.
2. The electrode of claim 1 wherein said fluid is light sensitive,
said second cover means comprising a material for preventing
penetration of light energy therethrough.
3. The electrode of claim 1 wherein said second cover means
comprises a material containing metal, said second cover means
being welded to said housing around its periphery.
4. The iontophoresis electrode of claim 3 wherein said housing
means includes a shoulder located on a different plane than the
plane of the periphery to which said second cover means is welded,
said first cover means being formed by filter paper of a thickness
substantially corresponding to the distance between the plane of
said shoulder and the plane of said periphery, said filter paper
being seated against said shoulder, whereby the engagement of the
filter paper with the shoulder is not disrupted when the weld of
said second cover means to the housing means is broken.
5. The self-contained electrode of claim 9 in which said
electrically insulated housing means includes an integral hollow
neck portion contiguous with and spaced from the chamber portion
defined by the housing means, the conductive neck of said
electrically conductive means being contained within said hollow
neck portion in liquid-tight sealing engagement therewith and
extending into contact with the chamber.
6. The self-contained electrode of claim 5 wherein the conductive
neck of said electrically conductive means has a hollow center
defining a receptacle for an electrical plug, the electrical plug
being inserted within said receptacle to allow external electrical
connection to the fluid, and the electrical plug being removable
from the receptacle in order to allow the electrode to be discarded
after use on a subject.
7. The self-contained electrode of claim 6 wherein said
electrically conductive means is formed of an electrically
conductive plastic material.
8. The iontophoresis electrode of claim 1 wherein said second cover
means includes a tab extending beyond the periphery of said
housing, whereby said tab may be lifted to break the attaching
means holding said second cover means to said housing.
Description
This invention relates to a self-contained iontophoresis electrode,
and more particularly to a iontophoresis electrode which is
prefilled with liquid and is disposable after use on a patient.
Iontophoresis is a medical technique for introducing drugs through
intact skin. In the detection of cystic fibrosis in children, it is
known that the great majority of children suffering with cystic
fibrosis have an abnormally high concentration of sodium chloride
in their sweat. An effective means of detecting such disease is to
collect sweat produced by pilocarpine iontophoresis, and analyze
the sweat for chloride ion concentration by using various standard
methods including conductivity of the sweat sample.
Localized sweating may be induced by using iontophoresis
electrodes. Such electrodes typically include a recessed area
covered by filter paper held by a retaining ring. An opening
through the housing of the electrode allows a technician to fill
the recessed area with liquids which induce iontophoresis. For
example, the technician may fill one electrode with 0.5 percent
solution of pilocarpine nitrate, and the second electrode with 1
percent solution of sodium nitrate. These electrodes are strapped
in contact with a patient's skin, conveniently to an arm or leg,
and electrical conductors are connected to the electrodes,
connecting the pilocarpine nitrate electrode to positive DC voltage
and the sodium nitrate electrode to negative DC voltage. After a
short time period, the electrodes are removed from the patient's
skin. The skin area into which pilocarpine has been induced will
now produce localized sweating, allowing the sweat to be collected
in order to be analyzed by standard methods.
After removing the electrodes from the patient, the technician must
disassemble the electrodes, discard the filter covers, and may
clean the electrodes. When another patient is to be tested, new
filter covers must be placed on the electrodes, and the electrodes
must be again filled with the proper solutions. This procedure is
both time consuming and subject to contamination and error, such as
filling of the electrodes with the wrong solutions.
In accordance with the present invention, an improved iontophoresis
electrode is provided which is completely self-contained, i.e., is
prefilled with the liquids which induce iontophoresis. To use, the
technician merely tears off a protective cover and straps the
electrode to the patient. The electrode includes improved structure
for effectuating pilocarpine utilizing iontophoresis. After use,
the electrode is discarded, resulting in substantial savings in the
technician's time and elimination of the problems of
contamination.
One object of this invention is the provision of a self-contained
iontophoresis electrode which includes all component parts and
liquids for effectuating iontophoresis when connected to an
external voltage source.
One feature of this invention is the provision of a self-contained
iontophoresis electrode which is prefilled with a liquid for
inducing iontophoresis, and includes a liquid penetrable cover for
applying the liquid to the skin of a patient and a protective cover
impenetrable by the liquid for sealing the electrode until use.
Another feature of this invention is the provision of a
self-contained iontophoresis electrode having a completely enclosed
chamber defined by a housing and a penetrable cover. The housing
includes an electrically conductive element, surrounded by
electrically insulated material, for connecting the liquid to an
external DC voltage source.
Yet another feature of this invention is the provision of a
disposable iontophoresis electrode which is prefilled with nitrate
solution. The electrode includes a detachable protective cover
impenetrable to liquids and impenetrable to light energy.
Further features and advantages of the invention will be apparent
from the following description and from the drawings, in which:
FIG. 1 is a perspective view of a pair of iontophoresis electrodes
strapped to the arm of a patient;
FIG. 2 is an exploded view of one of the iontophoresis electrodes
of FIG. 1; and
FIG. 3 is a cross-sectional view of the iontophoresis electrode of
FIG. 2, with the electrical connector being shown by a plane
view.
While an illustrative embodiment of the invention is shown in the
drawings and will be described in detail herein, the invention is
susceptible of embodiment in many different forms and it should be
understood that the present disclosure is to be considered as an
exemplification of the principles of the invention and is not
intended to limit the invention to the embodiment illustrated. The
scope of the invention will be pointed out in the appended
claims.
Turning to FIG. 1, a pair of iontophoresis electrodes 10 in
accordance with the present invention are held in place on a
patient's arm by a perforated rubber strap 12, having perforations
14 of a size sufficient to allow insertion therethrough of a neck
portion 16 of the electrodes 10. Although the electrodes are
illustrated as being strapped to the patient's arm, it will be
understood that they can just as easily be attached to another
portion of the patient's body, as for example, to a leg. As will
appear, a protective cover has already been removed from the
prefilled electrodes. After the electrodes are strapped to opposite
sides of the patient's arm, connection is made to a source of DC
voltage (not illustrated) by means of electrical conductors 18
which terminate in male plugs 20 insertable into an electrical
receptacle within each neck 16.
The electrode 10 illustrated in full view in the foreground is
filled with 0.5 percent solution of pilocarpine nitrate, and is
placed conveniently against the flexon portion of the patient's
forearm. This electrode is connected by plug 20 and its associated
conductor 18 to positive DC voltage. The other electrode, shown
partly in dashed lines, is filled with a 1 percent solution of
sodium nitrate, and is placed on the opposite side of the patient's
arm. It is connected by its plug 20 and associated conductor 18 to
negative DC voltage. The DC voltage may be provided from any
suitable source. By way of example, the DC voltage source may take
the form shown in a copending application of Donald A. Ninke and
James F. La Hay, entitled "Iontophoresis and Conductivity Analysis
Circuit" filed on even date herewith, Ser. No. 880,807 and assigned
to the assignee of the present application.
After about 5 minutes of iontophoresis, the plugs 20 may be removed
from electrodes 10 and the strap and electrodes removed from the
patient's arm. The electrodes 10 are now discarded, eliminating
problems of contamination and cleaning. When using the
iontophoresis technique for the detection of cystic fibrosis, the
forearm of the patient is then washed with distilled water and
wiped dry, after which a sweat collecting cup is placed over the
forearm where the electrode 10 containing pilocarpine nitrate was
located.
After about a 25 minute time period, the sweat collecting cup is
removed and the contents analyzed for sodium chloride, in order to
detect by known methods for the presence of cystic fibrosis in a
patient. By way of example, the sweat collecting cup may include an
electrode for direct connection with a cystic fibrosis analyzer.
Such a combination cup and electrode is shown in the copending
application of James F. La Hay, entitled "Collection and Measuring
Electrode", filed on even date herewith, Ser. No. 880,810 and
assigned to the assignee of the present application. The ion
content of the sweat may then be analyzed by the previously
identified circuit of Ninke and La Hay.
The pair of electrodes 10 are identical except for the solution
with which each is filled. The structure of each electrode 10 is
illustrated in detail in FIG. 2 and 3. A thin walled, electrically
insulated housing 25, formed from plastic, includes a generally
cup-shaped portion 26 with an integral elongated neck portion 16
extending outwardly therefrom. The centrally located neck 16 is
hollow as seen in FIG. 3. Cup portion 26 includes an arcuate
chamber 30 bounded by a generally semicircular trough surface, with
an opening only along the upper termination of the trough.
For making electrical connection with chamber 30, a conductive
insert 35 is press fit through the hollow center of neck 16 in
liquid-tight sealing engagement therewith. Insert 35, which may be
formed of electrically conductive plastic or other electrically
conductive material, consists of a hollow tubular neck 36 which
terminates in a flat, enlarged head 37. As seen in FIG. 3, the
hollow interior of neck 36 forms the female receptacle for
electrical plug 20, and is of a size adapted to receive a
compressible pin 40 of plug 20. Pin 40 is electrically connected
through plug 20 to conductor 18. Head 37 seats on a flat ridge 42
which connects trough 26 with neck 16. Insert 35 further encloses
chamber 30, so that the only fluid opening is confined to a space
between the top portion of head 37 and a shoulder 44 on the trough
surface.
The fluid penetrable opening of chamber 30 is enclosed by a disk
cover 50 which is absorbent to the liquid within the chamber. Such
cover 50 may take the form of filter paper which is saturable by
liquid. The disk 50 seats against shoulder 44 and rests on the
upper plane of head 37, thus completely enclosing chamber 30.
The liquid or fluid solution which is to cause iontophoresis is
placed within chamber 30 before disk 50 is seated in place. As
previously described, one of the pair of electrodes is filled with
a 0.5 percent solution of pilocarpine nitrate, and the other
electrode is filled with a 1 percent solution of sodium nitrate.
Desirably, housing 25 is color coded so as to identify the solution
contained within the chamber 30. This color coding may correspond
to a color coding on plug 20 and conductor 18, in order that a
technician may readily identify the correct manner to connect the
electrodes to the DC voltage source.
After disk 50 is seated against shoulder 44, a second cover 54 is
placed over disk 50 and sealed around its circumference to the flat
circular edge 56 of housing 25. Cover 54 is impenetrable to fluid
and further is substantially impenetrable to light energy, because
solutions used for iontophoresis are typically light sensitive.
Protective cover 54, preferably a flexible foil formed by an
aluminum metal, paper, polyethylene composite, is welded to edge 56
of the plastic housing 25. The welding allows cover 54 to be peeled
off edge 56 when the electrode is to be used, thereby exposing the
filter cover 50 which is placed against the patient's arm. For ease
in removing cover 54, it may include a tab 60 which is not welded
to housing 25 and extends beyond the circumference of edge 56, in
order to allow a technician to easily grasp the cover 54 and peel
or tear it off the housing.
The above construction allows protective cover 54 to be removed
without disrupting filter cover 50 from its engagement with the
housing 25. As seen best in FIG. 3, the thickness of filter cover
50 substantially corresponds to the distance between shoulder 44
and the plane of edge 56. This causes the exposed plane of filter
cover 50 to coincide with the plane of edge 56, allowing the
electrode to be placed flat against the skin of the patient.
The electrode 10 is disposable after a single use on a patient.
Because the electrode is prefilled with the nitrate solution, the
technician performing the analysis does not have to handle
chemicals nor fill and clean electrodes. The protective cover 54
prevents evaporation of the solution, and further protects the
solution from light energy. Because the electrodes are sealed and
used only once, contamination problems are reduced.
Although the electrode of the present invention has been described
with particular reference to its use in pilocarpine nitrate
iontophoresis, it will be understood that drugs other than
pilocarpine nitrate may be used in the electrode and introduced
through a patient's skin by iontophoresis in a manner similar to
that described above. Moreover, the electrode of the present
invention has use in applications other than iontophoresis. For
example, when filled with an electrolytic fluid and held in contact
with a patient's skin as described above, thereby establishing
electrical connection between the patient's skin and the fluid, the
electrode of this invention may be used in obtaining galvanic skin
response measurements, electrocardiograms, electroocculograms, and
various other biological voltage measurements requiring electrical
contact to be made with a patient's skin.
* * * * *