CA1050617A

CA1050617A - Apparatus for electrical pulse stimulation

Info

Publication number: CA1050617A
Application number: CA221,045A
Authority: CA
Inventors: Norman R. Hagfors; Alan C. Hymes
Original assignee: Stimulation Technology Inc
Current assignee: Stimulation Technology Inc
Priority date: 1974-03-01
Filing date: 1975-02-28
Publication date: 1979-03-13
Also published as: GB1488957A; AU7863175A; US3911930A

Abstract

ABSTRACT OF THE DISCLOSURE
A method and structure of artificially inducing the return of arrested body functions caused by paralytic ileus and pain associated therewith after surgery or accidental trauma on the human body. The equipment is in the form of electronic circuits producing a generally rectangular or square wave shape which is variable from 10 to 300 pulses per second having a pulse width of 50 to 1000 microseconds. The circuit includes a pair of constant current amplifiers capable of supplying two different output signals having a pulse ampli-tude of 80 milli-amperes maximum current to provide a current density range of 1 to 50 x 10-6 amperes per square millimeter depending on the electrode area or size. Electrodes are connect-ed to current generators and placed on the body in the area of the lower abdomen in accidental trauma or close to the area of incision post operatively. Posterior electrodes may also be placed on the body as well as over the nerves and particularly the intercostal nerves leading to the site of the incision to further aid in restoring body functions.

Description

:~6~7 This applica-tion relates to a method and structure for electrical stimulation of the body to restore arrested body functions and more specifically to trea-ting or preventing paralytic ileus and the pain associated with accidental trau~a and surgery~
It is well known -that when abdominal suryery is performed, a condition will generally be found characterized by inadequate peristaltic activity (a forward motion of the bowel) affecting the gastro intestinal system completely or locally which may result in paralytic ileus. Prolonged loss of the peristaltic activity of the gastro intestinal track generally leads to distension of bowel loops with fluid and ~-gas. If prolonged, a vicious cycle may occur and the more distention that occurs, the more paralyzed the bowel becomes.
Paralytic ileus may also result from conditions other than surgery such as accidental trauma or from a pathological condition.
The management of this condition has been trea-ted - by numerous means, directed at relieving distension by means of tube suction in the stomach and intestine. An internal electrical means attached to a suction tube to correct this , situation is found in U.S. Patent No. 3,411,507 but is also generally known that the results achieved by the method set forth therein has also been somewhat inconsistent and incomplete.
It has also been well established that complications ~- of the lung tissue may result from chest operations or accidental .

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~5~7 trauma and this may ta]~e the Lor-m o~ a partial internal collapse of the lung (cclIled atelectasis)~ A sic~nificarl-t reduc-tion of post operative OL traumatic pail~ allows dee~p respiratiorl arld coughing, thus preventing and treatiny atelectasis.
During the initial phases of the developrnent of the treatment ~nd method of placement of the electrodes in carrying out our invention and discovery, the patients were treated interrnittently once or -twice a day for a period of 20 to 30 minutes. It has also been established that for treatment of pain the best placement of the electrodes on the patient is close to the surgical wound or site of trawna.
Generally, the best results have been achieved by keeping the electrodes substantially parallel to the incision and on some occasions by placing a second pair of electrodes on the body covering the nerves leading to the site of the incision. Where the area of pain is produced by some means other than surgery, generally the electrodes are secured to the body within the localized area of pain. However, good results have also been achieved through the use of posterior electrodes alone and of cour3e where there are multiple areas of trauma such as may ~ result _rom an accident it may be necessary to use a number - of electrodes placed near the traumatic areas and require more than one generator to energize the same.
The electrodes are forrned of aluminum foil or other ; flexible electrically conductive material. They are generally secured to a piece of clear vinyl material or other flexible insulative backing rnaterial which will conform to the con-tour of the body. It has been found that the electrodes having a surface area greater than 3 square inches, depending upon the ~ 30 size of the surgical incision or localized area of pain and up :, "~

to 30 sq~lare inc~es yerlerally yive the maxim~n flux clensity penetration of the body that is required to correct the body function and pain associated therewith. The current densi-ty has been found to have a range of approximately l to 50 microamperes per square millime-ter, and is related -to the electrode area or si~e and the location of the same with respect to the area to be treated.
I-t was also determined that the use of electrode gel has been superior to the use of we-t sponges for connecting the stimulator to the body although generally there were no problems encountered in choice of gel or wet sponge.
In evaluating the method and equipment, various observations were made by comparison to a control group and a group usiny the structure and practicing the method disclosed herein, and specifically observations were made of: l. The incidence of post operative complications of ileus and atelect-asis. 2, The time spent in the intensive care unit. 3. In thoractomy patients, the angle their humerus could be raised before and after treatment. 4. The ability of each patien-t treated to cough.
By way of example, of 250 operations in which the abdominal cavity was opened, where electrical stimulation was used, there were no cases of ileus detectedO On -the other hand, the expected rate of ileus for the same operation without treatment is generally found to be approximately 13 percent.
By way of f~rther example, Or 22 patients wlth protracted ~ .

ileus .c,ecorldary t(~ suiq2ry al-ld t~aurncl, tr(~atrrlerlt with surface electrodes and sti.rnulation as describecl herein, all pa-tients subse~quently developed active bo~e:L tones and within 4~ hour~
the Inajority had bowel movements signifyillg a cure. In addi-tion, there was also a significant reduction i.n the t:ime spent in the intensive care unit for those patients being trea-ted w;th the electrical stimulation. On an average the leny-th of stay in the intensive care unit was reduced by approximately one day.
Thoracotomy patients treated with the elec-trical stimulation pulses and as contrasted to a similar group of patients who were not treated, showed that 5 patients of the treated group developed clinical atelectasis confirmed by X-ray for a rate of 13 percent compared to 15 patients of a control group of 30 who had post operative atelectasis in the untreated group for a rate of 50 percent. The treated group had an average stay in the intensive care unit of 3 days compared to 4.2 days for the control group. As a measurement of patient activity following thoractic surgery, patients could raise their arm so that the mean angle of the humerus to the thoractic cage prior to treatment was 91 . Following a few minutes of treatment, the average an~le of the h~erus to the thoractic cage was noted to be 154, or an increase of 63.
By way of further example, where 10 patients were treated as disclosed herein after suffering fractured ribs, only one developed atelectasis, for a rate of 10 percent.
Another patient suffering from atelectasis fully recovered after stimulation was applied. Out of 12 patients suffering _ ~ _ fractured rib~ who were not treated wi.th stimulation as set forth herein, 8 developed atelectasis, or i~ other words, 66% developed atelectasis as compared -to the 10% just described.
Subjective evaluation of these patients, however, revealed a pain reduction of about 80%, and as a result, coughing improved as noted by independent observers before and after treatment. The presently described treatment is unlike acupuncture which controls pains by needle stimulation at a distal site.
It became apparen-t that hyper activity Qf the gastro intestinal track was reduced by the electrical stimulation and that the majority of the patients treated with this electrical stimulus expelled flatus within a short time thereafter and had . a bowel movement soon thereafter. Clinically, the bowel tones .` became hyper active whereas preceding the stimulation they were hypo active to absent. :
.. It is therefore a general object of this invention to provide a method and structure to induce the return of impaired body functions causing atelectasis and paralytic ileus due to surgery, accidental trauma or pathologic processes.
It is another object of the present invention to provide a method and structure for treating pain in the human . body as a result of experiencing a traumatic condition such as surgery or accidental trauma.
- It is still a further objec-t of this invention to : provide a method and structure for treating pain associated with accidental trauma such as fractured ribs, a fractured clavical, a fractured coccyx, subperiosteal hematomas and all soft tissue injuries and fracture of bones.
It is still another object of the present invention : - 5 -.
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to provide si~lal generating means for generating signals of predetermined pulse frequency and pulse width for controlling post operative problems of atelectasis and paralytic ileusO
According to the present invention, the method of treating pain in the human body as a result of experiencing a traumatic condition such as surgery or accidental trauma comprises subjecting the localized area of traumatic pain in the body to a series of electrical pulses of 50-1000 micro-seconds duration having a repetition frequency of approximately 10-300 pulses per second and of substantially constant amplitude continuously until the pain caused by said traumatic condition is observed to be substantially overcome.
According to one embodiment of the present invention, the method includes the steps of: generating a series of electrical pulses of 50-1000 microseconds duration having a repetition frequency of approximately 10-300 pulses per second and of substantially constant amplitude; securing at least a pair of body electrodes in juxtaposition to the localized area of traumatic pain in the body, and applying said series of electrical pulses to said body electrodes continuously until the pain caused by said traumatic condition is observed to be - substantially overcome.
According to a further embodiment of the present invention, the method of treating pain in the human body as a result of experiencing a traumatic condition such as surgery or accidental trauma includes the steps of: generating a series of electrical rectangular, single frequency, fixed duration pulses within the range of 50-1000 microseconds duration and the repetition frequency range of approximately 10-3000 pulses per second and of substantially constant amplitude; securing at least a pair of rectangular body electrodes in juxtaposition on the skin surface and parallel ~ - 6 -, ~ .
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to the localized area of tra~ati~ pain in th~ body, and applying said series of electricaL pulses to said body via said electrodes with a current density of 1~50 microamperes per square millimeter continuously for a period of 20-30 minutes every 2-4 hours until the pain caused by said traumatic condition is observed to be substantlally overcome.
The apparatus according to the present invention comprises at least one pulse generatcr generating a sub-stantially rectangular wave signal having a repetition rate of 10-300 pulses per second and a pulse width variable from 50-1000 microseconds duration; at least one current generator excited by said pulse generator having an output circuit independent of a load to be connected thereto, a plurality of flexible elongated electrodes secured to the human body substantially within the localized area of pain and disposed in minimum spaced relation-ship thereto without contacting the same; and a plurality of electrical conductors connecting said plurality of electrodes to said at least one current generator.
According to one embodiment, the apparatus according to the present invention comprises: a pulse generator generating a substantially rectangular wave signal having a repetition rate of 10-300 pulses per second and a pulse width variable from 50 to 1000 microseconds duration; a pair of current generating means being excited by said pulse generator and each having an ` output circuit independent of a load to be connected thexeto, said means each being individually adjustable to supply a pulse amplitude of 10 to 80 milliamperes; a plurality of flexible elongated electrodes being positionable to the skin surface of the human body substantially within the localized area of pain, said electrodes each having a current conduction area of 3-30 square inches and a plurality of electrical conductors connecting said plurality of electrodes to said pair of current ~ I - 6a -.~ ., . ' : ~ ' ' ., ~5t~
generatin~ means.
These and other objects and advantages of the invention wil] more fully appear from the following descrip-tion, made in connection with the accompanying drawings, illus-trating the invention in preferred aspects, and in which:
YIGURE 1 is a diagrammatic view of a patient showing placement of electrodes after abdominal cavity surgery, FIGURE 2 is a diagrammatic view of a patient showing placement of electrodes after chest cavity surgery FIGURE 3 is a diagram of a typical current pulse wave shape applied to the electrodes; and FIGURE 4 is a schematic diagram of the electrical equipment and electrodes which are attached to the body of the patient.
Figure 1 discloses a pair of electrodes 10 and 11 which are placed ad]acent and parallel to the abdominal incision L~. A pair of conductors 13 and 14 are connected respectively to electrodes 10 and 11 and are also connected to a pai.r of jacks 17 and 18 at the front of a housing 19 which houses an electrical circuit 20 that will be described ; in more detail subsequently, and is shown in Figure 4.
Another pair of jacks 21 and 22 are used to energiæe another pair of electrodes 23 and 24 (E'igure 4) through another pair of electrical conductors 25 and 26 respectively, ,' :

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FicJ~re 2 discloses a patier-t having an incislor in the chest cavity ar-d electrodes 10 and 11 are sho~n placed substantially parall.el to and running the leng-th of the incision. It was found that durirly the various applica-tlons of the electrodes and use of the equipment that -the optimum results were obtained by using a pulse width of approximately 200 to 400 microseconds with a frequency of 100 to 160 pulses per second.
Figure 4 shows the electrical circuit 20, which generates the electrical signals. Transistors Ql and Q2 are connected in the form of a free running multivibrator producing a rectangular or square pulse wave, the frequency of which is controlled through a setting of variable resistor R3 and capacitor C3 to adjust the frequency or repetition rate. The repetition rate is adjustable from approximately 10 to 300 pulses per second.
A pulse width circuit is formed from transistors :
Q3, Q4, and Q5 which are connected to the multivibrator or oscillator through a capacitor C2. The pulse width is determined by a time constant developed through an RC network : of capacitor C4 and variable resistor Rll, and is adjustable from 50 to 1000 microseconds. A pulse signal. is obtained .~ -from the junction of the collectors of transis-tors Q3 and Q4.
The signal is applied to the bases of transistors Q6 and Q9 through resistors R13 and R14. The signals are amplified and appear across variable resistors R15 and R16 connected `:

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respectively to the collectors of transis-tors Q6 and Q9.
The ~irst output stage further amplifies the signal throuyh transistors Q7 and Q~ to provide a cons-tant current output which is independent of the load through transformer Tl.
Diode D2 is used to reduce the inductive voltage due to the collapse of the field at transformer Tl.
The second output circuit also includes a pair o~
transistors Q10 and Qll which further amplify the signal received from Q9 and apply the same to an output transformer T2 which also provides a constant current output siynal independent of the load connected thereto. Diode D3 acts in a manner similar to that of diode D2 in controlling the induced current flow through transformer ~2, Variable resistors R15 and R16 provide a means of varying the ampli-tude at the two output stages which may have a peak current amplitude, adjustable from 10 to 80 milliamperes. Expressed in a different manner, the electrical pulses generated should produce a peak current density range of approximately 1 to 50 microamperes per square millimeter of electrode area depending on the electrode size and its placement on the body with respect to the area to be treated or controlled. While the wave shape shown in Figure 3 has proven to be an optimum shape, it should also be understood that other peaked wave forms may ~e used such as triangular or saw tooth waves and those having some slope to their leading or trailing edges.

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A diode ~1 is connected :in series with the supply battery sl and the connection to transistors Ql, Q2, Q3, ~4 and Q5 forrning the pulse generator to decouple the gene-rator and output stages. Upon closing switch Sl, power is applied to the pulse generato:r and pulse width circuits as well as the current amplifiers, to supply an output voltage of the charactaristics disclosed in Figure 3.
Through the use of the teaching as disclosed herein, it will be apparent that post operat.ive pain, traumatic - 10 pain and other post operative complications may be alleviated so that the patlent may resume deep breathing and coughing thus reducing pulmonary complications for surgery performed in the chest and abdominal cavities. Through the u~e of electrical stimulation as disclosed herein, paralysis of the bowel is alleviated, thus preventing post operative ileus, a condition o~ paralysis of the bowel leading to distension : with fluid and gas which may lead to complication of bowel obstruction. As a result of the beneficial treatmant des- ~
cribed herein, there is a marked reduction of pulmonary - ~:
complication and bowel paralysis resulting in a reduced hos-pital stay by the patient in an intensive care unit.
Electrical stimulation, upon being applied to the localized area of pain and particularly adjacent each side of an in-cision, or area of pain, is generally given to the patient .
on a continuous basis for two or three days, or stimulation may be used intermittently from 20 to 30 minutes every 2-4 hours.
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It has been found that -reduction of pain permits the return of certain body functions such as deep breathing and cou~hing whlch may have beerl reduced due to accidental chest trauma resulting from fractured ribs and/or pulmonary contus-ions, i.e., hemorrhaging within the lungs. Similar results may be achieved in p~eventing ileus following trauma from a fractured pelvis and/or hematoma in -the retio pertoneal space, i.e., the area posterior to the abdominal cavity. In other words, stimulations by the elec-trical signals through the method and equipment disclosed herein has proven to be extre mely helpful in the control of post traumatic pain due to fractured ribs, a frac-tured clavical, and subperiosteal hem-atoma of the leg and other sites of fractures of bones or soft tissue contusions.
It has also been found that the use of posterior electrodes may function well by themselves without re~ard to ;~ their use with electrodes in a localized area. Where multi-, ple applications are needed it may be necessary;~-to use two units such as disclosed herein, particularly where multiple areas of application are required.
Through the teachings disclosed herein, treatment or control of pain in the chest cavity or aDdominal cavity caused traumatically, that is by accident, or by surgery, has proven to be highly successfulv It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the inven-tion which consists of the matter shown and described herein and set forth in the appended claims.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. Apparatus for treating pain in the human body as a result of experiencing a traumatic condition, such as surgery or accidental trauma, said apparatus comprising:-(a) at least one pulse generator generating a substan-tially rectangular wave signal having a repetition rate of 10-300 pulses per second and a pulse width variable from 50 to 1000 microseconds duration;
(b) at least one current generator excited by said pulse generator having an output circuit independent of a load to be connected thereto;
(c) a plurality of flexible elongated electrodes secured to the human body substantially within the localized area of pain and disposed in minimum spaced relationship thereto without contacting the same;
(d) and a plurality of electrical conductors connecting said plurality of electrodes to said at least one current generator.

2. The structure as set forth in claim 1, including:-(e) an electrical current conducting gel applied to said body electrodes and contacting the human body.

3. The structure as set forth in claim 1, wherein each of said electrodes includes an area of substantially 3 to 30 square inches to provide a maximum flux density.

4. The structure as set forth in claim 1, including:-a second plurality of electrodes secured to the human body posterior of said localized area of pain and over the nerves leading to said area of pain;
and a second plurality or electrical conductors connecting said later mentioned plurality of electrodes to said at least one current generator.

5. Apparatus for treating pain in the human body as a result of experiencing a traumatic condition such as surgery, or accidental trauma, said apparatus comprising:-(a) pulse generator means generating substantially rectangular wave signals having repetition rates of 10-300 pulses per second and pulse widths variable from 50 to 1000 microseconds duration;
(b) current generator means excited by said pulse generator means having output circuit means independent of any load to be connected thereto;
(c) a plurality of flexible elongated electrode means secured to the human body substantially within any localized area of pain and disposed in minimum spaced relationship thereto without contacting the same;
(d) and a plurality of electrical conductor means connecting said plurality of electrode means to said current generator means.

6. The structure as set forth in claim 5, including:-(e) electrical current conducting gel applied to said plurality of body electrode means and contacting the human body.

7. The structure as set forth in claim 5, wherein each of said electrode means includes an area of substantially 3 to 30 square inches to provide a maximum flux density.

8. Apparatus for treating or preventing paralytic ileus in the human body brought on by surgery, accidental trauma, or pathological conditions, said apparatus comprising:-(a) pulse generator means generating a substantially rectangular wave signal having repetition rates of 10-300 pulses per second and pulse widths variable from 50 to 1000 microseconds duration;

(b) current generator means excited by said pulse generator means having output circuit means independent of any load to be connected thereto;
(c) a plurality of flexible elongated electrode means secured to the human body in juxtaposition to at least one of a surgical incision made in the body, a localized area of accidental trauma or a localized area formed by a pathological condition, and disposed in minimum spaced relationship thereto without contacting the same;
(d) and a plurality of electrical conductor means connect-ing said plurality of electrode means to said current generator means.

9. The structure as set forth in claim 8, including:-(e) electrical current conducting gel applied to said plurality of electrode means and contacting the human body.

10. The structure as set forth in claim 9, wherein each of said electrode means includes an area of substantially 3 to 30 square inches to provide a maximum flux density.

11. Apparatus for treating pain and for treating and preventing paralytic ileus in the human body resulting from a traumatic condition, such as surgery or accidental trauma, said apparatus comprising:-(a) a pulse generator generating a substantially rec-tangular wave signal having a repetition rate of 10-300 pulses per second and a pulse width variable from 50 to 1000 micro-seconds duration;

(b) a pair of current generating means being excited by said pulse generator and each having an output circuit in-dependent of a load to be connected thereto, said means each being individually adjustable to supply a pulse amplitude of 10 to 80 milliamperes;

(c) a plurality of flexible elongated electrodes being positionable to the skin surface of the human body substantially within the localized area of pain, said electrodes each having a current conduction area of 3-30 square inches;
(d) and a plurality of electrical conductors connecting said plurality of electrodes to said pair of current generating means.

12. The structure as set forth in claim 11, including:-(e) an electrical current conducting gel applied to said body electrodes and contacting the human body, being in co-operation with said electrode in the conduction of current wherein the current density is 1-50 microamperes per square millimeter.