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Indian Journal of Physiotherapy and Occupational Therapy

High Voltage Pulsed Galvanic Stimulation: Effect of Treatment Durations on Healing of Chronic Pressure Ulcers

Author(s): Emad T. Ahmad

Vol. 2, No. 3 (2008-07 - 2008-09)

Emad T. Ahmad

Chairman, Physical Therapy Department, Health Sciences College for Males, Taif, Saudi Arabia

Abstract

The purpose of the current study was to determine the optimal treatment duration of high voltage pulsed galvanic current (HVPC) in treating Chronic pressure ulcer. Sixty volunteers suffering from chronic pressure ulcer were participated in this study for a treatment period of five weeks. They were divided randomly and equally into four groups (3 treatment groups and one control group). Patients in the treatment group (G1, G2, and G3) received HVPC for 45, 60, and 120 minutes for 7 days /week respectively. While patients in the control group received shame HVPC (45 minutes, 7 days/week) wound surface area(WSA) were used to measure the outcomes before starting the study and after 3rd and 5th weeks post-treatment. It was found that, there was a significant reduction in WSA in G2 (60 minutes) and G3 (120 minutes) when compared with G1(45 minutes) and control group (shame HVPC). On the other hand, there was no significant difference between G2(60 minutes) and G3(120 minutes). It could be concluded that the application of HVPC for 60-120 minutes, 7 days/week is the optimal duration in enhancing chronic dermal ulcer healing.

Introduction

A healing wound is an extremely complex and dynamic tissue process. Scientific enquiry into the many facts of wound healing is far from complete and consequently the knowledge base is continually being enriched by input, as much from the clinician at the bed side, as the researcher’s bench9.

Pressure ulcer is defined as “a maceration of skin and /or deeper tissues due to unrelieved pressure, shear force(s), and /or frictional force(s)2.Development of pressure ulcer is a problem that threatens the activities of every person. There are many precipitating factors for ulcer formation; intrinsic factors include sensory, autonomic, and motor impairment; obesity; mal nourishment; and diabetes.

Extrinsic factors include unrelieved pressure; friction, direct trauma, and inadequate skin hygiene10.

Conservative (non-surgical ) management of established pressure sores involves control of the causal factors, such as: removal of pressure, avoidance of skin maceration, correction of nutritional deficiencies, removal of necrotic tissue, control of infection, and encouragement of soft tissue repair(11). A plethora of methods for accelerating granulation and re-epithelialization of chronic wound exist in medical practice5

The role of electrotherapeutic intervention is not new within the realms of physiotherapy; there is in fact a long history of electrical, electromagnetic and electrophysical applications that have been employed to relieve pain promote tissue repair and assist in the restoration of function12.

It was reported that a 12 hours period of tourniquet –induced ischemia prevents the gangrene noted in the leg of control dogs15. Also it was found that a maximum effect on DNA and protein synthesis in cultured human fibroblasts using HVPC intensity of 50 to 75 V, stimulated frequency of 100PPs, and a negative electrode polarity. Maximal bactericidal effects were found using high voltage pulsed current (HVPC) with an intensity of 250V at the cathode for a treatment period of two hours1.

However, it was found that a 30 minutes application of HVPC produced no bactericidal effect at any intensity and it was hypothesized that a treatment time greater than 30 minutes may be required to produce a bactericidal effect in vitro with HVPC6. On the other hand, it was found that one hour application of HVPC produced a significant increase in the healing rate of pelvic ulcer in patients with spinal cord injury5. Moreover it was found that application of HVPC for 45 minutes, three times per week for four week produced a significant increase in the healing rate of chronic leg ulcers7. This study aimed to compare the effect of different treatment times of HVPC on chronic dermal ulcer healing.

Material and methods

Patients population

Sixty patients with 60 wounds at four investigating sites participated in the study. Subjects with indolent pressure ulcers grade (II) according to Yarkony-Kirk classification14 were randomly assigned into three treatment groups and one control group.

Treatment Groups: (15 wounds for each group)

Group I: Received HVPC for 45 minutes for seven days / week.
Group II: Received HVPC for 60 minutes for seven days / week.
Group III: Received HVPC for 120 minutes for seven days /week.

Control group: (15 wounds)

They received same HVPC for 45 minutes for seven days / week in addition to conventional wound therapy (wet dressing, and whirlpool therapy four to five times per week). All wounds were debrided before admission to the study, wounds were between four and ten cm2 in size. A table (1) provides general description of the study population either treatment groups or the control group. The subjects in this study had stage II chronic pressure ulcers. Their ages ranged from 30 to 50 years. There were no sex restrictions for participants in the study. The patients were participated in the study for five weeks, because we believed that same measurable effect on healing would occur in that amount of time. Patients were excluded from the study if they had cardiac pacemaker, peripheral vascular diseases, disposing them to thrombosis, or active osteomyelitis or if they were pregnant or receiving long-term radiation therapy, steroid therapy, or chemotherapy. Following the initial evaluation to determine whether the wound and the patients met the selection criteria, each patient signed an informed consent form.

Equipment

A small portable high voltage monophasic twin pulsed generator was used in this study. The unit parameters were set accurately at a frequency of 120 Hz, an interphase interval of 50 μsec, and a voltage just below that capable of producing a visible muscle contraction (100-175V).

Procedure of the study

HVPC Treatment protocol (Treatment phase) Patients in the treatment groups received 45, 60, and 120 minutes of HVPC applied to the ulcer site once daily, seven days per week. A piece of heavy –duty aluminum foil, slightly wet and larger than ulcer perimeter, was attached with alligator clip to negative lead of the HVPC unit. The foil electrode was placed over the ulcer on top of saline soaked gauze. A sand bag or elastic wrap was used if needed to hold the wound electrode in place. The dispersive electrode was strapped over the patients’ medial thigh, with wet gauze placed between the electrode and the patients’ skin. The active electrode was of negative polarity for the first three days of HVPC application, while the dispersive electrode was of positive polarity. After these three days period, the positive polarity was now at the active electrode and the negative polarity was the dispersive electrode. The positive polarity was maintained at the active electrode until the wound healed or a plateau in healing was noted, if such a plateau was reached the protocol of negative polarity at the wound site for three days period was restarted.

Control Group (Treatment phase)

Patients in the control group had electrodes applied in the same manner as patients in the treatment groups, but the voltage was maintained at zero.

Wound Healing Assessment phase

The measurement of wound surface area (WSA) was conducted by tracing of wound perimeter according Kloth and Feedar8. The WSA measurement was conducted by the following steps:

A sterilized transparency film was placed over the ulcer. The ulcer perimeter was traced by using the film tipped transparency marker. Each ulcer was traced three times to establish measurement reliability. After tracing the transparency film face which faced the ulcer was cleaned by a piece of cotton and alcohol. The carbon paper was placed over the metric graph paper one mm2. The traced transparency film was placed over the carbon paper with a white paper in between, and transcribed the tracing onto the metric graph paper. The number of square millimeters on the metric graph within the wound tracing was counted to determine the WSA. The mean of the three trials was calculated and considered as WSA. The WSA measurements were taken at zero(Pre), 3rd (Post I) and 5th (Post II) week.

Data analysis. A paired t Test was conducted to compare both wound area initially and after 3rd and 5th weeks of treatment. Unpaired t test was conducted to compare treatment groups (GI,GII,GIII) with control group.

Results

I-Results of treatment group

A-Results of the Group I(HVPC for 45 minutes) The mean value and standard deviation of WSA (Cm2) in this group before application of the treatment(Pre) was 7.12±1.63 Cm2, while the mean values of WSA after application of HVPC for 45 minutes measured after 3rd (Post I)and 5th weeks (Post II) were, (6.4±1.53 and 5.1±1.73 Cm2) respectively. There was a significant decrease in the WSA measured after 3rd (Post I) and 5th weeks (Post II) post application of HVPC for 45 minutes compared to initial measurement (before application of the treatment), (P<0.001) as shown in table (2), and fig(1).

B- Results of the Group II (HVPC for 60 minutes) The mean value and standard deviation of WSA (Cm2) in this group before application of the treatment was 7.12±1.62 Cm2, while the mean values of WSA after application of

Table 1: General characteristics of patients.

Groups Sex M/F Age (years)
Mean ±S.D.
Wound duration
(months)Mean ±S.D.
Group I(45 minutes) 6/9 38.4±6.82 4.41±0.9
Group II(60 minutes) 7/8 38.47±1.68 4.4±0.9
Group III 8/7 39.4±1.74 4.41±0.9
Control group 9/6 39.4±1.69 4.48±0.9

HVPC for 60 minutes measured after 3rd (Post I)and 5th weeks (Post II) were 3.46±0.82 and 0.6±0.35 Cm2, respectively. There was a significant decrease in the WSA measured after 3rd(Post I) and 5th weeks(Post II) post application of HVPC for 60 minutes compared to the initial measurement,(P<0.001), as in shown in table (3), and fig(2).

C- Results of the Group III (HVPC for 120 minutes) The mean value and standard deviation of WSA (Cm2) in this group before application of the treatment was7.14±1.57 Cm2while the mean values of WSA after application of HVPC for 120 minutes measured after 3rd (Post I) and 5th weeks (Post II) were 3.68±0.79 and 0.64±0.61 Cm2, respectively. There was a significant decrease in the WSA measured after 3rd (Post I)and 5th weeks (Post II) weeks post application of HVPC for 120 minutes compared to the initial measurement (P<0.001), as shown in table (4), and fig(3).

II-Results of the Control Group

The mean value WSA (Cm2) in the control group before application of the treatment was 7.21±1.54 Cm2, while the mean values of WSA after application of sham HVPC for 45 minutes, seven days per week, and conventional wound therapy (wet dressing, whirlpool therapy for four to five times per week) measured after 3rd (Post I) and 5th weeks were 6.65±1.47 and 5.39±1.79 Cm2, respectively. There was a significant reduction in the WSA measured after 3rd (Post I)and 5th weeks post application of sham HVPC compared to the initial measurement (P<0.001), as shown in table (5), and fig(4).

Fig. 1: The mean values of WSA in the group I (HVPC for 45 minutes) at, zero, (Pre), 3rd(Post I) and 5th week(Post II).

The mean values of WSA in the group I

Fig. 2: The mean values of WSA in the group II (HVPC for 60 minutes) at zero, (Pre) 3rd(Post I) and 5th week(Post II).

he mean values of WSA in the group II

Table 2: The WSA in the group I (HVPC for 45 minutes) at, zero, (Pre), 3rd(Post I) and 5th week(Post II).

  WSA Group 1 (45 minutes)
  Zero Pre 3rd week Post I Zero Pre 5th week Post II 3rd week Post I 5th week Post II
Mean 7.12 6.4 7.12 5.1 6.4 5.1
S.D.± 1.63 1.53 1.63 1.73 1.53 1.73
S.E. 0.42 0.39 0.42 0.44 0.39 0.44
t-value 9.66 14.56 12.72
P-value <0.0001 <0.0001 <0.0001

Table 3: The WSA in the group II (HVPC for 60 minutes) at, zero, (Pre) 3rd(Post I) and 5th week(Post II)

  WSA (Cm2) Group II (60 minutes)
  Zero Pre 3rd week Post I Zero Pre 5th week Post II 3rd week Post I 5th week Post II
Mean 7.12 3.46 7.12 0.6 3.46 0.6
S.D.± 1.62 0.82 1.62 0.35 0.82 0.35
S.E. 0.42 0.21 0.42 0.09 0.21 0.09
t-value 13.97 17.13 17.32
P-value <0.001 <0.0001 <0.001

Table 4: The WSA in the group III (HVPC for 120 minutes) zero, (Pre) 3rd(Post I) and 5th week(Post II)

  WSA Group III (120 minutes)
  Zero Pre 3rd week Post I Zero Pre 5th week Post II 3rd week Post I 5th week Post II
Mean 7.14 3.68 7.14 0.64 3.68 0.64
S.D.± 1.57 0.79 1.57 0.61 0.79 0.61
S.E. 0.4 0.2 0.4 0.15 0.2 0.15
t-value 16 22.78 29.2
P-value <0.0001 <0.0001 <0.0001

III- Comparison and analysis of the mean value of WSA for treatment groups and control group before application of the treatment (zero week) and after 3rd, and 5th week) post treatment.

A-Before application of treatment (Zero weeks)

There were no significant differences in WSA among control group and treatment groups (GI, GII, and GIII) (P>0.05).

B-After 3rd week post treatment

During this period of measurement, there was a significant reduction in WSA in the 3 treatment groups when compared with control group (P< 0.001). On the other hand, there was a significant reduction in WSA in GII compared to GI, (P<0.001). There was a significant reduction in WSA in GIII compared to GI (P<0.001). There was a significant reduction in WSA in GII compared to GIII, (P<0.001).

C-After 5th week post treatment

During this period of measurement, there was a significant reduction in WSA in the 3 treatment groups when compared with control group (P< 0.001). On the other hand, there was a significant reduction in WSA in GII compared to GI, (P<0.001). There was a significant reduction in WSA in G III, compared to GI, (P<0.001). On the other hand there was no significant reduction in WSA in GIII compared to GII (P>0.05).

Discussion

This study was designed to compare different HVPC application times on acceleration of pressure ulcer healing. No significant differences existed between the treatment groups and the control group which would be expected to affect treatment outcome.

Since the all treatment groups received identical ulcer management except for duration of application, any differences in healing between the three treatment groups may be attributed to the duration of application of HVPC. It was found that after the 3rd week of HVPC application there was significant reduction in WSA measured after 60 minutes of application more than that reported after 120 minutes of application. On the other hand at the 5th week post HVPC, there was no significant difference in WSA measured after 60 and 120 minutes of application.

The results of this study are agree with that of other studies showing that application of HVPC for 60 minutes enhance the rate and extent of healing of chronic wounds. A similar findings was reported by Kloth and Feedar8, who stated that the HVPC treatment time which satisfactorily enhanced tissue healing did not exceed 60 minutes per day for five to seven days a week. This treatment time is in contrast to the 20 to 45 hours of electrical stimulation treatment per week reported in other studies.

The treatment time between three to seven hours per week reported by Kloth and Feedar8, and seven hours per week reported in this study may be beneficial.

It was no surprising to us to find that there was a significant reduction in WSA in control group measured after 3rd and 5th weeks, because each of these wounds received an intensive amount of additional care, including maintenance of moist wound microenvironment as part of the sham treatment.

Table 5: The WSA in the control group at, zero, (Pre), 3rd(Post I) and 5th week(Post II).

  WSA (Cm2) Group III (120 minutes)
  Zero Pre 3rd week Post I Zero Pre 5th week Post II 3rd week Post I 5th week Post II
Mean 7.21 6.65 7.21 5.39 6.65 5.39
S.D.± 1.54 1.47 1.54 1.79 1.47 1.79
S.E. 0.39 0.38 0.39 0.46 0.38 0.46
t-value 16.7 15.69 10.28
P-value <0.001 <0.001 <0.001

Fig. 3: The mean values of WSA in the group III (HVPC for 120 minutes) at zero, (Pre) 3rd(Post I) and 5th week(Post II).

The mean values of WSA in the group III

Fig. 4: The mean values of WSA in the control group at, zero, (Pre), 3rd (Post I) and 5th week(Post II).

he mean values of WSA in the control group

There is a growing evidence that exogenous electrical currents can augment the healing process of dermal ulcer, perhaps by mimicking the body’s own bioelectrical signals. A convincing evidence exists that electrically augmented healing of delayed ulcer is best facilitated by HVPC stimulation for 60 minutes for seven days per week. Additional studies are needed to identify the mechanism involved in the promotion of wound healing with HVPC and to determine the stimulus variables that most effectively accelerate tissue repair.

It is well established that all cells are electrically active, not just those of the excitable tissue. The cell membrane has a membrane potential which averages 70mv, and this electrical cell membrane activity is critical to normal cell functions. The level of electrical activity of the cell membrane influences the general activity of the cell. If the membrane is electrically quiescent, the cell down regulates, and its functional capacity diminishes. Conversely, with increased levels of electrical activity, up-regulation occurs and the general cell activity levels increase3.

By influencing the activity levels of the cell membrane, it is possible to adjust the excitement level in the cell. This can be achieved with a variety of exogenous energy sources13.

Results from our study and previous studies led us to suggest that wound closure is enhanced with HVPC, if the selected duration of application is appropriate. This study confirms the efficacy of HVPC, as given for wound healing via epithelial closure. These results suggest that the use of HVPC in dosage and manner used in this study is a safe and effective way to treat stage II chronic dermal ulcer. The WSA significantly decreases after HVPC for 3rd and 5th weeks. However there was no significant difference between application of HVPC for 60 and 120 minutes.

It could be concluded that the application of HVPC for 60- 120 minutes, 7 days/week is the optimal duration in enhancing chronic dermal ulcer healing.

References

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