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DISCUSSION
 
Current research indicates that LIDC within the range of 200 to 800 μA is effective in promoting and accelerating wound healing. It is emphasized that in no study was blood or serous exudate observed, an indication that the intensity range of 200 to 800 μA is appropriate for low-intensity electrical stimulation. In Table 3, a protocol of application of LIC is presented on the basis of protocols used in studies.
Regarding LIPDCs, studies showed that an intensity of 630 μA is capable of stimulating healing of ulcers that were unsuccessfully treated with standard compression treatment and a current intensity of 300 to 600 μA, for stages II and III pressure ulcers. Thus, an intensity range of 300 to 630 μA appears to be an intensity of choice for treating these specific wounds.
The intensity proposed ranges from 300 to 630 μA on a daily basis for at least 30 minutes for 4 to 8 weeks. Reversal of polarity may be applied, and frequencies of 130 Hz may also be applied. Reversal of polarity in LIPDC has been proposed on the 3rd to 10th day of treatment, provided that no infection has taken place. Reversal may be repeated whenever wound healing has reached a plateau.
Another recommendation can be regarding wounds that have failed to heal using other forms of electric stimulation. The selection of the reverse polarity to the 1 used previously is proposed as employed in the studies by Wolcott et al,18 Carley and Wainapel,22 and Junger et al.23 The protocols presented in Tables 3 and 4 are then suggested.
A comparison of the results of studies on LIDC and LIPDC reveals that their results, despite the numerous differences in protocols, populations studied, and outcome measures, are largely comparable, a fact that weakens the initial hypothesis in the “Results” section, that pulsed LIC might be less effective in wound healing than LIDC.
Intensities of 0.001 to 200 μA and 800 to 1000 μA have not been studied, in either continuous-direct or pulsed-direct LIC. It can only be postulated that intensities of 800 to 1000 μA are effective, because amplitudes of 800 μA and 1 mA were both proven to be effective, although in different waveforms (800 μA in direct current and 1000 μA in alternating current).
A general lack of clinical studies demonstrating no effect of MCs on wound healing was observed. Only 1 study by Katelaris et al25 found MCs not to be statistically significantly beneficial for wound healing but this study was not included because this result was probably due to the cytotoxic effect of povidone iodine, as reported by Kloth,10 which was used in conjunction with stimulation. Therefore, it can be supported that LIC in wound healing appears to be effective.
Regarding methodological issues, retrieving studies using LIC for wound healing was challenging and required rigorous search strategies. This can be attributed to the lack of differentiation of LIC from other currents of an intensity over 1 mA in the literature, commonly referred to as electrical stimulation in general.
It has to be underlined that in all studies the control or sham-treatment group received standard wound care; therefore, treatment was not withheld, which would be contrary to basic medical ethics. Thus, the control group was a standard-treatment group, and acceleration of rate of healing was in relation to standard treatment and not to no treatment at all. This fact supports that LIC could not be used alone but could be used in conjunction with standard wound care as current research suggests.
A definite conclusion and generalization could not be reached regarding the effectiveness of LIC on wound healing. Only regarding intensity, is there an agreement among studies. All other parameters vary across trials. The effectiveness on a specific type of ulcer could not be established because of the small number of studies for each type of wound. The LIC generators used in the studies have been discontinued, a fact that is of limited significance because parameters and technical characteristics are adequately presented in all studies. Furthermore, another point to be taken is the presence of, to a certain extent, varying outcome measures and criteria, which have been used in studies, a fact that impedes comparison of results and reaching conclusions. Still, the positive results indicate that LICs appear to have a beneficial effect on stimulation and rate of wound healing. The factors mentioned above prevent conclusions on the efficacy and extent of efficacy of LICs in stimulating and accelerating wound healing.
The clinical implications of this study may also be considered. Wound healing is a challenge and a delicate healthcare issue for the clinician. Physicians, nurses, physiotherapists, and other members of the rehabilitation team occasionally have to dedicate treatment time on wound care.26 Healing is sometimes delayed, and the wound may not respond to standard treatment. These constitute implications, which require a part of patient services to be focused on wound healing. As a result, other healthcare issues might be overlooked or receive less attention, or the presence of the wound itself might slow down rehabilitation progress, impede patient recuperation, and discharge from hospital. Overcoming or restricting the effects of lengthy or treatment-resistant wound healing may enable the healthcare professional to address other health issues such as training transfers to a tetraplegic patient with a pressure sore in the sacral area. Furthermore, hospitalization may be reduced reflecting faster rehabilitation of the patient, improvement of patient services, and reduction of cost of care.
The review may also underline the need for a multidisciplinary approach to wound care, through exploring and gathering evidence on the effectiveness of LIC stimulation, a treatment applied by physiotherapists and physicians, who are a part of the rehabilitation team, as well as the nurse and other rehabilitation professionals.
Research studies unanimously support the efficacy of LIC, still the number of studies on the topic is limited and further research is needed to establish the effectiveness of LIC on promoting and accelerating wound healing. Future research may focus on specific wound types such as diabetic ulcers, or alternative methods of application, for instance, implanted electrodes. The type of electrical current used could be specified to direct research toward establishing the most effective treatment parameters and forms of current.