Effects of photobiomodulation in the treatment of pressure sores

Pressure ulcers (PUs) are a cause of concern in health care institutions due to the negative effects they cause to patients, such as pain, infection, and delayed functional recovery. From this perspective, in order to accelerate wound healing, more current treatments are being explored. Among these treatments, the photobiomodulation (FBM) offered by low power laser therapy (LBP) stands out. Given the above, this paper aims to analyze the effects of photobiomodulation in the treatment of PUs. This is an integrative literature review, with searches carried out in MEDLINE, SCIELO and BDENF databases, in which complete papers were included, in Portuguese and English, available electronically and free of charge, published from 2015 to 2021 and that addressed the proposed theme. Studies that did not address the subject of interest or did not answer the guiding question were excluded, as well as duplicate publications in more than one database. The study was composed of the analysis of 8 publications. The findings showed that this therapy contributes to pain reduction, increases local vascularization and accelerates the process of tissue healing, favoring a positive evolution during the treatment of injuries. Thus, it is emphasized that the use of MBP is of paramount importance for the treatment of PUs, because when used in the correct manner, with a qualified professional, it presents positive results in the healing period of the lesion, regardless of the type of associated dressing.


Introduction
In 2016, the National Pressure Ulcer Advisory Panel (NPUAP) changed the terminology from pressure ulcer (PU) to pressure ulcer injury (PLI). Thus, throughout the text both terms are applied in order to respect the title of the selected papers.
Pressure ulcers (PUs) are defined as an injury to the skin and/or underlying soft tissue that is usually over a bony prominence or associated with medical devices or other artifacts (National pressure ulcer advisory and pan pacific pressure injury alliance, 2015).
These injuries generate concern in health care units because of the negative effects they cause in patients, such as pain, infections and delay in functional recovery. In addition, they cause increased morbidity and mortality, prolonged hospitalizations and, consequently, higher costs for institutions (Galetto et al., 2019). Macedo et al., (2021) emphasize that this type of injury has a multifactorial cause, and may be related to intrinsic and/or extrinsic factors. Intrinsic factors include age, malnutrition, changes in body mass, obesity, vasomotor insufficiency, peripheral vasoconstriction, existence of chronic diseases, and urinary and fecal incontinence; and extrinsic factors include high temperature, increased humidity, friction, and shear.
As for the LPs classification, they may vary from stages 1 to 4, and may still be considered as unclassifiable pressure ulcers and deep tissue pressure ulcers. Such categorization will depend on the damage and tissues affected, and may compromise skin, muscles, and even bones. It is emphasized that depending on the depth and degree of the LP, several problems may arise, such as: septicemia, osteomyelitis, social isolation and reduced quality of life of the patient (Galetto et al., 2019;Loudet et al., 2017;Nogueira;Caliri & Santos, 2002). Therefore, it is important that during the evaluation of LPs, pain, pulse, exudate characteristics, size and depth of the wound, as well as signs indicating infection are taken into consideration. Therefore, these factors are relevant for an appropriate treatment approach, in which the wound healing process is considered an ongoing and, in some cases, prolonged treatment. It should be noted that the healing process, in most cases, is complex, with the appearance of cellular and vascular modifications, production and deposition of collagen, synthesis of elastin, cell proliferation, revascularization, until the reduction of the wound (Lucio & Paula, 2020).
One of the most implemented treatments is dressing with different coverings, however, the advantage of healing in the medium and long term will depend on the size and depth of the lesion, as well as the clinical condition of the patient. From this point of view, in order to accelerate wound healing, more current treatments are being explored. Among these treatments, photobiomodulation (FBM) offered by low-power laser therapy (LBP) stands out (Macedo et al., 2021).
Photobiomodulation with LBP has been employed in treatments of traumatic ulcers and chronic wounds with positive results. Due to its photochemical, photophysical and otobiological effects, the behavior of cells can be changed and, consequently, contributing to tissue repair, reduction of pain and edema, as well as anti-inflammatory effects, formation of new blood vessels, immune response and increase of fibroblasts (Macedo et al., 2021;Ribeiro & Marangoni, 2020).
Given the above, this study aims to analyze the effects of photobiomodulation in the treatment of PUs.

Methodology
This is an integrative review of literature, qualitative in nature, developed from qualitative data from studies through a systematic search on the effects of photobiomodulation in the treatment of PUs. The review followed the steps described by Mendes et al., (2008): 1) Choice of the theme and elaboration of the guiding question; 2) Definition of the inclusion and exclusion criteria; 3) Characterization of the information to be obtained from the selected articles; 4) Analysis of the chosen articles; 5) Interpretation of the collected results; 6) Presentation of the review and summary of knowledge. For Pereira et al., Research, Society and Development, v. 10, n. 4, e14110413936, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i4.13936 4 (2018), qualitative methods are essential for the researcher to know how to interpret with their opinions regarding the studied phenomenon.
At first, the theme established was the effects of photobiomodulation in the treatment of pressure injuries.
Subsequently, the guiding question was elaborated: What are the effects of photobiomodulation in the treatment of pressure sores? Next, data collection was carried out in the Medical Literature Analysis and Retrieval System Online (MEDLINE), Scientific Electronic Library Online (SCIELO) and Nursing Database (BDENF) databases.
The terms used for the search were selected using the Descriptors in Health Sciences (DECS): "pressure ulcers" and "laser therapy" and "wound healing" and "treatment outcome", in order to carry out an integrated search, the connective "and" was used, bringing together the descriptors.
In addition, the PICo strategy was used, where the Population (P) was defined: individuals with PUs; Intervention (I): use of photobiomodulation; Comparison (C): treatment of PUs by photobiomodulation; Outcomes (O): to reduce the healing time of the lesions. This is a strategy used to elaborate the guiding question and to search for scientific evidence in the literature (Santos et al., 2007).
Regarding the inclusion criteria, we included complete papers, in Portuguese and English, available electronically and free of charge, published between 2015 and 2021 and that addressed the proposed theme. Studies that did not address the subject of interest or did not answer the guiding question were excluded, as well as duplicate publications in more than one database. After a thorough reading of all complete articles, a data collection tool was applied, containing the following topics: Research, Society and Development, v. 10, n. 4, e14110413936, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i4.13936 5 title, authors, year of publication, type of study, objectives, and conclusion (Souza, Silva & Carvalho (2010).

Results and Discussion
After selecting and reading the articles resulting from the search in the databases through the associated descriptors, a table was produced to display the research covering information such as title, authors, year, type of study, objectives, and conclusion. It is worth mentioning that the articles were selected and analyzed aiming to answer the study's guiding question.
A total of eight articles were identified and selected from an extensive review following the methodological steps mentioned above. Subsequently, a discussion was held about the theme addressed in this research, in order to bring evidence on the use of photobiomodulation in the treatment of LPP, and how this method influences the healing process. There was improvement in the pressure ulcer healing process treated with adjuvant Low-Level Laser Therapy (LLLT) and the use of NOC enabled a more thorough and accurate assessment than PUSH Source: Authors (2021).

Morpho-physiological evolution of lesions during laser treatment and associations
The study by Bortoli, Prato and Kroth (2016) was a clinical study, with a sample of six patients with PU. They were divided into two groups, in which group 1 used as therapy the AlGaInP laser, 660 nm 4J/cm² low power pen, along with a essential fatty acid coverings. And group 2 used the same parameters of the laser, but with papain as coverings. During the analysis of the results, it could be observed that the wounds in which the oil lotion based on Essential Fatty Acid (EFA) with laser therapy was used presented a greater reduction in the area and physical aspects of the skin, such as color, vascularization, and absence of devitalized tissue on the edges; when compared to the wounds treated with papain, an improvement in the healing process was noted, however, a regression in the general condition of the skin, with alterations in color and the presence of devitalized tissue on the edges of the wounds. Palagi et al., (2015), conducted a case study, in which the patient presented LPP, and after 15 days of treatment with Low Intensity Laser (LLLT), it was observed that the dimensions of the lesion reduced from 7 cm to 1.5 cm in length and from 6 cm to 1.1 cm in width, in addition to the reduction of secretion and odor, and significant increase in epithelial and granulation tissue. Concluding, therefore, that the intervention with LLLT accelerated tissue proliferation, besides increasing local vascularization, forming granulation tissue by promoting rapid healing of the lesion. It is noteworthy that the coverings used was in accordance with the protocol of the institution, including the use of heated 0.9% saline solution, used for hygiene of the lesion and specific coverings used according to the evolution of the lesion, such as zinc oxide, medium chain triglycerides, hydrogel and silver alginate, along with LBP.
In the study by Lucio and Paula (2020) they report the treatment of a lesion in a 67-year-old patient with diabetes mellitus and hypertension. The treatment was the use of LBP together with silver hydrofilm and hydrogel with calcium and sodium alginate. After 55 days of treatment, there was a gradual improvement of the devitalized tissue, and thus total retraction of the lesion, occurring the healing process. Corroborating these findings, de Oliveira Bernardes and Jurado (2018) address that the healing period in elderly individuals is possibly reduced, due to the aging process. Besides being more vulnerable to the emergence of ulcers for other reasons, as in the case of diabetic wounds. Ribeiro and Marangoni (2020), concluded through a case study carried out in an 8-year-old child with traumatic ulcer, that photobiomodulation is an effective method in the treatment of this ulcer, because after starting treatment by irradiation with LLLT for analgesia and aid in the healing of the lesion, it was observed an immediate positive result after irradiation, in which the patient reported an improvement in pain. After 9 days, there was total repair of the lesion, and a score of 3 in relation to pain, showing an improvement with regard to the evolution of the traumatic ulcer.
Corroborating with the studies cited, de Oliveira et al., (2019), it was possible to observe several methodological strategies regarding the protocol for treatment with photobiomodulation, however, in all the manuscripts analyzed, it was noted an outcome presenting expressive improvement in the painful picture and in the healing process of the lesions regardless of the therapy used. Complementarily, despite the differences in treatment protocols and strategies, the findings indicate that photobiomodulation contributes to pain reduction, besides increasing local vascularization and accelerating tissue healing, contributing to a positive evolution during the treatment of PUs.

Multidimensional effectiveness of photobiomodulation in the healing process
In the research conducted by Macedo et al, (2021), concluded that photobiomodulation with LBP in the treatment of PU, associated or not with adjuvant therapies, such as essential fatty acid based coverings and microcurrent are effective in treating lesions. The efficacy was described in all groups evaluated with LBP with a wavelength in the 660 nm range (red) and a dose of 4 J/cm². This shows that the various approaches expose the heterogeneous nature of the studies, and that there is no effective standardization of the type of laser used, as well as the exposure time and periodicity.
The study by Palagi et al. (2015), brings as a possibility the use of LBP in protocols for the treatment of PU, because through this case study, associated with the literature, it could be observed that this method accelerated tissue proliferation, in addition to increasing local vascularization, favoring a rapid healing of the lesion. Through this study, we concluded on the effectiveness of the use of LBP in the process of pressure ulcer healing, and this therapy should be highlighted as an effective alternative in the treatment of PUs in a critically ill patient.
According to Ribeiro and Marangoni (2020), the present study points to photobiomodulation as an analgesic and reparative alternative for the treatment of traumatic ulcers. In agreement with this study, Lucio and Paula (2020), point out that the use of laser therapy is of paramount importance during the wound healing process, because it is a method that through its anti-inflammatory, analgesic and tissue repair action, provides improvement in the patient's well-being and possibly causes a positive impact on their quality of life. In this study, the treatment using laser therapy proved to be an effective resource, and that when performed by a trained professional, it becomes a safe treatment, showing a significant improvement in the patient's condition.
In this same sense, the study by de Oliveira Bernardes and Jurado (2018) shows that the healthcare professional must have knowledge about the theoretical basis of laser therapy, in addition to the purpose of the laser, because this way the treatment will become effective and obtain the maximum therapeutic benefit. It is noteworthy that according to this study, the use of LBP is capable of reducing the number of bacterial colonies present in pressure lesions.
These findings corroborate with Brauncajs et al., (2018) in which they bring in their study that LBP therapy has potential benefits in combating pathogens that infect pressure ulcers. In agreement with these findings, de Oliveira et al., (2019) point out that photobiomodulation is taken as an effective therapy with regard to the treatment of pressure ulcers. Thus, suggesting that it should be considered as a treatment method for these disorders, reducing the length of hospital stays.

Conclusion
Therefore, the use of photobiomodulation with LBP is of paramount importance for the treatment of PUs, because when used correctly, by a qualified professional, it presents as a positive result in the healing period of the lesion, regardless of the type of associated dressing. Furthermore, it is important to highlight the need for this therapy to be implemented in the treatment of this type of disease, as it was observed that it contributes significantly to improving the quality of life of patients, besides possibly reducing the length of hospital stays.
Furthermore, it is necessary to develop irradiation protocols that can elucidate the correct dose for each case, increasing the credibility of this type of therapy. More studies focused on this theme are essential, because through these findings, it is noted that photobiomodulation has been a promising method in the treatment of wounds, considering that it increases the speed of healing, promotes analgesia, improves circulation, and reduces the cost of conventional dressings. Thus, it is recommended that clinical studies be developed in different scenarios, seeking to bring more evidence regarding the treatment using LBP in the healing process of injuries, which would result in a standardization of the indication of this method.