Treating a pressure ulcer with bio-electric stimulation therapy

Anti-Biofilm Activity of a Tunable Hypochlorous Acid-Generating Electrochemical Bandage Controlled By a Wearable Potentiostat

Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic-resistant microorganisms and biofilm-specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. We designed an HOCl-generating electrochemical bandage (e-bandage) that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. We developed a battery-operated wearable potentiostat that controls the e-bandage electrodes at potentials suitable for HOCl generation. We demonstrated that e-bandage treatment was tunable by changing the applied potential. HOCl generation on electrode surfaces was verified using microelectrodes. The developed e-bandage showed time-dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to non-detectable levels within 6 and 12 hours of treatment, respectively. The developed e-bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections.

Possible Synergies of Nanomaterial-Assisted Tissue Regeneration in Plasma Medicine: Mechanisms and Safety Concerns

Cold atmospheric plasma and nanomedicine originally emerged as individual domains, but are increasingly applied in combination with each other. Most research is performed in the context of cancer treatment, with only little focus yet on the possible synergies. Many questions remain on the potential of this promising hybrid technology, particularly regarding regenerative medicine and tissue engineering. In this perspective article, we therefore start from the fundamental mechanisms in the individual technologies, in order to envision possible synergies for wound healing and tissue recovery, as well as research strategies to discover and optimize them. Among these strategies, we demonstrate how cold plasmas and nanomaterials can enhance each other's strengths and overcome each other's limitations. The parallels with cancer research, biotechnology and plasma surface modification further serve as inspiration for the envisioned synergies in tissue regeneration. The discovery and optimization of synergies may also be realized based on a profound understanding of the underlying redox- and field-related biological processes. Finally, we emphasize the toxicity concerns in plasma and nanomedicine, which may be partly remediated by their combination, but also partly amplified. A widespread use of standardized protocols and materials is therefore strongly recommended, to ensure both a fast and safe clinical implementation.

Electrical Stimulation to Enhance Wound Healing

Electrical stimulation (ES) can serve as a therapeutic modality accelerating the healing of wounds, particularly chronic wounds which have impaired healing due to complications from underlying pathology. This review explores how ES affects the cellular mechanisms of wound healing, and its effectiveness in treating acute and chronic wounds. Literature searches with no publication date restrictions were conducted using the Cochrane Library, Medline, Web of Science, Google Scholar and PubMed databases, and 30 full-text articles met the inclusion criteria. In vitro and in vivo experiments investigating the effect of ES on the general mechanisms of healing demonstrated increased epithelialization, fibroblast migration, and vascularity around wounds. Six in vitro studies demonstrated bactericidal effects upon exposure to alternating and pulsed current. Twelve randomized controlled trials (RCTs) investigated the effect of pulsed current on chronic wound healing. All reviewed RCTs demonstrated a larger reduction in wound size and increased healing rate when compared to control groups. In conclusion, ES therapy can contribute to improved chronic wound healing and potentially reduce the financial burden associated with wound management. However, the variations in the wound characteristics, patient demographics, and ES parameters used across studies present opportunities for systematic RCT studies in the future.

Hypochlorous-Acid-Generating Electrochemical Scaffold for Treatment of Wound Biofilms

Biofilm formation causes prolonged wound infections due to the dense biofilm structure, differential gene regulation to combat stress, and production of extracellular polymeric substances. Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa are three difficult-to-treat biofilm-forming bacteria frequently found in wound infections. This work describes a novel wound dressing in the form of an electrochemical scaffold (e-scaffold) that generates controlled, low concentrations of hypochlorous acid (HOCl) suitable for killing biofilm communities without substantially damaging host tissue. Production of HOCl near the e-scaffold surface was verified by measuring its concentration using needle-type microelectrodes. E-scaffolds producing 17, 10 and 7 mM HOCl completely eradicated S. aureus, A. baumannii, and P. aeruginosa biofilms after 3 hours, 2 hours, and 1 hour, respectively. Cytotoxicity and histopathological assessment showed no discernible harm to host tissues when e-scaffolds were applied to explant biofilms. The described strategy may provide a novel antibiotic-free strategy for treating persistent biofilm-associated infections, such as wound infections.

The Efficacy of Pressure Ulcer Treatment With Cathodal and Cathodal-Anodal High-Voltage Monophasic Pulsed Current: A Prospective, Randomized, Controlled Clinical Trial

BACKGROUND

Studies show that anode and cathode electrical stimulation (ES) promotes the healing of wounds, but specific protocols for both electrodes are not available.

OBJECTIVE

To compare the effectiveness of cathodal versus cathodal+anodal ES in the treatment of Category II-IV pressure ulcers (PrUs).

DESIGN

Prospective, randomized, controlled, clinical study.

SETTING

Three nursing and care centers.

PATIENTS

Sixty-three participants with PrUs were randomly formed into a cathodal ES group (CG: N = 23; mean age of 79.35; SD 8.48), a cathodal+anodal ES group (CAG: N = 20; mean age of 79.65; SD 11.44) and a placebo ES group (PG: N = 20; mean age of 76.75; SD 12.24).

INTERVENTION

All patients were treated with standard wound care and high-voltage monophasic pulsed current (HVMPC; twin-peak impulses; 154 μs; 100 pps; 0.25 A; 250 μC/s) for 50 minutes per day, 5 times a week, for 6 weeks. The CG, CAG, and PG received, respectively, cathodal, cathodal+anodal, and sham ES through electrodes placed on a moist gauze pad. The treatment electrode was placed on the wound, and the return electrode was positioned on healthy skin at least 20 cm from the PrU.

MEASUREMENTS

Measurements were made at baseline, and after each of the 6 weeks of treatment. Primary outcome was percentage wound surface area reduction at week 6.

RESULTS

Wound surface area decreased in the CG by 82.34% (95% confidence interval [CI] 70.06-94.63) and in the CAG by 70.77% (95% CI 53.51-88.04). These reductions were significantly greater than in the PG (40.53%; 95% CI 23.60-57.46). The CG and CAG were not statistically significantly different regarding treatment results.

LIMITATIONS

The time of treatment proved insufficient for PrUs to close.

CONCLUSIONS

Cathodal and cathodal+anodal HVMPC similarly reduced the area of Category II-IV PrUs.

Electrical Stimulation and Cutaneous Wound Healing: A Review of Clinical Evidence

Electrical stimulation (ES) has been shown to have beneficial effects in wound healing. It is important to assess the effects of ES on cutaneous wound healing in order to ensure optimization for clinical practice. Several different applications as well as modalities of ES have been described, including direct current (DC), alternating current (AC), high-voltage pulsed current (HVPC), low-intensity direct current (LIDC) and electrobiofeedback ES. However, no one method has been advocated as the most optimal for the treatment of cutaneous wound healing. Therefore, this review aims to examine the level of evidence (LOE) for the application of different types of ES to enhance cutaneous wound healing in the skin. An extensive search was conducted to identify relevant clinical studies utilising ES for cutaneous wound healing since 1980 using PubMed, Medline and EMBASE. A total of 48 studies were evaluated and assigned LOE. All types of ES demonstrated positive effects on cutaneous wound healing in the majority of studies. However, the reported studies demonstrate contrasting differences in the parameters and types of ES application, leading to an inability to generate sufficient evidence to support any one standard therapeutic approach. Despite variations in the type of current, duration, and dosing of ES, the majority of studies showed a significant improvement in wound area reduction or accelerated wound healing compared to the standard of care or sham therapy as well as improved local perfusion. The limited number of LOE-1 trials for investigating the effects of ES in wound healing make critical evaluation and assessment somewhat difficult. Further, better-designed clinical trials are needed to improve our understanding of the optimal dosing, timing and type of ES to be used.

Clinical Trials Involving Biphasic Pulsed Current, MicroCurrent, and/or Low-Intensity Direct Current

Significance: This invited critical review will summarize an expansive body of literature regarding electrical stimulation (ES) and wound healing. Several clinical reports have been published in which ES has been evaluated as a therapy to speed the closure of chronic wounds. Different forms of ES have been applied in varying ways and described using inconsistent terminology by researchers and clinicians around the world. It is important to compile this research and to critically appraise the findings so that clinicians who are not familiar with this field can interpret the research. Recent Advances: More recently, ES has been delivered at subsensory levels (termed microcurrent in this review) using very small electrical devices contained within wound dressing. While these newer technologies have obvious technical advances, what research has been published to date about these new devices has not produced findings that suggest this form of ES can accelerate wound closure. Critical Issues: Reviewing a collection of published reports on this subject reveals that not all forms of ES produce beneficial results. Rather, only certain ES protocols such as monophasic pulsed current applied to the wound and biphasic pulsed current current that is applied for 2 h daily to periulcer skin at intensities which produce motor responses have consistently demonstrated positive results. Future Directions: Optimal stimulus parameters and treatment schedule for ES used to treat chronic wounds need to be determined. Researchers publishing in this field should provide detailed information about their ES treatment protocol and use a similar terminology to describe the ES waveform and stimulus parameters.

Electrical Stimulation Technologies for Wound Healing

Objective: To discuss the physiological bases for using exogenously applied electric field (EF) energy to enhance wound healing with conductive electrical stimulation (ES) devices. Approach: To describe the types of electrical currents that have been reported to enhance chronic wound-healing rate and closure. Results: Commercial ES devices that generate direct current (DC), and mono and biphasic pulsed current waveforms represent the principal ES technologies which are reported to enhance wound healing. Innovation: Wafer-thin, disposable ES technologies (wound dressings) that utilize mini or micro-batteries to deliver low-level DC for wound healing and antibacterial wound-treatment purposes are commercially available. Microfluidic wound-healing chips are currently being used with greater accuracy to investigate the EF effects on cellular electrotaxis. Conclusion: Numerous clinical trials described in subsequent sections of this issue have demonstrated that ES used adjunctively with standard wound care (SWC), enhances wound healing rate faster than SWC alone.

Modulating endogenous electric currents in human corneal wounds--a novel approach of bioelectric stimulation without electrodes

PURPOSE

To measure electric current in human corneal wounds and test the feasibility of pharmacologically enhancing the current to promote corneal wound healing.

METHODS

Using a noninvasive vibrating probe, corneal electric current was measured before and after wounding of the epithelium of donated postmortem human corneas. The effects of drug aminophylline and chloride-free solution on wound current were also tested.

RESULTS

Unwounded cornea had small outward currents (0.07 μA/cm²). Wounding increased the current more than 5 fold (0.41 μA/cm²). Monitoring the wound current over time showed that it seemed to be actively regulated and maintained above normal unwounded levels for at least 6 hours. The time course was similar to that previously measured in rat cornea. Drug treatment or chloride-free solution more than doubled the size of wound currents.

CONCLUSIONS

Electric current at human corneal wounds can be significantly increased with aminophylline or chloride-free solution. Because corneal wound current directly correlates with wound healing rate, our results suggest a role for chloride-free and/or aminophylline eyedrops to enhance healing of damaged cornea in patients with reduced wound healing such as the elderly or diabetic patient. This novel approach offers bioelectric stimulation without electrodes and can be readily tested in patients.

Modelling the cost-utility of bio-electric stimulation therapy compared to standard care in the treatment of elderly patients with chronic non-healing wounds in the UK

OBJECTIVE

To estimate the cost-utility of bio-electric stimulation therapy (Posifect) compared to standard care in elderly patients with chronic, non-healing wounds of > 6 months duration, from the perspective of the National Health Service (NHS) in the UK.

METHODS

Clinical and resource use data from a 16 week clinical evaluation of bio-electric stimulation therapy among patients who had recalcitrant wounds were combined with utility data obtained from a standard gamble analysis to construct a 16 week Markov model. The model considers the decision by a clinician to continue with a patient's previous care plan or treat with bio-electric stimulation therapy. Unit resource costs at 2005/2006 prices were applied to the resource utilisation estimates within the model, enabling the cost-utility of bio-electric stimulation therapy compared to standard care to be estimated. The acquisition cost of Posifect had not been decided at the time of performing this study. Hence, the base case analysis used a cost of 50 pounds per dressing.

RESULTS

33% of all wounds are expected to heal within 16 weeks after the start of bio-electric stimulation therapy. Consequently, using bio-electric stimulation therapy is expected to lead to a 51% decrease in the number of domiciliary clinician visits, from 4.7 to 2.3 per week. The model also showed that using bio-electric stimulation therapy instead of patients' standard care is expected to reduce the NHS cost of managing them by 16% from 2287 pounds (95% CI: 1838 pounds; 2735 pounds) to 1921 pounds (95% CI: 1609 pounds; 2233 pounds) and result in a health gain of 0.023 QALYs over 16 weeks. Hence, bio-electric stimulation therapy was found to be a dominant treatment. Sensitivity analyses demonstrated that the cost-utility of using bio-electric stimulation therapy relative to standard care is very sensitive to the acquisition cost of the therapy, the acquisition cost of patients' drugs and the number of clinician visits and less sensitive to utility values and the acquisition cost of other dressings.

CONCLUSION

Within the limitations of the model, bio-electric stimulation therapy is expected to afford the NHS a cost-effective dressing compared to standard care in the management of chronic non-healing wounds of > 6 months duration. Bio-electric stimulation therapy's acquisition cost is expected to be offset by a reduction in the requirement for domiciliary clinician visits, leading to a release of NHS resources for use elsewhere in the system, thereby generating an increase in NHS efficiency.

An introduction to various types of leg ulcers and their management

There are many reasons for tissue breakdown in the leg, and each cause requires a different treatment to either correct the abnormality or to manage the symptoms that cause the patient distress. The pathway to appropriate treatment relies on a working knowledge of anatomy and physiology and good assessment. This article aims to provide a basic knowledge in how to recognize different leg ulcer types.