A prospective, randomized, controlled clinical trial on the efficacy of a single-use negative pressure wound therapy system, compared to traditional negative pressure wound therapy in the treatment of chronic ulcers of the lower extremities

The use of PICO™ single-use negative pressure wound therapy in the community settings

The prevalence and incidence of wounds is predicted to rise due to an ageing population, that is also likely to have an increasing number of comorbidities (Dowsett et al, 2017). This trend will invariably result in increased costs to the NHS. The estimated annual cost of wound management in 2017/2018 was £8.3 billion. The cost of managing 70% of wounds which healed was £2.7 billion while it cost £5.6 billion managing only 30% of unhealed wounds (Guest et al, 2020). In view of these figures, it is important that health professionals (HPs) recognise wounds that are not progressing to healing at an early stage and implement all available treatment modalities to ensure that the wound does not become non-healing or stalled. Therefore, this article defines non-healing wounds, how to identify wounds at risk of becoming non-healing and the timely implementation of advanced treatment modalities, such as single use negative pressure wound therapy (sNPWT).

Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure

Chronic wounds affect ~2% of the U.S. population and increase risks of amputation and mortality. Unfortunately, treatments for such wounds are often expensive, complex, and only moderately effective. Electrotherapy represents a cost-effective treatment; however, its reliance on bulky equipment limits its clinical use. Here, we introduce water-powered, electronics-free dressings (WPEDs) that offer a unique solution to this issue. The WPED performs even under harsh conditions-situations wherein many present treatments fail. It uses a flexible, biocompatible magnesium-silver/silver chloride battery and a pair of stimulation electrodes; upon the addition of water, the battery creates a radial electric field. Experiments in diabetic mice confirm the WPED's ability to accelerate wound closure and promote healing by increasing epidermal thickness, modulating inflammation, and promoting angiogenesis. Across preclinical wound models, the WPED-treated group heals faster than the control with wound closure rates comparable to treatments requiring expensive biologics and/or complex electronics. The results demonstrate the WPED's potential as an effective and more practical wound treatment dressing.

Breakthrough treatments for accelerated wound healing

Skin injuries across the body continue to disrupt everyday life for millions of patients and result in prolonged hospital stays, infection, and death. Advances in wound healing devices have improved clinical practice but have mainly focused on treating macroscale healing versus underlying microscale pathophysiology. Consensus is lacking on optimal treatment strategies using a spectrum of wound healing products, which has motivated the design of new therapies. We summarize advances in the development of novel drug, biologic products, and biomaterial therapies for wound healing for marketed therapies and those in clinical trials. We also share perspectives for successful and accelerated translation of novel integrated therapies for wound healing.

Effectiveness of negative pressure wound therapy on chronic wound healing: A systematic review and meta-analysis

BACKGROUND

Negative Pressure Wound Therapy (NPWT) is considered an effective treatment in facilitating the healing of chronic wounds. However, its effect remains inconsistent, which allows for further investigation.

OBJECTIVE

This study aimed to assess the effectiveness of the NPWT program in improving the management of chronic wound healing.

DESIGN

Systematic review and meta-analysis was used.

DATA SOURCES

The search strategy ranged from 2016 to 2021 in PubMed, CINAHL, ProQuest, and ScienceDirect.

REVIEW METHODS

Risk of bias was done based on the Risk of Bias 2.0 guideline using RevMan 5.4.1, and meta-analysis was done using Jeffreys's Amazing Statistics Program (JASP) software version 0.16.3. Critical appraisal of the included articles was done according to Joanna Briggs Institute's (JBI) appraisal checklist.

RESULTS

A total of 15 articles were included, with 3,599 patients with chronic wounds. There was no publication bias in this study seen from the results of the Egger's test value of 0.447 (p >0.05), symmetrical funnel plot, and fail-safe N of 137. However, heterogeneity among studies was present, with I2 value of 66.7%, Q = 41.663 (p <0.001); thus, Random Effect (RE) model was used. The RE model showed a significant positive effect of the NPWT on chronic wound healing, with z = 3.014, p = 0.003, 95% CI 0.085 to 0.400. The observed effects include decreased rate of surgical site infection, controlled inflammation, edema, and exudate, as well as increased tissue with varying forest plot size, as demonstrated by the small effect size (ES = 0.24, 95% CI -0.26 to 0.79, p <0.05).

CONCLUSION

The analysis results show that the standard low pressure of 80-125 mmHg could improve microcirculation and accelerate the healing process of chronic wounds. Therefore, applying the NPWT program could be an alternative to nursing interventions. However, it should be carried out by competent wound nurses who carry out procedure steps, implement general patient care, and give tips on overcoming device problems and evaluation.

PROSPERO REGISTRATION NUMBER

CRD42022348457.

The local physiological effects of a single-use topical negative pressure device in healthy volunteers: the PICO-1 study

OBJECTIVE

This study aimed to investigate the effects of a single-use negative pressure wound therapy (sNPWT) device on tissue perfusion, oxygenation and pressure in the intact skin of healthy volunteers.

METHOD

Healthy volunteers wore a PICO sNPWT device (Smith+Nephew, UK) on their right medial calf for one week. Perfusion, tissue oxygenation and tissue pressure were recorded in superficial and deep tissues over a period of seven days. At the baseline visit, measurements were recorded before and after dressing application without activation. Macrovascular flow and transduced needle pressure measures were recorded at 0 minutes, 30 minutes and 60 minutes after device activation. Superficial tissue perfusion and both oxygenation measures were recorded continuously over the hour following activation. All outcome measures were repeated at 24 hours and again after seven days, both with the dressing and following dressing removal.

RESULTS

The device was associated with a measurable increase in perfusion of the limb in 12 healthy volunteers. Superficial tissue oxygenation adjacent to the dressing was reduced during wear, while deeper tissue demonstrated an increase in oxygenation levels. Superficial skin perfusion was observed to differ between skin overlying muscle and that overlying bone. Pressure in tissue underneath the dressing pad was increased throughout dressing wear and returned to baseline levels on dressing removal.

CONCLUSION

sNPWT produced measurable changes in local physiology in healthy volunteers with intact skin, despite the absence of a wound. Effects may differ according to anatomical site and the composition of underlying tissues. Other factors that promote healing were not explored in this study.

DECLARATION OF INTEREST

This study was funded by Smith+Nephew investigator-initiated grant IIS 684. The funder had no input into study design, conduct, analysis, manuscript preparation or dissemination. The authors have no conflicts of interest to declare.

Effective negative pressure wound therapy for open wounds: The importance of consistent pressure delivery

Two distinct design concepts exist for single-use negative pressure wound therapy systems: Canister-based versus canisterless. The canister-based technology provides intrinsic stable delivery of the intended negative pressure, because exudate is constantly transferred from the wound into a canister, thereby preventing dressing saturation. In contrast, with a canisterless system, where delivery of the negative pressure depends on continuous evaporation of wound fluids from its dressing, loss of the intended wound-bed pressure may occur due to dressing saturation. To investigate whether these two designs differ in their mechanobiological effect with respect to magnitudes and distributions of tissue strain fields under the absorptive dressing, termed the influence zone, we integrated computational modelling with an animal study. This influence zone must be of biologically influential strain levels and extend sufficiently into the peri-wound for stimulating fibroblasts to migrate and progress the healing. We found that an effective influence zone requires continuous delivery of the intended pressure to the wound-bed. Loss of negative pressure at the wound-bed below 40 mmHg adversely lowered the peri-wound stimulation around a 120 × 70 mm sized wound to less than one-third of the baseline stimulation, and further pressure decreases to 20 mmHg or lower resulted in complete lack of peri-wound mechano-stimulation.

Chronic wounds: Treatment consensus

The Wound Healing Foundation (WHF) recognised a need for an unbiased consensus on the best treatment of chronic wounds. A panel of 13 experts were invited to a virtual meeting which took place on 27 March 2021. The proceedings were organised in the sub-sections diagnosis, debridement, infection control, dressings, grafting, pain management, oxygen treatment, outcomes and future needs. Eighty percent or better concurrence among the panellists was considered a consensus. A large number of critical questions were discussed and agreed upon. Important takeaways included that wound care needs to be simplified to a point that it can be delivered by the patient or the patient's family. Another one was that telemonitoring, which has proved very useful during the COVID-19 pandemic, can help reduce the frequency of interventions by a visiting nurse or a wound care center. Defining patient expectations is critical to designing a successful treatment. Patient outcomes might include wound specific outcomes such as time to heal, wound size reduction, as well as improvement in quality of life. For those patients with expectations of healing, an aggressive approach to achieve that goal is recommended. When healing is not an expectation, such as in patients receiving palliative wound care, outcomes might include pain reduction, exudate management, odour management and/or other quality of life benefits to wound care.

A prospective, randomized, controlled clinical study on the effectiveness of a single-use negative pressure wound therapy system, compared to traditional negative pressure wound therapy in the treatment of diabetic ulcers of the lower extremities

A multicenter, phase 4, randomized, comparative-efficacy study in subjects with lower extremity wounds was carried out to compare wound closure rates, for a single-use negative pressure wound therapy (s-NPWT) versus traditional NPWT (t-NPWT) systems over a 12-week treatment period. From the initial population of patients with diabetic foot ulcers (DFU) and venous leg ulcers (VLU), we analyzed a subgroup of patients with diabetes mellitus and leg and foot ulcers (either DFUs or VLUs in diabetics), termed, the diabetic lower extremity ulcers (DLEU). In the DLEU group, there were 95 patients in intention-to-treat (ITT) and 61 patients in per protocol (PP) populations, respectively. We found a significant difference in favor of s-NPWT over t-NPWT in the confirmed wound closures at 12 weeks both in ITT (p < 0.001) and PP populations (p = 0.017). Significantly higher wound closure rates in s-NPWT group suggest that s-NPWT should be preferred NPWT option for DLEU.

Pre-Clinical Assessment of Single-Use Negative Pressure Wound Therapy During In Vivo Porcine Wound Healing

Objective: Traditional negative pressure wound therapy (tNPWT) systems can be large and cumbersome, limiting patient mobility and adversely affecting quality of life. PICO™, a no canister single-use system, offers a lightweight, portable alternative to tNPWT, with improved clinical performance. The aim of this study was to determine the potential mechanism(s) of action of single-use NPWT (sNPWT) versus tNPWT. Approach: sNPWT and tNPWT were applied to an in vivo porcine excisional wound model, following product use guidelines. Macroscopic, histological, and biochemical analyses were performed at defined healing time points to assess multiple aspects of the healing response. Results: Wounds treated with single-use negative pressure displayed greater wound closure and increased reepithelialization versus those treated with traditional negative pressure. The resulting granulation tissue was more advanced with fewer neutrophils, reduced inflammatory markers, more mature collagen, and no wound filler-associated foreign body reactions. Of note, single-use negative pressure therapy failed to induce wound edge epithelial hyperproliferation, while traditional negative pressure therapy compromised periwound skin, which remained inflamed with high transepidermal water loss; features not observed following single-use treatment. Innovation: Single-use negative pressure was identified to improve multiple aspects of healing versus traditional negative pressure treatment. Conclusion: This study provides important new insight into the differing mode of action of single-use versus traditional negative pressure and may go some way to explaining the improved clinical outcomes observed with single-use negative pressure therapy.

Growth Promoting Effect of Vacuum Sealing Drainage in the Healing Processes of Diabetic Foot Ulcers

Aim

To explore the growth-promoting effect of vacuum sealing drainage (VSD) during the healing processes of diabetic foot ulcers (DFUs).

Methods

From November 2018 to December 2019, 38 patients with unilateral DFUs were enrolled in this retrospective study. All patients were divided into two groups according to the use of VSD or not: the VSD group (n=20) and the control group (n=18). The following parameters were used to evaluate the healing process: changes in the mean areas of the ulcers; healing rate (HR); epithelial hyperplasia and angiogenesis as determined by hematoxylin-eosin staining (HE staining); and expression of CD34, CD68 and VEGF as assessed through immunohistochemistry. Perioperative side effects and complications were also recorded.

Results

All patients received follow-up and eventually healed. The mean area of wounds was reduced in the VSD group compared to the control group (1.75±0.64 cm² vs 0.88±0.54 cm², P=0.031). The mean HR of the ulcers in the VSD group was significantly higher than that in the control group (35.23±2.87% vs 28.78±1.09%, P=0.017). HE staining showed that the amount of epithelial hyperplasia and angiogenesis increased significantly after VSD, and the immunohistochemistry results showed that the expression of CD34, CD68 and VEGF increased significantly in the VSD group.

Conclusion

VSD could significantly accelerate the wound healing process, probably by enhancing the inflammatory response and promoting granulation and angiogenesis in DFUs.

Cellular benefits of single-use negative pressure wound therapy demonstrated in a novel ex vivo human skin wound model

Negative pressure wound therapy is a widely used treatment for chronic, nonhealing wounds. Surprisingly, few studies have systematically evaluated the cellular and molecular effects of negative pressure treatment on human skin. In addition, no study to date has directly compared recently available single-use negative pressure modalities to traditional negative pressure devices in a controlled setting. Here we developed a novel large-scale ex vivo human skin culture system to effectively evaluate the efficacy of two different negative pressure wound therapy modalities. Single-use and traditional negative pressure devices were applied to human ex vivo wounded skin sheets cultured over a period of 48 hours. Cellular tissue response to therapy was evaluated via a combination of histological analysis and transcriptional profiling, in samples collected from the wound edge, skin adjacent to the wound, and an extended skin region. Single-use negative pressure wound therapy caused less damage to wound edge tissue than traditional application, demonstrated by improved skin barrier, reduced dermal-epidermal junction disruption and a dampened damage response. Transcriptional profiling confirmed significantly less activation of multiple pro-inflammatory markers in wound edge skin treated with single-use vs traditional negative pressure therapy. These findings may help to explain the greater efficacy of sNPWT in the clinic, while offering a noninvasive system to develop improved NPWT-based therapies.

A Wound Treatment Strategy for "Super Long-Term Difficult-to-Heal Wounds": A Single-Center Retrospective Study

Chronic wounds are a challenge for clinicians. Treating chronic wounds in elderly patients is difficult due to comorbidities and poor immunity, tissue renewal, and regeneration. This study shared the therapeutic experiences of 40 patients with super long-term difficult-to-heal wounds and to describe the effects of negative pressure wound therapy (NPWT)-assisted debridement and autologous scalp grafting. Elderly patients with chronic wounds for more than 60 years who underwent NPWT-assisted debridement and autologous scalp grafting between 2015 and 2017 were retrospectively analyzed. Forty patients were identified and analyzed. Among all patients, the average wound area was 56 (interquartile range 30-90) cm². The wound infection rate was 82.1%, and that before the first autologous scalp grafting was 51.3%. The average total number of surgeries was 3, and the number of times the NPWT device was replaced was once. A total of 97.4% of patients had one autologous scalp grafting performed. The transplanted scalp survived completely in 97.4% of patients. One hundred percent of patients had no postoperative complications and healed. The average wound healing time was 34.5 ± 10.1 days. This study showed that NPWT-assisted debridement and autologous scalp grafting have the advantages of high survival rate of the skin and decreased wound recurrence and may be a suitable treatment for super long-term difficult-to-heal wounds in elderly patients.