Effect Of Negative Pressure Wound Therapy Research Articles

Negative pressure wound therapy versus standard treatment in patients with acute conflict-related extremity wounds: a pragmatic, multisite, randomised controlled trial

In armed conflict, injuries among civilians are usually complex and commonly affect the extremities. Negative pressure wound therapy (NPWT) is an alternative to standard treatment of acute conflict-related extremity wounds. We aimed to compare the safety and effectiveness of NPWT with that of standard treatment. In this pragmatic, randomised, controlled superiority trial done at two civilian hospitals in Jordan and Iraq, we recruited patients aged 18 years or older, presenting with a conflict-related extremity wound within 72 h after injury. Participants were assigned (1:1) to receive either NPWT or standard treatment. We used a predefined, computer-generated randomisation list with three block sizes. Participants and their treating physicians were not masked to treatment allocation. The primary endpoint was wound closure by day 5. The coprimary endpoint was net clinical benefit, defined as a composite of wound closure by day 5 and freedom from any bleeding, wound infection, sepsis, or amputation of the index limb. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT02444598, and is closed to accrual. Between June 9, 2015, and Oct 24, 2018, 174 patients were randomly assigned to either the NPWT group (n=88) or the standard treatment group (n=86). Five patients in the NPWT group and four in the standard treatment group were excluded from the intention-to-treat analysis. By day 5, 41 (49%) of 83 participants in the NPWT group and 49 (60%) of 82 participants in the standard treatment group had closed wounds, with an absolute difference of 10 percentage points (95% CI -5 to 25, p=0·212; risk ratio [RR] 0·83, 95% CI 0·62 to 1·09). Net clinical benefit was seen in 33 (41%) of 81 participants in the NPWT group and 34 (44%) of 78 participants in the standard treatment group, with an absolute difference of 3 percentage points (95% CI -12 to 18, p=0·750; RR 0·93, 95% CI 0·65 to 1·35). There was one in-hospital death in the standard treatment group and none in the NPWT group. The proportion of participants with sepsis, bleeding leading to blood transfusion, and limb amputation did not differ between groups. NPWT did not yield superior clinical outcomes compared with standard treatment for acute conflict-related extremity wounds. The results of this study not only question the use of NPWT, but also question the tendency for new and costly treatments to be introduced into resource-limited conflict settings without supporting evidence for their effectiveness. This study shows that high-quality, randomised trials in challenging settings are possible, and our findings support the call for further research that will generate context-specific evidence. The Stockholm County Council, the Swedish National Board of Health and Welfare, and Médecins Sans Frontières.

The effectiveness of negative-pressure wound therapy for wound healing after stoma reversal: a randomised control study (SR-PICO study)

BackgroundAlthough the wound-healing period for purse-string closure (PSC) after stoma reversal is longer than that required for the primary closure method, the rate of wound infection is reduced. The application of negative-pressure wound therapy (NPWT) can reduce the healing period for many types of wounds. Herein, we describe a planned trial to test the hypothesis that NPWT can reduce the healing period for PSC after stoma reversal.Methods/designPatients undergoing stoma reversal will be recruited and allocated into intervention and control groups, with 1:1 randomisation. Patients in the control group will receive standard postsurgical wound care; patients in the intervention group will receive NPWT using the PICO™ system. The target sample size will be 38 patients, as this will provide 80% power at the 5% level of significance to detect a 7-day reduction in the wound-healing period in the intervention group compared to that in the control group. The primary endpoint will be the duration to wound healing, defined as the time to nearly complete epithelisation of the wound, without any discharge or surgical site infection (SSI). Secondary endpoints will be the SSI rate, length of postoperative hospital stay, number of wound dressings and visits to the hospital for wound dressing after discharge, total cost of wound dressings, and patient and observer scar assessment scale scores.DiscussionThe results of this planned randomised controlled study will clarify the role of NPWT in patients undergoing stoma reversal and strengthen the rationale for choosing a dressing technique.Trial registrationClinical Research Information Service (CRIS), KCT0004063. Registered on 6 June 2019.

What are the effects of negative-pressure wound therapy (NPWT) for people with surgical wounds healing by secondary intention?

What are the effects of negative-pressure wound therapy (NPWT) for people with surgical wounds healing by secondary intention?

What are the effects of negative-pressure wound therapy (NPWT) on surgical wounds healing by primary closure?

What are the effects of negative-pressure wound therapy (NPWT) on surgical wounds healing by primary closure?

Impact of negative-pressure wound therapy on bacterial behaviour and bioburden in a contaminated full-thickness wound.

The use of negative-pressure wound therapy (NPWT) has displayed significant clinical benefits in the healing of infected wounds. However, the effects of NPWT on bacterial colonisation and infection of traumatic wounds has been controversial. The aim of this study is to evaluate the impact of NPWT treatment in rabbits with a contaminated full-thickness wound on bacterial behaviour, including colony morphology, spatial distribution, fissional proliferation, and bacterial bioburden. Full-thickness wounds were created on the back of rabbits, and were inoculated with bioluminescent Staphylococcus aureus. The wounds were treated with sterile gauze dressings and NPWT with continuous negative pressure (-125 mm Hg). Wound samples were harvested on days 0 (6 hours after bacterial inoculation), 2, 4, 6, and 8 at the centre of wound beds before irrigation. Scanning electron microscopy and transmission electron microscopy (TEM) analyses were performed to determine the characteristic bacteriology. Laser scanning confocal microscopy was performed to obtain bioluminescent images, which were used to observe spatial distribution of the GFP-labelled S. aureus within the tissue and quantify the bacterial bioburden. NPWT resulted in sparse amounts of scattered bacteria on the wound surface or as sparsely spaced single colonies within the tissue. Wound bioburden on day 8 in the NPWT and gauze groups was 34.6 ± 5.5% and 141.9 ± 15.4% of the baseline values (N = 6), respectively (P < .0001). TEM showed a lack of S. aureus active fission within NPWT-treated tissue. NPWT can impact S. aureus colony morphology and spatial distribution both on the surface and within wound tissue, and reduce S. aureus as early as 48 hours after therapy initiation. Additionally, NPWT inhibits bacterial fissional proliferation in microcolonies.

Experience of negative pressure wound therapy over sternal wound healing: A retrospective review

Objectives The aim of this study was to retrospectively review the effectiveness of negative pressure wound therapy (NPWT) in sternal wound healing with the use of the validated Bates-Jensen Wound Assessment Tool (BWAT), and explore the role of NPWT over sternal wounds and future treatment pathways. Methods Data was gathered from patients' medical records and the institution's database clinical management system. Seventeen subjects, who had undergone cardiothoracic surgeries and subsequently consulted the wound care team in one year were reviewed. Fourteen of them were included in the analysis. Healing improvement of each sternal wound under continuous NPWT and continuous conventional dressings was studied. In total, 23 continuous NPWT and 13 conventional dressing episodes were analysed with the BWAT. Results Among conventional dressing episodes, sternal wound improvement was 2.5–3% over 10 days to 3.5 weeks, whereas 4–5% sternal healing was achieved in 5 days to 2 weeks with sternal wire presence. Better healing at 11% in 1 week by conventional dressing was attained after sternal wire removal. In NPWT episodes, 8–29%, 13–24%, and 15–46% of healing was observed in 2 weeks, 3.5 to 5 weeks and 6 to 7 weeks, respectively. Only 39% wound healing was acquired at the 13th week of NPWT in one subject. With sternal wire present, 6%–29% wound healing progress was achieved by NPWT in 1–4 weeks, and 16–23% wound improvement in 2 to 4.5 weeks by NWPT after further surgical debridement. After sternal wire removal, 6–34% sternal wound healing occurred by continuous NPWT for 1–2 weeks, and maximum healing at 46% after 2.5 weeks of NPWT were observed. Conclusions Better wound healing was achieved in the NPWT group in comparison to conventional dressings alone. However, suboptimal sternal wound healing by NPWT alone was observed. Removal of sternal wire may improve the effectiveness of NPWT. Successful tertiary closure after NPWT among subjects supports the important bridging role of NPWT in sternal wound healing. Factors causing stagnant sternal wound healing by NPWT alone are discussed.

631-P: Negative Pressure Wound Therapy May Affect Circulating Plasma MicroRNAs in Patients with Diabetic Foot Ulceration

Background: Negative pressure wound therapy (NPWT) has been successfully used as treatment for diabetic foot ulceration (DFU). However, the molecular mechanisms of its action, especially outside of the wound bed, are not fully understood. We assessed the effect of NPWT on levels of circulating plasma microRNAs in patients with type 2 diabetes (T2DM) and DFU. Methods: We included 33 patients with T2DM and DFU - 23 individuals were assigned to NPWT and 10 to standard treatment (ST). Assignment to NWPT was based on routine clinical recommendations and not random. MicroRNAs enriched RNA was extracted from plasma at two time points: before treatment and after 8±1 days of treatment. Prepared small RNA libraries were sequenced on the NextSeq 500 sequencer (Illumina). Generated reads were aligned to mirBase 21 using Bowtie and counted using miRDeep2 software. Statistical analysis of differentially expressed microRNAs was performed via the edgeR package in the R environment. Results: The NPWT and ST groups were similar in terms of basic clinical characteristics, such as age (67.8 vs. 67.8 years, p=0.95) and HbA1c level (7% vs. 7.8%, p=0.15). We identified three miRNAs - miR-6842, miR-3690 and miR-11400 - that were expressed at a higher level post-treatment in the NPWT group as compared to the ST group. Interestingly, miR-3690 has been previously predicted to target mRNA of T-cell surface glycoprotein CD3 gamma chain (CD3G), therefore, it may be hypothesized that it affects the expression of CD3 and modulate the immune response. Additionally, in the NPWT group we observed a downregulation of miR-9 as compared to the initial level. MiR-9 is expressed in human monocytes and neutrophils upon activation. Thus, it may regulate the synthesis of proinflammatory mediators. Conclusions: We found initial evidence that short-term NPWT use in T2DM patients with DFU may affect miRNA expression in plasma and act through promoting immune system factors in the wound bed. Disclosure P. Kapusta: None. J. Hohendorff: Other Relationship; Self; Abbott, Ascensia Diabetes Care, Novo Nordisk A/S, Sanofi-Aventis. J. Zuranska: None. S. Borys: None. P. Konieczny: None. B.M. Kiec-Wilk: None. P.P. Wolkow: None. M. Malecki: Advisory Panel; Self; Abbott Laboratories, AstraZeneca, Bioton, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Merck Sharp &amp; Dohme Corp., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Sanofi-Aventis. Speaker's Bureau; Self; Merck &amp; Co., Inc. Funding National Science Centre of Poland (2013/11/B/NZ5/03298)

Negative-Pressure Wound Therapy for Managing Complicated Wounds at Extracorporeal Membrane Oxygenation Sites.

To evaluate the effectiveness of negative-pressure wound therapy (NPWT) for management of wound complications at extracorporeal membrane oxygenation (ECMO) removal sites. The authors retrospectively reviewed patients who underwent NPWT at ECMO removal sites followed by the development of wound complications including skin necrosis, lymphorrhea, and femoral vessel exposure. A nonadhesive bacteria-binding mesh was used as a wound contact layer of NPWT application. Patient characteristics and clinical outcomes were evaluated. Nine patients underwent NPWT for complicated wounds at ECMO sites. The mean age of patients was 49.2 years (range, 14-64 years). All patients exhibited wound complications with lymphorrhea and skin necrosis. Seven of nine patients had wound cultures that were positive for microorganisms, but culture conversion to negative was achieved after NPWT application for a mean period of 21.2 days (range, 12-30 days). Lymphorrhea was successfully managed, and formation of fresh granulation tissue was observed in all patients. Wound healing either by primary closure, skin graft, or secondary healing was achieved without recurrence of wound complications. There were no cases of femoral vessel injury or aneurysm during NPWT application. Negative-pressure wound therapy appears to be a safe and effective treatment option in the management of complicated wounds at ECMO sites.

Wound Healing In Surgery for Trauma (WHIST): statistical analysis plan for a randomised controlled trial comparing standard wound management with negative pressure wound therapy

BackgroundIn the context of major trauma, the rate of wound infection in surgical incisions created during fracture fixation amongst patients with closed high-energy injuries is high. One of the factors which may reduce the risk of surgical site infection is the type of dressing applied over the closed incision. The WHIST trial evaluates the effects of negative-pressure wound therapy (NPWT) compared with standard dressings.Methods/designThe WHIST trial is a multicentre, parallel group, randomised controlled trial. The primary outcome is the rate of deep surgical site infection at 30 days after major trauma. Secondary outcomes are measured at 3 and 6 months post-randomisation and include the Disability Rating Index, the EuroQoL EQ-5D-5 L, the Doleur Neuropathique Questionnaire, a patient-reported scar assessment, and record of complications. The analysis approaches for the primary and secondary outcomes are described here, as are the descriptive statistics which will be reported. The full WHIST protocol has already been published.DiscussionThis paper provides details of the planned statistical analyses for this trial and will reduce the risks of outcome reporting bias and data driven results.Trial registrationInternational Standard Randomised Controlled Trials database, ISRCTN12702354. Registered on 9 December 2015.

Effect of negative-pressure wound therapy on the circulating number of peripheral endothelial progenitor cells in diabetic patients with mild to moderate degrees of ischaemic foot ulcer.

Objective To investigate the effect of negative-pressure wound therapy (NPWT) on the circulating number of endothelial progenitor cells (EPCs) in diabetic patients with mild to moderate degrees of ischemic foot ulcer. Methods We selected 84 diabetic patients who had a foot ulcer with a duration of at least four weeks and who had an ankle-brachial index of 0.5–0.9. Patients were assigned to one two groups according to 2:1 randomization: NPWT group ( n = 56) and non-NPWT (patients who did not receive NPWT) group ( n = 28). The control group (NC group) was composed of 18 patients who had normal glucose tolerance and lower extremity ulcer without arteriovenous disease. NPWT was performed on the ulcer after debridement for one week for patients in both the NPWT group and the NC group, and the patients in the non-NPWT group received conventional treatment process. The circulating number of EPCs was measured before and after various treatments, and the factors influencing their changes were analysed. Results After NPWT, the circulating number of EPCs significantly increased in both the NPWT group and the NC group ((85.3 ± 18.1) vs. (34.1 ± 12.5)/106 cells; (119.9 ± 14.4) vs. (66.1 ± 10.6)/106 cells, both P &lt; 0.05). In contrast, the circulating number of EPCs had no significant change in the non-NPWT group ((45.2 ± 19.4) vs. (34.7 ± 16.8)/106 cells, P &gt; 0.05). In addition, the circulating levels of vascular endothelial growth factor (VEGF) and the protein expressions of VEGF and stromal cell-derived factor-1α (SDF-1α) in the granulation tissue significantly increased after NPWT in both the NPWT and the NC group, but there was no significant change in the non-NPWT group. Compared with the non-NPWT group, the changes in VEGF and SDF-1α levels in the sera and granulation tissue were all significantly higher in both the NPWT and NC groups ( P &lt; 0.05, P &lt; 0.01, respectively). There was no significant difference in changes in the circulating number of EPCs in the peripheral blood and levels of VEGF and SDF-1α in the sera and granulation tissue between the NPWT and NC groups. Correlation analysis showed that the change in the circulating number of EPCs was correlated with the changes of VEGF and SDF-1α levels in the sera and granulation of the NPWT and NC groups ( P &lt; 0.05). Conclusion NPWT may increase the circulating number of EPCs in diabetic patients with mild to moderate ischaemic foot ulcer as in non-diabetic controls, which may be attributed to the upregulation of systemic and local VEGF and SDF-1α levels.

Effectiveness of Negative-Pressure Wound Therapy following Total Hip and Knee Replacements.

In this review, we assess the effects of negative-pressure wound therapy (NPWT) following primary hip and knee replacement surgery with a systematic review of randomized controlled trials (RCTs). We searched the Cochrane Bone, Joint, and Muscle Trauma Group's Specialized Registry on June 12, 2018; the Cochrane Central Register of Controlled Trials (CENTRAL, 2018, Issue 1); Ovid MEDLINE (1946-2018); and Embase (1980-2018). To identify RCTs, we combined a subject-specific search strategy with a sensitivity-maximizing version of the Cochrane highly sensitive search strategy. Included were RCTs and quasi-RCTs that compare NPWT with other treatments or no treatment following primary hip and knee replacements. We excluded trials that were focused on patients undergoing revision hip or knee replacements or who had pathological bone disease or periprosthetic fractures. Five RCTs met the inclusion criteria and are included in this review, making a total of 382 patients with primary total hip/knee replacements. Included trials were of varying quality, with little consistency in control groups or outcome measures; therefore, a meta-analysis could not be performed. Overall, three RCTs reported no significant differences in primary outcomes after NPWT, in comparison to standard or conventional wound care. One trial reported significant reduction in wound seroma size in patients undergoing primary hip replacements after NPWT, compared to standard dressings (NPWT, 1.97 vs. 5.08 mL [p = 0.021]; n = 19). Finally, one trial that compared NPWT with standard dressings following primary hip/knee replacements (n = 209) reported statistically significant differences that favored NPWT for overall reduction in length of hospital stay (mean difference, 0.9 d, 95% confidence interval [CI], -0.2-2.5; p = 0.07), number of dressing changes (mean difference, 1.7; 95% CI, 0.8-2.5; p = 0.002), and a fourfold reduction in reported postoperative surgical wound complications (8.4% vs. 2.0%; p = 0.06). Cost-effectiveness quality adjusted life years showed greater savings for higher-risk patients (body mass index ≥ 35; ASA ≥ 3). We find no justification for applying NPWT to all postoperative wounds after routine total hip and knee replacement; however, NPWT may benefit selected patients who are at high risk for wound complications.

Advances in managing the noninfected open chest after cardiac surgery: Negative-pressure wound therapy

ObjectiveThe objective of this study was to compare safety and clinical effectiveness of negative-pressure wound therapy (NPWT) with traditional wound therapy for managing noninfected open chests with delayed sternal closure after cardiac surgery. MethodsFrom January 2000 to July 2015, 452 of 47,325 patients who underwent full sternotomy left the operating room with a noninfected open chest (0.96%), managed using NPWT in 214—with frequency of use rapidly increasing to near 100%—and traditionally in 238. Predominant indications for open-chest management were uncontrolled coagulopathy or hemodynamic compromise on attempted chest closure. Weighted propensity-score matching was used to assess in-hospital complications and time-related survival. ResultsNPWT and traditionally managed patients had similar high-risk preoperative profiles. Most underwent reoperations (63% of the NPWT group and 57% of the traditional group), and 21% versus 25% were emergency procedures. Reexplorations for bleeding were less common with NPWT versus traditional wound therapy (n = 63 [29%] vs 104 [44%], P = .002). Median duration of open-chest to definitive sternal closure was 3.5 days for NPWT versus 3.1 for traditionally managed patients (P[log rank] = .07). Seven patients (3.3%) were converted from NPWT to traditional therapy because of hemodynamic intolerance and 6 (2.5%) from traditional to NPWT. No NPWT-related cardiovascular injuries occurred. Among matched patients, NPWT was associated with better early survival (61% vs 44% at 6 months; P = .02). ConclusionsNPWT is safe and effective for managing noninfected open chests after cardiac surgery. By facilitating open-chest management and potentially improving outcomes, it has become our therapy of choice and perhaps has lowered our threshold for leaving the chest open after cardiac surgery.

Advances in the research of biomechanical effects of negative-pressure wound therapy in promoting wound healing

Recently, researchers have focused on the micro-mechano-environment and the resulting mechanical cues which can regulate the morphology, structure, and function of cells. As a novel mechanotherapy, negative-pressure wound therapy (NPWT) has revolutionized the treatment of acute and chronic wounds. The effects of mechanics in use of NPWT has been noticed by researchers, and sporadic results have been reported, while the mechanisms of mechanosensitivity and mechanotransduction in affecting cell behaviors and promoting wound healing haven't been elucidated yet. In this article, we review the progress about the relevant mechanical forces of NPWT and the mechanical effects on major repairing cells involved in wound healing, in order to provide references for the better understanding of mechanobiology of NPWT to better wound healing.

Negative pressure wound therapy reduces the motility of Pseudomonas aeruginosa and enhances wound healing in a rabbit ear biofilm infection model

Pseudomonas aeruginosa motility, virulence factors and biofilms are known to be detrimental to wound healing. The efficacy of negative pressure wound therapy (NPWT) against P. aeruginosa has been little studied, either in vitro or in vivo. The present study evaluated the effect of negative pressure (NP) on P. aeruginosa motility in vitro, and the effect of NPWT on virulence factors and biofilms in vivo. P. aeruginosa motility was quantified under different levels of NP (atmospheric pressure, − 75, − 125, − 200 mmHg) using an in vitro model. Swimming, swarming and twitching motility were significantly inhibited by NP (− 125 and − 200 mmHg) compared with atmospheric pressure (p = 0.05). Virulence factors and biofilm components were quantified in NPWT and gauze treated groups using a rabbit ear biofilm model. Biofilm structure was studied with fluorescence microscopy and scanning electron microscopy. Additionally, viable bacterial counts and histological wound healing parameters were measured. Compared with the control, NPWT treatment resulted in a significant reduction in expression of all virulence factors assayed including exotoxin A, rhamnolipid and elastase (p = 0.01). A significant reduction of biofilm components (eDNA) (p = 0.01) was also observed in the NPWT group. The reduction of biofilm matrix was verified by fluorescence- and scanning electron-microscopy. NPWT lead to better histologic parameters (p = 0.01) and decreased bacterial counts (p = 0.05) compared with the control. NPWT treatment was demonstrated to be an effective strategy to reduce virulence factors and biofilm components, which may explain the increased wound healing observed.

Virulence analysis of Staphylococcus aureus in a rabbit model of infected full-thickness wound under negative pressure wound therapy

The aim of this study was to evaluate the virulence of Staphylococcus aureus in a controlled animal study using the standard sterile gauze and negative pressure wound therapy (NPWT), including activation of agr, gene expression and production of virulence foctors and depth of bacterial invasion. The tissue specimens were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds. Laser scanning confocal microscopy was performed to obtain bioluminescent images which were used to measure the depth of bacterial invasion. The agrA expression of S.aureus and the transcription and production of virulence factors including Eap, Spa and α-toxin were significantly different. The bacterial invasion depth was significantly less with effect of NPWT. The markedly different activation of quorum sensing systems that enable cell-to-cell communication and regulation of numerous colonization and virulence factors result in distinct gene expression and pathogenicity over time in different microenvironment. Thus, the agr system represents a fundamental regulatory paradigm that can encompass different adaptive strategies and accommodate horizontally acquired virulence determinants.

Negative Pressure Wound Therapy—An Effective, Minimally Invasive Therapeutic Modality in Burn Wound Management

Despite the advancement in burn therapy in the last decades the treatment of burn wounds still remains a challenging task. Infection is still a common complication; while sepsis remains the leading cause of death in severe burns. The research guided integration of new and effective techniques in burn wound management is mandatory. Negative pressure wound therapy (NPWT) is an effective and widely used technique in the management of problematic wounds. Previously existing indications include soft tissue traumas and chronic wounds such as diabetic, arterial, venous and pressure ulcers. The characteristics and challenges of these wounds have a lot in common with burns. Since the early 2000’s there are experiences with the use of NPWT for the healing of second degree burn wounds. Our clinical experience shows that it is a minimally invasive and effective way of improving burn wound management. In this article we give a review of the literature showing the mechanisms, unmapped future opportunities, financial issues, and possible adverse effects of NPWT in burn therapy.

Negative pressure wound therapy for skin grafts and surgical wounds healing by primary intention.

Indications for the use of negative pressure wound therapy (NPWT) are broadening with a range of systems now available on the market, including those designed for use on clean, closed incisions and skin grafts. Reviews have concluded that the evidence for the effectiveness of NPWT remains uncertain, however, it is a rapidly evolving therapy. Consequently, an updated systematic review of the evidence for the effects of NPWT on postoperative wounds expected to heal by primary intention is required. To assess the effects of NPWT on surgical wounds (primary closure, skin grafting or flap closure) that are expected to heal by primary intention. We searched the following electronic databases to identify reports of relevant randomised clinical trials:the Cochrane Wounds Group Specialised Register (searched 28 January 2014); the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, issue 12); Database of Abstracts of Reviews of Effects (2013, issue 12); Ovid MEDLINE (2011 to January 2014); Ovid MEDLINE (In-Process & Other Non-Indexed Citations 24 January 2014); Ovid EMBASE (2011 to January 2014 Week 44); and EBSCO CINAHL (2011 to January 2014). We conducted a separate search to identify economic evaluations. We included trials if they allocated patients to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with a different type of NPWT. We assessed trials for their appropriateness for inclusion and for their quality. This was done by three review authors working independently, using pre-determined inclusion and quality criteria. In this first update, we included an additional four trials, taking the total number of trials included to nine (785 participants). Three trials involved skin grafts, four included orthopaedic patients and two included general surgery and trauma surgery patients; all the included trials had unclear or high risk of bias for one or more of the quality indicators we assessed. Seven trials compared NPWT with a standard dressing (two of these were 'home-made' NPWT devices), one trial compared one 'home-made' NPWT with a commercially available device. In trials where the individual was the unit of randomisation, there were no differences in the incidence of surgical site infections (SSI); wound dehiscence, re-operation (in incisional wounds); seroma/haematoma; or failed skin grafts. Lower re-operation rates were observed among skin graft patients in the 'home-made' NPWT group (7/65; 10.8%) compared to the standard dressing group (17/66; 25.8%) (risk ratio (RR) 0.42; 95% CI 0.19 to 0.92). The mean cost to supply equipment for VAC® therapy was USD 96.51/day compared to USD 4.22/day for one of the 'home-made' devices (P value 0.01); labour costs for dressing changes were similar for both treatments. Pain intensity score was also reported to be lower in the 'home-made' group when compared with the VAC® group (P value 0.02). One of the trials in orthopaedic patients was stopped early because of a high incidence of fracture blisters in the NPWT group (15/24; 62.5%) compared with the standard dressing group (3/36; 8.3%) (RR 7.50; 95% CI 2.43 to 23.14). Evidence for the effects of negative pressure wound therapy (NPWT) for reducing SSI and wound dehiscence remains unclear, as does the effect of NPWT on time to complete healing. Rates of graft loss may be lower when NPWT is used, but hospital-designed and built products are as effective in this area as commercial applications. There are clear cost benefits when non-commercial systems are used to create the negative pressure required for wound therapy, with no evidence of a negative effect on clinical outcome. In one study, pain levels were also rated lower when a 'home-made' system was compared with a commercial counterpart. The high incidence of blisters occurring when NPWT is used following orthopaedic surgery suggests that the therapy should be limited until safety in this population is established. Given the cost and widespread use of NPWT, there is an urgent need for suitably powered, high-quality trials to evaluate the effects of the newer NPWT products that are designed for use on clean, closed surgical incisions. Such trials should focus initially on wounds that may be difficult to heal, such as sternal wounds or incisions on obese patients.

The Influence Manufacturers Have on Negative-Pressure Wound Therapy Research

Studies investigating the effects of negative-pressure wound therapy using the Chariker-Jeter system (gauze-based interface) and the vacuum-assisted closure system often have outcomes that favor one particular system. This study attempts to examine whether manufacturer involvement could be related to the outcomes of these scientific studies. A literature review was undertaken to identify a cohort of studies that compared these two forms of negative-pressure wound therapy. Clinical outcomes studies, basic research studies, and published conference abstracts were included. Allthe articles' abstracts and conclusions were given to five surgeons, who were blinded to the titles and authors. They were individually asked to record what they would consider to be the take-home message of each article (in terms of which system is superior). After categorizing each study according to the system that it appears to favor, the level of manufacturer involvement in each study was evaluated. The relationship between the outcome of a study and the level of manufacturer involvement in that study was then investigated. Of the total of 24 studies found to match the inclusion criteria, 22 were considered to favor a particular system (the other two were categorized as impartial). Of the 24 studies, 19 had some form of manufacturer involvement. Of the 19 that had some form of manufacturer involvement, 18 had outcomes that were deemed beneficial to the involved manufacturer, whereas one was deemed to have an impartial outcome. This study suggests that manufacturer involvement in these studies (regardless of level) correlates with the outcomes being beneficial to the involved manufacturer in almost all cases. Potential reasons for this and the implications thereof are discussed.

Negative-pressure wound therapy enhances local inflammatory responses in acute infected soft-tissue wound.

Clinical studies found that negative-pressure wound therapy (NPWT) displayed significant clinical benefits in the healing of infected wounds. However, the effect of NPWT on local inflammatory responses in acute infected soft-tissue wound has not been investigated thoroughly. The purpose of this study was to test the impact of NPWT on local expression of proinflammatory cytokines, amount of neutrophils, and bacterial bioburden in wound from acute infected soft-tissue wounds. Full-thickness wounds were created on the back of rabbits, and were inoculated with Staphylococcus aureus strain ATCC29213. The wounds were treated with sterile saline-moistened gauze dressings and NPWT with continuous negative pressure (-125 mmHg). Wound samples were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds before irrigation for real-time PCR analysis of gene expression of IL-1β, IL-8, and TNF-α. Wound biopsies were examined histologically for neutrophil quantification in different layers of tissue. Quantitative bacterial cultures at the same time point were analyzed for bacterial clearance. Application of NPWT to acute infected wounds in rabbits was compared with treatment with sterile saline-moistened gauze, over an 8-day period. NPWT-treated wounds exhibited earlier and greater peaking of IL-1β and IL-8 expression and decrease in TNF-α expression over the early 4 days (P < 0.05). Furthermore, histologic examination revealed that significantly increased neutrophil count was observed in the shallow layer in wound biopsies of NPWT treatment at day 2 (P < 0.001). In addition, there was a statistically significant decrease of bacteria load from baseline (day 0) at days 2 and 8 in NPWT group (P < 0.05). In conclusion, this study demonstrates that NPWT of acute infected soft-tissue wounds leads to increased local IL-1β and IL-8 expression in early phase of inflammation, which may trigger accumulation of neutrophils and thus accelerate bacterial clearance. Meanwhile, the success of NPWT in the treatment of acute wounds can attenuate the expression of TNF-α, and the result may partly explain how NPWT can avoid significantly impairing wound healing.

CLINICAL TECHNIQUE: Negative Pressure Wound Therapy-General Principles and Use in Avian Species

Negative pressure wound therapy (NPWT) is an adjunctive wound management modality that has been shown to augment the treatment of acute and chronic dermal and subdermal wounds in human and veterinary medicine. The proposed effects of NPWT are multifactorial and include improvement of wound perfusion, reduction of interstitial edema and substances inhibitory to wound healing, enhancement of granulation tissue formation, and reduction in bacterial contamination from a wound bed. Together, the proposed benefits of NWPT can lead to enhanced efficiency of wound healing when this treatment modality is applied to a wound. In this article, the authors provide an overview of the mechanism of action of NPWT. Case selection, system application and management, as well as contraindications to NPWT therapy are presented. Potential uses, practical application, and limitations of use of NPWT in avian species are discussed.