Integrated negative pressure wound therapy system with volumetric automated fluid instillation in wounds at risk for compromised healing

Assessment between antiseptic and normal saline for negative pressure wound therapy with instillation and dwell time in diabetic foot infections

Negative pressure wound therapy with instillation and dwell time (NPWTi-d) is increasingly used for a diverse range of wounds. Meanwhile, the topical wound irrigation solution consisting of polyhexamethylene biguanide and betaine (PHMB-B) has shown efficacy in managing wound infections. However, the effectiveness of this solution as a topical instillation solution for NPWTi-d in patients with diabetic foot infections (DFIs) has not been thoroughly studied. The objective of this retrospective study was to evaluate the impact of using PHMB-B as the instillation solution during NPWTi-d on reducing bioburden and improving clinical outcomes in patients with DFIs. Between January 2017 and December 2022, a series of patients with DFIs received treatment with NPWTi-d, using either PHMB-B or normal saline as the instillation solution. Data collected retrospectively included demographic information, baseline wound characteristics, and treatment outcomes. The study included 61 patients in the PHMB-B group and 73 patients in the normal saline group, all diagnosed with DFIs. In comparison to patients treated with normal saline, patients with PHMB-B exhibited no significant differences in terms of wound bed preparation time (P = 0.5034), length of hospital stay (P = 0.6783), NPWTi-d application times (P = 0.1458), duration of systematic antimicrobial administration (P = 0.3567), or overall cost of hospitalization (P = 0.6713). The findings of the study suggest that the use of either PHMB-B or normal saline as an instillation solution in NPWTi-d for DFIs shows promise and effectiveness, yet no clinical distinction was observed between the two solutions.

Negative Pressure Wound Therapy With and Without Instillation in Necrotizing Soft Tissue Infections

Background: Necrotizing soft tissue infections (NSTIs) are rare but deadly infections that require early and often extensive surgical debridement. After debridement, patients frequently have substantial morbidity because of large, open wounds. Hypothesis: Negative pressure wound therapy with instillation (NPWTi) results in higher wound closure rates compared with traditional negative pressure wound therapy (NPWT) or wet to dry dressings (moist wound care dressing). Patients and Methods: A prospectively maintained Acute and Critical Care Surgery database spanning 2008-2018 was queried for patients with a diagnosis of necrotizing fasciitis, Fournier gangrene, or gas gangrene. Data were collected on patient comorbidities, operative management, and clinical outcomes. Patients were stratified by use of moist wound care dressing, traditional NPWT, or NPWTi. Data were analyzed using analysis of variance (ANOVA), χ2, and logistic regression. Results: During the 10-year study period, patients were treated for NSTI; 173 were managed with moist wound care dressing, 150 with NPWT, and 48 with NPWTi. Patients were similar in terms of demographics, body mass index (BMI), diabetes mellitus, and smoking rates. Overall, complication rates were not substantially different, but mortality was higher in the moist wound care dressing group (16.2% vs. 10.7% NPWT vs. 2.1% NPWTi; p = 0.02). In the moist wound care dressing group, 81.5% of patients had an open wound at discharge compared with 52.7% of the NPWT group and only 14.6% of the NPWTi group (p < 0.001). On multivariable regression, NPWTi was associated with closure rates five times higher than the NPWT group (odds ratio [OR], 5.28; 95% confidence interval [CI], 2.40-11.61; p < 0.001) after controlling for smoking status, intravenous drug use, number of operations, and involvement of the most common region of the body. Conclusions: Negative pressure wound therapy with instillation is associated with higher rates of wound closure without increasing complication rates in patients with NSTI compared with traditional NPWT or moist wound care dressing. Although prospective studies are needed, this indicates the potential to improve patient quality of life through reduced pain and outpatient home health needs.

Evolving Role of Negative Pressure Wound Therapy with Instillation and Dwell Time (NPWTi-d-) in Management of Trauma and Orthopaedic Wounds: Mechanism, Applications and Future Perspectives

Introduction

Negative Pressure Wound Therapy (NPWT) is a well-established method to promote wound healing by delivering negative pressure (a vacuum) at the wound site. Enhancement of NPWT techniques may allow an innovative way of treating trauma and orthopaedic wounds which provide unique challenges. We explore the role of negative pressure wound therapy with instillation and dwell time (NPWTi-d-) in the management of trauma and orthopaedic wounds.

Materials and Methods

A comprehensive search strategy was conducted using databases of PubMed, Web of Science, Google Scholar, and Cochrane Library with the search words of 'NPWTid' or 'NPWTi-d-' or 'NPWT with instillation' or 'Negative pressure wound treatment with instillation' to generate this narrative review. The mechanism of action of NPWTi-d-, installation solutions and current applications in the trauma and orthopaedic wounds is evaluated.

Results

NPWTi-d- provides additional mechanism to promote wound healing in a spectrum of acute and chronic orthopaedic wounds. The technique allows local delivery of hydration and elution of antibiotics to support growth of healthy granulation tissue. Various mechanism of actions contribute in drawing the wound edges together, reduce oedema, help decontamination, deliver local antibiotic and promote healing.

Conclusion

NPWTi-d- permits an enhanced, supplementary technique to encourage wound healing in challenging traumatic and orthopaedic wounds. Future applications of NPWTi-d- will depend on cost-effectiveness analysis and development of its application guidelines based on longitudinal, randomized controlled research trials.

Effects of negative pressure wound therapy with instillation and dwell time (NPWTi-d) versus NPWT or standard of care in orthoplastic surgery: A systematic review and meta-analysis

Negative pressure wound therapy (NPWT) is a wound-dressing system that applies sub-atmospheric pressure on the surface of a wound to promote healing. An evolution of this technology, NPWT with solution instillation and dwell time (NPWTi-d), is increasingly being used to maximise wound closure and reduce failure rates. However, there is still a lack of evidence concerning its use in orthoplastic surgery. Therefore, the aim of this study is to compare NPWTi-d with NPWT and standard of care for wound management in orthoplastic surgery. A comprehensive literature search using PubMed, Web of Science, and Cochrane databases up to 15 March 2022 was performed, including studies describing the outcomes of NPWTi-d for traumatic/orthopaedic injuries. A meta-analysis on the number of surgical debridements, as well as the rate of complete wound closure and complications was carried out, although for other outcomes, a descriptive statistic was applied. Risk of bias and quality of evidence were assessed using the Downs& Black's Checklist for Measuring Quality. Thirteen studies with a total number of 871 patients were included, in which NPWTi-d demonstrated significantly higher primary wound closure and lower complication rates (P < .05). No difference in the number of surgical procedures required for final wound healing was observed. Moreover, five out of six studies showed better results for NPWTi-d when the change of the bioburden and bacterial count of the wound were analysed. A singular study investigating the length of the hospital stay of patients treated with NPWTi-d showed a reduction in the latter. The present meta-analysis proves that NPWTi-d is superior to NPTW or conventional dressings in orthoplastic wound care management, in terms of complete wound closure rate and the reduced number of complications. Still, the limited quality of the studies analysed shows that future randomised studies are needed to confirm the benefits and to identify the most appropriate recommendations for using NPWTi-d in orthoplastic surgery, as well as to investigate the cost-effectiveness of this wound-dressing system.

Preoperative contaminated wound management using short-term negative pressure wound therapy with instillation

BACKGROUND

The short-term application of negative pressure wound therapy with instillation and dwell time (NPWTi-d) enables the delivery of topical wound solutions, the solubilisation of debris and cleansing of the wound bed. The application of NPWTi-d may support the transition of the wound to a more manageable state and minimises the use of more invasive techniques.

METHOD

In this case series, we describe the process of applying NPWTi-d early as part of a contaminated wound treatment plan.

RESULTS

The case series included 15 patients in the preoperative setting. Wound types included surgical dehiscence, hard-to-heal wounds, heel pressure ulcers, diabetic foot ulcers, a cat bite and an amputation left open. Normal saline or a 0.125% sodium hypochlorite solution were instilled and allowed to dwell for five minutes, followed by 15 minutes of continuous negative pressure at -125mmHg. NPWTi-d was continued for 4-36 hours, or until the operating room became available. After NPWTi-d, we observed a decreased amount of devitalised tissue in the wound bed and reduced oedema and erythema in the periwound area. Patient white blood cells also significantly decreased in all cases after NPWTi-d (p<0.001).

CONCLUSION

Short-term use of NPWTi-d may be a useful option for supporting the surgical treatment of contaminated lower extremity wounds.

Non-surgical Management of Complex Refractory Pyoderma Gangrenosum With Negative Pressure Wound Therapy With Instillation

Pyoderma gangrenosum (PG) is a rare skin disorder primarily treated with immunosuppression medication. We report a case of a large, chronic PG wound treated with adjunct negative pressure wound therapy with instillation and dwell time (NPWTi-d) using nonadherent dressing (Mepitel) and reticular open-cell foam with through holes (ROCF-CC) with positive outcomes. The patient was a 62-year-old female with rheumatoid arthritis, Hashimoto’s thyroiditis, lymphedema, and morbid obesity who presented with a 19.5 cm x 13.2 cm x 2.1 cm wound of three years duration on the right posterolateral lower extremity that successfully responded to a multimodality approach of immunosuppression and wound vac therapy. We conclude in our case that NPWTi-d with Mepitel and ROCF-CC enhanced the wound healing process, and we discuss NPWTi-d’s potential role and benefit as an adjunctive therapy option for chronic and poorly controlled PG on patients taking concurrent immunosuppression.

Sacral and Ischial Pressure Ulcer Management With Negative-Pressure Wound Therapy With Instillation and Dwell

BACKGROUND

The addition of topical fluid instillation, a programmable "dwell" time and a novel foam-wound interface to the established wound healing benefits of negative-pressure wound therapy (NPWT) works synergistically to benefit patients with complex wounds. This engineering breakthrough for wound care has been termed NPWT with instillation and dwell (NPWTi-d), and the new foam dressings are reticulated open cell foam dressings specifically designed for use with NPWTi-d. This combined technology has shown promise in chronic, complex wounds and has potential for the management of sacral and ischial pressure wounds.

METHODS

A qualitative comprehensive review was performed analyzing articles from PubMed and Medline that reported on the use of NPWTi-d in sacral or ischial pressure ulcers. Case series and case reports were predominant, and results of cases specific to sacral and ischial pressure wounds were extracted from larger studies and summarized for presentation.

RESULTS

Compared with conventional NPWT alone, NPWTi-d has been shown to help irrigate the wound, remove fibrinous debris, and promote granulation tissue formation. This is associated with a decreased number of operative debridements and decreased hospital length of stay.

CONCLUSIONS

This technology is rapidly demonstrating expanded utilization in hospitalized patients with chronic sacral and ischial pressure ulcers. When used correctly, NPWTi-d serves as an effective "bridge to defined endpoint": whether that is a flap reconstruction, skin grafting, or discharge home with a stable chronic wound and simplified wound care.

Management of Wounds With Orthopedic Fixation Hardware Using Negative-Pressure Wound Therapy With Instillation and Dwell

SUMMARY

Negative-pressure wound therapy with instillation and dwell (NPWTi-d) is an option for management of wounds with exposed orthopedic fixation hardware. The mechanical effect of the negative-pressure therapy works to contract the wound edges, and the instillation of solution and its subsequent removal help remove infectious material. NPWTi-d also promotes robust granulation tissue formation. In this article, we discuss the science behind NPWTi-d and its role in the treatment of wounds with indwelling orthopedic fixation hardware.

Comparison of Negative Pressure Wound Therapy With and Without Instillation of Saline in the Management of Infected Wounds

Background 

Negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d) includes periodic instillation of topical solution into the wound followed by a negative pressure. Our objective was to evaluate potential differences in wound outcomes in patients receiving NPWT and those receiving NPWTi-d using saline.

Methods

An analysis was performed using two previously published independent studies from a single investigator and hospital to compare patient characteristics and clinical outcomes of infected wounds from 74 NPWT-treated patients with 42 NPWTi-d-treated patients.

Results 

Patient demographics and comorbidities, wound etiologies, and anatomical locations of wounds were similar between groups, although a significantly higher percentage of NPWT-treated patients had end-stage renal disease (P = 0.0119). Compared with patients treated with standard NPWT, NPWTi-d-treated patients had a significantly lower number of operations (P = 0.0048), shorter length of hospital stay (P = 0.0443), shorter time to final surgical procedure (P = 0.0001), higher percentage of closed wounds (P = 0.0004), and a higher percentage of wounds that remained closed at one month (P = 0.0001).

Conclusions

The results of this analysis suggest that management of infected wounds with NPWTi-d using saline leads to favorable wound outcomes when compared to those managed with NPWT.

Topical negative-pressure wound therapy: emerging devices and techniques

Introduction: The treatment of chronic wounds constitutes a massive financial burden to society and our health-care system. Therefore, efficient wound care is of great importance to all kinds of medical fields. The implementation and modification of negative-pressure wound therapy can be seen as a major improvement in wound healing. Many different NPWT applications evolved trying to address various wound etiologies.Areas covered: This review aims to give an overview of various NPWT applications, show its effects on wound healing, and discuss future modifications.Expert opinion: NPWT as a delivery device for cold plasma, growth factors, or targeted stem cells to the wound bed and the ability to monitor the inflammatory activity, bacterial load and wound healing factors can be seen as possible future steps to individualized wound care. In addition, it requires high-quality experimental studies to develop the ideal foam in terms of microstructure, pore size, and material properties.

Instillation negative pressure wound therapy: An effective approach for hardware salvage

Wound infection involving hardware can be notoriously difficult to treat, often requiring the removal of the infected implant. The goal of this study was to determine the utility of instillation negative pressure wound therapy to help eradicate infection and allow for definitive wound closure in patients without removing the infected hardware. A retrospective review was performed on the outcomes of 28 patients who presented with open wounds with exposed or infected hardware and who were treated with a combination of surgical debridement and negative pressure wound therapy with instillation (NPWTi). Eleven patients were treated for infected spinal hardware, 12 for extremity, and 5 for sternal hardware. Twenty-five of 28 (89%) patients had successful retention or replacement of hardware, with clearance of infection and healed wounds. Original hardware was maintained in 17 of 28 (61%) patients. In 11 patients, original hardware was removed, with subsequent replacement in eight of those patients after a clean wound was achieved. Average time to definitive closure was 12.6 days. Average follow-up was 135 days. This series supports NPWTi as an effective adjunct therapy to help expeditiously eradicate hardware infection, allowing for hardware retention.

Comparing Negative Pressure Wound Therapy with Instillation and Conventional Dressings for Sternal Wound Reconstructions

Background:

Muscle flap reconstruction has become a mainstay of therapy following treatment of sternal wound complications; however, success depends on removing wound exudate and infectious material from the wound before reconstruction and closure. Importantly, time to closure is a key factor affecting morbidity/mortality and cost-to-treat for this wound type.

Methods:

A retrospective analysis of 30 patients who were treated for sternal wound complications between June 2015 and October 2017 was performed. After surgical debridement, group 1 patients (n = 15) received negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d), instilling 1/8-strength Dakin’s solution with a 20-minute dwell time followed by 2 hours of NPWT (-125 mm Hg); group 2 patients (n = 15) were treated with wet-to-moist dressings soaked in 1/8-strength Dakin’s solution. After muscle flap reconstruction and closure with sutures, group 1 patients received closed incision negative pressure therapy, and group 2 patients received Benzoin and wound closure strips. Data collected included time to closure, therapy duration, number of debridements/dressing changes, drain duration, and complications.

Results:

There was a significantly shorter time to closure (P < 0.0001) for group 1 when compared with group 2. In addition, there were fewer therapy days (P = 0.0041), fewer debridements/dressing changes (P = 0.0011), and shorter drain duration (P = 0.0001) for group 1 when compared with group 2.

Conclusions:

We describe a novel regimen consisting of adjunctive NPWTi-d, along with debridement and systemic antibiotics, followed by closed incision negative pressure therapy after muscle flap reconstruction and closure, to help manage preexisting sternal wounds that had failed to close following a previous cardiac procedure.

Temporary Abdominal Closure Combined With an Irrigating System Utilizing Hypochlorous Acid Solution to Decrease Abdominal Mucopurulence

Introduction: Leaving the abdominal cavity open is a well-described and frequently utilized technique in the treatment of severe intra-abdominal sepsis. Irrigation through a negative pressure wound therapy device is a technique employed to assist in the closure of wounds as well as the reduction of bacterial contamination. Furthermore, hypochlorous acid has been found to be safe and effective in microorganismal elimination from extremity wounds. There is no literature regarding the infusion of hypochlorous solution into the abdominal cavity for intra-abdominal sepsis or mucopurulent abscesses or biofilm. Objectives: A 47-year-old man with granulomatosis polyangiitis was started on weekly rituximab. After 4 infusions, skin sloughing, ultimately diagnosed as toxic epidermal necrolysis, developed. During the hospital course, he developed sepsis and bowel perforation necessitating an exploratory laparotomy. The abdomen was left open with a temporary abdominal closure using the Abthera open abdomen negative wound therapy device; however, the abdomen remained infected with visually diffuse, thickening mucopurulence despite multiple washouts. Therefore, a VAC Vera-Flo irrigation device was combined with the Abthera open abdomen negative wound therapy device and cyclical irrigation of hypochlorous acid. After 72 hours, the purulence visually was improved and no adverse events were recorded with the placement of intra-abdominal hypochlorous acid. Conclusions: The combination of two medical devices for the intra-abdominal instillation of irrigation is considered "off-label use" from the manufacturer's recommendations. In addition, the repeated instillation of hypochlorous acid solution has not been described but was noted to have visually decreased the contaminated effluent within the intra-abdominal fluid.

Initial Management of Traumatic Wounds

When traumatic wounds are quickly and accurately treated, morbidity and costs can be significantly decreased. Several factors, such as time delay between injury and treatment, the degree of contamination, extension and depth of the wound, and the mechanism of injury, influence the treatment and prognosis and stress the importance of a patient-specific approach. Although all traumatic wounds are contaminated, antibiotic therapy is seldom required if correct wound management is installed.

Instillation Therapy for the Treatment of Necrotizing Fasciitis: A Case Study

A 57-year-old obese female with uncontrolled diabetes mellitus type I presented to the emergency department (ED) with the main complaint of worsening pain and redness in her right groin and inguinal regions. In the ED, a CT scan confirmed the likely presence of necrotizing fasciitis in the right groin and thigh. She was also found to be febrile and septic on admission. She was urgently taken to the OR for extensive debridement then admitted to the ICU for medical stabilization. She was subsequently taken back for serial debridements, and a negative pressure wound therapy with instillation (NPWTi-d) Veraflo device was placed once the wound was successfully debrided down to viable tissue. This is a case study on the wound progression of this patient.

Simplified negative pressure wound therapy with instillation: advances and recommendations

Positive results have been demonstrated with the adjunctive use of negative pressure wound therapy (NPWT) and instillation (NPWTi) for stalled and/or complex wounds. With these combined therapies, instillation assists in wound bed preparation and cleansing by loosening soluble material in the wound bed, which can be subsequently removed during the NPWT phase. Previously reported instilled solutions have included saline, topical cleansers, and antiseptics. Recently, a new NPWTi system (V.A.C. VeraFlo™ Therapy, KCI USA, Inc., San Antonio, TX) has been introduced that includes automated, volumetrically controlled delivery of solutions and new foam dressings specifically designed for use with NPWTi. We present the latest NPWTi technologies, provide nursing recommendations for patient management, and conclude with a case study.

The evolution of negative pressure wound therapy: negative pressure wound therapy with instillation

Complex wounds pose a considerable burden to patients and the health-care system. The development of negative pressure wound therapy (NPWT) has revolutionised the treatment of these wounds. NPWT helps create a favourable wound healing environment by removing infectious material, decreasing oedema and promoting perfusion and granulation tissue formation. Additionally, NPWT has been reported to help reduce time to wound closure and length of hospital stay. Modifications of this foundation of wound care have added intermittent instillation with a dwell time to NPWT (NPWTi-d). This new system offers more comprehensive wound care through automated wound irrigation, allowing more control over the wound environment and the opportunity to deliver topical wound solutions directly to the affected tissues. A comparison between the two therapies, NPWT and NPWTi-d, is described, and two real-world applications of NPWTi-d are presented.

Use of negative pressure wound therapy with instillation in the management of cervical necrotizing fasciitis

BACKGROUND

Cervical necrotizing fasciitis is an aggressive infection that can be rapidly fatal if aggressive therapies are not initiated early. Negative pressure wound therapy has been established as an effective tool in promoting wound healing, but its use in the acutely infected wound has been avoided because it limits frequent irrigations and standard dressing changes.

METHODS

We discuss a novel application of negative pressure wound therapy with instillation in an immunocompromised patient with extensive cervical necrotizing fasciitis.

RESULTS

The negative pressure wound therapy with instillation provided pain relief by minimizing the frequency of dressing changes, increased the speed of healing, helped to control infection, and facilitated the development of a healthy wound bed sufficient for reconstruction with a split thickness skin graft.

CONCLUSION

The role of negative pressure wound therapy with instillation continues to expand and can be used in the management of both acute and chronic wounds in the head and neck.

Clinical recommendations and practical guide for negative pressure wound therapy with instillation

Effective wound management involves a comprehensive assessment of the patient and the wound to determine an optimal wound treatment plan. It is critical to identify and address factors that may impair wound healing, prior to selecting the most appropriate therapy for each patient. Negative pressure wound therapy (NPWT) is a well-established advanced therapy that has been successful in adjunctive management of acute and chronic wounds. In recent years, the introduction of topical wound solution delivery in combination with NPWT has provided further benefits to wound healing. A commercially available system now offers automated, volumetric control of instilled topical wound solutions with a dwell time in combination with NPWT (NPWTi-d; V.A.C. VeraFlo Therapy, KCI, an Acelity company, San Antonio, TX). This NPWTi-d system differs from other instillation systems in that a timed, predetermined volume of topical wound solution is intermittently delivered (versus continuously fed) and allowed to dwell in the wound bed (without NPWT), for a user-selected period of time before NPWT is resumed. This added accuracy and process simplification of solution delivery in tandem with NPWT have prompted use of NPWTi-d as first-line therapy in a wider subset of complex wounds. However, considerably more research is required to validate efficacy of NPWTi-d in various wound types. The purpose of this review is to provide a relevant overview of wound healing, describe current literature supporting the adjunctive use of NPWTi-d, propose a clinical approach for appropriate application of NPWTi-d and conclude with case studies demonstrating successful use of NPWTi-d. Based on this review, we conclude that either a large case series examining effects of NPWTi-d on different wound types or possibly a large prospective registry evaluating NPWTi-d with real-world topical wound solutions versus immediate debridement and closure would be valuable to the medical community in evaluating the efficacy of this promising therapy.

Genomic and proteomic evaluation of tissue quality of porcine wounds treated with negative pressure wound therapy in continuous, noncontinuous, and instillation modes

OBJECTIVE

Negative pressure wound therapy with instillation (NPWTi-d) combines NPWT with automated delivery and removal of topical wound treatment solutions. This porcine study compared genomic and proteomic responses of wounds treated with NPWTi-d with saline to wounds treated with NPWT in continuous and noncontinuous modes.

METHODS

Full-thickness porcine dorsal excisional wounds were treated with continuous NPWT, intermittent NPWT, dynamic NPWT, or NPWTi-d with saline (n = 10 wounds per group). On day 7, animals were euthanized and tissues collected. Real-time quantitative polymerase chain reaction arrays profiled expression of 84 genes including extracellular matrix remodeling factors, inflammatory cytokines and chemokines, and growth factors and major signaling molecules. Concentrations of proteins associated with angiogenesis, extracellular matrix components, and cellular energetics were analyzed via enzyme-linked immunosorbent assays.

RESULTS

Gene expression profiles for NPWTi-d with saline and continuous NPWT were similar. There were 5 upregulated and 18 downregulated genes overexpressed in NPWTi-d compared to NPWT wounds. Protein content was comparable in all treatment groups and similar to unwounded tissue.

CONCLUSIONS

Previous preclinical studies have reported an increased rate of granulation tissue formation with NPWTi-d with saline compared to NPWT in continuous and noncontinuous modes. This evaluation of gene and protein expression suggests that the granulation tissue in these wounds has a similar quality. This first look at the differences in gene expression, particularly in genes related to remodeling, cell adhesion, inflammation, and growth factors, could help to clarify the observed differences in granulation rates.

Use of negative pressure wound therapy with automated, volumetric instillation for the treatment of extremity and trunk wounds: clinical outcomes and potential cost-effectiveness

OBJECTIVE

A growing body of literature supports use of negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d) with positive clinical outcomes and potential cost savings. A retrospective analysis was performed to compare clinical outcomes of wounds treated with NPWTi-d versus NPWT and to estimate cost-differences between treatments based on clinical outcomes.

METHODS

Data were extracted from records of patients with extremity or trunk wounds treated with NPWT (n = 34) or NPWTi-d using saline or polyhexanide (n = 48). On the basis of outcomes data, a hypothetical economic model using cost assumptions was created to calculate cost savings for NPWTi-d (related to) number of debridements and length of therapy. Operating room debridement cost was $3393 according to Granick et al. Daily therapy cost for each modality was $194.80 (NPWTi-d) and $106.08 (NPWT) based on internal company information.

RESULTS

RESULTS showed significant differences (P < 0.0001) between NPWTi-d and NPWT patients, respectively, for the following: mean operating room debridements (2.0 vs 4.4), mean hospital stay (8.1 vs 27.4 days), mean length of therapy (4.1 vs 20.9 days), and mean time to wound closure (4.1 vs 20.9 days). Hypothetical economic model showed potential average reduction of $8143 for operating room debridements between NPWTi-d ($6786) and NPWT ($14,929) patients. There was a $1418 difference in average therapy costs between groups ($799/NPWTi-d vs $2217/NPWT).

CONCLUSIONS

In this study, NPWTi-d appeared to assist in wound cleansing and exudate removal, which may have allowed for earlier wound closure compared to NPWT. Hypothetical economic model findings illustrate potential cost-effectiveness of NPWTi-d compared to NPWT.

The effect of negative pressure wound therapy with periodic instillation using antimicrobial solutions on Pseudomonas aeruginosa biofilm on porcine skin explants

Negative pressure wound therapy with instillation (NPWTi) is increasingly used as an adjunct therapy for a wide variety of infected wounds. However, the effect of NPWTi on mature biofilm in wounds has not been determined. This study assessed the effects of NPWTi using saline or various antimicrobial solutions on mature Pseudomonas aeruginosa biofilm using an ex vivo porcine skin explant biofilm model. Treatment consisted of six cycles with 10-minute exposure to instillation solution followed by 4 hours of negative pressure at -125 mm Hg over a 24-hour period. NPWTi using saline reduced bacterial levels by 1-log (logarithmic) of 7-log total colony-forming units (CFUs). In contrast, instillation of 1% povidone iodine (2-log), L-solution (3-log), 0·05% chlorhexidine gluconate (3-log), 0·1% polyhexamethylene biguanide (4-log), 0·2% polydiallyldimethylammonium chloride (4-log) and 10% povidone iodine (5-log), all significantly reduced (P < 0·001) total CFUs. Scanning electron micrographs showed disrupted exopolymeric matrix of biofilms and damaged bacterial cells that correlated with CFU levels. Compared with previous studies assessing microbicidal effects of topical antimicrobial dressings on biofilms cultured on porcine skin explants, these ex vivo model data suggest that NPWTi with delivery of active antimicrobial agents enhances the reduction of CFUs by increasing destruction and removal of biofilm bacteria. These results must be confirmed in human studies.

Negative pressure wound therapy with saline instillation: 131 patient case series

Negative pressure wound therapy combined with timed, cyclical instillation (NPWTi) of topical wound solutions has been recently presented as a new adjunctive modality for treating wounds with signs of infection. Normal saline, antiseptics and antimicrobials all have been proposed in scientific and clinical studies as potentially effective when used with NPWTi for treating heavily infected wounds. This is a prospective clinical study of 131 patients with 131 wounds treated with NPWTi using saline between January 2012 and December 2012 in two orthopaedic centres and one surgical wound healing centre in France. Saline was exclusively used. Results were favourable: in 98% of the cases, the wounds could be closed after debridement and following the use of NPWTi. Mean duration of NPWTi was 12·19 days. This does not preclude the need for treating the biofilm appropriately with more active antibacterial products when biofilm has been documented.

Recommendations on negative pressure wound therapy with instillation and antimicrobial solutions - when, where and how to use: what does the evidence show?

Infections of contaminated or colonised acute or chronic wounds remain a grave risk for patients even today. Despite modern surgical debridement concepts and antibiotics, a great need exists for new therapies in wound management. Since the late 1990s, advantageous effects of negative pressure wound therapy (NPWT) have been combined with local antiseptic wound cleansing in the development of NPWT with instillation (NPWTi). This article summarises the current scientific knowledge on this topic. MEDLINE literature searches were performed on the subject of negative pressure wound and instillation therapy covering publications from the years 1990 to 2013 (36 peer-reviewed citations) and regarding randomised controlled trials (RCTs) covering wound care with bone involvement (27 publications) or soft-tissue wounds without bone participation (11 publications) from 2005 to 2012. The use of NPWTi in the therapy of infected wounds appears to be not yet widespread, and literature is poor and inhomogeneous. However, some reports indicate an outstanding benefit of NPWTi for patients, using antiseptics such as polyhexanide (concentration 0·005-0·04%) and acetic acid (concentration 0·25-1%) in acute and chronic infected wounds and povidone-iodine (10% solution) as prophylaxis in contaminated wounds with potential viral infection. Soaking times are recommended to be 20 minutes each, using cycle frequencies of four to eight cycles per day. Additionally, the prophylactic use of NPWTi with these substances can be recommended in contaminated wounds that cannot be closed primarily with surgical means. Although first recommendations may be given currently, there is a great need for RCTs and multicentre studies to define evidence-based guidelines for an easier approach to reach the decision on how to use NPWTi.

Comparison of the Effects of Different Negative Pressure Wound Therapy Modes-Continuous, Noncontinuous, and With Instillation-on Porcine Excisional Wounds

OBJECTIVE

Negative pressure wound therapy (NPWT) can be delivered in continuous or noncontinuous modes, while NPWT with instillation (NPWTi) couples NPWT with automated delivery and removal of topical wound treatment solutions and suspensions. This porcine study compared granulation response of NPWTi (instillation foam dressing with saline) to NPWT (standard foam dressing) in continuous and noncontinuous modes.

METHODS

Full-thickness dorsal excisional wounds in pigs were treated with continuous NPWT, intermittent NPWT, dynamic (controlled variable) NPWT, and NPWTi with saline (n = 10 per group). Wound dimensions were determined from 3D images collected on days 0, 2, 5, and 7. On day 7, animals were euthanized and specimens were harvested for histopathological review.

RESULTS

Average granulation thickness was not statistically different among continuous (3.29 ± 0.33 mm), intermittent (3.03 ± 0.47 mm), and dynamic (3.40 ± 0.34 mm) NPWT wounds at day 7. Average granulation thickness of NPWTi wounds (4.75 ± 0.54 mm), however, was statistically greater (P < .05) by 44%, 57%, and 40%, respectively, than that of wounds treated with continuous, intermittent, and dynamic NPWT. Analysis of 3D images revealed a greater reduction in wound area and perimeter in NPWTi wounds compared to all NPWT wounds (P < .05). In addition, the average wound fill rate for NPWTi wounds was faster than that for continuous (40%; P < .05), intermittent (25%; P > .05), and dynamic (65%; P < .05) NPWT wounds.

CONCLUSIONS

Although not confirmed in humans, these porcine data suggest that NPWTi with saline may stimulate a faster rate of wound granulation than NPWT in continuous and noncontinuous modes.

[Special indications for negative pressure wound therapy in dermatologic surgery]

In recent years negative pressure wound therapy (NPWT) has gained more and more supporters in dermatologic surgery. NPWT has become one of the standard therapeutic options, especially for non-healing diabetic, venous and arterial ulcers of the legs. When managing large wounds after tumor surgery, NPWT is frequently used to induce granulation tissue and reduce wound size before the wound is closed with split- or full-thickness skin grafts or local flaps. In addition to these well-established uses, NPWT can be also employed for a variety of "new" or rare indications, some of which are presented in this review.