Fluorescence imaging guided dressing change frequency during negative pressure wound therapy: a case series

Optimization and advances in negative pressure wound therapy for the management of necrotizing fasciitis in the upper limb

Necrotizing fasciitis (NF) is a rapidly progressing, life-threatening soft tissue infection, with upper limb NF posing a particularly serious threat to patient survival and quality of life. Negative pressure wound therapy (NPWT) has shown considerable advantages in accelerating wound healing and mitigating functional impairment. A retrospective study by Lipatov et al. demonstrated that NPWT significantly reduced the time needed for wound closure preparation while enhancing the success rate of local repair. Despite its benefits, certain limitations highlight the need for further optimization. This paper investigates the potential for personalized dynamic regulation of NPWT, its integration with adjunctive therapies, and the role of multidisciplinary collaboration. Furthermore, it explores the incorporation of advanced technologies such as artificial intelligence, imaging modalities, and biomaterials, presenting novel pathways for the personalized management and global standardization of NF treatment.

Improving Wound Healing and Infection Control in Long-term Care with Bacterial Fluorescence Imaging

BACKGROUND

High bacterial burden stalls wound healing and can quickly progress to infection and sepsis in complex, older-adult patients in long-term care (LTC) or skilled nursing facilities (SNFs).

OBJECTIVE

To investigate the outcomes of point-of-care fluorescence (FL) imaging (MolecuLight i:X) of bacterial loads, which are frequently asymptomatic, to inform customized wound treatment plans for patients in LTC/SNFs.

METHODS

In this retrospective pre/postinterventional cohort study, the authors compared the healing and infection-associated outcomes of 167 pressure injuries from 100 Medicare beneficiaries before and after implementation of FL imaging.

RESULTS

Most patient demographics and wound characteristics did not differ significantly between the standard-of-care (SOC; n = 71 wounds) and FL (n = 96 wounds) cohorts. Significantly more wounds (+71.0%) healed by 12 weeks in the FL cohort (38.5%) versus the SoC cohort (22.5%). Wounds in the FL cohort also healed 27.7% faster (-4.8 weeks), on average, and were 1.4 times more likely to heal per Kaplan-Meier survival analysis (hazard ratio = 1.40; 95% CI, 0.90-2.12). Infection-related complications decreased by 75.3% in the FL cohort, and a significant shift from largely systemic to topical antibiotic prescribing was evidenced.

CONCLUSIONS

Fluorescence-imaging-guided management of wounds significantly improved healing and infection outcomes in highly complex and multimorbid patients in LTC/SNFs. Proactive bacterial infection management via local treatments was enabled by earlier, objective detection. These reported outcome improvements are comparable to randomized controlled trials and cohort studies from less compromised, selectively controlled outpatient populations. Fluorescence imaging supports proactive monitoring and management of planktonic and biofilm-encased bacteria, improving patient care in a complex, real-world setting.

Current and Future Directions in Fluorescence Imaging-Guided Debridement

Significance: Sterility and reduction of the bioburden are crucial for healing in chronic wounds such as diabetic foot ulcers. Although there are methods for measuring bioburdens, such as semiquantitative analysis of swab/biopsy samples, microbiological sampling, and molecular diagnostics, these tools are less accessible owing to costs or not being as quick as other methods. These methods are also dependent on clinical assessment by the clinician, and high bacterial burden may appear asymptomatic. Recent Advances: Autofluorescence (AF) imaging is a novel technology for identifying and quantifying chronic inhibitory bacterial load in chronic wounds. Eighty-seven percent of bacteria that frequent chronic wounds have fluorophores that fluoresce under violet light as red or cyan, depending on the type of fluorophore. Therefore, AF image-guided treatment is becoming increasingly effective for physicians to implement wound dressing changes and debridement because bacterial burdens are difficult to locate clinically. Critical Issue: Products such as the commercially available MolecuLight i:X and MolecuLight DX function as handheld cameras for physicians to use as a reference but require additional work to ensure that the photograph will be taken with adequate lighting. Future Directions: Designs for Vision Inc. introduced a device called REVEAL, an AF imaging form factor that allows the device to be worn on top of a pair of glasses, which the physician would wear intraoperatively. The benefits of this form factor include not requiring certain lighting conditions and not having to interpret the results using a handheld camera, allowing the device to be used during active surgical debridement.

Use of fluorescence imaging to optimize location of tissue sampling in hard-to-heal wounds

Introduction

Wound microflora in hard-to-heal wounds is invariably complex and diverse. Determining the interfering organisms(s) is therefore challenging. Tissue sampling, particularly in large wounds, is subjective and, when performed, might involve swabbing or biopsy of several locations. Fluorescence (FL) imaging of bacterial loads is a rapid, non-invasive method to objectively locate microbial hotspots (loads >104 CFU/gr). When sampling is deemed clinically necessary, imaging may indicate an optimal site for tissue biopsy. This study aimed to investigate the microbiology of wound tissue incisional biopsies taken from sites identified by FL imaging compared with sites selected by clinical judgment.

Methods

A post hoc analysis of the 350-patient FLAAG wound trial was conducted; 78 wounds were included in the present study. All 78 wounds were biopsied at two sites: one at the center of the wound per standard of care (SoC) and one site guided by FL-imaging findings, allowing for comparison of total bacterial load (TBL) and species present.

Results

The comparison between the two biopsy sites revealed that clinical uncertainty was higher as wound surface area increased. The sensitivity of a FL-informed biopsy was 98.7% for accurately finding any bacterial loads >104 CFU/g, compared to 87.2% for SoC (p=0.0059; McNemar test). Regarding species detected, FL-informed biopsies detected an average of 3 bacterial species per biopsy versus 2.2 species with SoC (p < 0.001; t-test). Microbial hotspots with a higher number of pathogens also included the CDC's pathogens of interest.

Conclusions & perspective

FL imaging provides a more accurate and relevant microbiological profile that guides optimal wound sampling compared to clinical judgment. This is particularly interesting in large, complex wounds, as evidenced in the wounds studied in this post hoc analysis. In addition, fluorescence imaging enables earlier bacterial detection and intervention, guiding early and appropriate wound hygiene and potentially reducing the need for antibiotic use. When indicated, this diagnostic partnership with antibiotic stewardship initiatives is key to ameliorating the continuing threat of antibiotic resistance.

The Effectiveness of Negative Pressure Therapy: Nursing Approach

INTRODUCTION

Complex wounds require advanced techniques for their management and care. Wound care costs are high, so healthcare professionals need to be aware of available therapies. Negative pressure therapy is a technology for which more and more data on its effectiveness in complex wounds are being collected.

OBJECTIVE

The objectives of this review were to analyze if the application of negative pressure therapy in complex wounds is effective; to compare the effectiveness of negative pressure therapy with other conventional treatments, as well as its combination with other therapies; and to evaluate the quality of life of patients undergoing negative pressure therapy and collect their main characteristics.

METHODOLOGY

A bibliographic review focused on articles published between November 2015 and June 2022 was carried out. The following databases were consulted: PubMed (Medline), Google Scholar, Web of Science (WOS), Scielo and Scopus.

RESULTS

The most used pressures in the studies coincide at -125 mmHg and in the range of -125 mmHg to -150 mmHg. In the pediatric population, pressure levels vary by age group. A pressure of -75 to -125 mmHg is recommended for children over 12 years of age, and -50 to -75 mmHg is recommended for children under 2 years of age.

CONCLUSIONS

Negative pressure therapy stands out for its rapid rate of granulation, the prevention and effective treatment of infections, the variety and malleability of dressings, its various applications and the possibility of using it with other therapies to accelerate wound closure.

What COVID-19 taught us: New opportunities and pathways from telemedicine and novel antiseptics in wound healing

The COVID-19 pandemic deeply impacted the capacity of the health systems to maintain preventive and curative services, especially for the most vulnerable populations. During the pandemic, the wound healing centres in Italy assisted a significant reduction of the frequency of their hospital admission, since only urgencies, such as severe infections or wound haemorrhagic complications, were allowed to the hospital. The aim of this multidisciplinary work is to highlight the importance of a new pathway of wound care with patient-based therapeutic approach, tailored treatments based on the characteristics of the wound and fast tracks focused on the outpatient management, reserving hospital assessment only for patients with complicated or complex wounds. This analysis highlights the point that patients with chronic wounds need to be critically evaluated in order to find the best and most appropriate care pathway, which should vary according to the patient and, especially, to the characteristics of the wound. Moreover, the most adequate topic antiseptic should be started as soon as possible. An appropriate and correct management of the wound care will allow to link the knowledge based on years of clinical practice with the new challenges and the need to visit patients remotely, when possible.

Guidelines for Point-of-Care Fluorescence Imaging for Detection of Wound Bacterial Burden Based on Delphi Consensus

Excessive levels of bacteria impede wound healing and can lead to infectious complications. Unfortunately, clinical signs and symptoms of elevated bacterial burden are often unreliable. As a result, point--of--care fluorescence imaging, used to detect critical bacterial burden in wounds, is becoming widely recognized and adopted by clinicians across the globe as an accepted and added component of wound assessment protocol. A Delphi method was employed to establish consensus guidelines describing fluorescence imaging use. A multidisciplinary panel of 32 wound experts (56% MD, 22% podiatrist, 12.5% nurses/nurse practitioners) representing multiple sites of service (e.g., hospital outpatient, inpatient, private office, long-term care) completed two rounds of online questionnaires. The Delphi included key topics, including competencies required to perform imaging, clinical indications for imaging (e.g., signs/symptoms present, procedures warranting imaging), frequency of imaging, and a clinical workflow algorithm. Describing their clinical experiences of imaging impact, >80% reported changes in treatment plans, 96% reported that imaging-informed treatment plans led to improved wound healing, 78% reported reduced rates of amputations, and 83% reported reduced rates of microbiological sampling. The guidelines provided here will help to standardize use of fluorescence imaging among wound care providers and enhance the quality of patient care.

Evaluation of the combination of a biofilm-disrupting agent and negative pressure wound therapy: a case series

OBJECTIVE

Approximately three million people in the US have hard-to-heal pressure ulcers (PUs), including 10% of hospitalised patients. Healing depends on ulcer stage and patient comorbidities. Despite advances in nutrition and wound care, PUs can take months or years to reach complete closure. To date, clinical studies have focused on single modality therapy. However, there is no one therapy that can address all of the deficits in these complex, hard-to-heal wounds. A commonly used treatment for PUs, negative pressure wound therapy (NPWT), has demonstrated improved healing in Stage 3 and 4 PUs. NPWT entails applying suction to a porous sponge fitted into the wound cavity and sealed with an occlusive dressing. Negative pressure facilitates wound healing by removing wound fluid containing harmful proteases, stimulating the formation of granulation tissue and promoting wound contracture. However, it does not affect biofilm formation. We hypothesised that adding an antibiofilm agent might increase the effectiveness of NPWT in recalcitrant PUs.

METHOD

A prospective case series was conducted in outpatient wound care centres and a skilled nursing facility to examine the combination of a biofilm-disrupting antimicrobial agent (Blast-X, Next Science, US) in combination with NPWT (VAC, 3M, US) in healing and reducing bacterial burden in treatment-resistant pressure ulcers. Patients consented to application of the antibiofilm agent and NPWT three times per week for four weeks. The wounds were measured, imaged for bacteria and tested for host and bacterial protease activity weekly.

RESULTS

Of the 10 patients, four dropped out of the study before the end of the four weeks. Of the remaining six, four patients experienced a reduction in wound surface area and volume, reduced protease activity and lower bacterial levels.

CONCLUSION

The results of this study showed that multimodal therapy, including NPWT and biofilm disruption, may restart the healing of stagnant treatment-resistant PUs.

Bacterial Autofluorescence Digital Imaging Guides Treatment in Stage 4 Pelvic Pressure Injuries: A Preliminary Case Series

Pelvic pressure injuries in long-term care facilities are at high risk for undetected infection and complications from bacterial contamination and stalling of wound healing. Contemporary wound healing methods must address this problem with mechanical debridement, wound irrigation, and balanced dressings that reduce bacterial burden to enable the normal healing process. This study evaluated the impact of bacterial autofluorescence imaging to indicate wound bacterial contamination and guide treatment for severe stage 4 pelvic pressure injuries. A handheld digital imaging system was used to perform bacterial autofluorescence imaging in darkness on five elderly, high-risk, long-term care patients with advanced stage 4 pelvic pressure injuries who were being treated for significant bacterial contamination. The prescient findings of bacterial autofluorescence imaging instigated treatment strategies and enabled close monitoring of the treatment efficacy to ameliorate the bacterial contamination. Wound sepsis recurrence, adequate wound cleansing, and diagnosis of underlying periprosthetic total joint infection were confirmed with autofluorescence imaging showing regions of high bacterial load. By providing objective information at the point of care, imaging improved understanding of the bacterial infections and guided treatment strategies.

Use of a bacterial fluorescence imaging system to target wound debridement and accelerate healing: a pilot study

OBJECTIVE

Optimal wound-bed preparation consists of regular debridement to remove devitalised tissues, reduce bacterial load, and to establish an environment that promotes healing. However, lack of diagnostic information at point-of-care limits effectiveness of debridement.

METHOD

This observational case series investigated use of point-of-care fluorescence imaging to detect bacteria (loads >10⁴CFU/g) and guide wound bed preparation. Lower extremity hard-to-heal wounds were imaged over a 12-week period for bacterial fluorescence and wound area.

RESULTS

A total of 11 wounds were included in the study. Bacterial fluorescence was present in 10 wounds and persisted, on average, for 3.7 weeks over the course of the study. The presence of red or cyan fluorescent signatures from bacteria correlated with an average increase in wound area of 6.5% per week, indicating stalled or delayed wound healing. Fluorescence imaging information assisted in determining the location and extent of wound debridement, and the selection of dressings and/or antimicrobials. Elimination of bacterial fluorescence signature with targeted debridement and other treatments correlated with an average reduction in wound area of 27.7% per week (p<0.05), indicative of a healing trajectory.

CONCLUSION

These results demonstrate that use of fluorescence imaging as part of routine wound care enhances assessment and treatment selection, thus facilitating improved wound healing.

Diagnostic Accuracy of Point-of-Care Fluorescence Imaging for the Detection of Bacterial Burden in Wounds: Results from the 350-Patient Fluorescence Imaging Assessment and Guidance Trial

Objective: High bacterial load contributes to chronicity of wounds and is diagnosed based on assessment of clinical signs and symptoms (CSS) of infection, but these characteristics are poor predictors of bacterial burden. Point-of-care fluorescence imaging (FL) MolecuLight i:X can improve identification of wounds with high bacterial burden (>10⁴ colony-forming unit [CFU]/g). FL detects bacteria, whether planktonic or in biofilm, but does not distinguish between the two. In this study, diagnostic accuracy of FL was compared to CSS during routine wound assessment. Postassessment, clinicians were surveyed to assess impact of FL on treatment plan. Approach: A prospective multicenter controlled study was conducted by 20 study clinicians from 14 outpatient advanced wound care centers across the United States. Wounds underwent assessment for CSS followed by FL. Biopsies were collected to confirm total bacterial load. Three hundred fifty patients completed the study (138 diabetic foot ulcers, 106 venous leg ulcers, 60 surgical sites, 22 pressure ulcers, and 24 others). Results: Around 287/350 wounds (82%) had bacterial loads >10⁴ CFU/g, and CSS missed detection of 85% of these wounds. FL significantly increased detection of bacteria (>10⁴ CFU/g) by fourfold, and this was consistent across wound types (p < 0.001). Specificity of CSS+FL remained comparably high to CSS (p = 1.0). FL information modified treatment plans (69% of wounds), influenced wound bed preparation (85%), and improved overall patient care (90%) as reported by study clinicians. Innovation: This novel noncontact, handheld FL device provides immediate, objective information on presence, location, and load of bacteria at point of care. Conclusion: Use of FL facilitates adherence to clinical guidelines recommending prompt detection and removal of bacterial burden to reduce wound infection and facilitate healing.

Rapid Diagnosis of Pseudomonas aeruginosa in Wounds with Point-Of-Care Fluorescence Imaing

Pseudomonas aeruginosa (PA) is a common bacterial pathogen in chronic wounds known for its propensity to form biofilms and evade conventional treatment methods. Early detection of PA in wounds is critical to the mitigation of more severe wound outcomes. Point-of-care bacterial fluorescence imaging illuminates wounds with safe, violet light, triggering the production of cyan fluorescence from PA. A prospective single blind clinical study was conducted to determine the positive predictive value (PPV) of cyan fluorescence for the detection of PA in wounds. Bacterial fluorescence using the MolecuLight i:X imaging device revealed cyan fluorescence signal in 28 chronic wounds, including venous leg ulcers, surgical wounds, diabetic foot ulcers and other wound types. To correlate the cyan signal to the presence of PA, wound regions positive for cyan fluorescence were sampled via curettage. A semi-quantitative culture analysis of curettage samples confirmed the presence of PA in 26/28 wounds, resulting in a PPV of 92.9%. The bacterial load of PA from cyan-positive regions ranged from light to heavy. Less than 20% of wounds that were positive for PA exhibited the classic symptoms of PA infection. These findings suggest that cyan detected on fluorescence images can be used to reliably predict bacteria, specifically PA at the point-of-care.

Diagnosing Burn Wounds Infection: The Practice Gap & Advances with MolecuLight Bacterial Imaging

Burn injuries constitute a critical economic burden on healthcare infrastructures worldwide. They are often associated with high mortality rates due to severe complications. Infection is the most common complication, highlighting the importance of prompt and precise diagnosis in order to prevent detrimental consequences and to optimize patient outcomes. Here we examine the current standard of care for diagnosing infection in both burn and chronic wounds followed by an investigation into the research surrounding a relatively new technique for bacterial detection, fluorescence imaging. With five years of published research on bacterial fluorescence imaging (MolecuLight i:X device), we have summarized and analysed the validity of the procedure and compared it to the current standard of care; clinical assessment and microbiological analysis. We highlight the benefits that could be obtained through the use of this technology as well as the limitations and the feasibility of incorporating this novel procedure into the standard of care.

Use of a bacterial fluorescence imaging device: wound measurement, bacterial detection and targeted debridement

OBJECTIVE

Diagnostics which provide objective information to facilitate evidence-based treatment decisions could improve the chance of wound healing. Accurate wound measurements, objective bacterial assessment, and the regular, consistent tracking of these parameters are important aspects of wound care. This study aimed to assess the accuracy, clinical incorporation and documentation capabilities of a handheld bacterial fluorescence imaging device (MolecuLight i:X).

METHOD

Benchtop wound models with known dimensions and clinical wound images were repeatedly measured by trained clinicians to quantify accuracy and intra/inter-user coefficients of variation (COV) of the imaging device measurement software. In a clinical trial of 50 wounds, wound dimensions were digitally measured and fluorescence images were acquired to assess for the presence of bacteria at moderate-to-heavy loads. Finally, fluorescence imaging was implemented into the routine assessment of 22 routine diabetic foot ulcers (DFU) to determine appropriate debridement level and location based on bacterial fluorescence signals.

RESULTS

Wound measurement accuracy was >95% (COV <3%). In the clinical trial of 50 wounds, 72% of study wounds demonstrated positive bacterial fluorescence signals. Levine sampling of wounds was found to under-report bacterial loads relative to fluorescence-guided curettage samples. Furthermore, fluorescence documentation of bacterial presence and location(s) resulted in more aggressive, fluorescence-targeted debridement in 17/20 DFUs after standard of care debridement failed to eliminate bacterial fluorescence in 100% of DFU debridements.

CONCLUSION

The bacterial fluorescence imaging device can be readily implemented for objective, evidenced-based wound assessment and documentation at the bedside. Bedside localisation of regions with moderate-to-heavy bacterial loads facilitated improved sampling, debridement targeting and improved wound bed preparation.