Impact on wound healing and efficacy of various leg ulcer debridement techniques

Classification of chronic venous diseases based on skin temperature patterns

Objective. Infrared thermography has the potential to complement the classification of chronic venous diseases (CVD), but lacks sophisticated insights on the association between recorded skin temperatures and the severity of CVD. This research aims to identify temperature patterns in the lower legs of patients that are distinct in specific forms of CVD, including florid ulcers.Approach. Infrared images were acquired in a clinical trial with 36 patients and segmented using a region selection algorithm. The regions were analyzed with respect to seven predefined features. The most prominent thermal features were translated into rules to classify CVD.Main results. Patients with mild forms of CVD show local increases in skin temperature by more than 1.5 °C. These regions were 2.0 °C warmer when CVD is more severe. Temperature variations of on average 0.4 °C occurred within venous leg ulcers. Furthermore, these wounds were 1.1 °C-6.3 °C colder than periwound skin.Significance. Temperature patterns characterized by differences in temperature that occur within a few centimeters or millimeters are distinct to specific stages of CVD. These patterns are present in the locations of varicose veins and tissue damages.Significance. The findings increase the body of knowledge on the potential for the early detection of CVD using infrared thermography. Applying the presented algorithms and rules, infrared thermography may become a complementary tool for the objective classification of CVD.

Consensus on the diagnosis and management of chronic leg ulcers - Brazilian Society of Dermatology

BACKGROUND

Chronic leg ulcers affect a large portion of the adult population and cause a significant social and economic impact, related to outpatient and hospital care, absence from work, social security expenses, and reduced quality of life. The correct diagnosis and therapeutic approach are essential for a favorable evolution.

OBJECTIVE

To gather the experience of Brazilian dermatologists, reviewing the specialized literature to prepare recommendations for the diagnosis and treatment of the main types of chronic leg ulcers.

METHODS

Seven specialists from six university centers with experience in chronic leg ulcers were appointed by the Brazilian Society of Dermatology to reach a consensus on the diagnosis and therapeutic management of these ulcers. Based on the adapted DELPHI methodology, relevant elements were considered in the diagnosis and treatment of chronic leg ulcers of the most common causes; then, the recent literature was analyzed using the best scientific evidence.

RESULTS

The following themes were defined as relevant for this consensus - the most prevalent differential etiological diagnoses of chronic leg ulcers (venous, arterial, neuropathic, and hypertensive ulcers), as well as the management of each one. It also included the topic of general principles for local management, common to chronic ulcers, regardless of the etiology.

CONCLUSION

This consensus addressed the main etiologies of chronic leg ulcers and their management based on scientific evidence to assist dermatologists and other health professionals and benefit the greatest number of patients with this condition.

Advantages of Maggot Debridement Therapy for Chronic Wounds: A Bibliographic Review

GENERAL PURPOSE

To present an overview of the advantages of maggot debridement therapy as a treatment for chronic wounds through the review of several larval properties.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will be able to:1. Summarize the use, process, and precautions for maggot debridement to treat chronic wounds.2. Synthesize the results of the bibliographic review of the use of maggot debridement to treat chronic wounds.

ABSTRACT

Maggot debridement therapy (MDT) is effective for ulcer debridement, achieving it in less time than other therapies. It offers a benefit to healing. However, it is unclear whether maggots reduce treatment time and there is considerable controversy around the treatment's potential antimicrobial action and cost-effectiveness. Nevertheless, it can be effective in preventing amputations and reducing the need for systemic antibiotics. This bibliographic review assesses the advantages of MDT as a treatment for chronic wounds through the review of several larval properties. The review was carried out by consulting biomedical databases including CINAHL, MEDLINE (PubMed), and Scopus, and concludes that MDT is an effective debridement and potential technique to facilitate healing. However, more data is needed on the wound type application frequency and the efficacy of treatment.

A compact hyperspectral camera for measurement of perfusion parameters in medicine

Worldwide, chronic wounds are still a major and increasing problem area in medicine with protracted suffering of patients and enormous costs. Beside conventional wound treatment, for instance kinds of oxygen therapy and cold plasma technology have been tested, providing an improvement in the perfusion of wounds and their healing potential, but these methods are unfortunately not sufficiently validated and accepted for clinical practice to date. Using hyperspectral imaging technology in the visible (VIS) and near infrared (NIR) region with high spectral and spatial resolution, perfusion parameters of tissue and wounds can be determined. We present a new compact hyperspectral camera which can be used in clinical practice. From hyperspectral data the hemoglobin oxygenation (StO2), the relative concentration of hemoglobin [tissue hemoglobin index (THI)] and the so-called NIR-perfusion index can be determined. The first two parameters are calculated from the VIS-part of the spectrum and represent the perfusion of superficial tissue layers, whereas the NIR-perfusion index is calculated from the NIR-part representing the perfusion in deeper layers. First clinical measurements of transplanted flaps and chronic ulcer wounds show, that the perfusion level can be determined quantitatively allowing sensitive evaluation and monitoring for an optimization of the wound treatment planning and for validation of new treatment methods.

Bromelain-based enzymatic debridement of chronic wounds: A preliminary report

Sharp debridement is currently considered most effective for debridement of chronic wounds; however, some patients do not have access to or cannot be treated by surgical methods. This study was designed to provide a first impression of the safety and efficacy of bromelain-based enzymatic debridement of chronic wounds. Two consecutive single-arm studies assessing the enzymatic debridement efficacy of a concentrate of proteolytic enzymes enriched in bromelain in chronic wounds was conducted in 2 medical centres. Patients were treated with up to 11 consecutive 4-hour enzymatic debridement sessions and then treated until wound closure. Twenty-four patients with chronic wounds of different aetiologies were enrolled. All wounds achieved an average of 68% ± 30% debridement in an average of 3.5 ± 2.8 enzymatic debridement 4-hour sessions. Seventeen responding wounds (venous, diabetic, pressure, and post-traumatic aetiologies) achieved an average 85% ± 12% debridement in 3.2 ± 2.5 applications. Seven non-responding wounds (arterial and post-surgical aetiologies) achieved an average 26% ± 13% debridement in 4.3 ± 3.5 applications. No treatment-related serious adverse events were observed, and the only adverse event attributed to the enzymatic debridement was pain. These preliminary results indicate the potential safety and efficacy of bromelain-based enzymatic debridement in chronic wounds. Larger controlled studies are needed to further investigate this indication.

In Vitro Evaluation and Mechanism Analysis of the Fiber Shedding Property of Textile Pile Debridement Materials

Fiber shedding is a critical problem in biomedical textile debridement materials, which leads to infection and impairs wound healing. In this work, single fiber pull-out test was proposed as an in vitro evaluation for the fiber shedding property of a textile pile debridement material. Samples with different structural design (pile densities, numbers of ground yarns and coating times) were prepared and estimated under this testing method. Results show that single fiber pull-out test offers an appropriate in vitro evaluation for the fiber shedding property of textile pile debridement materials. Pull-out force for samples without back-coating exhibited a slight escalating trend with the supplement in pile density and number of ground yarn plies, while back-coating process significantly raised the single fiber pull-out force. For fiber shedding mechanism analysis, typical pull-out behavior and failure modes of the single fiber pull-out test were analyzed in detail. Three failure modes were found in this study, i.e., fiber slippage, coating point rupture and fiber breakage. In summary, to obtain samples with desirable fiber shedding property, fabric structural design, preparation process and raw materials selection should be taken into full consideration.

Cold adaptation, ca2+ dependency and autolytic stability are related features in a highly active cold-adapted trypsin resistant to autoproteolysis engineered for biotechnological applications

Pig trypsin is routinely used as a biotechnological tool, due to its high specificity and ability to be stored as an inactive stable zymogen. However, it is not an optimum enzyme for conditions found in wound debriding for medical uses and trypsinization processes for protein analysis and animal cell culturing, where low Ca(2+) dependency, high activity in mild conditions and easy inactivation are crucial. We isolated and thermodynamically characterized a highly active cold-adapted trypsin for medical and laboratory use that is four times more active than pig trypsin at 10(°) C and at least 50% more active than pig trypsin up to 50(°) C. Contrary to pig trypsin, this enzyme has a broad optimum pH between 7 and 10 and is very insensitive to Ca(2+) concentration. The enzyme is only distantly related to previously described cryophilic trypsins. We built and studied molecular structure models of this trypsin and performed molecular dynamic calculations. Key residues and structures associated with calcium dependency and cryophilicity were identified. Experiments indicated that the protein is unstable and susceptible to autoproteolysis. Correlating experimental results and structural predictions, we designed mutations to improve the resistance to autoproteolysis and conserve activity for longer periods after activation. One single mutation provided around 25 times more proteolytic stability. Due to its cryophilic nature, this trypsin is easily inactivated by mild denaturation conditions, which is ideal for controlled proteolysis processes without requiring inhibitors or dilution. We clearly show that cold adaptation, Ca(2+) dependency and autolytic stability in trypsins are related phenomena that are linked to shared structural features and evolve in a concerted fashion. Hence, both structurally and evolutionarily they cannot be interpreted and studied separately as previously done.

[Surgical therapy of wounds and scars]

Surgery can be very useful in all phases of wound healing and in treating scars. It can be employed along with conservative therapy, either simultaneously or in a sequential manner. The spectrum of surgical measures includes debridement with excision of wound edges or necrotic areas, skin transplantation to cover granulating wounds, and simple excision or complex reconstructive approaches to scars. The advantages of surgical treatment are seen in all phases of wound healing and include rapid onset of action, avoidance of secondary infection and improved function. The shortened healing time helps save personal and material costs.