Wound exudate: a survey of current understanding and clinical competency

Performance of a silicone foam dressing in management of wounds in a community setting: a sub-analysis of the VIPES study

OBJECTIVE

Managing the gap between the dressing and the wound bed can facilitate the healing of exuding wounds. A silicone foam dressing (Biatain Silicone; Coloplast A/S, Denmark) was developed for application to exuding wounds. A sub-analysis of the real-world, prospective, observational VIPES (Observatoire en Ville des Plaies ExSudatives) study was conducted to investigate the use and performance of the silicone foam dressing in a community nursing setting in France.

METHOD

The sub-analysis included patients from the VIPES study who received the silicone foam dressing as a primary dressing for an acute or hard-to-heal (chronic) wound. Epidemiological and wound healing outcomes were reported via a smartphone application.

RESULTS

Overall, 64 patients were included in the sub-analysis. At baseline, most wounds (n=33/40; 82.5%) were in treatment failure (i.e., were stagnant, non-healing or had poor exudate management). At the last follow-up visit, a median of 22.5 (range: 3-151) days post baseline, 48.4% of wounds had healed and 25.0% were progressing towards healing. From baseline to the last follow-up visit, significant reductions in exudate level (p<0.0001) and exudate pooling (p<0.0001), and significant improvements in wound edges (p≤0.0001) and periwound skin (p<0.01) were observed. A total of 62.3% of patients had re-epithelialising wounds at the last follow-up visit. The majority of nurses (88.3%) and patients (85.0%) reported that the wound had improved and, at most dressing removals (93.5%), nurses reported that the dressing conformed closely to the wound bed.

CONCLUSION

Overall, the data suggest that use of the silicone foam dressing in community practice supported the healing of wounds, illustrating the importance of exudate and gap management.

A Viscous-Biofluid Self-Pumping Organohydrogel Dressing to Accelerate Diabetic Wound Healing

Viscous biofluids on wounds challenge conventional "water-absorbing" wound dressings in efficient drainage due to their poor fluidity, generally causing prolonged inflammation, anti-angiogenesis, and delayed wound closure. Herein, it is reported that a self-pumping organohydrogel dressing (SPD) with aligned hydrated hydrogel channels, prepared by a three-dimensional-templated wetting-enabled-transfer (3D-WET) polymerization process, can efficiently drain viscous fluids and accelerate diabetic wound healing. The asymmetric wettability of the hydrophobic-hydrophilic layers and aligned hydrated hydrogel channels enable unidirectional and efficient drainage of viscous fluids away from the wounds, preventing their overhydration and inflammatory stimulation. The organogel layer can adhere onto the skin around the wounds but can be easily detached from the wet wound area, avoiding secondary trauma to the newly formed tissues. Taking a diabetic rat model as an example, the SPD can significantly downregulate the inflammation response by ≈70.8%, enhance the dermal remodeling by ≈14.3%, and shorten wound closure time by about 1/3 compared with the commercial dressing (3M, Tegaderm hydrocolloid thin dressing). This study sheds light on the development of the next generation of functional dressings for chronic wounds involving viscous biofluids.

Topical lyophilized thrombin application improves wound healing for posterior spinal surgery

Background

The erector spinae plane block (ESPB) was proposed as a part of the postoperative multimodal analgesic regimen to improve pain management after posterior spinal surgery. However, ESPB might cause more surgical incisional wound exudate and poor wound healing, which might be improved after topical lyophilized thrombin application.

Materials and methods

We performed a retrospective study on patients who received posterior spinal surgery between January 2018 and December 2021. These patients were assigned into three groups: group A (general anesthesia), group B (general anesthesia with ESPB), and group C (general anesthesia with ESPB and topical 1000-unit thrombin application). Postoperative outcomes, including times of dressing changes, duration of suture removal, and incisional wound healing, were compared among these groups.

Results

Our study included 89 patients, with 48, 20, and 21 patients in groups A, B, and C, respectively. Baseline demographics, height, weight, comorbidities, and operation duration were comparable among the three groups. Group B required statistically significantly more dressing changes and had a prolonged duration of suture removal than group A (9.4 ± 4.7 versus 6.5 ± 2.0 times, 16.2 ± 3.7 versus 14.2 ± 1.4 days, respectively), which could be statistically significantly improved after the thrombin application in group C. Group B also had more frequent poor wound healing (25.0 %), which could also be improved after the thrombin application (0.0 %).

Conclusions

ESPB could cause more dressing changes and poor surgical wound healing after posterior spinal surgery, which could be improved by topical lyophilized thrombin powder application.

Systematic review and quality assessment of clinical and economic evidence for superabsorbent wound dressings in a population with chronic ulcers

Effective exudate management is key for optimal ulcer healing. Superabsorbent dressings are designed to have high fluid handling capacity, reduced risk of exudate leakage, fluid retention under compression, and to sequester harmful exudate components. This study aimed to systematically identify existing evidence for the clinical efficacy and cost-effectiveness of superabsorbent dressings for the treatment of moderate-to-highly exudating chronic ulcers of various etiologies. The aim is focused on examining the 'class' effect of all superabsorbers, not any particular dressing. Clinical and cost effectiveness systematic reviews were conducted, searching Embase, MEDLINE, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature. The Cost Effectiveness Analysis Registry and Econ papers were also searched for the economic review. Outcomes of interest included ulcer closure, dressing properties, hospital- and infection-related outcomes, safety, and economic outcomes. Fourteen studies were included in the clinical systematic review. Eleven were case series, with one randomised controlled trial, one retrospective matched observational study, and one retrospective cohort study. The studies investigated eight superabsorbent dressings and were heterogeneous in their patient population and outcomes. Superabsorbent dressings may result in favourable outcomes, including reductions in frequency of dressing change and pain scores. As most studies were case series, drawing firm conclusions was difficult due to absence of a comparator arm. The economic systematic review identified seven studies, five of which were cost-utility analyses. These suggested superabsorbent dressings are a more cost-effective option for the treatment of chronic ulcers compared with standard dressings. However, the small number and low quality of studies identified in both reviews highlights the need for future research.

Does exudate viscosity affect its rate of absorption into wound dressings?

OBJECTIVE

Exudate is a vital component of healing wounds. There are differences between acute and chronic exudate, with the latter seen as highly toxic to the healing environment. Wound exudate assessment is not easy for clinicians. The viscosity of wound fluid/exudate is as important as its quantity. Wound fluid viscosity increases when it contains more protein. As wound dressings exhibit a variety of fluid-handling mechanisms, it is important to understand how they interact with the different exudate types, which may alter the wound/dressing interface. This knowledge will ensure a healing wound environment that is beneficial, not one that leaves harmful exudate on the wound surface. This study aimed to evaluate if the viscosity of exudate affected absorption time in four wound dressing types.

METHODS

This study evaluated the viscosities of two solutions and their effect on the absorption times of four dressing types. The viscosities of the solutions were calculated using Ostwald viscometers, then 2 ml of each of these liquids was applied to each of the four dressing types and repeated 10 times for each dressing, as per British Standards Institution requirements. The parameters for temperature and frequency were applied, and the absorption times recorded. A two-way repeated analysis of variance (ANOVA) was conducted to examine if exudate viscosity and dressing type, or their interaction, affected the absorption time.

RESULTS

The results indicated that the viscosity of the solution alone had a significant effect on absorption time (p<0.01), and that the combined effect of dressing type and viscosity also affected absorption (p<0.01). The type of dressing alone was found to have a significant effect on absorption time (p<0.01). When looking at the between-subject effects of the dressings (between the four types) the only non-significant finding was between two dressings-the superabsorbent and the moderate (foam) absorbing dressing (p=0.097). All other dressings had a between-subject effect of (p<0.01).

CONCLUSION

A significant difference in absorption times was found in this investigation of dressing types and viscosity of test solutions. The greater the viscosity of the fluid, the longer it took for it to be absorbed into all dressing types tested. This delay was not determined simply by the dressing or by the viscosity of the fluid, but likely to be a combination of the mode of action of the dressing, its pore size and particulate composition of the exudate, all of which require further investigation.

The performance of gelling fibre wound dressings under clinically relevant robotic laboratory tests

The effectiveness of wound dressing performance in exudate management is commonly gauged in simple, non‐realistic laboratory setups, typically, where dressing specimens are submersed in vessels containing aqueous solutions, rather than by means of clinically relevant test configurations. Specifically, two key fluid–structure interaction concepts: sorptivity—the ability of wound dressings to transfer exudate, including viscous fluids, away from the wound bed by capillary action and durability—the capacity of dressings to maintain their structural integrity over time and particularly, at removal events, have not been properly addressed in existing test protocols. The present article reviews our recent published research concerning the development of clinically relevant testing methods for wound dressings, focussing on the clinical relevance of the tests as well as on the standardisation and automation of laboratory measurements of dressing performance. A second objective of this work was to compile the experimental results characterising the performance of gelling fibre dressings, which were acquired using advanced testing methods, to demonstrate differences across products that apparently belong to the same “gelling fibre” family but differ remarkably in materials, structure and composition and, thereby, in performance.

Not all superabsorbent wound dressings are born equal: theory and experiments

Among the advanced wound dressing types, superabsorbent (SA) dressings form an important class of dressings, particularly for the management of medium to highly exuding wounds. However, SA dressings are not all made the same. This educational article describes distinct, common SA dressing designs, which differ fundamentally in structure and composition, and, thereby, in their exudate absorption function and clinical efficacy. The diverse design families of SA dressings, including dressings with an SA polymer-sheet core, versus dressings with an air laid core, where the SA polymer grains are embedded in fluff, relate to different manufacturing processes, production techniques and associated fabrication costs. These fundamental structural and material differences across SA dressing designs from different manufacturers naturally lead to wide variations in the fluid handling characteristics of the products, which are analysed here using both theoretical and experimental bioengineering laboratory approaches. This work is primarily aimed at promoting critical thinking among health professionals who should ask manufacturers to present relevant testing data for an informed clinical decision-making with regards to the choice of the safest and best performing SA dressing for each treated wound case.

A tale of two alginates

BACKGROUND

All fibrous wound dressings are considered to have the same action and value to the support of wound healing. Although clear distinction has been accepted between cotton gauze and calcium alginates, there is still no formally recognised distinction between calcium alginates and the more rapidly gelling fibre dressings.

METHOD

Scientific and clinical evaluations were used to differentiate two different fibrous wound care products. One is derived from polymer extraction of algae (alginate dressings); the other has been manufactured from a uniquely patented carboxymethylation process that produces 100% carboxymethyl cellulose (CMC)-based dressings. Structural differences between these dressings were evaluated with respect to three important areas of wound care management: optimal wound moisture control; the ability to reduce risk of complication by locking away harmful components (e.g. bacteria); and reducing the overall cost of wound care by promoting more efficient use of nursing time.

RESULTS

Clear differentiation was illustrated through both scientific and clinical evaluations.

CONCLUSION

This study supports the potential advantages of using a technically advanced fibrous wound dressing over the traditional fibrous alginate wound care product.

Bioaerogels: Promising Nanostructured Materials in Fluid Management, Healing and Regeneration of Wounds

Wounds affect one's quality of life and should be managed on a patient-specific approach, based on the particular healing phase and wound condition. During wound healing, exudate is produced as a natural response towards healing. However, excessive production can be detrimental, representing a challenge for wound management. The design and development of new healing devices and therapeutics with improved performance is a constant demand from the healthcare services. Aerogels can combine high porosity and low density with the adequate fluid interaction and drug loading capacity, to establish hemostasis and promote the healing and regeneration of exudative and chronic wounds. Bio-based aerogels, i.e., those produced from natural polymers, are particularly attractive since they encompass their intrinsic chemical properties and the physical features of their nanostructure. In this work, the emerging research on aerogels for wound treatment is reviewed for the first time. The current scenario and the opportunities provided by aerogels in the form of films, membranes and particles are identified to face current unmet demands in fluid managing and wound healing and regeneration.

A prospective, randomized, controlled, crossover study comparing three multilayered foam dressings for the management of chronic wounds

Aim: Compare foam dressings - Mepilex Border Flex (MxBF), Allevyn Life (AL) and Optifoam Gentle EX (OGEX) - in treatment of chronic wounds. Materials & methods: Prospective, randomized, controlled trial (crossover design). Subjects received one dressing for 2 weeks, then comparator dressing for following 2 weeks. Wound/periwound characteristics evaluated weekly at dressing change. Primary end point: dressing durability (incidence of exudate strikethrough). Results: Higher incidence of intact dressings (no strikethrough) at Day 7 (Week 1) with MxBF (6/17; 35.3%) compared with AL (1/18; 5.6%), and with MxBF (7/16; 43.8%) compared with OGEX (2/16; 12.5%; p < 0.05). No significant differences between groups regarding wound size reduction. Conclusion: MxBF had statistically greater durability than AL/OGEX during first critical week of treatment.

The sorptivity and durability of gelling fibre dressings tested in a simulated sacral pressure ulcer system

Wound‐dressing performances are affected by exudate viscosity, resistance to flow because of gravity, and bodyweight loads, the level of which is related to the body position. Here, we focussed on two dressing properties: (a) Sorptivity—the ability of dressings to transfer exudate away from the wound bed by capillary action—and (b) Durability—the capacity of dressings to maintain their integrity over time and during their removal. Both properties are critically important for avoiding further tissue damage but require the development of new laboratory tests for their measurement. A computer‐controlled phantom of an exuding sacral pressure ulcer has therefore been developed and used to compare the performances of Exufiber (Mölnlycke Health Care) vs an alternative market‐leading dressing. Sorptivity was determined using weight tests, and durability was measured through tensile tests of the used dressings. For a supine configuration, the Exufiber dressing demonstrated ~three times higher sorptivity and better durability, withstanding ~five times greater strain energy than the other product before failure occurred. This work paves the way for quantitative, standardised testing of dressings in all aspects of exudate management. The reported tests are further suitable for testing dressing combinations or how dressings interact with negative pressure wound therapy.

Understanding the elements of a holistic wound assessment

Wounds have become a significant public health challenge and consume a large amount of healthcare resources. Wounds can have severe negative effects on patients' quality of life, causing psychological and social distress, and may lead to significant periods of lost employment, resulting in financial loss. For nurses to manage wounds effectively, they need to be competent in undertaking holistic wound assessments. This article supports nurses' understanding by providing information on various types of wounds and their differing aetiologies. It also outlines the elements of a wound assessment and discusses some of the challenges that may be encountered during this process.

Evaluation of a superabsorbent wound dressing, patient and clinician perspective: a case series

Objective:

The primary objective of this study was to evaluate the fluid management capabilities of a superabsorbent wound dressing (Zetuvit Plus Silicone), with secondary objectives related to parameters that support whether the dressing enables undisturbed healing.

Method:

This study was an open labelled non-comparative study. Patients included in the study were selected by the clinical investigator(s) according to whether the patient required a dressing for the management of moderately to highly exuding wounds.

Results:

A total of 50 patients were included in the study. Results related to the primary objective demonstrated that the superabsorbent wound dressing was able to absorb all levels of exudate across the range (low to high). At each assessment time point these results show that in 98% of assessments the superabsorbent dressing was rated as ‘very good’ (91%) or ‘good’ (7%) at exudate management. Secondary objectives relating to wound bed preparation, healing and management of pain were also positive. Additionally, at the end of each patient treatment, the dressing's fluid management capabilities were rated overall as ‘excellent’ (100% of cases). There was little pain associated with the wound or at dressing change throughout the study and its flexibility/conformability allowed for comfort and patient satisfaction aligned with increased quality of life. Additionally, inclusion of a silicone adhesive layer allowed painless and atraumatic removal of the dressing, increasing patient comfort, both during wear and at dressing removal, and supported the description of enabling undisturbed wound healing.

Conclusion:

The superabsorbent wound dressing achieved the primary objective relating to wound exudate management in all the assessments undertaken in this study. In addition, the silicone interface allowed for undisturbed healing as evidenced by little or no adherence of the dressing to underlying tissue, preventing damage to periwound skin. Overall, the superabsorbent wound dressing with the addition of the silicone interface could offer advantages over other superabsorbent polymer dressings (that might adhere to the wound surface) or silicone wound dressings (that might not have the absorbent properties of this type of dressing).

Computer-Assisted Wound Assessment and Care Education Program in Registered Nurses: Use of an Interactive Online Program by 418 Registered Nurses

PURPOSE

The purpose of this descriptive study was to evaluate use of a previously validated, online, interactive wound assessment and wound care clinical pathway in a group of RNs. Specific aims were to (a) evaluate the proportions of correct, partially correct, and incorrect algorithmic decisions and dressing selections, (b) compare response rates between nurses who are and who are not wound care certified, and (c) evaluate its ease of use, educational value, and applicability in clinical practice.

DESIGN

Descriptive study.

SUBJECTS AND SETTING

Participants were recruited using convenience and snowball sampling methods. Four hundred eighteen nurses completed all 15 assessments; nearly half held a bachelors' degree in nursing (189, 45%), more than two-thirds worked in an inpatient acute care settings (277, 68%), and 293 (70%) were not certified in wound care.

METHODS

After providing written informed consent and completing the participant demographics form, participants assessed 15 photographs of wounds with accompanying moisture descriptions and completed an algorithm and dressing selection for each. All responses were anonymously collected by the program. Existing, retrospective, program data were also downloaded and data from nurses who completed all assessments were extracted and analyzed. Descriptive statistics were used to analyze all variables. Selection outcomes and survey responses between nurses who were and who were not wound care certified were compared using a 2-sample Student t test assuming unequal variances. Individual responses for the first 6 wounds were compared to the last 6 wounds using a paired t test.

RESULTS

The mean (M) proportions of fully or partially correct (operationally defined as safe but not fully correct) algorithm and dressing choice were 81% (SE: 0.88, 95% confidence level: 1.73) and 78.1% (SE: 0.70, 95% confidence level: 1.39), respectively. Wound care-certified nurses had higher mean algorithm scores than those who were not certified (M: 89.2%, SE: 1.27 vs M: 77.8%, SE: 1.10, P < .001). Most incorrect/partially correct choices were attributable to incorrect necrotic tissue assessment (n = 845, 58%). The difference between fully correct first 6 and last 6 algorithm choices was statistically significant (M: 310, SE: 0.02 vs M: 337, SE: 9.32, P = .04). On a Likert scale of 1 (not at all) to 5 (very), average scores for ease of program and algorithm use, educational value, and usefulness for clinicians ranged from M: 4.14, SE: 0.08 to M: 4.22, SE: 0.08.

CONCLUSIONS

Results suggest that the algorithm is valid and has potential educational value. Initial evaluation also suggests that program refinements are needed. Evaluation of participant responses indicated potential problems with the definitions used for necrotic tissue or assessment knowledge deficits. Results also substantiate the importance of instructional design and testing online education programs. More research is needed to uncover potential gaps in nurses' wound care knowledge that may hamper evidence-based practices adoption and the need to develop effective, evidence-based education-delivery techniques.