Review Article
Wound dressings, does it matter and why? Marjolein Birgitte Maessen-Visch1 and Catherine van Montfrans2
Phlebology 2016, Vol. 31(1S) 63–67 ! The Author(s) 2016 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0268355516633383 phl.sagepub.com
Abstract Compression therapy and treating venous insufficiency is the standard of care for venous leg ulcers. The need for debridement on healing venous leg ulcers is still debated. Dressings are often used under compression bandages to promote faster healing and prevent adherence of the bandage to the ulcer. A wide range of dressings is available, including modern dressings with different kinds of biological activity. Microbial burden is believed to underlie delayed healing, but the exact role of microbiofilm in wound healing is uncertain. Before choosing a specific wound dressing, four main functions should be considered: (1) cleaning, (2) absorbing, (3) regulating or (4) the necessity of adding medication. There is no clear evidence to support the use of one dressing over another, as demonstrated by many Cochrane review studies. In addition, the prescriber should enquire about contact allergies that may also develop during wound treatment. It is shown that early intervention and early investment may reduce the cost of treatment. The choice of wound dressings should be guided by cost, ease of application and patient and physician preference and be part of the complete strategy. The role of the medical specialist is evident. Wound dressings matter as part of the optimal treatment in VLU patients.
Keywords Leg ulcers, wound care, microbiology
Introduction What is the influence of dressings on wound healing? A difficult question to answer, the world of wound dressings is large and complex. First of all, one has to realize that a dressing may be beneficial for a certain type of wound in a certain phase of healing, during a different phase of healing or in a wound of another etiology this may not be the case. Secondly, both patient-specific factors such as comorbidity or polypharmacy, and local factors such as compromised vascularization and microbacterial colonization need to be specified before determining the efficacy of a dressing. Currently special attention is paid to the microbial burden in studies on wound healing. The choice for the appropriate type of wound dressing should also take into account other qualities, such as patient comfort and absorbance capacity. And last but not the least, a certain type of venous leg ulcer (VLU), such as the recalcitrant venous leg ulcer, shows no healing tendency at all, regardless of the wound dressing.1 In this article, we will focus on the clinical practice related to the current evidence for the effect of dressings on wound healing (of VLU) and the considerations necessary to make a balanced choice. Emphasis is placed on the functional classification of dressings,
the microbiome and allergic aspects in relation to wound dressings, and on how clinicians should use the conclusions of studies and weigh the importance of scientific evidence.
Wound dressings The number of different types of wound dressings, including those used beneath compression bandages, is increasing. Modern wound dressings include gauzes, (impregnated) films, gels, foams, hydrocolloids, alginates, hydrogels and other polymers. Many dressings are being designed to have a biological activity itself, either on its own or by releasing bioactive constituents incorporated within the dressing. Hydrogels, hydrocolloids, foams, films and wafers can be used to deliver a variety of compounds such as antimicrobials, 1 2
Rijnstate Ziekenhuis, Arnhem, The Netherlands VU Medical Centre, Amsterdam, The Netherlands
Corresponding author: Marjolein Birgitte Maessen-Visch, Department of Dermatology, Rijnstate Ziekenhuis, President Kennedylaan 100, 6883 AZ Velp, Arnhem, The Netherlands. Email: [email protected]
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
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anti-inflammatory agents, analgesics, growth factors and proteins.2 Therefore the original classification of different types of wound dressings is no longer more suitable. Four main functions of wound dressings can now be identified: cleaning, absorbing, regulating and the possibility of adding medication. Before choosing a modern dressing the desired function and the expected result should be considered. A dressing with an absorbing function differs completely from an anti-microbial dressing. Several studies show good healing tendencies with modern dressings and although there is not one superior dressing, the advantage of the modern dressings for individual patients cannot be neglected; a large metaanalysis on patients with chronic wounds, including VLU, have shown their general superiority of modern dressings on complete healing.3 In addition to efficacy, reasons for choosing one dressing over another will vary according to a wide range of factors relating to the needs of the patient, cost-effectiveness data and the resources available within the health-care setting.4 The choice of wound dressing should be part of the complete strategy for treatment of wounds and should not be randomly selected. Of course in general practice standard therapy should be optimized before more modern wound dressings are used.
Microbial burden Microbial burden is believed to influence healing, although little is known of clinical factors that may influence the microbial load. Microbial burden or microbial bioburden includes the diversity and pathogenicity of bacteria and the microbial load. Compared to topical treatment with antibiotics, systemic antibiotics have a positive effect on wound healing, if they are used for a prolonged period of time (e.g. several months). Huovinen et al.5 showed in 1994 a significant increase in healing rates with ciprofloxacin, after 16 weeks of use, and Valtonen et al.6 showed the same significant effect in VLU. Since the use of oral antibiotics is associated with many side effects, and its use leads to bacterial resistance to antibiotics, in daily practice one should be cautious to prescribe systemic antibiotics. For non-healing VLU the use of systemic antibiotics can be considered occasionally, also before for instance skin grafting. It is hypothesized that the anti-inflammatory effect of antibiotics might be the reason for a positive effect on wound healing. This supports the theory that bacteria in chronic wounds grow in biofilms, with a complexity of anaerobes and other species which are hard to identify and it explains the lack of other studies to prove the effect of antibiotics.7 The fact that culture swabs are not always reliable makes it more complex to make a proper choice for wound dressings.8,9 For instance Pseudomonas might
be located deep in ulcers and missed with a normal swab. A recent study in diabetic ulcers without clinical signs of infection showed the presence of the bacterial 16 S ribosomal RNA gene, showing heterogeneous microbiomes, which could be clustered in several groups, mainly distinguished by dominant bacteria and diversity.8 For VLU Thomsen et al.9 stated that the differences between the culture-based and molecularbased approaches for bacterial growth demonstrate that with a single approach not all bacteria present in wounds can be identified. More studies are necessary to understand the role of microbial film in wound healing. Finally, since we still are not certain when VLU are falsely labelled to have no bacterial importance, do really not have bacterial importance, and it can be therefore concluded that the choice for a proper wound dressing in this aspect remains limited.
Evidence During the past 10 years, Cochrane reviews on wounds, wound dressings and wound therapy have increased up to over 300 reviews. For VLU there are 14 different reviews, five concerning topical wound dressings (Table 1), which are all part of extensive Cochrane reviews on leg ulcers. Although these reviews provide the clinician with increasingly more evidence, this does not make clinical decision-making less complex. For instance most guidelines advise to start wound
Table 1. Cochrane review studies for topical wound dressings and debridement for VLU. 2012
Topical agents or dressings for reducing pain
2013
Foam dressings
2014
Antibiotics and antiseptics
2015
Alginate dressings
2015
Debridement
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
Ibuprofen dressings may offer pain relief Emla 5% appears to provide pain relief during debridement Foam dressings are not more effective in healing VLU than other wound dressing treatments Topical: some evidence supports the use of cadexomer iodine Alginate dressings are not more effective in healing VLU than hydrocolloid or plain non-adherent dressings Limited evidence that actively debriding has clinically significant impact on healing
Maessen-Visch and van Montfrans
65
treatment with debridement and to remove devital tissue from VLU. A striking result was however presented in a recent Cochrane review on debridement: the evidence for the efficacy of debridement on healing of VLU appeared to be very limited.10 In clinical practice, debridement may be either sharp or surgical, mechanical, enzymatic, autolytic and biosurgical (e.g. maggots). In this Cochrane review no studies could be identified that compared debridement to no debridement. Moreover, no studies that tested sharp or mechanical methods of debridement could be included. Most studies reviewed were small, their overall quality was identified as low and the studies were of short duration. There were differences between the studies in terms of the amount of slough in the wound bed of the ulcers at the start of the trial, in treatment regimes, in the variety of set-up, in the duration of treatments and in the outcome measurements. This Cochrane review confirms that although there may be quite a number of studies, a final evidence-based recommendation on the if and how to perform debridement is difficult to be made. This demonstrates that although Cochrane reviews are valuable, they are sometimes only of limited additional value for clinical practice. In addition, in spite of the present guideline recommendations to perform debridement, the authors have the impression that in clinical practice debridement of wounds in VLU is not performed regularly and not always as effective as suggested. A recent RCT study showed that maggots improve wound debridement in VLU, but that no improvement in healing rate was seen;11 this confirms that the need for debridement in VLU is still debated. The clinical presentation of VLU may vary, as the amount of slough in the ulcers, and therefore the advice of debridement should be individualized. Studies on wound dressings show a similar problem of having low or unclear methodological quality, small size and short duration. In general it is accepted that there is no superior dressing for VLU since there seems to be no additional beneficial effect from any of the wound dressings in VLU without clinical bacterial importance (Table 1).12 Classical wound dressings have been used to protect the wound from contamination and do not take an active part in the wound-healing process. In VLU with clinical bacterial importance the choice of a wound dressing is difficult. Around the year 2000 silver sulfadiazine showed significant wound-healing effect in several studies and therefore English, American, Australian, German and Dutch guidelines recommended the use of silver sulfadiazine. In the same period wound dressings using silver became very popular and a lot of different types of wound dressings containing silver were developed. The positive effect of silver on bacterial growth in in-vitro studies was stated.
One meta-analysis on mixed leg ulcers reported that topical silver and silver dressings are more effective on wound size reduction compared to placebo, conservative wound care and non-silver therapies.13 Although silver is proved to have better wound healing properties than cotton- and chitosan-based dressings, the additive effect of using silver in modern dressings could not be shown for VLU.14 In the opinion of the authors, it cannot be concluded, however, that silver should not be used. As stated before: the clinical presentation of leg ulcers may vary and several types of wounds may be hard to define. Evidence does not always help in making the decision for the proper choice of wound dressing. Some recent studies showed an effect on wound healing using cadexomer iodine in VLU with suspected bacterial involvement, resulting in the advice to consider using this as a wound dressing.15 At this moment several guidelines advise using cadexomer iodine instead of silver products when a VLU shows signs of infection. In this review there is no evidence for the routine use of oral antibiotics, as discussed before. In general practice for therapeutic-resistant VLU the use of oral antibiotics might be considered. Wound dressings do matter, but how is still unclear.
Allergy It is often assumed that modern wound dressings, because of their hypoallergenic or anti-allergic properties and their comfort to patients, seldom cause allergic reactions. However, sensitization to topical treatments for leg ulcers is still frequent and, moreover, continues to increase, also for new products.16 It was already proved that wound dressings cause allergies.17 A recent French study showed that modern dressings which are frequently used also cause allergic reactions. Up to 60% of patients with VLU showed a positive patch test (13% for fragrance and 4% lanoline, which might be relevant) and 19% of the 354 patients had at least one sensitization to a modern wound dressing.18 A remarkable aspect was that a positive allergic reaction correlated with the duration of the ulcerative disease, not with duration of the active ulcer. Other studies frequently show polysensitization in patients with VLU. This risk increases with the duration of the ulcer.19
Considerations The choice for a specific wound dressing is part of the complete treatment strategy in VLU patients. The choice for a wound dressing may be based on the conclusion that the dressing will only be used to protect the wound and to create a moist environment, or that a
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
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more active role is necessary for instance by applying a drug. First the diagnosis VLU should conform to the guidelines with duplex scanning and an ankle-brachial index to exclude arterial disease. The underlying superficial venous insufficiency should be treated if feasible, with special attention to veins with drainage to the VLU. It is the view of the authors that in general practice the dermatologist and surgeons are best equipped to diagnose a VLU and to make an adequate differential diagnosis, assessing venous insufficiency and all aspect of wound dressings including allergic aspects through patch testing. There is great variation in recurrence rates of VLU varying from 0% after 6 months up to 56% after 54 months.20 It is important both to try to prevent recurrence of VLU and to heal the wound as fast as possible. Active participation in treatment is an important part of any treatment strategy, not only for the individual patient, but also to reduce costs.21 Appropriate wound dressings may initially increase costs, but finally reduce total costs. As an integral part of the treatment strategy, efficacy and wound characteristic should be considered. Many patients seems to have a pharmacy at home, because there is a lack of consensus in daily practice on dressings especially which, when and how frequent to use dressings. It is important that local agreements are made using only a limited number of wound dressings. There is not always a need for expensive wound dressings with all kinds of biological activity. Besides the efficacy, the reasons for choosing one dressing over another will vary according to a wide range of factors related to the needs of the patient, cost-effectiveness data and the resources available within the health-care setting.4 With active participation in the treatment of VLU the use of additional therapy, such as oral pentoxyfilline or split-thickness skin grafting, should be considered. It may be outlined that these additional therapies should be considered in recurrent leg ulcers, or when a primary VLU does not show healing tendencies within 6 to 8 weeks. Of course standard therapy should be optimized first. Since the number of well performed studies is limited, more studies should be performed to optimize treatment strategies.
Conclusions The choice for a specific wound dressing is part of the complete treatment strategy in VLU patients, in which treating venous insufficiency remains most important. The need for debridement on healing VLU is still not proven. The microbial burden is believed to underlie delayed healing, but swabs seem not to be representative and the exact role of microbial film in wound healing is uncertain. The choice for a wound dressing is
based on the need for a dressing used only to protect the wound and creating a moist environment, or the need for a more active role and the use of a drug. Cochrane review studies on wounds are numerous, but often neither sustain nor contradict the choice for a certain dressing. To avoid using too many and unnecessary wound dressing local agreements with specialist, nurses and pharmacologists are recommended. Allergies for wound dressings may be present often even if eczema is absent. The incidence of allergy for topical treatments and modern wound dressings in VLU continues to increase. To reduce healing time and subsequently to reduce cost early intervention and early investment pays. So the choice for the wound dressings should be part of the complete strategy, in which the necessity of the medical specialist is evident. Consequently, wound dressings do matter as part of the optimal treatment in VLU patients. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Reeder SWI, Maessen-Visch MB, Langendoen SI, et al. The recalcitrant venous leg ulcer - a never ending story? Phlebologie 2013; 42: 332–339. 2. Boateng J and Catanzano O. Advanced therapeutic dressings for effective wound healing - a review. J Pharm Sciences 2015; 104: 3653–3680. 3. Heyer K, Augustin M, Protz K, et al. Effectiveness of advanced versus conventional wound dressings on healing of chronic wounds: systematic review and meta-analysis. Dermatology 2013; 226: 172–184. 4. Gottrup F, Apelqvist J and Price P. Outcomes in controlled and comparative studies on non-healing wounds: recommendations to improve the quality of evidence in wound management. J Woundcare 2010; 19: 239–268. 5. Huovinen S, Kotilainen P, Ja¨rvinen H, et al. Comparison of ciprofloxacin or trimethoprim therapy for venous leg ulcers: results of a pilot study. J Am Acad Dermatol 1994; 31: 279–281. 6. Valtonen V, Karpinen V and Kariniemi AL. A comparative study of ciprofloxacin and conventional therapy in the treatment of patients with chronic lower leg ulcers infected with Pseudomonas aeruginosa or other gram-negative rods. Scand J Infect Dis Suppl 1989; 60: 79–83. 7. Tuttle MS. Association between microbial bioburden and healing outcomes in venous leg ulcers: a review of the evidence. Adv Wound Care (New Rochelle) 2015; 4: 1–11.
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
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8. Gardner SE, Hills SL, Heilmann K, et al. The neuropathic diabetic foot ulcer microbiome is associated with clinical factors. Diabetes 2013; 62: 923–930. 9. Thomsen TR, Aasholm MS, Rudkjøbing VB, et al. The bacteriology of chronic venous leg ulcer examined by culture-independent molecular methods. Wound Repair Regen 2010; 18: 38–49. 10. Gethin G, Cowman S and Kolbach DN. Debridement for venous leg ulcers. Cochrane Database Syst Rev 2015; 9: CD008599. 11. Davies CE, Woolfrey G, Hogg N, et al. Maggots as a wound debridement agent for chronic venous leg ulcers under graduated compression bandages: a randomised controlled trial. Phlebology 2015; 30: 693–699. 12. Maessen-Visch MB and de Roos K-P. Dutch venous ulcer guideline update. Phlebology 2014; 29: 152–155. 13. Carter MJ, Tingley-Kelley K and Warriner RA. Silver treatments and silver-impregnated dressings for the healing of leg wounds and ulcers: a systematic review and meta-analysis. J Am Acad Dermatol 2010; 63: 668–679. 14. Archana D, Singh BK, Dutta J, et al. Chitosan-PVPnano silver oxide wound dressing: in vitro and in vivo evaluation. Int J Biol Macromol 2015; 73: 49–57. 15. O’Meara S, Al-Kurdi D, Ologun Y, et al. Antibiotics and antiseptics for venous leg ulcers. Cochrane Database Syst Rev 2014; 1: CD003557.
16. Machet L, Couhe´ C, Perrinaeud A, et al. A high prevalence of sensitization still persists in leg ulcer patients: a retrospective series of 106 patients tested between 2001 and 2002 and a meta-analysis of 1975–2003 data. Br J Dermatol 2004; 150: 929–935. 17. Malten KE and Kuiper JP. Contact cutaneous allergy in 100 cases of varicose ulcers. Phlebologie 1974; 27: 417–420. 18. Valois A, Waton J, Avenel-Audran M, et al. Contact sensitization to modern dressings: a multicentre study on 354 patients with chronic leg ulcers. Contact Dermatitis 2014; 72: 90–96. 19. Barbaud A, Collet E, Le Coz CJ, et al. Contact allergy in chronic leg ulcers: results of a multicentre study carried out in 423 patients and proposal for an updated series of patch tests. Contact Dermatitis 2009; 60: 279–287. 20. Reeder SWI, Eggen C, Maessen-Visch MB, et al. Recurrence of venous leg ulceration. Rev Vasc Med 2013; 1: 63–65. 21. Augustin M. Gesundheitso¨konomische Aspekte der Wundversorgung. In: Augustin M and Debus S (eds.) Moderne Wundversorgung. mhp Verlag, 2009.
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
Wound dressings, does it matter and why? Marjolein Birgitte Maessen-Visch1 and Catherine van Montfrans2
Phlebology 2016, Vol. 31(1S) 63–67 ! The Author(s) 2016 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0268355516633383 phl.sagepub.com
Abstract Compression therapy and treating venous insufficiency is the standard of care for venous leg ulcers. The need for debridement on healing venous leg ulcers is still debated. Dressings are often used under compression bandages to promote faster healing and prevent adherence of the bandage to the ulcer. A wide range of dressings is available, including modern dressings with different kinds of biological activity. Microbial burden is believed to underlie delayed healing, but the exact role of microbiofilm in wound healing is uncertain. Before choosing a specific wound dressing, four main functions should be considered: (1) cleaning, (2) absorbing, (3) regulating or (4) the necessity of adding medication. There is no clear evidence to support the use of one dressing over another, as demonstrated by many Cochrane review studies. In addition, the prescriber should enquire about contact allergies that may also develop during wound treatment. It is shown that early intervention and early investment may reduce the cost of treatment. The choice of wound dressings should be guided by cost, ease of application and patient and physician preference and be part of the complete strategy. The role of the medical specialist is evident. Wound dressings matter as part of the optimal treatment in VLU patients.
Keywords Leg ulcers, wound care, microbiology
Introduction What is the influence of dressings on wound healing? A difficult question to answer, the world of wound dressings is large and complex. First of all, one has to realize that a dressing may be beneficial for a certain type of wound in a certain phase of healing, during a different phase of healing or in a wound of another etiology this may not be the case. Secondly, both patient-specific factors such as comorbidity or polypharmacy, and local factors such as compromised vascularization and microbacterial colonization need to be specified before determining the efficacy of a dressing. Currently special attention is paid to the microbial burden in studies on wound healing. The choice for the appropriate type of wound dressing should also take into account other qualities, such as patient comfort and absorbance capacity. And last but not the least, a certain type of venous leg ulcer (VLU), such as the recalcitrant venous leg ulcer, shows no healing tendency at all, regardless of the wound dressing.1 In this article, we will focus on the clinical practice related to the current evidence for the effect of dressings on wound healing (of VLU) and the considerations necessary to make a balanced choice. Emphasis is placed on the functional classification of dressings,
the microbiome and allergic aspects in relation to wound dressings, and on how clinicians should use the conclusions of studies and weigh the importance of scientific evidence.
Wound dressings The number of different types of wound dressings, including those used beneath compression bandages, is increasing. Modern wound dressings include gauzes, (impregnated) films, gels, foams, hydrocolloids, alginates, hydrogels and other polymers. Many dressings are being designed to have a biological activity itself, either on its own or by releasing bioactive constituents incorporated within the dressing. Hydrogels, hydrocolloids, foams, films and wafers can be used to deliver a variety of compounds such as antimicrobials, 1 2
Rijnstate Ziekenhuis, Arnhem, The Netherlands VU Medical Centre, Amsterdam, The Netherlands
Corresponding author: Marjolein Birgitte Maessen-Visch, Department of Dermatology, Rijnstate Ziekenhuis, President Kennedylaan 100, 6883 AZ Velp, Arnhem, The Netherlands. Email: [email protected]
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
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anti-inflammatory agents, analgesics, growth factors and proteins.2 Therefore the original classification of different types of wound dressings is no longer more suitable. Four main functions of wound dressings can now be identified: cleaning, absorbing, regulating and the possibility of adding medication. Before choosing a modern dressing the desired function and the expected result should be considered. A dressing with an absorbing function differs completely from an anti-microbial dressing. Several studies show good healing tendencies with modern dressings and although there is not one superior dressing, the advantage of the modern dressings for individual patients cannot be neglected; a large metaanalysis on patients with chronic wounds, including VLU, have shown their general superiority of modern dressings on complete healing.3 In addition to efficacy, reasons for choosing one dressing over another will vary according to a wide range of factors relating to the needs of the patient, cost-effectiveness data and the resources available within the health-care setting.4 The choice of wound dressing should be part of the complete strategy for treatment of wounds and should not be randomly selected. Of course in general practice standard therapy should be optimized before more modern wound dressings are used.
Microbial burden Microbial burden is believed to influence healing, although little is known of clinical factors that may influence the microbial load. Microbial burden or microbial bioburden includes the diversity and pathogenicity of bacteria and the microbial load. Compared to topical treatment with antibiotics, systemic antibiotics have a positive effect on wound healing, if they are used for a prolonged period of time (e.g. several months). Huovinen et al.5 showed in 1994 a significant increase in healing rates with ciprofloxacin, after 16 weeks of use, and Valtonen et al.6 showed the same significant effect in VLU. Since the use of oral antibiotics is associated with many side effects, and its use leads to bacterial resistance to antibiotics, in daily practice one should be cautious to prescribe systemic antibiotics. For non-healing VLU the use of systemic antibiotics can be considered occasionally, also before for instance skin grafting. It is hypothesized that the anti-inflammatory effect of antibiotics might be the reason for a positive effect on wound healing. This supports the theory that bacteria in chronic wounds grow in biofilms, with a complexity of anaerobes and other species which are hard to identify and it explains the lack of other studies to prove the effect of antibiotics.7 The fact that culture swabs are not always reliable makes it more complex to make a proper choice for wound dressings.8,9 For instance Pseudomonas might
be located deep in ulcers and missed with a normal swab. A recent study in diabetic ulcers without clinical signs of infection showed the presence of the bacterial 16 S ribosomal RNA gene, showing heterogeneous microbiomes, which could be clustered in several groups, mainly distinguished by dominant bacteria and diversity.8 For VLU Thomsen et al.9 stated that the differences between the culture-based and molecularbased approaches for bacterial growth demonstrate that with a single approach not all bacteria present in wounds can be identified. More studies are necessary to understand the role of microbial film in wound healing. Finally, since we still are not certain when VLU are falsely labelled to have no bacterial importance, do really not have bacterial importance, and it can be therefore concluded that the choice for a proper wound dressing in this aspect remains limited.
Evidence During the past 10 years, Cochrane reviews on wounds, wound dressings and wound therapy have increased up to over 300 reviews. For VLU there are 14 different reviews, five concerning topical wound dressings (Table 1), which are all part of extensive Cochrane reviews on leg ulcers. Although these reviews provide the clinician with increasingly more evidence, this does not make clinical decision-making less complex. For instance most guidelines advise to start wound
Table 1. Cochrane review studies for topical wound dressings and debridement for VLU. 2012
Topical agents or dressings for reducing pain
2013
Foam dressings
2014
Antibiotics and antiseptics
2015
Alginate dressings
2015
Debridement
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
Ibuprofen dressings may offer pain relief Emla 5% appears to provide pain relief during debridement Foam dressings are not more effective in healing VLU than other wound dressing treatments Topical: some evidence supports the use of cadexomer iodine Alginate dressings are not more effective in healing VLU than hydrocolloid or plain non-adherent dressings Limited evidence that actively debriding has clinically significant impact on healing
Maessen-Visch and van Montfrans
65
treatment with debridement and to remove devital tissue from VLU. A striking result was however presented in a recent Cochrane review on debridement: the evidence for the efficacy of debridement on healing of VLU appeared to be very limited.10 In clinical practice, debridement may be either sharp or surgical, mechanical, enzymatic, autolytic and biosurgical (e.g. maggots). In this Cochrane review no studies could be identified that compared debridement to no debridement. Moreover, no studies that tested sharp or mechanical methods of debridement could be included. Most studies reviewed were small, their overall quality was identified as low and the studies were of short duration. There were differences between the studies in terms of the amount of slough in the wound bed of the ulcers at the start of the trial, in treatment regimes, in the variety of set-up, in the duration of treatments and in the outcome measurements. This Cochrane review confirms that although there may be quite a number of studies, a final evidence-based recommendation on the if and how to perform debridement is difficult to be made. This demonstrates that although Cochrane reviews are valuable, they are sometimes only of limited additional value for clinical practice. In addition, in spite of the present guideline recommendations to perform debridement, the authors have the impression that in clinical practice debridement of wounds in VLU is not performed regularly and not always as effective as suggested. A recent RCT study showed that maggots improve wound debridement in VLU, but that no improvement in healing rate was seen;11 this confirms that the need for debridement in VLU is still debated. The clinical presentation of VLU may vary, as the amount of slough in the ulcers, and therefore the advice of debridement should be individualized. Studies on wound dressings show a similar problem of having low or unclear methodological quality, small size and short duration. In general it is accepted that there is no superior dressing for VLU since there seems to be no additional beneficial effect from any of the wound dressings in VLU without clinical bacterial importance (Table 1).12 Classical wound dressings have been used to protect the wound from contamination and do not take an active part in the wound-healing process. In VLU with clinical bacterial importance the choice of a wound dressing is difficult. Around the year 2000 silver sulfadiazine showed significant wound-healing effect in several studies and therefore English, American, Australian, German and Dutch guidelines recommended the use of silver sulfadiazine. In the same period wound dressings using silver became very popular and a lot of different types of wound dressings containing silver were developed. The positive effect of silver on bacterial growth in in-vitro studies was stated.
One meta-analysis on mixed leg ulcers reported that topical silver and silver dressings are more effective on wound size reduction compared to placebo, conservative wound care and non-silver therapies.13 Although silver is proved to have better wound healing properties than cotton- and chitosan-based dressings, the additive effect of using silver in modern dressings could not be shown for VLU.14 In the opinion of the authors, it cannot be concluded, however, that silver should not be used. As stated before: the clinical presentation of leg ulcers may vary and several types of wounds may be hard to define. Evidence does not always help in making the decision for the proper choice of wound dressing. Some recent studies showed an effect on wound healing using cadexomer iodine in VLU with suspected bacterial involvement, resulting in the advice to consider using this as a wound dressing.15 At this moment several guidelines advise using cadexomer iodine instead of silver products when a VLU shows signs of infection. In this review there is no evidence for the routine use of oral antibiotics, as discussed before. In general practice for therapeutic-resistant VLU the use of oral antibiotics might be considered. Wound dressings do matter, but how is still unclear.
Allergy It is often assumed that modern wound dressings, because of their hypoallergenic or anti-allergic properties and their comfort to patients, seldom cause allergic reactions. However, sensitization to topical treatments for leg ulcers is still frequent and, moreover, continues to increase, also for new products.16 It was already proved that wound dressings cause allergies.17 A recent French study showed that modern dressings which are frequently used also cause allergic reactions. Up to 60% of patients with VLU showed a positive patch test (13% for fragrance and 4% lanoline, which might be relevant) and 19% of the 354 patients had at least one sensitization to a modern wound dressing.18 A remarkable aspect was that a positive allergic reaction correlated with the duration of the ulcerative disease, not with duration of the active ulcer. Other studies frequently show polysensitization in patients with VLU. This risk increases with the duration of the ulcer.19
Considerations The choice for a specific wound dressing is part of the complete treatment strategy in VLU patients. The choice for a wound dressing may be based on the conclusion that the dressing will only be used to protect the wound and to create a moist environment, or that a
Downloaded from phl.sagepub.com at University of Otago Library on February 27, 2016
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more active role is necessary for instance by applying a drug. First the diagnosis VLU should conform to the guidelines with duplex scanning and an ankle-brachial index to exclude arterial disease. The underlying superficial venous insufficiency should be treated if feasible, with special attention to veins with drainage to the VLU. It is the view of the authors that in general practice the dermatologist and surgeons are best equipped to diagnose a VLU and to make an adequate differential diagnosis, assessing venous insufficiency and all aspect of wound dressings including allergic aspects through patch testing. There is great variation in recurrence rates of VLU varying from 0% after 6 months up to 56% after 54 months.20 It is important both to try to prevent recurrence of VLU and to heal the wound as fast as possible. Active participation in treatment is an important part of any treatment strategy, not only for the individual patient, but also to reduce costs.21 Appropriate wound dressings may initially increase costs, but finally reduce total costs. As an integral part of the treatment strategy, efficacy and wound characteristic should be considered. Many patients seems to have a pharmacy at home, because there is a lack of consensus in daily practice on dressings especially which, when and how frequent to use dressings. It is important that local agreements are made using only a limited number of wound dressings. There is not always a need for expensive wound dressings with all kinds of biological activity. Besides the efficacy, the reasons for choosing one dressing over another will vary according to a wide range of factors related to the needs of the patient, cost-effectiveness data and the resources available within the health-care setting.4 With active participation in the treatment of VLU the use of additional therapy, such as oral pentoxyfilline or split-thickness skin grafting, should be considered. It may be outlined that these additional therapies should be considered in recurrent leg ulcers, or when a primary VLU does not show healing tendencies within 6 to 8 weeks. Of course standard therapy should be optimized first. Since the number of well performed studies is limited, more studies should be performed to optimize treatment strategies.
Conclusions The choice for a specific wound dressing is part of the complete treatment strategy in VLU patients, in which treating venous insufficiency remains most important. The need for debridement on healing VLU is still not proven. The microbial burden is believed to underlie delayed healing, but swabs seem not to be representative and the exact role of microbial film in wound healing is uncertain. The choice for a wound dressing is
based on the need for a dressing used only to protect the wound and creating a moist environment, or the need for a more active role and the use of a drug. Cochrane review studies on wounds are numerous, but often neither sustain nor contradict the choice for a certain dressing. To avoid using too many and unnecessary wound dressing local agreements with specialist, nurses and pharmacologists are recommended. Allergies for wound dressings may be present often even if eczema is absent. The incidence of allergy for topical treatments and modern wound dressings in VLU continues to increase. To reduce healing time and subsequently to reduce cost early intervention and early investment pays. So the choice for the wound dressings should be part of the complete strategy, in which the necessity of the medical specialist is evident. Consequently, wound dressings do matter as part of the optimal treatment in VLU patients. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
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