Evidence Corner: Wound Cleansing: How Far Have We Come?

  Forty years ago, Rodeheaver and colleagues¹ reported that adding surfactant to a wound cleansing solution could reduce the wound irrigation pressure required to remove kaolin from acute incisions in rats and improve ensuing inflammation and infection.   Recent Cochrane systematic review updates reported no strong evidence supporting a healing or infection benefit of saline compared to potable tap water, or tap water compared to no wound cleansing of chronic or acute wounds,^2,3 though 3 weeks of once-daily pulsatile lavage at 11 pounds per square inch reduced more grade 3 or 4 pressure ulcer volume at the last treatment (n = 14 per group) than a similarly applied sham procedure directing the lavage stream into a wash basin.³ Both reviews appealed for more and better quality evidence on cleansing, with more uniform outcomes measures that could support proper meta-analyses. Though we appear to have not made much progress in finding out what works to cleanse acute or chronic wounds, looking past the abstract of one of the reviews² to the results section reveals a clinical practice pearl: a quasi-randomized study that alternately assigned adult subjects with acute wounds sutured less than 6 hours after injury to cleansing with tap water at 37°C (n = 295) or room temperature saline (n = 322). Warm tap water was more effective than nonwarmed saline in reducing the infection rate.⁴ What if the significant reduction in infection rate was due to cleansing solution warmth, not composition? Has research so focused on techniques and composition of cleansing fluids that the importance of maintaining wound physiologic warmth escaped notice? What other cleansing variables do we gaze at but never see? Are we similarly ignoring important outcomes of cleansing? What other outcomes should researchers explore that may offer clinically important patient-centered benefits? Below are 2 studies beyond the scope of the above reviews that reported alternative benefits of wound cleansing before burn graft application⁵ and for venous ulcers.⁶

Laura Bolton, PhD
Adjunct Associate Professor Department of Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ

  Reference: Mohammadi AA, Seyed Jafari SM, Kiasat M, Pakyari MR, Ahrari I. Efficacy of debridement and wound cleansing with 2% hydrogen peroxide on graft take in the chronic-colonized burn wounds: a randomized controlled clinical trial. Burns. 2013;39(6):1131-1136.

  Rationale. Use of topical anti-infective wound cleansers remains controversial. Despite its concentration-dependent cytotoxicity in vitro, the broad-spectrum antimicrobial effects and reported healing effects of low-concentration hydrogen peroxide merit exploration of its effects on graft take.

  Objective. Conduct a randomized controlled trial (RCT) evaluating effects of topical debridement and cleansing of infected, chronic burn wounds with 2% hydrogen peroxide-soaked gauze in preparing the burn wound bed for graft take.

  Methods. A quasi-RCT in an Iranian burn center conducted with ethics committee approval, from January 2009 to September 2011, enrolled 49 consecutive consenting patients between the ages of 16 and 60 years, with serum albumin of at least 2.5 g/dl, and comparable, symmetric chronic colonized burns (CCB) on arms or legs (98 limbs total). Subjects with a history of cardiovascular disease, diabetes, or renal failure were excluded. Chronic colonized burns were defined as those with granulation tissue easily dislodged from the wound bed by minimal digital pressure more than 2 weeks post-burn and colonized with bacteria > 105 CFU/g of tissue. Baseline type and sensitivity of each CCB’s bacterial burdened from tissue culture of a 1 cm³ biopsy determined the subject’s systemic antibiotic regimen. Standard (control) procedures for all enrolled burn sites began with debridement and curetting followed by normal saline irrigation and split-thickness skin grafting. All grafts were dressed and splinted for immobility. Immediately after debridement, the right (test) limb of each patient was treated for 5 minutes with 2% hydrogen peroxide solution in gauze before saline irrigation. The primary outcome was the success rate of each graft, defined as percentage of graft take, 21 days after grafting. This was calculated as cm² area of graft take divided by cm² of original area grafted. Statistical significance of the difference between test and control graft success rate was tested using the Wilcoxon signed-rank test with P < 0.05 designating statistical significance.

  Results. Median time between burn and study surgery was 54 days. Causes of burn chronicity on the 49 patients were delayed patient admission (45%), infection (33%), general anesthesia risk (18%), or shortage of donor site skin for grafting (4%). Colonizing organisms were mainly Staphylococcus (59%), Pseudomonas (22%), or both (8%). Mean graft size measured by the rule of nines was 13.2% for the right (test) limb or 12.5% for the left (control). Mean graft take success rate was higher in the test group: 83% for test grafts or 66% for controls (P < 0.05). No adverse events or skin irritation were recorded from 2% hydrogen peroxide administration.

  Authors’ Conclusions. Administration of 2% hydrogen peroxide immediately after debridement significantly increased the mean success rate of burn graft take without adverse effects.

  Reference: Romanelli M, Dini V, Barbanera S, Bertone MS. Evaluation of the efficacy and tolerability of a solution containing propyl betaine and polihexanide for wound irrigation. Skin Pharmacol Physiol. 2010;23(Suppl):41-44.

  Rationale. Objective measurement of wound parameters may contribute to understanding of biofilms and other pathogenic wound characteristics and permit development and evaluation of new wound therapies such as those for wound cleansing agents.

  Objective. This RCT used objective wound measurements to evaluate efficacy and tolerability of a wound cleansing solution containing propyl betaine and polihexanide in managing the bacterial burden of painful, chronic venous leg ulcers.

  Methods. Two groups of 20 patients, each with a painful, chronic (ie, > 8 week duration) venous leg ulcer up to 100 cm² in area, were randomly assigned to be cleansed every other day for 4 weeks with either a commercial wound cleanser containing undecylenamido-propyl betaine and propylaminopropyl biguanide, sodium hydroxide, and water (test cleanser), or physiologic saline (control). Both groups received standardized care including a polyurethane foam primary wound dressing and elastic compression. Outcomes were measured objectively under standardized conditions on enrollment, then weekly through week 4. These included planimetry to determine wound area, and wound surface pH measured using a flat glass electrode at 2 averaged locations on the wound bed and 1 hirsute adjacent skin surface. Patient-reported pain was measured using a visual analog scale. Analysis of variance tested for differences in wound surface pH and pain. The Wilcoxon signed rank test assessed significance (set at P < 0.05) of wound healing time and planimetry differences.

  Results. All study subjects except 2 in the saline group completed all 4 weeks of the study. Subjects in both groups were comparable at baseline on mean age (62 years), wound area, wound pH (8.9), intact skin pH (4 to 5), disease duration (24 months), and pain score (9 to 10). Wound pain and pH both decreased significantly more in subjects whose venous ulcers were cleansed for 4 weeks with the test cleanser as compared to saline controls. Venous ulcer healing differences during the 4-week study were not statistically significant.

  Authors’ Conclusions. The quantitative pH assessment used in this study was sufficiently sensitive to demonstrate a greater shift toward the pH of normal intact skin in the group cleansed with the test cleanser, accompanied by a significantly greater decrease in patient-reported pain. More studies are needed to explore association of these findings with microbial wound burdens.

  There’s an old adage that “we find what we look for.” The studies reviewed here suggest wound cleansing may have a broader impact on patient-centered, clinical, and economic outcomes than effects on healing or infection reported in recent systematic reviews.^2,3 Outcomes measured and their timing can affect reported results. Reliable, valid wound outcome measures to focus on in future studies include time to complete wound healing or percent completely healed by 4-12 weeks (depending on baseline wound depth and area), patient-reported wound pain, wound bed granulation, fibrin slough, or necrotic tissue.^7,8 Valid infection measures include increased wound pain, exudate, odor, or purulent exudate, surrounding skin erythema, edema, and warmth; or, for closed wounds, dehiscence.⁹ Clinical and economic indicators include medications required for wound management, including pain medications or antibiotics.

  Is 4-12 weeks the optimal time to examine healing or infection results for chronic or acute wounds? The operational definition of wound cleansing also appears vague. Reviewing wound cleansing literature makes one wonder what clarity may have been lost in translating early rat incision irritation and infection findings into practice recommendations for chronic wounds. What variables, such as cleansing frequency, timing, and temperature, remain to be explored? Which chronic wounds, if any, require the same timing, frequency, pressure, and other wound cleansing parameters as acute “dirty” wounds? What about acute “clean” wounds? What can health care providers and caregivers do to optimize patient comfort during the cleansing procedure? It seems we have some cleaning up to do before achieving evidence-based wound cleansing.

This article was not subject to the WOUNDS peer-review process.