Clinical Evaluation Comparing the Efficacy of Aquacel

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1 Clinical Evaluation Comparing the Efficacy of Aquacel Ag Hydrofiber Dressing Versus Petrolatum Gauze With Antibiotic Ointment in Partial-Thickness Burns in a Pediatric Burn Center Salim Charles Saba, MD,* Roger Tsai, MD, Paul Glat, MD We conducted this Institutional Review Board-approved retrospective study to compare Aquacel Ag Hydrofiber dressing (Aquacel Ag) to a standard dressing for the treatment of partial thickness burns in children. We used the St. Christopher s Hospital burn center registry to identify 20 pediatric patients who had sustained partial thickness burns over a 10- month period. Ten of these patients had been treated with Aquacel Ag Hydrofiber dressing and 10 were treated with conventional Xeroflo gauze with Bacitracin Zinc ointment, the institutional standard of care for nonoperative partial-thickness burn wounds. Inclusion criteria included anyone with partial-thickness burns below the age of 18 years and in excellent baseline health. Exclusion criteria included inhalation injury, presence of full-thickness burns necessitating surgical debridement, cellulitic, or infected wounds, and percentage total body surface area involvement greater than 40%. Outcomes measured for the Aquacel Ag versus the Xeroflo gauze with Bacitracin Zinc ointment group included hospital length of stay (2.4 vs. 9.6 days), total number of in-house dressing changes (2.7 vs. 17.1), pain on a 10-point scale associated with dressing changes (6.4 vs. 8.2), total number of intravenous narcotic administrations (2.3 vs. 14.4), nursing time adjusted for percentage total body surface area (1.9 vs. 3.5 min), time to wound reepithelialization (10.3 vs days), and patient primary caregiver satisfaction score using a 4-point scale with four delineating maximum satisfaction (3.8 vs. 1.8). Aquacel Ag proved to be a safe and effective means of treating partial thickness burns with a significant reduction in nursing time and patient pain involved with dressing changes. (J Burn Care Res 2009;30: ) Every year, approximately 2 million people seek medical treatment for serious burn injuries in the United States. 1 Pediatric and elderly populations are at particular risk for full and partial-thickness burns with systemic infection and pain being major concerns. Although the treatment algorithms for first-degree and full-thickness burn wounds are clearly defined, the approach to mixed partial-thickness burns is more varied. 2 Early debridement before full wound demarcation could lead to unnecessary excision and grafting of a wound that could have otherwise healed spontaneously. Conversely, wounds deemed superficial on From the *Department of Surgery, Drexel University College of Medicine, Philadelphia, Pennsylvania. Address correspondence to Salim Charles Saba, MD, Drexel University College of Medicine, 219 North Broad Street, Philadelphia, Pennsylvania Copyright 2009 by the American Burn Association X/2009 DOI: /BCR.0b013e3181a2898f initial examination may deepen through spontaneous conversion secondary to infection or desiccation. 3 5 In an effort to curtail this problem, various moistureretention, antimicrobial dressings have been used to promote wound healing of superficial areas, while preventing infection in deeper, nonhealing wounds. The ideal burn dressing should aim to accomplish several functions. These include, maintenance of a moist ph-balanced environment, management of exudates, provision of an antimicrobial barrier during wound exposure to prevent local and systemic infection, minimal disturbance of healing tissue beneath the dressing, and reduced pain to the patient during dressing changes Two of the most commonly used products today include silver sulfadiazine (SSD) and petrolatum gauze with antibiotic ointment. SSD is applied as an antimicrobial cream. Patients generally have to endure frequent and painful daily reapplication to avoid infection. Petrolatum gauze with antibiotic ointment is another commonly used dress- 380

2 Volume 30, Number 3 Saba, Tsai, and Glat 381 ing. One such dressing, Xeroflo gauze dressing (The Kendall Company, Mansfield, MA), is composed of finely meshed gauze impregnated with petrolatum and 3% bismuth tribromophenate. Bismuth acts as a mild astringent and deodorizer and has some bacteriostatic properties. Its adherent yet nonocclusive nature is particularly useful in heavily draining and superficial burn wounds. An absorptive dressing is generally added to avoid wound maceration. An antimicrobial ointment is also usually added for deeper partial thickness wounds to prevent infection. 12 The absorptive and microbicidal properties of Xeroflo gauze with antibiotic ointment are suboptimal and often requires frequent painful dressing changes and unnecessary disruption of the healing wound surface. In the quest for the ideal burn dressing, Aquacel Ag Hydrofiber (ConvaTec, Bristol-Myers Squibb Company, Skillman, NJ) has recently been developed and was approved for use in partial-thickness burns. Aquacel Ag Hydrofiber (Aquacel Ag) seems to possess many of the qualities of the ideal dressing for partial thickness burns. The sodium ions in the carboxymethylcellulose lattice are replaced by ionic silver, an antimicrobial shown to be effective against a broad range of yeasts, clinical fungi, and antibiotic resistant clinical isolates of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus, P. aeruginosa, and S. marcescens. 13 Previous studies have shown the efficacy of Aquacel Ag in treating partial thickness burns as a primary dressing. Since gaining Food and Drug Administration approval in 2002, two major studies have compared Aquacel Ag with SSD in the management of partial thickness burn wounds. The first study, a multicenter, prospective, randomized phase III clinical trial, by Caruso et al, 6 compared Aquacel Ag favorably against SSD. Besner et al 14 conducted a retrospective analysis that compared cost and hospital length of stay (LOS), and similarly showed that Aquacel Ag compared favorably against SSD. However, few studies to date have compared Aquacel Ag with other conventional burn treatment modalities, ie, nonsilver-based dressings. In this retrospective study, we compared Aquacel Ag s efficacy to conventional Xeroflo gauze and Bacitracin zinc ointment (Xeroflo and Bacitracin). METHODS We conducted an Institutional Review Board approved retrospective analysis of 20 patients admitted to the Saint Christopher s Hospital Burn Center with partial thickness burns. The Aquacel Ag was placed directly on the wounds with 4 to 5 cm overlap. Cover gauze and retention dressings were then applied and changed on day 1 and every 2 to 3 days thereafter on follow-up. The non-aquacel group had generous amounts of Bacitracin zinc ointment applied to the wound surface and then covered with Xeroflo gauze. Dressing changes were conducted twice daily in accordance with the package insert and unit s standard practices. Discharge criteria were met when intravenous pain medications were no longer required, and when dressing changes could be managed by the patient s caregiver at home. Chart reviews and patient/family interviews were used to determine various endpoints. These included: hospital LOS in days, number of in-house dressing changes, pain associated with dressing changes, total in-hospital administrations of intravenous narcotics adjusted for total number of dressing changes, time to fell reepithelialization in days, nursing time required per dressing change, and patient family satisfaction score. Patient Selection Pediatric patients admitted to the Saint Christopher s Hospital Burn Center between March 2006 and January 2007 were included in this study (n 20). Individual patients were identified in the Aquacel Ag (n 10) or the Xeroflo and Bacitracin group (n 10). Inclusion criteria included patients at least 2 months and up to 18 years of age, treated within 24 hours of the burn injury, sustaining superficial, middermal, or mixed partial-thickness burns, and burns involving 5 to 40% total body surface area (TBSA). Exclusion criteria was defined by electrical, chemical, or frostbite burns, deep partial- or full-thickness burns, evidence of inhalational injury, fractures and/or neurological injury, and any oral, intravenous, or topical antibiotic usage within 2 days of the burn. Pain Management and Quantification During hospitalization, pain was routinely assessed and recorded by the nursing staff during each dressing change using a standard 1 to 10 scale. For patients younger than 3 years of age, the Wong-Baker FACES pain rating scale was used. 15 Pain scores were then averaged over the entire duration of a patient s inhospital stay. Intravenous narcotics consisted of either morphine sulfate or fentanyl administrations before, during, or after each dressing change. The total number of administrations was determined and then adjusted for the total number of dressing changes to account for variability in each individual s hospital LOS. Oral narcotic medications were not assessed as they were lib-

3 382 Saba, Tsai, and Glat May/June 2009 erally administered as needed in the interval between dressing changes or on discharge. Nursing Care The average nursing time per dressing change was routinely recorded in nursing flowcharts. This data were collected and then adjusted to account for differences in %TBSA involved between individual patients. In contrast, the number of in-hospital dressing changes was not adjusted, as that value was reflective of hospital LOS. Healing Time to reepithelialization was chosen as the point at which the wound was completely healed. Wound healing was assessed at each dressing change in both the Xeroflo and Bacitracin and the Aquacel Ag groups. Discharged patients treated with either Xeroflo and Bacitracin or Aquacel Ag were seen every 2 to 3 days in our clinic, where the dressing was trimmed off slowly (Aquacel Ag) or changed (Xeroflo and Bacitracin) and healing assessed. The wound was deemed fully healed when the dressing was completely detached and the wound was 100% epithelialized. Caregiver Satisfaction After full recovery, caregivers were asked to rate their overall satisfaction based on in-hospital and home care needs for their children. A qualitative scale, which ranged from unsatisfied to extremely satisfied, was converted to a numeric scale. Unsatisfied, satisfied, very satisfied, and extremely satisfied caregivers were assigned scores of 1, 2, 3, and 4, respectively. Data Analysis GraphPad Instat software was used for statistical analysis. Mean and standard deviation values were obtained for each of the outcomes mentioned. Statistical differences in the means of the Aquacel Ag and Xeroflo with Bacitracin groups were then determined using the Mann-Whitney U test for unpaired data assuming a non-gaussian distribution. P.05 was considered statistically significant. Table 1. Patient characteristics Aquacel Ag (n 10) Xeroflo Gauze/ Bacitracin Ointment (n 10) Mean age in (14 180) (3 180) mo (range) Gender (no.) Male 7 6 Female 3 4 Burn, overall mean % (5 20) (6 30) TBSA (range) Burn injury type (no.) Scald 7 5 Flash 1 1 Flame 1 0 Contact 1 1 Other 0 3 TBSA, total body surface area. patients had partial-thickness burns secondary to various types of burns; however, all were in excellent baseline health on admission, and none had any burns requiring surgical excision and grafting. Patients treated with Aquacel Ag had a mean %TBSA involvement of , whereas those treated with Xeroflo and Bacitracin had a mean of % TBSA involvement (P.97) (Table 1). Hospital Length of Stay Mean LOS for those patients treated with the Aquacel Ag dressing was days (median 2 days). Patients treated with Xeroflo and Bacitracin ointment remained in the hospital an average of days (median 9 days, P.0005) (Figure 1). Pain, Intravenous Narcotics, and In-Hospital Dressing Changes Patient pain levels were recorded by the nursing staff on a 1 to 10 scale. The Wong/Baker FACES pain rating RESULTS Patient Characteristics This study period spanned from March 2006 until January Ten consecutive patients fitting the characteristics of each study group were identified for a total of 20 patients. The mean age of the Aquacel Ag and Xeroflo with Bacitracin groups was and months, respectively (P.43). All of the Figure 1. Mean hospital length of stay (LOS) in days.

4 Volume 30, Number 3 Saba, Tsai, and Glat 383 Table 2. Individual and mean patient ages (mo) and associated pain levels* Xeroflo and Bacitracin Ointment Aquacel * The Wong/Baker Faces Pain Scale was used by nursing staff to assess pain levels for children age 3 yr or younger. scale 15 was used by the nursing staff to assess pain levels for children younger than 3 years of age. Mean pain scores for the Aquacel Ag and Xeroflo and Bacitracin groups was (median 7) and (median 8), respectively (P.01) (Table 2). Total number of intravenous narcotic administrations was calculated as an absolute number. Children in the Aquacel Ag group did not require as much intravenous narcotics during their hospital stay ( vs ; P.0005). The latter is consistent with a smaller overall number of dressing changes for those treated with Aquacel Ag ( vs ; P.0005). However, when the narcotic administrations were adjusted for number of dressing changes obtained by dividing total number of narcotic administrations by total number of dressing changes both groups exhibited similar mean values of only one narcotic administration per dressing change (P.7) (Figure 2). Nursing Care Nursing times were obtained by reviewing nursing flow sheets. Significantly less time was involved in caring for the Aquacel Ag dressings ( vs minutes; P.001). Likewise, when adjusted for the %TBSA, however obtained by dividing mean time per dressing change by the %TBSA for each individual less nursing time was involved with the care of the Aquacel Ag (1.9 vs. 3.5; P.06) (Figure 3). Healing and Caregiver Satisfaction Time to reepithelialization was defined as the point when the wound was fully epithelialized. A significantly shorter time to reepithelialization was observed with Aquacel Ag ( vs days; P.005) (Figure 4). On completion of healing, caregivers were rated on their overall satisfaction with each product. Each person was asked to take into account the product s convenience and overall comfort level associated with its use. A qualitative scale was provided, which we then converted into a numeric one. Overall, Aquacel Ag rated much higher than Xeroflo on the satisfaction scale ( vs ; P.0005). No patient from either group suffered any adverse events, as defined by wound/systemic infection or dressing dysfunction. None of the patients had required operative debridement once treatment had begun. All patients were eventually discharged home, Figure 2. A, Mean number of dressing changes (left) and administrations of intravenous narcotics (right). B, Mean number of administrations of intravenous narcotics per dressing change. Figure 3. Mean time (minutes) associated with dressing changes after adjusting for % total body surface area (TBSA).

5 384 Saba, Tsai, and Glat May/June 2009 Figure 4. Mean time (days) to full wound reepithelialization. and all had completely healed wounds at a 6-week follow-up visit. DISCUSSION Although not as common as SSD, Xeroflo gauze with Bacitracin zinc ointment is commonly used to treat partial or mixed partial-thickness burns. It combines a modest degree of moisture retention with some antimicrobial activity. However, it requires frequent dressing changes as it has a tendency to dry out quickly and adhere tightly to the wound surface. In this study, we obtained comparative data between Aquacel Ag and conventional Xeroflo gauze and Bacitracin ointment dressing in the treatment of partial thickness burn wounds. Aquacel Ag combines the antimicrobial activity of silver with the moistureretaining properties of a carboxymethylcellulose hydrofiber dressing. Aquacel Ag s excellent adherent properties allows for increased wound conformability. Unlike Xeroflo, it draws fluid by wicking, which then causes vertical expansion. In contrast, Xeroflo gauze contracts tangentially and exerts a higher shearing force on the healing wound surface. Adherence to the wound bed is also essential to Aquacel Ag s therapeutic action. In fact, failure of the dressing to adhere within 1 to 2 days of contact with the burn surface may suggest wound infection or deepening. 2 The major difference between Aquacel Ag and other adherent dressings is the relative ease with which it can be lifted off the wound bed when moistened. This allows for minimal disruption of the underlying surface when inspection of the burn wound is desired. Wound reepithelialization was noted to occur almost 7 days earlier with Aquacel Ag. This observed effect may be attributed to Aquacel Ag s moistureretaining and microbicidal properties. Xeroflo and Bacitracin dries out quickly and loses much of its microbicidal activity necessitating regular dressing changes. The tightly adhered gauze also acts as a wetto-dry dressing exerting considerable shearing forces on the healing wound bed beneath. 16 In contrast, Aquacel Ag traps proinflammatory wound exudates and colonizing bacteria in the silver-containing, microbicidal gel substance, effectively isolating them from the wound surface. Avidity to the wound surface combined with persistent antimicrobial activity adds durability to the Aquacel Ag dressing allowing it to be left in place for many days thus avoiding the need for frequent dressing changes and wound surface disruption. One notable downside to the tightly adherent dressings is compromised flexibility when applied over joint spaces. Caruso et al 2,6 noted that Aquacel Ag caused restricted mobility when it was used over joint spaces. In our institution, joint flexibility could be preserved by applying smaller pieces of the Aquacel Ag over the wound surface. All patients reported return of baseline joint mobility on discontinuation of the dressing. Another benefit associated with Aquacel Ag is a significant reduction in the number of in-hospital dressing changes. This translated to lower overall usage of intravenous narcotics, less in-hospital nursing care and most importantly, a shorter hospital stay. The implications for reduced healthcare expenditure are promising despite Aquacel Ag s higher cost (one 6 6 in sheet of Aquacel Ag costs approximately $61, whereas a 5 9 in sheet of Xeroflo costs approximately $3). Despite being more expensive, however, a cost benefit with the use of Aquacel Ag can be inferred from previous published studies. Paddock et al 14 retrospectively analyzed a group of 77 pediatric burn patients (39 treated with SSD, and 38 treated with Aquacel Ag) and calculated direct cost consisting of product and staffing, and total cost that included administrative and overhead expenses. Direct and total costs associated with Aquacel Ag were lower mainly due to a greater overall usage of SSD leading to lengthier hospital admissions. Caruso et al 6 demonstrated this prospectively in his study. The primary cost of each dressing material and the cost of secondary retention dressings were calculated. When combined with secondary dressings, the cost associated with Aquacel Ag was comparable with SSD primarily due to lower hospital LOS (Aquacel Ag mean total cost of $ vs. $ for the SSD per patient hospital stay). Likewise, our study illustrates a lower hospital LOS associated with the use of Aquacel Ag, and thus lower labor and administrative costs are implied. A cost-benefit analysis was not conducted in our study and would be a worthwhile venture in a future study. In addition to the economic benefits,

6 Volume 30, Number 3 Saba, Tsai, and Glat 385 Aquacel Ag also confers a social benefit. This relates directly to minimizing the psychological trauma associated with frequent in-patient dressing changes, and allowing this task to be performed in a more familiar home environment. CONCLUSION Aquacel Ag Hydrofiber has been an important addition to our assembly of nonsurgical burn wound care. Several studies have shown its effectiveness in terms of ease of use, cost, and pain management. In this study, we confirmed its safe use in the management of partial thickness burns while allowing for reduced in-hospital stays. Although our preliminary results are promising, a randomized prospective trial looking at the same variables while incorporating a cost-benefit analysis still needs to be performed before Aquacel Ag can be considered the standard first-line agent in the treatment of pediatric partial-thickness burn wounds. REFERENCES 1. Warden GD, Heimbach DM. Principles of surgery. 7th ed. New York, NY: McGraw Hill; p Caruso DM, Foster KN, Hermans MHE, Rick C. Aquacel Ag in the management of partial-thickness burns: results of a clinical trial. J Burn Care Rehabil 2004;25: Zawacki BE. The natural history of reversible burn injury. Surg Gynecol Obstet 1974;139: Zawacki BE. Reversal of capillary stasis and prevention of necrosis in burns. Ann Surg 1974;180: Jackson DM. In search of an acceptable burn classification. Br J Plast Surg 1970;23: Caruso DM, Foster KN, Blome-Eberwein SA, et al. Randomized clinical study of hydrofiber dressing with silver or silver sulfadiazine in the management of partial-thickness burns. J Burn Care Res 2006;27: Waring MJ, Parsons D. Physico-chemical characterisation of carboxymethylated spun cellulose fibres. Biomaterials 2001; 22: Foster L, Moore P. The application of a cellulose-based fibre dressing in surgical wounds. J Wound Care 1997;6: Robinson BJ. The use of a hydrofibre dressing in wound management. J Wound Care 2000;9: Armstrong SH, Ruckley CV. Use of a fibrous dressing in exuding leg ulcers. J Wound Care 1997;6: Parsons D, Jacques C, Bowler P, inventors. Bristol-Myers Squibb Company, assignee. Light stabilized antimicrobial materials. US patent 6,669,981 B2. December 30, Adams SB Jr, Sabesan VJ, Easley ME. Wound healing agents. Foot Ankle Clin 2006;11: Bowler PG, Jones SA, Walker M, Parsons D. Microbial properties of a silver-containing Hydrofiber dressing against a variety of burn wound pathogens. J Burn Care Rehabil 2004; 25: Paddock HN, Fabia R, Giles S, Hayes J, Lowell W, et al. A silver-impregnated antimicrobial dressing reduces hospital costs for pediatric burn patients. J Pediatr Surg 2007;42: Wong DL, Hockenberry-Eaton M, Wilson D, Winkelstein ML, Schwartz P. Wong s essentials of pediatric nursing. 6th ed. St. Louis, MO: 2001; p Cohn SM, Lopez PP, Brown M, et al. Open surgical wounds: how does Aquacel compare with wet-to-dry gauze? J Wound Care 2004;13:10 12.