Treatment of Burns in Adult Patients With a Concentrated Surfactant Gel: A Real-life Retrospective Evaluation

Introduction. Debridement is often a necessary step in wound care. In burn care, typically, surgery or enzymes are used for this purpose. Objective. In a real-life retrospective study, the autolytic debridement properties of a concentrated surfactant gel (CSG) were assessed. Materials and Methods. Thirty patients who had burns that ranged from superficial partial thickness to full thickness and did not exceed 10% total body surface area were evaluated retrospectively with regard to outcomes of their treatment with CSG alone or in combination with bacitracin ointment (CSG-BA). Both materials were applied daily. The hypothesis of the study was that CSG, by providing moisture to the wound in combination with debridement via micelle action, would provide debridement without the need for surgery or enzymes and would lead to healing times similar to those for wounds treated with other modalities. Burn depth was determined visually. Results. Of the CSG-treated burns, 88.2% were mixed partial thickness, deep partial, or full thickness, and 64.7% of these lesions reepithelialized completely or showed satisfactory healing progression within a time frame that is similar to published results with other treatment modalities. Secondary autografting was necessary in 1 lesion. Conclusions. On average, the CSG-BA–treated burns were less deep and smaller than the CSG alone. All wounds reached complete healing or showed continued healing progress.

For proper and rapid healing, wounds need to be clean and free of necrotic tissue. In burn care, this means that wounds of any significant depth often require debridement. Surgical modalities for debridement include excision and hydrosurgery^1-4; both techniques, although reliable, have side effects, such as blood loss and a significant learning curve.^5,6 As an alternative to excision for deep partial- and full-thickness burns, a bromelain-based compound has been used successfully,⁷ but this also is associated with a learning curve as well as significant postprocedural pain.^8,9 Less common modalities include physical disruption (eg, hydrotherapy¹⁰), adjuncts to autolysis (eg, honey^11,12), and enzymes (eg, collagenase^13,14). In the United States, these modalities are sometimes used for the debridement of more superficial partial-thickness burns.^13-15

Surfactants provide an alternative for assisting in wound debridement. A surfactant is an organic compound (typically a macromolecule or polymer) that contains a hydrophilic as well as a hydrophobic region. In an aqueous system and in a high enough concentration, surfactants are arranged in spherical aggregates called micelles. In a wound, the hydrophobic region of the micelle traps fragments of loose tissue, such as necrotic material or microbial particles. The hydrophilic external surface of the micelle provides solubility in fluids.

Concentrated surfactant gel (CSG; PluroGel; Medline Industries, Inc) consists of micelles in a water-soluble gel matrix, which contains a high percentage of poloxamer 188 (P-188). Like other poloxamers, the viscosity of this material is a function of temperature¹⁶: with increasing temperature and above a critical concentration, P-188 transits from a (viscoelastic) liquid to a solid gel.¹⁷ In other words, the rheological properties of P-188 make the gel thicker at higher temperatures,^16,18 which means that, when cold, it can easily be applied (poured) and distributed over a wound and, once in situ, the gelling under influence of the bodily heat leads to the material staying in place.

Concentrated surfactant gel helps provide a moist wound environment while softening necrosis in the wound over time. This aiding in autolytic debridement may be described as surfactant driven. Concentrated surfactant gel is biocompatible and water soluble and may be liquefied by cooling in a refrigerator, which aids in application.

A real-life retrospective evaluation was undertaken to study the effects of CSG in the management of burns. The hypothesis of the study was that the materials would aid in autolytic debridement, thus assisting the wounds in healing without the need for other debridement methods. In certain cases, CSG treatment was combined with the application of bacitracin ointment, a topical antimicrobial agent that is sometimes used in the care of partial-thickness burns.^13,19,20

The retrospective evaluation described here was a subset of a larger one, and it includes only adult patients with different types of burns. The evaluation period started in June 2016 and lasted until April 2018. In the authors' institution, bacitracin is part of the standard, nonsurgical treatment; it is used as an adjunct therapy, particularly in seriously contaminated wounds, and wounds that have been left untreated for some time. When indicated, bacitracin was used in combination with CSG in this evaluation as well. Thus, patients were treated with CSG or, when indicated, with a combination of CSG with bacitracin ointment (CSG-BA). Concentrated surfactant gel was always applied directly to the wound and covered with gauze. If bacitracin was used as well, it was applied onto the gauze dressing prior to application of the gauze onto the wound. Dressings usually were changed daily (maximum wear time for CSG is 3 days); the previous layer of CSG was gently washed off, and a new dressing was poured over the wound. The depth of the burn was assessed visually, and, upon each dressing change, the wound was evaluated for healing progress.

Because this was a real-life, retrospective evaluation, the study was not registered. For the same reason, only a limited number of exclusion and inclusion criteria were used. The overall burn size had to be less than or equal to 10% total body surface area (TBSA), and patients who had an inhalation injury were also excluded. The primary indication for the use of CSG was in patients who were not primarily candidates for excisional procedures because of the type of burn or who were referred to us at a later stage, after the injury was treated elsewhere. The primary objective of the evaluation was the assessment of healing progress and time to complete reepithelialization, as judged clinically by the investigators.

A total of 35 patients participated in the evaluation. Of these, 22 (11 males) were treated with CSG and 13 (7 males) with CSG-BA. The average age of the patients in the CSG group was 40.6 years (range, 23–60 years) and in the CSG-BA group was 36.5 years (range, 18–59 years). With regard to concomitant circumstances known to influence wound healing, in the CSG group, 1 patient had peripheral vascular disease (although this patient’s burn was on his upper leg), 2 patients had type 2 diabetes mellitus, and 10 patients were smokers. In the CSG-BA group, 4 patients were smokers. Statistical analysis was not performed, because the numbers in both treatment groups were too small to provide significant differences.

Scalds were the most common type of burn in the CSG group (n = 6, 27%), and flame and scald burns were the most common types in the CSG-BA–treated group (n = 4, 30.8%) for each etiology (Figure 1; percentages may not add up to 100 due to rounding). The distribution of the burns by anatomic location was largely similar between the 2 evaluation groups, with lower leg, upper arm, forearm, hand, and fingers being the most common locations of the injuries (Figure 2).

With regard to the depth of the study burns, those in the CSG group were deeper overall: 2 lesions (9.1%) were superficial partial thickness, 7 (31.8%) were mixed partial thickness, 6 (27.3%) were deep partial thickness, and 7 (31.8%) were full thickness (Figure 3). In the CSG-BA–treated cohort, burns were only mixed partial thickness (n = 11, 84.6%) or deep partial thickness (n = 2, 15.4%) (Figure 3).

The average size of all burns in the CSG group was 4.5% TBSA (range, 1.0%–10.0%), and for all burns in the CSG-BA group the average size was 3.2% TBSA (range, 0.1%–10.0%) (Figure 4). The size of the study burns was 2.6% TBSA on average for the CSG-treated burns (range, 0.5%–9.0%) and 2.6% TBSA (range, 0.1%–9.0%) for the CSG-BA–treated cohort (Figure 4).

In 2 patients (9.0%), CSG treatment was started on post burn day (PBD) 0. On average, CSG treatment was started on PDB 4.4 (range, 0–13 days), and CSG-BA treatment was started on PBD 3.4 (range, 1–8 days).

In the CSG group, 14 burns (63.6%) showed complete reepithelialization or good wound progression (Figure 5). For those 10 burns that reached complete reepithelialization (45.4%), the average healing time was 19.8 days (range, 12–35 days) (Figure 6). Within the group of 4 lesions (18.2%) that showed significant progress toward reepithelialization, no further indication for continuing treatment with CSG existed in 3 wounds because they were without necrosis and treatment was changed to a glucan dressing. Four lesions (18.2%) showed little or no progress toward healing. One of these was full thickness and autografted. Local, or non-local, non-specified (non-evaluation, product-related) complications developed in 4 patients (18.2%) (Figure 5).

In the CSG-BA group, 9 of 13 burns (69.2%) progressed to complete reepithelialization and 4 (30.8%) showed satisfactory healing progress (Figure 5). The average time to complete reepithelialization for the patients whose lesions reepithelialized completely was 16.9 days (range, 7–28 days) (Figure 6).

Ease of use (application and removal) for all dressing changes, as assessed by the health care providers using a choice of poor, normal, and good, was rated as good. There were no study materials-related adverse events. See Figure 7 for results.

The presence of necrosis in a wound hinders healing, encourages infection,^21,22 and, in burns, may lead to secondary deepening.²³ Therefore, debridement or excisionof necrosis is necessary in many types of wounds. In deeper burns, debridement is commonly performed, using surgical techniques via excision,^1,2 typically with a dermatome.²⁴ The procedure is relatively quick and, when performed by trained surgeons, safe, though it may be associated with serious side effects such as significant blood loss.²⁵ Mechanical alternatives, particularly hydrosurgery^26,27 and, to a lesser extent, ultrasonic devices,^28,29 are also being used. Bromelain-based compounds are an alternative for surgical techniques.⁷ All of these methods are associated with learning curves.^8,9,25 

The use of a micelle-based compound may be a nonsurgical alternative for the removal of necrosis in burns because these materials assist in autolytic, surfactant-driven debridement.

The study material used in this evaluation, CSG, contains micelles and is specifically designed to maintain a moist wound healing environment and soften any necrosis in the wound, thus aiding in autolytic debridement.³⁰

Poloxamer 188, the main ingredient in CSG, has been assessed extensively, both in laboratory settings as well as in human trials. In a test with human fibroblasts and keratinocytes, P-188 was shown to have an excellent safety profile, with low cytotoxicity on both types of cells.³¹

Secondary deepening of a burn wound may occur within 72 hours after the initial injury, because the area around the burn has a significant reduction in circulation due to the inflammatory response to the injury.^32-36 In a rodent burn model, blood flow around and within a burn lesion within the first 24 hours after injury was assessed, with the speed of erythrocyte flow (SEF) used as a test parameter. Immediately after the injury was inflicted, burns were covered with P-188 or saline. An area extending from 1 mm to 3 mm outside the lesion showed a 50% decrease in SEF in wounds treated with saline while the P-188–treated lesions showed no decrease in SEF. Twenty-four hours after injury, the zone of coagulation (where the SEF had been reduced) became significantly smaller in P188-treated wounds (P < .01); this suggests that the application of P-188 may assist in preventing the development of the zone of stasis and, thus, secondary deepening.³⁷

The physical behavior of (hen egg) lysozymes was assessed at temperatures ranging from 20ºC to 90ºC.³⁷ The presence of P-188 was shown to prevent aggregation of the lysozymes to a high extent, which allowed them to refold and revert to their functions once temperature had returned to a physiological range. The authors of the study stated that, in burn care, this property of P-188 may be useful because it may assist in the prevention of denaturing of proteins in the wound³⁸ and, thus, prevent secondary deepening.^32-36

Pig-explant and other biofilm models were used in different scenarios and with different bacteria, including Pseudomonas aeruginosa PA01 and Acinetobacter baumannii, to study the prevention of biofilm formation and disruption of a present biofilm. Although the results depend on the type of microorganism, with A baumannii being more resistant, P-188 and, in some studies CSG, was shown to be a very effective “anti-biofilm” agent in vitro and in vivo.^39-42

In a large study aimed at improving outcomes for nonhealing wounds, a version of CSG was combined with 1% silver sulfadiazine. A total of 1036 patients with different types of lesions participated in the study. Closure was observed in 70% of all wounds, with the majority (56%) reaching this endpoint within 11 weeks of treatment.⁴³

In a case series, CSG was used on 18 patients with “difficult-to-heal” venous and arterial leg ulcers. The Pressure Ulcer Scale for Healing (PUSH) tool^44,45 was used for scoring the wound. The study showed a decrease in the mean pretreatment PUSH score from 10.7 at study start to 8.3 upon study end, indicating that the CSG dressing was effective for the management of ulcers of the lower extremity.⁴⁶

In this retrospective study, CSG was used primarily in lesions that were not appropriate for surgical excision, either because of their initial depth (being superficial partial thickness) or, mainly, because the patients were transferred to our center at a late stage; this represents a typical clinical situation, as do the patients in this real-life evaluation, who presented with different types, sizes, and depths of burns.

All patients who did not meet the exclusion criteria and who were potential candidates for debridement through nonsurgical means were included in the evaluation. Treatment was with CSG and CSG-BA.

The CSG-treated patients showed a high percentage (63.6%, n = 14) of wounds with good healing progress or complete reepithelialization, in spite of the fact that 20 of them (90.9%) were mixed-partial thickness, deep partial thickness, or full thickness. Secondary grafting was necessary for 1 of these lesions.

The CSG-BA–treated burns either reached complete healing or showed continued healing progress. They were less deep (only 2 were deep partial thickness and none was full thickness) and smaller on average, while treatment with CSG-BA started earlier on average.

Healing times, observed for lesions treated with CSG or CSG-BA that were not grafted, are very similar to those observed with other dressing regimens, including xenograft and silver-impregnated foam dressings,⁴⁷ hydrofibers,^48,49 porcine dermal collagen/silicone membranes,^50,51 skin allografts,⁵² amnion dressings,^53,54 hydrocolloids,⁵⁵ and many more. In none of the patients were treatment regimen-associated adverse events observed, and the overall ease of use of the dressings (application and removal) was rated good for all dressing changes.

A real-life evaluation has a series of intrinsic limitations. A large number of patients with an even larger number of variables is typically included in this type of study. Thus, stratification (ie, per burn size, burn depth, or anatomic location) is usually unwarranted, because the numbers in subcohorts of patients would be too small to draw any statistically significant conclusions. At the same time, real-life studies provide a look into patient cohorts and wounds that reflect the actual situation in the general population, without the bias of a series of strict inclusion and exclusion criteria. In the evaluation presented here, which analyzed a subset (only adults) of a larger study, this seems to be the case because the patients presented with burn wounds of different depths and sizes, and many of the wounds were first seen at the authors' institution after a delay of a few days.

In a retrospective real-life evaluation, CSG (a micelle-based treatment with P-188) and CSG-BA were used as means of debridement and treatment for a series of burns. The CSG is designed to provide a combination of a moist environment and assistance in autolytic debridement.

The results of this evaluation show overall good results in most burns, including deep and larger ones, whether they were treated with the primary product, CSG, or the combination product (CSG-BA). A significant number of patients in both cohorts showed either complete reepithelialization or wound healing in spite of the fact that many of the burns, particularly in the CSG cohort, were indeed deep. For those lesions that healed spontaneously and without grafting, healing times were similar to those obtained with other dressings. The CSG dressing was judged to be easy to use. Although the numbers in this pilot evaluation are small, they indicate that CSG with or without the addition of bacitracin ointment is a valuable addition to treatment options for burn wounds. A randomized clinical trial is necessary to confirm these results.

Authors: Timothy Pittinger, MD¹; Danielle Curran, PA-C¹; and Michel Hermans, MD²

Affiliations: ¹Akron Children’s Hospital, Cleveland, OH; and ²Hermans Consulting, Doral, FL

Correspondence: Michel H.E. Hermans, MD, Hermans Consulting, 10184 NW 52^nd Terrace, Doral, FL 33178; mhermans@hermans-hci.com

Disclosure: Dr. Pittinger and Dr. Hermans are paid consultants for Medline Industries, Inc. Medline provided financial support for the writing and research associated with this article.