BACTERIAL NANOCELLULOSE DRESSING COMPARED WITH HYDROCOLLOID DRESSING FOR THE TREATMENT OF PARTIAL-THICKNESS SECOND-DEGREE BURNS: A PROSPECTIVE, RANDOMIZED CONTROL TRIAL

SUMMARY

The management of burn wounds is a major challenge throughout the globe. Superficial and partial-thickness burns generally do not need any surgical intervention, however, severe cases of burn injury require dressings (antimicrobial) and surgery in the worst-case scenario. The present study was conducted to assess the efficacy of bacterial nanocellulose dressing versus hydrocolloid dressing. All patients presenting with partial-thickness second-degree burns from June 2021 to May 2022 were screened for this randomized control trial; 65 burn patients were included in each group of this trial. The control group of patients was treated with hydrocolloid dressing and the experimental group with bacterial nanocellulose dressing sheets. Every third day, the wound was assessed. Other data collected included age, sex, %TBSA burned, signs of infection, time for epithelialization, and length of hospital stay. Statistical analyses were performed to see the significance of differences between the treatment groups by adjusting for size and depth of burn, and the patient’s age. There were 130 patients (65 in each group). The median age for the whole group was 17.4 years, and 51.53% (n=67) were males. The average TBSA was 22.4%, with a minimum of 10% and a maximum of 31%. Eleven of the patients had their burns excised, and four were given skin grafts in the control group. In the case of the experimental group, four excisions were performed, and one skin graft. Wound-related pain scores were low (mean of 2.6) for the bacterial nanocellulose group and higher for the hydrocolloid group. Hydrocolloid dressing is more cost effective than bacterial nanocellulose dressing. However, the pain scores were high, and healing time was less in the bacterial nanocellulose group. Moreover, the hydrocolloid group is more prone to infection due to frequent dressing changes.

Introduction

Burns are a public health dilemma, burdening the healthcare delivery system across the globe. The majority of burn injuries are attributed to scalds (heat from hot liquids or steam), or flame. Other key sources include cold, radiation, chemical, or electric burn.¹ It is a common type of traumatic injury and patients with severe burns often endure life-threatening wounds, necessitating a multi-faceted approach to providing thorough and long-term care and treatment.²

Mortality rate due to burn injuries varies by as much as a factor of ten across the various parts of the world. Not surprisingly, the low and middle HDI (human development index) countries account for 95% of all burn-related mortalities, and almost two-thirds in the African and South-East Asia regions of the World Health Organization (WHO).³

The management of burn injury wounds is considered a major challenge. The first two types of burns, i.e. superficial and superficial partial-thickness, generally settle without surgery. However, comparatively severe burns require cautious management, which comprises topical antimicrobial dressing sheets and/or surgery.

Autografts are taken as the standard for deep burn management care, nevertheless, their utilization is restricted by many factors. The hunt for alternative dressings is therefore imperative and must possess certain properties to be an effective burn wound dressing. With the advancement in developing bio-materials and the growth in tissue engineering biotechnology, some state-of-the-art dressings and tissue engineering scaffolds are commonly accessible. Numerous studies have explored the specifications of an ideal burn dressing, which ought to be non-adherent, absorbent and anti-infective, but should also involve few dressing changes that should be without pain.^4-6

Hydrocolloid dressings, often termed hydro active dressings, are considered the standard treatment for partial-thickness second-degree burns in many countries. These are designated as wafers, powders or pastes, made up of materials including gelatin, pectin and carboxymethyl-cellulose. In recent times, bacterial cellulose has emerged as the more suited dressing option. It is a biotechnologically generated bacterial nanocellulose synthesized by Komagataeibacter xylinus and 95% water⁷ and has revealed certain encouraging properties that endorse it as a wound healing therapeutic. The high amount of water integrated in the cellulose decreases the intradermal temperature, wound progress and pain through an evaporative cooling effect.⁸ Furthermore, it is loadable with antiseptic elements.^9-12 Earlier studies have proven that bacterial nanocellulose can be an efficient alternative, well-tolerated dressing choice for superficial partial-thickness second-degree burn wounds.^13-15

The current management for the partial-thickness second-degree burn at the study site is hydrocolloid dressing, as it is readily available, cost-effective, and minimizes bacterial growth in wound infection. Commercially, more advanced dressings have been introduced in the country, including bacterial nanocellulose that has shown encouraging results. The aim of the present study was, therefore, to directly compare hydrocolloid with its significantly more expensive competitor bacterial nanocellulose for partial-thickness burns with regards to patient comfort, burn wound healing, and scar formation.

Methodology

The current study was conducted at the National Burn Care Centre, Department of Burns Surgery, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad. This was a single-center prospective randomized control trial study on patients with partial-thickness second-degree burn injuries. The study was approved by the ethical committee of the Shaheed Zulfiqar Ali Bhutto Medical University. The study protocol followed the ethical guidelines of the Helsinki Declaration.¹⁶ Informed consent was taken from all study participants. In the case of minors, consent from the parents was sought. The patient’s data confidentiality was ensured as access to data for collection and analysis was limited to the researchers.

The sample size was calculated using the WHO sample size calculator with the level of significance set at 5% and the power of tests at 80%. The sample size turned out to be 65 patients in each group and a total of 130 were included in the study.

The partial-thickness second-degree burn injury patients were screened according to CONSORT guidelines (Consolidated Standards of Reporting Trials) as shown in Fig. 1. The study included patients aged ≥18 year with scald burns that resulted in a superficial or deep partial-thickness burn and was fresh (within the first 24 hours). All patients were in normal healthy conditions and without comorbidities at the time of the burn accident. Those with full-thickness burns, regardless of size, and women who were pregnant or breastfeeding, flame burns, and non-compliance in the follow-up examinations were excluded from the study. Patients with more than 40% TBSA, second-degree old wounds (more than 24 hours from the time of injury), and patients with other co-morbid or associated injuries were also excluded from the study. Only scald (spillover, immersion) burns were included with superficial or deep partial-thickness burn.

Fig. 1.

CONSORT Flowchart¹⁷

The potentially suitable study participants (or their guardians) were informed about the purpose, methods, effect, and possible complications of the study, and were given the chance to ask questions. In the event they opted to participate, written informed consent was obtained. Patients were randomly assigned to either the bacterial cellulose group (experimental group) or the hydrocolloid group (control group).

The care of each wound was evaluated by the attending surgeon. A photograph of the burn was taken. Pain was assessed using the VRS (verbal rating scale). Infection diagnosis was done by the attending physician and was based on the following clinical signs: an increase in white blood cell count above reference values after the first two days after injury, a considerable rise of plasma-C reactive protein concentration, fever exceeding 39°C, visible signs of local wound infection (rubor, tumor, calor) and severe wound pain. We considered full healing to have been achieved when the granulation tissue was totally covered with the epidermis, and further evaluation was made by the attending surgeon as before. Percentage of area excised (if any), time to epithelialization, and duration of hospital stay were recorded.

For the control group of patients, hydrocolloid dressing sheets (DUODERM™ Extra Thin ConvaTec Inc. USA) were applied under aseptic conditions. The wound was inspected and cleaned with normal saline to remove fibrin, biofilm, and unviable tissue. The dressing was rolled gently over the wound without stretching. The dressing was molded into place with a hand for secure adhesion around wound margins. The dressing was then covered with surgical gauze and crepe bandage. In the case of difficult anatomical locations such as the sacral area, securing edges of the dressing with hypoallergenic tape was useful. The wound was inspected after three days to assess progress. If the wound (totally or partially) was deeper than it appeared at the primary assessment (had become full-thickness), it was excised and grafted if necessary.

For the experimental group, Bacterial NanoCellulose (BNC) dressing sheets of Epicite^hydro (QRSKIN GmbH, Würzburg, Germany) were applied. The wound was inspected and cleaned with normal saline to remove fibrin, biofilm, and unviable tissue. Bacterial nanocellulose dressing sheets were applied under aseptic conditions, covered by plastic film, surgical gauze and an elastic bandage. In the case of facial burns, bacterial nanocellulose was applied alone. The wound was inspected after three days to assess progress. If signs of infection were present, the cellulose was replaced by a new sheet. If the wound (totally or partially) was deeper than it appeared at the primary assessment (had become full-thickness), it was excised and grafted where necessary.

The data studied included age, %TBSA, sex, burn site, clinical history, photographs of burn injury before during, and after treatment. All data produced from the current study was recorded in Microsoft Excel 2013 and transferred to the IBM Statistical Package for the Social Sciences (SPSS) version 25.0. Armonk, NY: IBM Corp. for statistical analyses. Quantitative variables (age, size, number of days of healing) were presented in the form of mean and standard deviation. Frequency and percentages were presented for qualitative variables like gender, infection, and scarring. An independent sample t-test was applied to compare quantitative variables between both groups. A Chi-square test was applied to compare qualitative variables. P-value < 0.05 was considered significant.

Results

There were 130 patients (65 in each group). The median age for the whole group was 17.4 years, and 51.53% (n=67) were males. The average TBSA was 22.4%, with a minimum of 10% and a maximum of 31% (Table I). The most common burned site in the control group was the trunk, followed by the face and lower extremities. In the experimental group, the face was the most affected area followed by the trunk and extremities.

Table I.

Demographic features of the studied patients

	Total (n=130)	Experimental group (n=65)	Control group (n=65)	p-value
Age (years)	17.4 (1.0-37.5)	19.2 (1-41.5)	21.6 (3-39.5)
TBSA%	22.4% (10-31%)	20.6% (10-29%)	23.2% (10-36%)
Male	51.53% (n=67)
Female	48.47% (n=63)
Site of burn
Trunk	47	18	29
Face	44	26	18
Leg	22	11	11
Arm	19	8	11
Hand	14	5	9
Neck	3	2	1
Excisions	15	4	11
Skin grafts	5	1	4
Hospital stay (days)	14.8	11.7	18	0.02
Healing time (days)	15.2	13	17.4	0.02

The control group had a larger total burns surface area than the experimental group, they were more frequently burned on the trunk, and there was a tendency for a smaller proportion of facial burns. Other than that, there were no baseline differences between the groups (Table I). Eleven of the patients had their burns excised, and four were given skin grafts in the control group. In the case of the experimental group, four excisions were performed and one skin graft.

The bacterial nanocellulose sheet was mainly applied to the face, followed by the trunk, lower and upper extremities. 41 out of 65 of the patients had it applied to more than one site (face, neck, chest, arm, and hand). The median duration of hospital stay was 18 days for the control group while it was 6.3 days shorter in the bacterial nanocellulose group (11.7 days).

Both dressings were placed on the wounds and gradually cut back as re-epithelialization progressed until the dressings were completely detached. They were highly flexible, adapted to the skin surface easily during the primary application, and turned stiff as they gradually dried out throughout the wound healing procedure. The time for epithelialization was 13 days for the experimental group and 17.4 days for the control group (Table I). The average dressing changes in the control group were 4.2, and 1.3 in the case of the experimental group.

Patients (adult) rated their pain level using the VRS (0 = no pain at all to 10 = extreme pain). Wound-related pain scores were low (mean of 2.6) for BNC and higher for hydrocolloid (mean of 4.8) on day 1; P = .051. The pain score decreased during the healing process (Fig. 2) solely with a significant difference between the two dressings on day 1 (P = .043).

Fig. 2.

Pain during wound healing (verbal rating scale 0-10). CI, confidence intervals

In the experimental group, there was no infection seen, whereas in the control group one positive case of infection was observed, as evidenced by the rise in white blood cells and fever exceeding 39°C. In terms of anesthesia, use of opioids was greater in the control group (44/65 patients) and less in the experimental group (13/65). Fig. 3 shows results of single bacterial nanocellulose dressing in partial thickness deep burns.

Fig. 3.

A) Deep partial thickness wound at day 1 after dead skin removed; B) Application of bacterial nanocellulose dressing; C) After removal of single dressing at day 5; D) After application of topical steroids at day 14

Discussion

The findings of the present study indicated that patients with partial-thickness burns treated with bacterial nanocellulose (BNC) had a smaller length of hospital stay, lower pain scores both during and after wound care, and they required fewer dressing changes. There was also a propensity for epithelialization to be quicker in the BNC group.

Karlsson et al. described their experiences in the use of biosynthetic cellulose dressings in burns and reported an infection rate of 39%, which is very high compared to our findings. The median healing time (epithelialization) was 28 days (13-80 days), which is significantly higher than the current study (15.4 days).⁹

Another study by Maurer et al. compared polyurethane foam dressings with bacterial nanocellulose sheets and reported that the length of hospital stay and procedures requiring anesthesia were considerably reduced in the nanocellulose group.¹⁸

Partial-thickness burn injuries are escorted by pain. Therefore, pain lessening is one of the most vital properties of a burn wound dressing. There are studies reporting an analgesic effect on burn wounds.^19,20 In the present study, the reported pain scores for burn wounds were mostly low for both dressings (slightly higher in the control group) and reduced through the healing process. Due to ethical reasons, no burn wound received neither of the two dressings. Hence, we do not know if both dressings had an analgesic outcome. Nevertheless, the experimental group showed better pain scores, which is in accordance with findings reported in preceding studies.⁹, ²¹

Superficial partial-thickness burn wounds normally heal without scarring or with minimal scarring. With professional wound care and infection prevention techniques, wound healing is completed in 2 to 4 weeks.²² The experimental group BNC is an advanced biosynthetic burn wound dressing that quickens wound healing and minimizes scar formation.²³ In the current study, healing of partial-thickness second degree burns was accomplished after 17.4 and 13 days with hydrocolloid and BNC respectively. Similarity in healing days was found in past studies i.e. 12 days²⁴ and 13 days,²⁵ 10.2 days,²⁶ 10 days,¹⁴ and 12 days.²⁷

Recurrent dressing changes are problematic in burn wound care, primarily because they cause pain, but also because more dressings indicate higher costs and greater risk of infections. The less often the dressing is changed the better, according to many authors,^28,29 and we also observed this to be the case in the BNC group, where the changes were comparatively fewer, the pain score lower and there was no infection.

At our national burn care center, hydrocolloid is 10 times cheaper than BNC. A randomized trial reported from the USA by Cassidy et al. supports this observation and highlights the fact that hydrocolloid is statistically less expensive and can be considered a first-line treatment option for intermediate-thickness burn wounds.³⁰

Another study from Ireland by Martin et al. proved that the use of hydrocolloid dressing in pediatric burns leads to a lower amount of operative intervention rates and should be favorably used.³¹

Conclusion

In the BNC experimental group, healing was complete in 13 days compared to 17.4 days for the hydrocolloid control group. Hydrocolloid is cheaper than BNC. However, pain scores were high in the hydrocolloid group, and patients in this group were more prone to infection due to frequent dressing changes. Still, hydrocolloid can be used as an alternative, cost-effective, wound dressing to BNC for the treatment of second-degree partial-thickness burn injuries.

Limitations

The study had a limitation in that it was a single-center study that included a limited number of patients, which made it difficult to detect some significant differences. A multicenter study with a higher sample size is recommended.