A Comparative Study of Collagen Dressing versus Petrolatum Gauze Dressing in reducing Pain at the Donor Area

INTRODUCTION

Collagen sheet dressing is a common procedure for covering exposed dermis of superficial thermal burns. It covers the exposed free nerve endings in the dermis, thereby reducing pain and infection. Skin graft is one of the commonly done procedures by plastic surgeons, dermato surgeons and general surgeons. After harvesting the split skin graft dermis is exposed at the donor site, resulting commonly with postoperative pain. Conventionally, the donor area is dressed with non-adherent petroleum gauze. In this study collagen sheet was used for covering the donor site after split thickness skin graft harvest. The donor site pain in the post-operative period can be assessed by numerical pain rating (NPR) scale. NPR scale involves asking the patient to rate their pain from 0 to 10 (11-point scale).

MATERIALS AND METHODS

The study was done from November 2014 to May 2016 in a tertiary care centre. The inclusion criteria were those with post-traumatic or post-infective raw area and surgically created defect. The exclusion criteria were children below 12 years of age, patients with burns whose analgesic requirement were more and difficult to compare with the study proposed, immunocompromised patients where wound healing may be affected, mentally-ill patients and any condition which influences pain recording.

Procedure for the study included dividing the selected sample into two groups. The donor site dressing was done in two different ways. One was dressed with meshed collagen sheet which was dried with warm air dryer and other with petroleum gauze dressing. Randomly permuted block size of 4 which is the most effective method for small sample size randomisation was used in this study. The sample was split into groups of four, namely CPCP, CPPC, PCCP, PCPC, PPCC and CCPP. C stands for collagen and P stands for petroleum gauze dressing. Each block was randomly chosen, and samples were operated accordingly. For example, if CPCP is chosen, collagen was applied for the first surgical donor area and petroleum gauze for second. Assessment of post-operative pain was done by NPR scale from 0 to 10 (11-point scale), with the understanding that 0 represents one end of the pain intensity (no pain) and 10 represents the other extreme of pain severity (unbearable pain). All patients were prescribed paracetamol tablets thrice daily as analgesic. The NPR recording was done in morning before paracetamol was administered. Staff nurse did the recording of pain scale. The staff nurse was not aware whether patient had collagen or petroleum gauze dressing. Pain was recorded on the 1^st, 2^nd, 3^rd, 4^th, 5^th, 10^th and 14^th days by NPR [Tables 1 and 2]. On the 10^th post-operative day when the superficial dressing was changed by the surgeon, pain was recorded by staff nurse without seeing the wound. If the patient developed dressing soakage, in between, the dressing was changed immediately. Deeper dressing covering the collagen and petroleum gauze was not opened. Standard antibiotics were given to all patients for 5 days.

Table 1 Control group NPR record

Table 2 Study group NPR record

RESULTS

From the population of a total of 52 cases operated, forty samples were chosen. Twelve patients were excluded from the study. The reason being nine patients wanted early discharge, one patient in study group and two patients in control group developed infection on donor site during the 1^st week. The sampling size was forty; collection of information on pain was done by the NPR scale. The source of information was from sample. The data collected from control and study groups were represented on notched boxplots [Figures 1 and 2]. The pain was analysed using statistics in both groups on days 1, 2, 3, 4, 5, 10 and 14. The average pain score in study group (i.e. collagen sheet dressing) was found to be less compared to control group (i.e., petroleum gauze dressing).

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Figure 1

Control group notched boxplot

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Figure 2

Study group notched boxplot

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For our study, twenty samples of control and twenty samples of study group were selected. Out of them, 34 (85%) were male and remaining 6 (15%) were females [Table 3]. The control group age was in the range of 34.70 % 18.24 and study group age was in 36.70 % 19.52 [Table 4].

Table 3 Frequency and percentage distribution of gender

Table 4 Descriptive statistics for age variable

Statistical data provide detailed information regarding the study. Using inferential statistical methods, Levene's test F value was calculated on days 1, 2, 3, 4, 5, 10 and 14. Independent t-test value of study group and control group was analysed [Table 5]. Evaluation of results from tests, Levene's test of equality of variances and independent t-test showed that the study group had less pain. Therefore, the collagen sheet dressing was found to produce statistically significant reduction of pain (P < 0.05). The study design has adequately assessed the null hypothesis. The hypothesis is supported by the statistical results. Thus, collagen sheet was found to be superior to petroleum gauze dressing in reducing the pain in the donor site.

Table 5 Test for effectiveness of control and study groups :Independent t-test

DISCUSSION

The study was done to assess the true role of collagen in post-operative pain control. The role of collagen dressing in better pain control and superior wound healing is found in literature.[123] Collagen sheets, when applied to a wound, not only promote angiogenesis, but also enhance body's repair mechanisms. Collagen dressing is reported to lead to early and greater degree of mobilisation and more comfort. Collagen is a biomaterial that encourages wound healing through deposition and organisation of freshly formed fibres in the wound bed, thus creating a good environment for wound healing. Collagen is easy to apply and has the additional advantage of stopping bleeding.[45] The closed-dressing method shows qualitatively superior healing when compared with open- and semi-open donor sites. This is due to protection from dehydration and mechanical injury and avoidance of contamination.[6] Comparison between collagen dressing and polyurethane showed that collagen was superior in reducing the discomfort and increasing healing.[7] Collagen dressings help to maintain a moist wound environment which is important for better wound healing.[89] The commonly described moist dressings in literature are Kaltostat, Opsite, Duoderm and Allevyn and nonmoist dressings include Xeroform, Scarlet Red and Jelonet.[10111213]

CONCLUSION

We conclude that pain relief was superior with collagen sheet dressing when compared with petroleum gauze dressing and was statistically significant (P < 0.05).