A haemostatic technique using silicone gel dressing for burn surgery

Abstract

Significant blood loss and high rates of transfusion remain ongoing concerns in burn surgery. We have reported a haemostatic technique using silicone gel dressing to minimise bleeding during tangential excision in burn surgery. The purpose of this study was to identify the efficacy of our novel haemostatic technique for burn surgery. This study was a retrospective observational study. From 1 April 2011 to 31 March 2015, we collated data including pre‐ and 24‐hour postoperative haemoglobin levels from patients over 15 years of age who underwent tangential excision for burn injuries. We also collected data on the amounts of measured blood loss, blood transfusions, excised areas, harvest areas and duration of surgeries. The collected data were divided into a conventional group and a silicone gel dressing group. Then, we analysed the differences between the two groups. During the study period, 357 patients were admitted to our burn centre, and 60 operations (44 patients) were performed by tangential excision. The conventional group comprised 28 operations (20 patients), and the silicone gel dressing group comprised 32 operations (26 patients). Excised areas and harvested areas were significantly larger in the silicone gel dressing group than in the conventional group. The amount of blood loss per percent excised and the number of units of blood transfused were significantly lower in the silicone gel dressing group. Duration of the surgeries was almost the same between the two groups. Application of our new technique during tangential excision for burn injuries resulted in a remarkable reduction in blood loss and transfusion requirements.

Introduction

Significant blood loss continues to plague the treatment of burn wounds, especially during debridement by tangential excision 1, 2. There is an absence of uniformity and consistency in the application of tangential excision, although various techniques have been described to reduce intraoperative blood loss. The amount of blood loss with a comprehensive intraoperative blood conservation strategy, including topical and subcutaneous infiltration of epinephrine, topical thrombin and tourniquets, was estimated to be about 120 ml per percentage excision 3. However, although tangential excision can be applied to partial‐thickness burns, patients with extensive burns might require fascial excision to avoid massive blood loss. We often face the dilemma of whether to perform tangential excision to preserve the dermic layer or fascial excision to minimise bleeding. However, although we have reported that fascial excision can act as a damage control surgery for extensive burn injuries 4, we believe tangential excision is better for patients if applicable.

To minimise blood loss in tangential excision, we developed a novel haemostatic technique using silicone gel dressings 5. In this study, we aimed to determine the efficacy of the technique in reducing bleeding in burn surgery.

Patients

This was a retrospective observational study. From 1 April 2011 to 31 March 2015, patients older than 15 years who were admitted to the Department of Trauma, Critical Care Medicine and Burn Centre, Japan Community Healthcare Organization Chukyo Hospital, Nagoya, Japan and who underwent tangential excision were serially enrolled. This study was approved by the Institutional Review Board of Chukyo Hospital.

Haemostasis techniques

Our new silicone gel dressing technique has been reported earlier 5. Soon after tangential excision with a Humby knife, the burn wounds were sprayed with thrombin (bovine, 1000 IU/ml) and a 1:100 000 adrenalin solution (final concentrations: thrombin 500 IU/ml and 1:200 000 adrenalin), and they were wrapped tightly with silicone gel dressing (SI‐AID^®; ALCARE Co., Ltd, Tokyo, Japan) for a full 10 minutes. The key to success in this technique is keeping the gap between the wound and the dressing as small as possible. To ensure that this happens, we wrapped the wounds with silicone gel dressing soon after spraying the soaking solution. Burn wounds on the limbs were tangentially excised under tourniquet control and wrapped tightly with the silicone gel dressing before deflation of the tourniquet. After deflation, we waited for a full 10 minutes. When the silicone gel dressing was removed, any major bleeders were cauterised. If dermal oozing persisted, we wrapped the wound again with another silicone gel dressing for another 5 minutes. After achieving haemostasis, we washed the excised area with saline and then applied a skin graft. For treatment at the donor site, we usually applied a tightly wrapped alginate dressing. The conventional group patients were treated using epinephrine‐soaked gauze pads and sprayed thrombin without silicone gel dressing.

Data collection

The collected data included age, sex, burn size [percentage total body surface area (BSA) second and third degree burns (%TBSA)], preoperative haemoglobin level (HGBpre), percentage body surface area excised (%EX), percentage BSA harvested (%HV), number of intraoperative units of blood transfused and the total number of intraoperative and 24‐hour postoperative units of blood transfused (one unit of blood contains 200 ml of donor blood in Japan). Information about the 24‐hour postoperative haemoglobin levels (HGBpost) and the duration of surgery were also collected. Blood loss was measured by nurses who were blinded to this research and was also calculated using the formula described by Gross 6 as objective data and to compare previous reports 3, 7:

$$\begin{array}{cc}\text{Calculated blood loss}& =\mathrm{E}\mathrm{B}\mathrm{V}\times \left[\left(\text{HGBpre}–\text{HGBpost}\right)/\right.\\ & \left.\text{HGBav}\right]+T_{\mathrm{x}}\text{,}\end{array}$$

where HGBav is the mean of the HGBpre and HGBpost values, and EBV is estimated blood volume. We chose 70 ml/kg for the calculation of EBV because women and men may have EBVs ranging from 55 to 70 ml/kg and 60 to 75 ml/kg, respectively, depending on their body habitus 6. T _x is the total volume of blood transfused intraoperatively and at 24‐hours postoperatively (in milliliters). The collected data were divided into a conventional group and a silicone gel group, and the differences between the two groups were analysed.

Statistical analysis

Data are presented as the median, interquartile range (IQR: 25th–75th percentile). Differences between groups were assessed with the Student two‐tailed unpaired t‐test using SAS for Windows 11.2.1 (SAS Institute, Cary, NC). P value < 0·05 was considered significant.

Results

From 1 April 2011 to 31 March 2015, 357 patients were admitted to our burn centre, 115 of whom underwent 287 burn surgeries including tangential excision, fascial excision, amputation or others. Sixty operations were done by tangential excision on 46 patients. These operations were divided into the conventional group (20 patients, 28 operations) and the silicone gel dressing group (26 patients, 32 operations). We developed the silicone gel dressing in November 2012. Before that, all the patients were in the conventional group, and after that, most patients were in the silicone gel dressing group. The patients' backgrounds were similar in the two groups (Table 1). Excised and harvested areas were significantly larger in the silicone gel dressing group than in the conventional group. Blood loss per %EX and per %EX + %HV were significantly lower in the silicone gel group, and the amount of blood transfusion in the perioperative period was less in the silicone gel dressing group than in the conventional group. Duration of the surgeries was almost the same in the two groups (Table 2).

Table 1.

Patient characteristics

Patients	Conventional (n = 20)	Silicone gel dressing (n = 26)	P value
Age (years)	70 (47, 83)	65 (43, 78)	NS
%TBSA	20 (14, 37)	28 (12, 35)	NS
Sex (male/female)	9/11	16/10	NS

%TBSA, total body surface area of second‐ and third‐degree burns; NS, not significant.

Values are median (interquartile range).

Table 2.

Blood loss, transfusion requirements and surgery duration

	Conventional (n = 28)	Silicone gel dressing (n = 32)	P value
%EX	4·0 (2·0, 6·8)	7·0 (3·3, 10·0)	0·02
%HV	2·0 (1·6, 4·0)	4·0 (2·3, 5·8)	<0·01
Blood loss
Calculated
Total (ml)	401·9 (191·3, 766·8)	296·7 (123·6, 559·9)	NS
/%EX (ml)	110·7 (32·5, 186·0)	41·6 (19·4, 97·1)	<0·01
/%EX + %HV (ml)	76·8 (20·8, 125·0)	24·7 (12·6, 61·6)	<0·01
Measured
Total (ml)	335 (143, 439)	314 (152, 497)	NS
/%EX (ml)	65·0 (32·1, 109·5)	41·9 (19·8, 57·6)	0·01
/%EX + %HV (ml)	38·3 (22·6, 63·8)	26·2 (16·4, 42·7)	0·01
Transfusion
Intraoperative (unit)	1 (0, 4)	0 (0, 2)	NS.
Total 24‐hour (unit)	2 (0, 4)	0 (0, 2)	0·03
HGBpre (g/dl)	9·6 (8·7, 10·6)	10·3 (8·7, 11·1)	NS
HGBpost (g/dl)	9·4 (8·2, 10·2)	9·4 (8·8, 10·4)	NS
Duration of surgery (minutes)	118 (90, 140)	128 (110, 168)	NS

%EX, percent body surface area excised; HGBpre, preoperative haemoglobin; HGBpost, postoperative haemoglobin; %HV, percent body surface area harvested; NS, not significant.

Values are median (interquartile range).

Measured blood loss in the silicone gel group was more than that of calculated blood loss. In the conventional group, we could not obtain the amount of measured blood loss from eight operation records because surgical nurses just noted it as unmeasurable. The calculated blood loss of these eight patients was 307 ml (IQR 77·9–550·0 ml). The difference between measured and calculated blood loss was probably caused by the difficulty in measuring blood loss correctly during the burn operation because of fluid soaking from the applied epinephrine and/or saline solution. We treated the measured blood loss of the eight patients as missing value.

In the silicone gel dressing group, the maximum calculated blood loss per %EX was 197·4 ml for 3%BSA excision at the posterior cervical region, where astriction was difficult because of the markedly uneven area over the vertebra. In the conventional group, the maximum calculated blood loss per %EX was 405·0 ml for 2%BSA excision at the axillary region. In the silicone gel dressing group, intraoperative transfusion requirements were zero (IQR 0–2) units per case, and we did not need to perform any additional transfusions after the operations. In contrast, most of the patients in the conventional group required one unit of transfusion intraoperatively and another unit after the operation.

Discussion

Despite advancements in medical technology, the large volume of blood loss associated with surgical intervention continues to be an ongoing problem plaguing burn surgery 8. Even though multiple haemostatic techniques have been proposed to address this problem, there are as yet no definitive answers 7. The previously reported techniques include the application of topical epinephrine with or without thrombin to excised wounds and/or donor sites 9, 10, 11, 12; the subcutaneous infiltration of vasoconstrictors such as epinephrine 13, 14, 15, 16, 17, 18, phenylephrine 13 or vasopressin 2 at donor and/or excision sites; the administration of systemic vasopressin 19; excision with a laser 20, 21, 22 and the use of limb tourniquets 23, 24. Under the blood conservation strategy using these techniques, the amount of blood loss was about 120 ml per percentage excised 3. Under this condition, we previously reported that fascial excision could be applied for the surgical treatment of extensively burned patients because fascial excision could reduce blood loss more effectively than tangential excision 4. Tangential excision removes burnt skin while preserving the underlying viable dermis, which results in better skin grafting than when performed after fascial excision. The problem with tangential excision is that it is difficult to stop the oozing from the dermal surface, especially in operations to treat extensive burns. Tangential excision causes more bleeding and prolongs the operation. Moreover, cauterisation creates more burn tissue, which worsens the conditions for skin grafting. We have applied tourniquets, epinephrine (topical and/or tumescence) and topical thrombin, but we still feel the need for more effective and simpler techniques to reduce bleeding.

Basically, the current haemostatic methods are astriction and cauterisation of major bleeders. We have found that the removal of gauze pads results in rebleeding because of the irritation caused by peeling the gauze pads away, and the pads rarely adhere to the excision site without creating space between the pads and the site, which allows the formation of coagula. We reasoned that if we could compress the wound properly with no formation of coagula, tangential excision might be more easily applied to burn patients. We tried multiple materials for astriction and found that silicone gel dressing is probably the best for now 5. The structure of the silicone gel dressing allows it to adhere gently to the skin around the wounds, and any exudates including blood are absorbed by means of its silicone adhesion technology. Although silicone gel mesh is non‐absorbent, it contains multiple pores that allow the passage of blood from the wound into a secondary absorbent layer. The silicone gel mesh can be attached to the excision site without creating any free space, which is why the silicone gel dressing prevents the formation of coagula. The silicone gel dressing has a tendency towards low detachability and low peel irritation 25, which results in no rebleeding on removal. Therefore, oozing can be almost completely stopped, and bleeding from major bleeders is absorbed into the absorbent layer through the silicone gel mesh with no formation of coagula (Figure 1).

Figure 1.

The mechanism behind our new procedure to stop bleeding during tangential excision. (A) Conventional procedure includes thrombin and epinephrine soak with gauze pads. Dermal oozing usually occurs when the gauze pads are removed because removal of the pads with coagula can cause rebleeding from the excised wound bed. (B) Silicone gel dressing with inadequate compression. Some coagula formation can occur. When the coagulum is removed, additional dermal oozing can occur. (C) Our new procedure with silicone gel dressing and adequate compression (indicated by the arrow). The silicone gel dressing sticks to the wound and absorbs blood into the absorbent layer through the silicone gel mesh with no formation of coagula. No additional dermal oozing occurs because of the less irritation when the silicone gel dressing is removed.

It is difficult to apply this silicone gel dressing technique to round‐shaped areas such as the head or to concave–convex surfaces such as the area around the spine or collarbone. We usually take a graft from the patient's scalp if applicable, and this is one reason why we use an alginate dressing for the donor site. Presently, we are looking for materials such as a viscoelastic foam mattress that can be compressed suitably over round and concave–convex surfaces.

The current paper shows that by using the silicone gel dressing technique, we could achieve significant reduction of blood loss compared with conventional techniques or other reports 3, 7. Because this technique is easy, the simple substitution of silicone gel dressings for gauze pads might shorten the duration of the surgery, which was around 2 hours in the present study with relatively large debridement and grafted areas. To date, we have applied this technique for <20% BSA excised to lessen the chance of unexpected bleeding. The present data indicate that our surgeons tend to increase the excised and harvested areas using this technique, probably because they have gained confidence with the efficacy of this technique.

The limitation of this study is that this is a retrospective, non‐randomised study. A prospective multicentre randomised control trial is warranted.

In conclusion, following tangential excision, wrapping of the burn wound with silicone gel dressing following spray application of thrombin and epinephrine appears to be a practical and effective technique that can be applied easily, and significantly reduces the amount of intraoperative bleeding during tangential excision in burn surgery.