practice

j o u r n a l o f wo u n d c a r e vo l 2 0 , n o 6 , J U n E 2 0 1 1 3 0 1

Are postoperative dressings necessary?l objective: To determine whether or not the routine use of postoperative dressings prevents surgical site infection and wound dehiscence. l Material and methods: Patients with clean or clean-contaminated (e.g. hernia, orchidectomy cystolithotomy, ureterolithotomy, appendectomy) sutured surgical wounds were randomised into two groups: those who did not receive postoperative dressings (the study group) and those who did (the control group). variables like adequate haemostasis, sterile techniques, obliteration of all wound cavities, and approximation of divided structures were not controlled for. Wounds were assessed after 6 and 24 hours, and on the third and fifth postoperative days for clinical signs of infection and dehiscence.l results: A total of 123 patients with 124 clean surgical wounds were recruited into the study. The mean age and ratio of men and women in each group were comparable. There was no significant difference in the rate of wound complications between the two groups: 4.76% for the study group and 4.92% for control.l conclusion: Based on these preliminary data, surgical wounds left open do not have an increased incidence of surgical site infection and wound dehiscence, compared with similar types of wounds dressed postoperatively. In a large teaching hospital, the extrapolated cost savings of dressing materials alone can be significant. larger studies are needed to confirm these results.l conflict of interest: none.

postoperative dressings; sutured wounds; wound complications; surgical site infection

The use of sterile dressings on sutured post-operative wounds is considered a routine conclusion to an aseptic operation. The main objective is to restrict the ingress of bacteria into wound and thus prevent

contamination.1 In recent decades, the management of clean sutured, postoperative wounds shifted from a reliance on prolonged dressing coverage, to early exposure of the wound. This reflected a change in understanding of the extent to which these wounds are at risk of infection. The pioneering work done in 1952–53 by Heiftz et al.1,2 on the need for postopera-tive dressings showed that a coagulum of blood and fibrin is impermeable to bacteria. It was observed that sepsis generally did not occur in clean sutured wounds in a surgical ward after a dressing acciden-tally slipped off.3 Similarly, there was an acknowl-edgment that sutured facial and scalp wounds, which are not covered with a dressing, are not asso-ciated with high infection rates. Furthermore, it was noted that use of prophylactic antibiotics prior to the ‘decisive period’ — the 4-hour interval between the breach of the epithelial surface, whether by trau-ma or surgery, and the mobilisation of the host defences — could prevent the occurrence of infec-tion.4 This led to the current trend of preoperative administration of prophylactic antibiotics. Finally, there is no need to use dressings to promote healing in these acute wounds: once the wound edges are apposed, healing progresses rapidly to closure.

The type of dressing used ranges from a totally occlusive dressing, whose edge is sealed with tape, to a light gauze bandage, held in place by a few adhe-sive tape strips. However, even though dressings are applied for short periods, there are still disadvantag-es to their use. The most common disadvantage of using gauze on clean wounds is that it becomes wet with perspiration.5 This results in maceration of the skin edges, failure to form a firm crust and increased capillarity of the skin sutures. In order to minimise these effects, the dressing must be changed regularly to keep it dry. In India, this is a big problem during the hot summer months. There are other disadvan-tages. The dressing has to be removed before the wound can be assessed. Common skin reactions to adhesive tapes include vesication, folliculitis, itching and irritation.6,7 Furthermore, removal of adhesive tape is not pain free; in our experience, most patients remember the painful experience of dressing change, rather than the wound itself.

Very few studies have investigated whether elimi-nating the use of these dressings on this wound type would cause no harm and might even be benefi-cial.5,8,9,10 None have been performed in an Indian Government hospital setting. Even modern stand-ard surgery textbooks do not give guidelines, so decisions about this are largely based on tradition. We therefore conducted a randomised controlled trial (RCT) to determine whether postoperative dressings prevent surgical site infection.

n.B. Borkar,1 MS (Surgery), Asst. Professor, Department of Surgery, AvBRH Sawangi, Wardha, Maharashtra, India;M.V. Khubalkar,2 MBBS, MS (Surgery), Associate Professor, Department of Surgery, Government Medical College, Akola, Maharashta, India.Email: drnitinborkar25@gmail.com;

practice

j o u r n a l o f wo u n d c a r e vo l 2 0 , n o 6 , J U n E 2 0 1 13 0 2

references1 Heifetz, C.J., Richards, F.o., lawrence M.S. Wound healing without dressing. Arch Surg 1953; 67: 5, 661–669. 2 Heifetz, C.J., lawrence, M.S., Richards, F.o. Comparison of wound healing with and without dressing. Arch Surg 1952; 65: 5, 746–751. 3 Howells, C.H.l., Young, H.B. A study of completely undressed surgical wound. Br J Surg 1966; 53: 5, 436–439.4 leaper, D.J. Wound infection. In: Russel, R.C.G., norman, S., Christopher, W., Bulstrode, J.K. (eds). Bailey and love’s Short Practice of Surgery (24th edn). Hodder Arnold, 2004.5 Kleitsch, W.P., Reiser, H.G.. The open treatment of surgical wounds. Am J Surg 1954; 88: 4, 609–612. 6 Tokumura, F., Umekage, K., Sado, M. et al. Skin irritation due to repetitive application of adhesive tape: the influence of adhesive strength and seasonal variability. Skin Res Technol 2005; 11: 2, 102-106.7 Greiner, D., Weber, J., Kaufmann, R., Boehncke, W.H. Benzoyl peroxide as a contact allergen in adhesive tape. Contact Dermatitis 1999; 41: 4, 233.8 Merei, J.M. Pediatric clean surgical wounds: is dressing necessary? J Pediatr Surg 2004; 39: 12, 1871-1873.9 Chrintz, H., vibits, H., Cordtz, T.o. et al. need for surgical wound dressing. Br J Surg 1989; 76: 204.10 Herman, R.E., Flowers, R.S., Wasylenki, E.W. Early exposure in the management of the postoperative wound. Surg Gynecol obstet 1965; 120: 503–506.11 Robertoson, G.S. local and regional anesthesia. In: Kyle, J., Smith, J.A.R., Johnston, D. (eds). Pye’s surgical handicraft (22nd edn). Butterworth-Heinmann, 1992.

Material and methodsThe study was conducted in a general surgery unit of Government Medical College Hospital, Nagpur, India, over a 2-year period between June 2005 and May 2007. All patients undergoing elective or emer-gency surgery in this unit were considered for inclu-sion. To be included, patients had to have clean or clean-contaminated, postoperative wounds: hernia, appendectomy, laparotomy, cystolithotomy, ure-terolithotomy and high orchidectomy wounds. Patients with contaminated surgical wounds, such as those associated with a perforated appendix and perforation peritonitis and trauma surgery, were excluded. Other exclusion criteria were clean con-taminated surgeries where postoperative drainage is required, such as transvesical prostatectomy, and the presence of comorbidities such as diabetes mel-litus and jaundice.

Patients were randomised into either the study group (‘no dressings’ applied postoperatively) or to a control group (‘dressing’ applied postoperatively). A simple randomisation procedure was used, whereby ‘no dressing’ (n=75) or ‘dressing’ (n=75) was written on 150 blank sheets of paper, which were then mixed at random. Unscrubbed nursing staff in the operation theatre then selected one sheet of paper, while blindfolded, which determined the group allo-cation. The operating surgeon was blinded to each patient’s allocation as randomisation took place immediately after the wound had been sutured and before the time when a dressing would be applied.

The research protocol was first reviewed by the department of surgery and approved by the Govern-ment Medical College ethics committee. The com-mitted also approved the informed consent form. All patients gave written, informed consent.

Variables, such as the provision of adequate hae-mostasis, sterile techniques, obliteration of all wound cavities and approximation of divided struc-tures, all of which can influence wound infection or healing, were not standardised between the two groups during surgery.

Clean surgical wounds were given a single dose of antibiotics at induction of anaesthesia. Clean con-taminated wounds received a perioperative umbrel-la of broad-spectrum antibiotics, as per the standard unit protocol. In both groups, prior to surgery the skin was cleansed with denatured alcohol and 5% povidone-iodine aqueous solution, which was left to dry, as per unit protocol. This procedure normally lasted 5–7  minutes. Whenever possible, incisions were made in the skin creases. Diathermy was used to ensure adequate haemostasis. All wounds were irrigated with normal saline before closure.

In the study group, following cleansing, a single piece of sterile gauze was placed over the wound, without adhesive tape or other means of fixation, and allowed to fall off on its own.

In the control group, sterile dressings consisted of a small surgical pad (medical grade absorbent cot-ton between two layers of cotton gauze, cut to size to cover the wound) held in place with adhesive tape. The pads were locally made in the hospital from Government Hospital supplies and autoclaved in central sterile supplies. The first dressing change took place 48  hours after surgery, unless required sooner. Following this, the dressing was changed when needed — for example, to examine the wound, when the patient complained of excessive pain at the surgical site, and when there was a high pulse rate and/or pyrexia. The final dressing change took place at the time of suture removal. A mini-mum of three dressing changes was required. In both groups, when drainage was required, the drains were placed in separate incisions and the drain sites were dressed separately. The drains were removed when they were no longer needed.

Wounds in both groups were assessed postopera-tively after 6 hours, after 24 hours, on the third and fifth postoperative days, and at suture removal. They were observed for the following clinical signs of infection — excessive pain at the surgical site, erythema, discharge of serous exudate, discharge of pus and the need for aspiration or drainage — and for wound dehiscence. All of the wound observa-tions were noted by a single surgeon from the unit, who had been involved in the study design. In both groups, sutures of major abdominal surgeries were removed on the tenth postoperative day and appen-dicectomy and hernia surgery sutures were removed on eighth day with sterile scissors.

Statistical analysis The Fischer exact test was used to compare the dif-ference in the number of wound complications between the two groups. Epi-Info Software was used.

ResultsPatient demographicsA total of 123  patients with 124  surgical wounds were recruited into the study. No patients refused to give consent and none dropped out or were with-drawn from the study.

Ninety-five patients were male and 28 female. The baseline data for the two groups were comparable. The age range for the group as a whole was 6 months to 75 years, with a mean of 28 years and 29 years in the study and control groups, respectively. (Medians were 32 and 30 years, respectively.) The gender ratio was similar with 49 males and 14 females in the study group, versus 47 males and 14 females in the control group. Table 1 lists the wound types in both groups.

A very similar number of patients in both groups had emergency surgery: 22 patients (36.5%) in the study group versus 22 patients (37.7%) in the con-trol group.

practice

j o u r n a l o f wo u n d c a r e vo l 2 0 , n o 6 , J U n E 2 0 1 1 3 0 3

Table 1. distribution of wounds according to type of surgery (all open)

Type of surgery with dressing group with no dressing group

no. of wounds no. of wounds

Appendectomy 22 22

Hernia repair 25 23

Herniotomy 8 11

High orchidectomy 1 2

Epigastric hernia 2 1

Cystogastrostomy 1 1 (pancreatic pseudocysts)

Ureterolithotomy 1 1

Cystolithotomy 1 2

Total 61 63

Of the entire sample, 82 (67.4%) received a spinal anaesthesia, 21 (17.07%) general anaesthesia and 20 (16.26%) local anaesthesia.

Six of the 124 surgical wounds developed compli-cations: three in each group. These comprised three appendicectomy wounds (one in the control group and two in the study group) and three hernia repairs (two in the control group and one in the study group). Of these six wounds, three were gaping and were discharging pus (one in the control group and two in the study group), two had serous discharge (both in the control group, one with erythema) and one was erythematous (study group). The difference in the percentage of wound complications between two groups was not statistically significant.

DiscussionThe routine use of dressings on sutured surgical wounds is based on tradition and is not scientifical-ly supported.8-10 The results of this RCT showed that there was no significant difference in the number of wound complications between dressed and undressed postoperative surgical wounds (4.92%  versus  4.76%, respectively). None of the wounds with complications required debridement or a prolonged course of antibiotics. All complica-tions responded well to conservative measures, such as dressing changes and use of honey dressings.

Study limitations include the small sample size and lack of blinding on the surgeon’s side. We did not perform a power calculation to determine the sample size needed to achieve statistical signifi-cance. A large study is therefore needed to authenti-cate our results.

Our sample included a 75-year-old man with a bilateral inguinal hernia, where the right hernia was randomised to the study group and left hernia to the control group. This inclusion (which was delib-erate) could have introduced a unit of analysis error into the results.

Heiftz et al. excluded patients given local anaes-thesia because the epinephrine used in it gives a false assurance of haemostasis.1 In our study, we used lignocaine with epinephrine as local infiltra-tion anaesthesia for 20 patients. Of these, 17 patients had inguinal hernias, two had epigastric hernias and one had a high orchidectomy. In the patients with an inguinal hernia, we used the three-point block, local anaesthesia technique.11 In contrast to Heiftz et al.,1 we did not observe any instances of postoperative soiling of the dressing.

After the study had been completed, we attempt-ed to calculate the cost savings that might be achieved by not using dressings on these wounds. We estimated that the cost of dressing materials, such as the sterile cotton pad, an adhesive plaster, a pair of gloves and antiseptics, required for each dressing change is 50–100 rupees, depending on the

length of the wound. (US$1 = approximately 45 rupees and £1 = approximately 72 rupees.) Based on this, we calculated that avoiding the use of such dressings in 1000 postoperative wounds would achieve significant cost savings: Rs 100 x 3 x 1000 = Rs 300 000). This does not take into account the considerable cost of purchasing and sterilising instruments used at dressing change, nurse and surgeon time, and the costs incurred dur-ing waste disposal.

Leaving the sutured wounds exposed to air was well accepted by the patients. None objected to it, all agreeing to give their consent to participate, and none of those randomised to the study group subse-quently asked for a dressing to be applied.

ConclusionWhile a larger study is needed to confirm these pre-liminary findings, it appears that leaving clean and clean contaminated primarily sutured wounds undressed does not result in an increased incidence of wound complications, compared with dressed wounds. Benefits associated with exposure to air include convenience, savings in surgical dressing costs as well as medical and nursing time, the elimi-nation of cumbersome dressings, absence of adhesive tape irritation, avoidance of pain at dressing change, and easy access to an open wound for assessment.

Based on these results, the use of wound dressings does not play a significant role in preventing post-operative wound complications, including surgical site infections. We believe that more surgical wounds than those included in this study could safely be left undressed. n

Copyright of Journal of Wound Care is the property of Mark Allen Publishing Ltd and its content may not be

copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written

permission. However, users may print, download, or email articles for individual use.