Antibiotic prophylaxis in clean surgery: clean non-implant wounds.

Wound infection after clean surgery (the majority being hernia, varicose vein and breast surgery) is often greatly underestimated. If a trained and blinded observer is involved using close and prolonged surveillance to at least 30 days postoperatively with appropriate definitions or wound scores, an infection rate of up to 15% or more may be found. Equally controversial is the value of prophylactic antibiotics in preventing postoperative wound infection; there is no clear cut evidence of efficacy and some random controlled trials (RCTs) have shown no differences at all. There is a need for guidelines to be drawn up but further RCTs may be needed. An alternative to antibiotics is the systemic warming of patients or the local warming of the operative site prior to surgery. In day case surgery in particular, patients may have been deprived of fluids for 12h prior to surgery; they may become cold whilst waiting for surgery dressed in a theatre gown; and their apprehension may not be controlled with anxiolytics. The inflammatory response may be obtunded with an increased risk of superadded infection or poor healing in cutaneous tissue resulting in wound separation and fat necrosis. Only a third of sampled purulent discharges grow skin organisms such as Staphylococcus aureus or epidermidis. In a study of 421 patients the 138 randomly assigned to local warming (Warm Up, Augustine Medical) had a wound infection rate of 3.6% compared with another group of 139 randomly assigned to systemic warming (Bair Hugger, Augustine Medical) of 5.8%. A standard-treated third group of 139 had a wound infection rate of 13.7% (P<0.001). The warmed patients also had significantly lower wound scores based on 4 systems, had higher skin temperatures and capillary flow prior to surgery and were prescribed fewer postoperative antibiotics by their family doctors in the 6 postoperative weeks (15.9% vs 6.5%; P=0.002). Wound infections are more common than generally accepted if they are looked for by close surveillance. Antibiotics may be avoided by the use of warming with the lessening of the risks of allergy, resistance and emergence. It is uncertain whether antibiotic prophylaxis has a role in clean wound surgery. Breast surgery carries the highest risk of wound infection and this may risk delay in receiving planned adjuvant chemotherapy or radiotherapy. Perioperative warming of the operative site may be of greatest value in this group of patients.