- Prophylactic antibiotic therapy reduces the risk of surgical site infection.
- The need for surgical antibiotic prophylaxis depends on the nature of the expected wound from the procedure.
- Wounds that are expected to be clean (defined as no inflammation encountered; and the respiratory, alimentary, genital, or uninfected urinary tracts were not entered) generally do not require antibiotic prophylaxis, except where the consequences of surgical site infection could be severe (e.g. joint replacement in orthopaedic surgery).
- Antibiotic prophylaxis is indicated for procedures with clean-contaminated wounds (defined as entering the respiratory, alimentary, genital, or urinary tracts under controlled conditions; and without unusual contamination).
- A course of antibiotic treatment, not antibiotic prophylaxis, is required for procedures with contaminated wounds (defined as fresh open accidental wounds, or operations with major breaks in sterile technique), or dirty or infected wounds (defined as old traumatic wounds with retained devitalized tissue; and those that involve existing clinical infection or perforated viscera).
(See Emergencies and Injury: for antibiotic treatment).
- The antibiotic of choice should be active against Gram positive organisms, notably Staphylococcus aureus, which is the commonest cause of surgical site infections, with additional cover for other common pathogens according to the surgical site (e.g. anaerobic bacteria for GIT surgery).
- Give prophylaxis at induction.
- If a tourniquet is used at the site of surgery, administer the entire antibiotic dose before the tourniquet is inflated.
- Implement perioperative glycaemic control and use blood glucose target levels less than 11.1 mmol/L in patients with and without diabetes.
- Maintain perioperative normothermia.
- Antibiotic prophylaxis should be used in conjunction with good pre- and intra-operative infection prevention strategies.
- Advise patient to shower or bathe with soap or antiseptic agent on at least the night before the procedure.
- Do not remove hair preoperatively unless the hair at or around the incision site will interfere with the operation. If hair removal is necessary, remove immediately before the operation, with clippers.
Dosage recommendations :
- Cefazolin, IV.
| <60 kg | 1 g |
| 60–120 kg and BMI ≤35 | 2 g |
| ≥120 kg or BMI >35 | 3 g |
Pregnant women:
| <60 kg | 1 g |
| 60–100 kg | 2 g |
| >100 kg | 3 g |
- Metronidazole, IV, 500 mg.
- Azithromycin, IV, 500 mg.
- Gentamicin, IV, 6 mg/kg (See Appendix II, for guidance on prescribing).
- Clindamycin, IV, 600 mg.
In most instances a single antibiotic dose prior to the procedure is sufficient for prophylaxis. Postoperative antimicrobial administration is not recommended for most surgeries as this selects for antimicrobial resistance.
- Additional intra-operative doses should be administered in circumstances of significant blood loss (>1500 mL) in order to ensure an adequate antimicrobial level until wound closure.
- With prolonged procedures, antibiotics are required to be re-dosed (i.e. > 4 hours for cefazolin; > 8 hours for metronidazole; > 6 hours for clindamycin and gentamicin).