Prophylactic antibiotics in gut surgery

Wound infections:

• Occur in 20-60% of those undergoing GI surgery
• Sepsis may lead to:
• Delayed mobilisation
• Haemorrhage
• Wound dihescence
• A fatal chain of events

• Prophylaxis substantially reduces infection rates

Rules for success:

• Give the antibiotic just before (e.g. 1 hour) surgery
• Give the antibiotic IV or IM (or as a suppository for metronidazole)
• Usually the antibiotic can be stopped after 24 hours
• Use antibiotics which will kill anaerobes and coliforms (e.g. metronidazole and gentamicin)

Antibiotic regimens:

There is usually a local preference. Examples include:

Biliary surgery:

Broad spectrum penicillin (e.g. ampicillin 500mg IV/8h for 3 doses), or

Cephalosporin (e.g. cefuroxime IV/IM 1.5g/8h for 3 doses)

Appendicectomy:

• A 3-dose regimen of metronidazole suppositories (1g/8h) plus cefuroxime 1.5g/8h IV or gentamicin IV

Colorectal surgery:

• Cefuroxime 1.5g/8h IV/IM for 3 doses plus metronidazole 500mg/8h IV for 3 doses

Vascular surgery:

• Co-amoxiclav 1.2g IV on induction
• If penicillin-allergic, use cefuroxime 1.5g IV/IM plus metronidazole 500mg IV