Surgical procedures are classified according to the risk of wound infections into:
- clean (risk < 5%).
- clean-contaminated (risk 5 to 10%).
- contaminated (risk 10 to 20%).
- dirty (risk > 20%).
Antibiotics are given prophylactically because they significantly reduce the risk of infection in clean-contaminated and contaminated procedures.
Dirty procedures, where contamination is so extensive that wound infection occurs very frequently, such as treatment of a perforation of a hollow viscus >24 hours old, require multi-day therapy.
In clean procedures the small benefit of antibiotics does not outweigh the possible adverse consequences (allergy, toxicity, selection of resistant strains, higher costs). An exception is clean procedures where infection would have disastrous consequences, such as the insertion of prostheses (e.g. joint prostheses).
Indications for prophylaxis:
- clean procedures: no prophylaxis.
- clean procedures involving insertion of prostheses: perioperative prophylaxis.
- clean-contaminated and contaminated procedures: perioperative prophylaxis.
- dirty procedures: therapy.
Choice:
As a rule, the antibiotic of choice for perioperative prophylaxis should be active against Staphylococcus aureus, the main cause of wound infections. For contaminated procedures below the diaphragm, an agent covering the main Enterobacteriaceae from the gut is required. In addition, for colorectal and gynaecological surgery and some ENT procedures an agent with anti-anaerobic activity should be added.
Uniformity and simplicity are very important to reduce the chance of errors. It is also desirable to use in prophylaxis an agent that is not used in therapy. This has important logistical advantages and aims to limit the selection of resistance.
The SWAB therefore recommends:
the first-generation cephalosporin cefazolin 2 g IV. For procedures in which the wound is closed within one hour of administration of cefazolin, 1 g IV is sufficient.
combined with metronidazole IV (500 mg) when an anaerobic spectrum is required.
Timing:
- To ensure appropriate timing of perioperative antibiotic prophylaxis before and during surgery, this should be the responsibility of the anaesthetist.
- Perioperative antibiotic prophylaxis should be administered within 60 minutes before incision, ideally at the time of induction of anaesthesia.
- In the case of vancomycin, which with a standard dose of 1 g can be given over one hour, and ciprofloxacin, where up to 400 mg can be given in one hour, the infusion should therefore start at least one hour before incision.
Duration:
- A single dose of perioperative antibiotic prophylaxis is preferred, but re-dosing is required for an operation lasting > twice the half-life (t1/2) (for cefazolin: 1.5 – 2 hours) and in case of blood loss > 1500 ml.
- It is generally accepted that the prophylactic administration of antibiotics is only beneficial perioperatively. Prophylaxis for longer than 24 hours after a procedure is not useful.
Indication:
Surgical procedures are classified according to the risk of wound infections into:
- clean (risk < 5%).
- clean-contaminated (risk 5 to 10%).
- contaminated (risk 10 to 20%).
- dirty (risk > 20%).
Antibiotics are given prophylactically because they significantly reduce the risk of infection in clean-contaminated and contaminated procedures.
Dirty procedures, where contamination is so extensive that wound infection occurs very frequently, such as treatment of a perforation of a hollow viscus >24 hours old, require multi-day therapy.
In clean procedures the small benefit of antibiotics does not outweigh the possible adverse consequences (allergy, toxicity, selection of resistant strains, higher costs). An exception is clean procedures where infection would have disastrous consequences, such as the insertion of prostheses (e.g. joint prostheses).
Indications for prophylaxis:
- clean procedures: no prophylaxis.
- clean procedures involving insertion of prostheses: perioperative prophylaxis.
- clean-contaminated and contaminated procedures: perioperative prophylaxis.
- dirty procedures: therapy.
Choice:
As a rule, the antibiotic of choice for perioperative prophylaxis should be active against Staphylococcus aureus, the main cause of wound infections. For contaminated procedures below the diaphragm, an agent covering the main Enterobacteriaceae from the gut is required. In addition, for colorectal and gynaecological surgery and some ENT procedures an agent with anti-anaerobic activity should be added.
Uniformity and simplicity are very important to reduce the chance of errors. It is also desirable to use in prophylaxis an agent that is not used in therapy. This has important logistical advantages and aims to limit the selection of resistance.
The SWAB therefore recommends:
the first-generation cephalosporin cefazolin 2 g IV. For procedures in which the wound is closed within one hour of administration of cefazolin, 1 g IV is sufficient.
combined with metronidazole IV (500 mg) when an anaerobic spectrum is required.
Timing:
- To ensure appropriate timing of perioperative antibiotic prophylaxis before and during surgery, this should be the responsibility of the anaesthetist.
- Perioperative antibiotic prophylaxis should be administered within 60 minutes before incision, ideally at the time of induction of anaesthesia.
- In the case of vancomycin, which with a standard dose of 1 g can be given over one hour, and ciprofloxacin, where up to 400 mg can be given in one hour, the infusion should therefore start at least one hour before incision.
Duration:
- A single dose of perioperative antibiotic prophylaxis is preferred, but re-dosing is required for an operation lasting > twice the half-life (t1/2) (for cefazolin: 1.5 – 2 hours) and in case of blood loss > 1500 ml.
- It is generally accepted that the prophylactic administration of antibiotics is only beneficial perioperatively. Prophylaxis for longer than 24 hours after a procedure is not useful.