The surgical guidelines have been developed in response to a survey we completed in 2016 that identified a need for widely accessible antimicrobial guidelines for surgical prophylaxis.
National Research Council’s risk index for surgical infection:
|Clean||Non-traumatic, uninfected. No break in aseptic technique, no inflammation encountered. Elective, closed primarily and no drain used|
|Clean-contaminated||Controlled entering of a hollow muscular viscus, minor break in aseptic technique|
|Contaminated||Open, fresh traumatic wound. Incision into a site with acute, non-purulent inflammation. Major break in aseptic technique.|
|Dirty||Pus encountered during surgery. Perforated viscus found. Traumatic wound with devitalised tissue, foreign material or faecal contamination, or of more than 4-hour duration|
|Surgical conditions||Mitigating factors||Antimicrobial recommendation||Duration of therapy|
|Uncomplicated hernia repair75||None||N/A|
|Unsanitary conditions||Oxytetracycline||Preoperatively only78|
|Surgery >1.5h||Oxytetracycline||No evidence, in other species preoperatively only|
|Clean-contaminated||Oxytetracycline||No evidence, in other species stop by 24h|
|Contaminated||Oxytetracycline||No evidence, in other species 24-48h|
|Dirty||Choose appropriate to infection||Choose appropriate to infection|
Timing of prophylactic antimicrobials:
Tissue levels of antimicrobials are required at the time of first incision to confer protection from surgical site infection.
Intravenous antimicrobials: Administer 30-60 mins prior to surgery
Intramuscular procaine penicillin: 2h prior to surgery
Intramuscular oxytetracycline: ~8 h prior to surgery
Tmax for individual drugs given by different routes can be used to assess optimal timing to achieve peak serum levels at the time of first incision.
Dosing interval should be measured from the time of the preoperative dose. The dosing interval can be calculated as twice the elimination half-life of the antimicrobial.
Intravenous oxytetracycline: 6 hours