Approximately 15% of all antibiotics in hospitals are prescribed for surgical prophylaxis. It is very important to prescribe appropriately surgical antibiotic prophylaxis (SAP).
SAP is defined as the use of antibiotics to prevent infections at the surgical site and it should be always used to prevent surgical site infections (SSI).
SAP should be always differentiated from antibiotic therapy.
Ideally, an antimicrobial agent for surgical prophylaxis should:
(1) Prevent SSI,
(2) prevent SSI-related morbidity and mortality,
(3) Reduce the duration and cost of health care (when the costs associated with the management of SSI are considered, the cost-effectiveness of prophylaxis becomes evident)
(4) Produce no adverse effects such as Clostridium difficile infection or acute kidney injury
(5) Have no adverse consequences for the microbial flora of the patient or the hospital. Inappropriate and prolonged surgical antibiotic prophylaxis can alter individual and institutional bacterial flora, leading to changes in colonization rates and increased antibiotic resistance.
To achieve these goals, 8 simple principles should be always respected in prescribing antibiotic surgical prophylaxis
Although appropriate SAP plays a pivotal role in reducing the rate of SSIs, other factors that impact SSI rates should not be ignored. SAP should never substitute for good medical practices.
Antibiotics alone are unable to prevent surgical site infections. Strategies to prevent surgical site infections should always include attention to Infection prevention and strategies including:
- Correct and compliant hand hygiene practices
- Meticulous surgical techniques and minimization of tissue trauma
- Hospital and operating room environments
- Instrument sterilization processes
- Perioperative optimization of patient risk factors
- Perioperative temperature, fluid and oxygenation management
- Targeted glycemic control
- Appropriate management of surgical wounds
Surgical antibiotic prophylaxis should be administered for operative procedures that are associated with a high rate of infection and in certain clean procedures where there are severe consequences of infection (e.g., prosthetic implants), even if infection is unlikely.
Antibiotic given as prophylaxis should be effective against the aerobic and anaerobic pathogens most likely to contaminate the surgical site i.e., Gram-positive skin commensals or normal flora colonizing the incised mucosae. Antibiotic agents with the narrowest spectrum of activity required for efficacy in preventing infection should be prescribed. For most procedures, cefazolin is the drug of choice for prophylaxis because it is the most widely studied antimicrobial agent, with proven efficacy. It has a desirable duration of action, spectrum of activity against organisms commonly encountered in surgery, reasonable safety, and low cost. There is little evidence to suggest that broad-spectrum antibiotic agents result in lower rates of post-operative SSI compared with older antibiotic agents with a narrower spectrum of activity.
Successful SAP requires the delivery of the antibiotic to the operative site before contamination occurs. Thus, the antibiotic should be administered at such a time to provide serum and tissue concentrations exceeding the minimum inhibitory concentration (MIC) for the probable organisms associated with the procedure, at the time of incision.
Antibiotic prophylaxis should be administered within 120 minutes prior to the incision. However, administration of the first dose of antibiotics beginning within 30-60 minutes before surgical incision is recommended for most antibiotics (e.g. Cefazolin), to ensure adequate serum and tissue concentrations during the period of potential contamination. Obese patients ≥ 120 kg require higher doses of antibiotic.
Intraoperative redosing is needed to ensure adequate serum and tissue concentrations of the antibiotic. Additional antibiotic doses should be administered intraoperatively for procedures >2-4 hours (typically where duration exceeds 2 half-lives of the antibiotic) or with associated significant blood loss (>1.5L).
The redosing interval should be measured from the time of administration of the preoperative dose, not from the beginning of the procedure. Redosing may not be warranted in patients in whom the half-life of the antibiotic agent is prolonged (e.g., patients with renal insufficiency or renal failure).
Antibiotic incisional wound irrigation before closure should not be used for the purpose of preventing SSI.
Considering that the evidence shows that this procedure has no benefit with regard to SSI prevention, this practice is associated with an unnecessary risk of contributing to antibiotic resistance.
There is no evidence to support the use of post-operative antibiotic prophylaxis. Evidence is mounting that post-operative antibiotic administration is not necessary as a general principle.
Each institution is encouraged to develop local guidelines for the proper surgical prophylaxis.
Individual health systems must consider local resistance patterns of organisms and overall SSI rates at their site when adopting international recommendations.
Standardizing a shared protocol of antibiotic prophylaxis should represent the first step of any antimicrobial stewardship program. Since surgeons are primarily responsible for the decision to use antibiotics, educating them and changing the attitudes and knowledge that underlie their prescribing behavior are crucial for improving antibiotic prescription.