What is the rationale for the appropriate use of antibiotics in surgical procedures?

From the Guidelines

Rational antibiotic use in surgery requires administering antibiotics within 60 minutes before surgical incision, with appropriate agent selection based on the specific procedure and likely pathogens, to maximize infection prevention while minimizing resistance development. The most recent and highest quality study, 1, published in 2023, provides evidence-based recommendations for the prevention of device-related infections in patients with cancer. According to this study, prophylactic antimicrobials should be infused within 60 minutes of the incision, whereas vancomycin, aminoglycosides, and quinolones should be infused within 120 minutes. Some key points to consider when using antibiotics in surgery include:

• Administering antibiotics within the recommended time frame to ensure adequate tissue concentrations during the period of potential contamination
• Selecting the appropriate antibiotic agent based on the specific procedure and likely pathogens
• Adjusting the dose of antibiotics based on the patient's weight and re-dosing at intervals of every two half-lives or when excessive blood loss occurs during the procedure
• Limiting the use of antibiotics to 24 hours postoperatively for most procedures, with exceptions for certain contaminated or dirty surgeries
• Considering alternative agents for patients with beta-lactam allergies, renal impairment, or MRSA colonization
• Using therapeutic antibiotics for established infections in a culture-guided manner, with initial empiric therapy based on local resistance patterns and narrowed once susceptibility results are available, as recommended by 1 and 1. Overall, a balanced approach to antibiotic use in surgery is crucial to prevent surgical site infections while preserving antibiotic effectiveness.

From the FDA Drug Label

To prevent postoperative infection in contaminated or potentially contaminated surgery, recommended doses are: 1 gram IV or IM administered 1/2 hour to 1 hour prior to the start of surgery. For lengthy operative procedures (e.g., 2 hours or more), 500 mg to 1 gram IV or IM during surgery (administration modified depending on the duration of the operative procedure). 500 mg to 1 gram IV or IM every 6 to 8 hours for 24 hours postoperatively It is important that (1) the preoperative dose be given just (1/2 to 1 hour) prior to the start of surgery so that adequate antibiotic levels are present in the serum and tissues at the time of initial surgical incision; and (2) cefazolin for injection be administered, if necessary, at appropriate intervals during surgery to provide sufficient levels of the antibiotic at the anticipated moments of greatest exposure to infective organisms.

The rational use of antibiotics in surgery involves administering cefazolin 1 gram IV or IM 30 minutes to 1 hour prior to surgery to prevent postoperative infection.

• Key considerations for the rational use of antibiotics in surgery include:
  • Administering the preoperative dose at the correct time to ensure adequate antibiotic levels
  • Administering additional doses during lengthy operative procedures as needed
  • Continuing prophylactic administration for 3 to 5 days in high-risk surgeries, such as open-heart surgery and prosthetic arthroplasty 2
• Dosage adjustments may be necessary for patients with reduced renal function.

From the Research

Rational Use of Antibiotics in Surgery

The rational use of antibiotics in surgery is crucial to prevent surgical site infections (SSIs) and promote optimal patient outcomes. According to 3, surgical antibiotic prophylaxis (SAP) is an effective measure for preventing SSIs, and its appropriate administration is essential to counteract the introduction of bacteria into the surgical site.

Principles of Antibiotic Prophylaxis

The principles of antibiotic prophylaxis in surgery include:

• Administering prophylactic antibiotics preoperatively to achieve effective tissue concentration at the time of incision 4
• Choosing an antibiotic based on its activity against endogenous flora, toxicity, and cost 4
• Using a maximum dose of a prophylactic antibiotic preoperatively and not continuing it beyond the operative day unless there is evidence of infection 4
• Selecting antibiotics that are effective against the most common pathogens involved in SSIs 5

Timing of Prophylactic Antibiotic Administration

The timing of prophylactic antibiotic administration is a critical factor in preventing SSIs. According to 5, the administration of prophylactic antibiotics within 60 minutes prior to incision is associated with lower SSI rates. However, the study found no significant association between prophylactic antibiotic timing and SSI when adjusted for patient, procedure, and antibiotic variables.

Specific Procedures and Antibiotic Regimens

Different surgical procedures require specific antibiotic regimens to prevent SSIs. For example:

• Breast cancer surgery: Prophylactic antibiotics administered preoperatively probably reduce the incidence of SSI 6
• Orthopedic procedures: Vancomycin hydrochloride is associated with higher SSI occurrence, while cefazolin sodium and quinolone in combination with an anaerobic agent are associated with fewer SSI events 5
• Colorectal procedures: Cefazolin sodium and quinolone in combination with an anaerobic agent are associated with fewer SSI events 5

Prevention of Surgical Site Infections

Prevention of SSIs requires a bundled approach that includes:

• Appropriate use of prophylactic antibiotics 7
• Optimal surgical technique and wound care 3
• Patient education and awareness 7
• Monitoring and reporting of SSI rates 7