Podcast
Questions and Answers
What is the primary purpose of prophylactic antibiotics in surgery?
What is the primary purpose of prophylactic antibiotics in surgery?
Which ASA score indicates a patient is at an increased risk of wound infection?
Which ASA score indicates a patient is at an increased risk of wound infection?
Which class of surgical wounds has the highest risk of postoperative infection?
Which class of surgical wounds has the highest risk of postoperative infection?
What is the recommended timing for administering prophylactic antibiotics before surgical incision?
What is the recommended timing for administering prophylactic antibiotics before surgical incision?
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Which factor is NOT considered a risk factor for surgical site infections?
Which factor is NOT considered a risk factor for surgical site infections?
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What type of therapy is utilized when contamination has already occurred during surgery?
What type of therapy is utilized when contamination has already occurred during surgery?
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What is the recommended approach for postoperative doses of antibiotics?
What is the recommended approach for postoperative doses of antibiotics?
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Which type of surgical wound is classified as having no break in aseptic technique?
Which type of surgical wound is classified as having no break in aseptic technique?
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Which pathogen is most likely associated with surgical site infections?
Which pathogen is most likely associated with surgical site infections?
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What is the recommendation for additional intra-operative antibiotic dosing?
What is the recommendation for additional intra-operative antibiotic dosing?
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What has been established about the duration of antimicrobial regimens for cesarean sections?
What has been established about the duration of antimicrobial regimens for cesarean sections?
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What is the recommended dosing of cefazolin for patients undergoing cardiac procedures?
What is the recommended dosing of cefazolin for patients undergoing cardiac procedures?
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Which alternative agent is advised for patients with a beta-lactam allergy undergoing a thoracic procedure?
Which alternative agent is advised for patients with a beta-lactam allergy undergoing a thoracic procedure?
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What considerations should be taken for patients colonized with methicillin-resistant Staphylococcus aureus?
What considerations should be taken for patients colonized with methicillin-resistant Staphylococcus aureus?
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What is the recommended treatment duration for using cefuroxime in thoracic procedures?
What is the recommended treatment duration for using cefuroxime in thoracic procedures?
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Which factor determines the dosing adjustment for cefazolin in patients?
Which factor determines the dosing adjustment for cefazolin in patients?
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For patients undergoing device insertion procedures, what is the primary recommended agent?
For patients undergoing device insertion procedures, what is the primary recommended agent?
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What is one characteristic of first-generation cephalosporins regarding their use in thoracic prophylaxis?
What is one characteristic of first-generation cephalosporins regarding their use in thoracic prophylaxis?
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What criterion is critical for applying a preoperative dose of vancomycin?
What criterion is critical for applying a preoperative dose of vancomycin?
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What is the advised dosing for vancomycin when used in areas with high prevalence of resistant bacteria?
What is the advised dosing for vancomycin when used in areas with high prevalence of resistant bacteria?
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What is the recommended vancomycin administration rate for a patient weighing less than or equal to 80kg?
What is the recommended vancomycin administration rate for a patient weighing less than or equal to 80kg?
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For patients with beta-lactam allergy undergoing appendectomy, what alternative agent is NOT recommended?
For patients with beta-lactam allergy undergoing appendectomy, what alternative agent is NOT recommended?
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Which of the following is a common characteristic to identify a 'high-risk' patient for MRSA?
Which of the following is a common characteristic to identify a 'high-risk' patient for MRSA?
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What is the recommended dosing for Cefazolin during a clean surgical procedure with prosthesis implantation?
What is the recommended dosing for Cefazolin during a clean surgical procedure with prosthesis implantation?
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What is the correct alternative agent for gastroduodenal surgery in a patient with a beta-lactam allergy?
What is the correct alternative agent for gastroduodenal surgery in a patient with a beta-lactam allergy?
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Which antibiotic regimen is indicated for colorectal surgery where infection risk is moderate?
Which antibiotic regimen is indicated for colorectal surgery where infection risk is moderate?
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In what scenario is the administration of fluconazole 400 mg particularly recommended?
In what scenario is the administration of fluconazole 400 mg particularly recommended?
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What is the recommended action for patients undergoing neurosurgery who have a beta-lactam allergy?
What is the recommended action for patients undergoing neurosurgery who have a beta-lactam allergy?
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What is the duration of Cefazolin administration for cardiothoracic procedures?
What is the duration of Cefazolin administration for cardiothoracic procedures?
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For which surgical procedure is the use of Clindamycin 900 mg definitely indicated?
For which surgical procedure is the use of Clindamycin 900 mg definitely indicated?
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Study Notes
Antimicrobial Prophylaxis in Surgery
- Antimicrobial prophylaxis aims to reduce postoperative wound infections.
- Surgical site infections (SSIs) are infections related to incisions occurring within 30 days of surgery, or within 90 days if a prosthetic implant is involved.
- SSIs occur when a pathogenic organism multiplies in a surgical wound.
- SSIs can lead to local and sometimes systemic signs and symptoms.
- SSIs are associated with increased morbidity and extended duration of hospitalizations.
- Prophylactic antibiotics reduce SSI prevalence at the surgical site.
- Antibiotic prophylaxis involves pre-operative or intra-operative antibiotic administration to reduce post-operative infection risk.
Objectives
- The impact of surgical site infections (SSIs)
- Wound classification types
- Risk factors for postoperative surgical site infections
- Pathogens associated with different surgical operations
- Antimicrobial prophylaxis itself
- Importance of timing, duration, and re-dosing of antibiotics
- Recommendation of appropriate prophylactic antibiotics for a given surgical operation
Introduction
- Clinical use of antibiotics:
- Prophylactic therapy: Given before contamination/infection.
- Anticipatory therapy: Given when contamination has already occurred to minimize post-operative infections.
- Empiric therapy: Non-directed therapy in the absence of pathogen identification.
- Directed therapy: Therapy after pathogen identification.
Surgical Site Infection (SSI)
- Defined as infection related to incision
- Occurs within 30 days of operative procedure or within 90 days if prosthetic material implanted.
- Pathogenic organism multiplies in a surgical wound, leading to local and sometimes systemic signs and symptoms.
- Increased morbidity and extended duration of hospitalizations are associated with SSIs.
By Definition
- SSI must occur within 30 days of surgery.
- If a prosthetic implant is involved, deep incisional or organ/space SSI can be reported up to 1 year from the surgery date.
Pathogenesis of SSI
-
Endogenous:
- Patient flora
- Skin
- GI tract
- Mucous membranes (seeding from pre-existing infection sites)
-
Exogenous:
- Surgical personnel flora
- Breaks in aseptic techniques
- Inadequate hand hygiene
- Equipment, surgical tools, materials within operative field
- OR environment (ventilation)
SSI Pathogens
- Staphylococcus aureus (20-30%)
- Coagulase-negative staphylococci (13.7%)
- Enterococcus spp (11.2%)
- Escherichia coli (8-9.6%)
- Pseudomonas aeruginosa (5.6-8%)
- Enterobacter spp (4.2-7%)
- Klebsiella pneumoniae (3.0%)
- Candida spp (2.0%)
- Klebsiella oxytoca (0.7%)
- Acinetobacter baumannii (0.6%)
Risk Factors for SSI
- Patient characteristics:
- Extremes of age
- Obesity
- Tobacco use
- Malnutrition
- Prolonged postoperative stay
- Comorbid states
- Diabetes
- Remote infection
- Ischemia
- Colonization with microorganisms
- Immunosuppressive therapy
- Operation characteristics:
- Length of surgical scrub
- Skin antisepsis
- Preoperative shaving
- Preoperative skin preparation
- Length of operation
- Inadequate instrument sterilization
- Foreign material in surgical site
- Surgical technique
- Surgical wound class
- ASA score
- Unexpected contamination
- Operating room ventilation
American Society of Anesthesiologists (ASA)
- Devised a preoperative risk score based on the presence of co-morbidities at the time of surgery.
- ASA score ≥ 2 is associated with increased risk of wound infection.
Wound Class
- Operations categorized into four classes:
- Clean
- Clean contaminated
- Contaminated
- Dirty
- Increasing incidence of bacterial contamination correlates to increasing postoperative infection rates.
Clean
- Uninfected operative wound with no inflammation.
- No entry into respiratory, alimentary, genital or urinary tracts.
- No break in aseptic technique.
- Wounds primarily closed following non-penetrating trauma.
- Infection Rate > 5%
Clean-Contaminated
- Operation with controlled opening of respiratory, alimentary, genital or urinary tracts.
- No evidence of infection, no major breaks in technique, no unusual contamination.
- Operation involving biliary tract, appendix, vagina, and/or oropharynx.
- Infection Rate > 10%
Contaminated
- Penetrating trauma or operation following open, fresh, accidental wounds.
- Operation with major breaks in sterile technique.
- Includes operations where acute, non-purulent inflammation is encountered.
- Infection Rate: 15-20%
Dirty
- Definition suggests organisms causing post-operative infection were present before the operation.
- Operation involving old traumatic wounds with retained devitalized tissue, or existing clinical infection, or perforated viscera.
- Obvious pre-existing infection present (abscess or necrotic tissue).
- Infection Rate: 30-40%
Recommendations for Surgical Prophylaxis
- Clean surgeries involving prosthetic material implantation.
- Clean-contaminated surgeries.
- Selected contaminated wounds.
- Dirty: Prophylaxis not indicated, antibiotics used for treatment.
Antibiotic Prophylaxis Goals
- Prevent infection & related morbidity/mortality.
- Reduce duration and healthcare costs.
- Minimize adverse effects on patient & hospital flora.
- Augment host defense mechanisms at the time of bacterial invasion (decrease inoculum size).
- Adjunct to good surgical technique, not a substitute.
Benefits & Risks
- Benefits: Decreased incidence of infection, lower costs, shorter hospital stays.
- Risks: Toxic reactions, allergic reactions, drug interactions, emergence of resistant bacteria, super-infection.
Principles of Surgical Antimicrobial Prophylaxis
- Principle 1: Use antibiotic when infection risk is high or sequelae is significant.
- Principle 2: Select the appropriate antibiotic effective against anticipated pathogens.
- Principle 3: Don't start too early or too late, administer when tissue levels will peak during the incision.
- Principle 4: Intravenous administration is preferred, effective dose based on patient weight.
- Principle 5: Additional intra-operative doses only necessary in long procedures or high blood loss cases.
- Principle 6: Keep post-operative doses minimal.
Prophylactic Antibiotics
- Most effective when administered within 1 hour before surgical incision.
- Should be administered ≤30 minutes pre-operatively for all surgical categories except cesarean section.
- Rates of infection increase significantly if antibiotics administered more than 1 hour before incision or postoperatively.
- Vancomycin and fluoroquinolones: administer first dose within 120 minutes of surgical incision (due to prolonged infusion times).
Summary
- Duration of surgical procedure and antibiotic half-life should be considered.
- Longer procedures may require additional intra-operative doses.
- Cefazolin 2 g (30 mg/kg in children and 3 g in adults ≥120 kg as single IV dose within 60 minutes prior to incision) is generally preferred regimen in surgical prophylaxis.
- Use Clindamycin or Vancomycin if patient has β-lactam allergy.
Summary of Specific cases
- Cardiothoracic: Cefazolin 2 g IV every 8 hours or Cefuroxime 1.5 g IV every 12 hours for a total of 48 hours.
Important Notes
- For patients with MRSA colonization, additional vancomycin dose is reasonable.
- Defined MRSA risk: History of MRSA colonization and infection or a high risk hospital patient for more than 5 days.
- Vancomycin administration: Give 1 g IV (1.5 g for patients >80 kg) 30-120 minutes before surgical incision and at 1g/hour (1.5g in 90 minutes).
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Description
This quiz covers the essential aspects of antimicrobial prophylaxis in surgery. It addresses the significance of preventing surgical site infections (SSIs), risk factors, and pathogens involved in these infections. Additionally, the quiz discusses the appropriate timing and administration of prophylactic antibiotics to minimize postoperative infections.
