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Surgical prophylaxis involves administering antibiotics after contamination of sterile tissues.
Surgical prophylaxis involves administering antibiotics after contamination of sterile tissues.
False
The predominant organisms causing surgical site infections after clean procedures are primarily gram-negative rods and enterococci.
The predominant organisms causing surgical site infections after clean procedures are primarily gram-negative rods and enterococci.
False
First-generation cephalosporins are the preferred choice for prophylaxis in clean surgical procedures.
First-generation cephalosporins are the preferred choice for prophylaxis in clean surgical procedures.
True
Dirty operations are classified as those that involve existing infection and are treated with prophylactic antimicrobials.
Dirty operations are classified as those that involve existing infection and are treated with prophylactic antimicrobials.
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Vancomycin can be used for surgical prophylaxis when the risk of MRSA is high.
Vancomycin can be used for surgical prophylaxis when the risk of MRSA is high.
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Intravenous administration is preferred over intramuscular administration for antimicrobial prophylaxis due to its more reliable serum concentration.
Intravenous administration is preferred over intramuscular administration for antimicrobial prophylaxis due to its more reliable serum concentration.
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Oral administration is sufficient as a standalone treatment for antimicrobial prophylaxis in bowel operations.
Oral administration is sufficient as a standalone treatment for antimicrobial prophylaxis in bowel operations.
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Antimicrobials for surgical prophylaxis should be infused at least 60 minutes before the first incision to prevent surgical site infections.
Antimicrobials for surgical prophylaxis should be infused at least 60 minutes before the first incision to prevent surgical site infections.
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Fluoroquinolones and vancomycin can be infused as much as 120 minutes prior to surgery to avoid infusion-related reactions.
Fluoroquinolones and vancomycin can be infused as much as 120 minutes prior to surgery to avoid infusion-related reactions.
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If an operation lasts longer than two half-lives of the antimicrobial, an additional dose is not necessary.
If an operation lasts longer than two half-lives of the antimicrobial, an additional dose is not necessary.
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Cefazolin has a half-life of about 2 hours, requiring a repeat dose if the operation lasts more than 4 hours.
Cefazolin has a half-life of about 2 hours, requiring a repeat dose if the operation lasts more than 4 hours.
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Antimicrobial prophylaxis should continue beyond wound closure to reduce infection rates.
Antimicrobial prophylaxis should continue beyond wound closure to reduce infection rates.
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For cardiac surgery, the duration of antimicrobial prophylaxis can be extended up to 48 hours.
For cardiac surgery, the duration of antimicrobial prophylaxis can be extended up to 48 hours.
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Administering antibiotics until all drains are removed is a common practice supported by substantial evidence.
Administering antibiotics until all drains are removed is a common practice supported by substantial evidence.
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Administering antibiotics post-surgery has been proven to consistently lower infection rates.
Administering antibiotics post-surgery has been proven to consistently lower infection rates.
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Study Notes
Surgical Prophylaxis
- Antibiotics are administered before contamination of previously sterile tissues or fluids to prevent infection. The goal is to prevent infections from developing.
- Common surgical pathogens after clean procedures include skin flora like S. Aureus and coagulase-negative staphylococci (e.g., Staphylococcus epidermidis).
- In clean-contaminated procedures (e.g., abdominal, heart, kidney, and liver transplantations), the predominant organisms are gram-negative rods and enterococci, in addition to skin flora.
Antimicrobial Selection
- The choice of prophylactic antimicrobial depends on the type of procedure, pathogen likelihood, safety, efficacy, current evidence, and cost.
- Gram-positive coverage is usually included in the choices for surgical prophylaxis because organisms like S. aureus and S. epidermidis are common skin flora.
- Parenteral antibiotic administration is preferred for reliable and substantial tissue concentrations.
- First-generation cephalosporins (particularly cefazolin) are preferred for clean surgical procedures.
- Cefoxitin or cefotetan are used when broad-spectrum anaerobic and gram-negative coverage is needed.
- Vancomycin may be considered for procedures with high MRSA risk if a B-lactam allergy exists. Clindamycin can be substituted for cefazolin to limit vancomycin use, if the MRSA risk is low.
Types of Surgical Operations & Wound Classification
- Surgical operations are classified as clean, clean-contaminated, contaminated, or dirty based on risk of infection.
- In clean operations, no inflammation, and the respiratory, alimentary, genital or uninfected urinary tracts aren't entered.
- Clean-contaminated operations involve entering the respiratory, alimentary, genital, or urinary tracts under controlled conditions without unusual contamination (e.g., biliary tract, appendix, vagina, oropharynx). Clean procedures performed emergently or with a major technique are also considered.
- Contaminated involves open, fresh, accidental wounds, surgical procedures with broken sterile techniques (e.g., open cardiac massage, or gastrointestinal tract spillage) or incisions with acute non-purulent inflammation.
- Dirty operations involve preexisting infections (e.g., abscess, pus, or necrotic tissue).
Principles of Antimicrobial Prophylaxis
- Intravenous (IV) administration of antibiotics provides more reliable serum and tissue concentrations compared to intramuscular.
- Oral administration can be used in some bowel operations, but it's typically supplemental rather than a replacement for IV. Nonabsorbable oral antibiotics (e.g., erythromycin or neomycin), given 24 hours before surgery, can help reduce bowel microbes.
Timing of First Dose
- Administration timing is crucial to maintaining therapeutic levels of antibiotics in the blood and tissues during surgery.
- Antibiotics should be infused within 60 minutes of the first incision.
- Exceptions include fluoroquinolones and vancomycin, where administration 120 minutes prior to the procedure can avoid infusion-related reactions.
Dosing and Redosing
- Maintaining antibiotic concentrations above the Minimum Inhibitory Concentration (MIC) of the suspected organisms for the whole operation is the goal.
- If an operation exceeds the antimicrobial's two half-lives, another dose is required to maintain effective concentrations. For example, cefazolin's half-life is approximately 2 hours. Prolonged operations, therefore, necessitate additional doses.
Duration
- The continuation of prophylaxis beyond wound closure is generally unnecessary.
- The standard duration should not exceed 24 hours, except for cardiac surgery, which may extend prophylaxis up to 48 hours.
- Giving antibiotics until drains are removed is not supported by evidence. Prolonged antimicrobial administration can encourage resistance and increase cost. Longer durations are not universally recommended.
Combination Antimicrobial Therapy
- Combinations of antibiotics are often used to widen the spectrum of coverage, achieve synergistic action against organisms and prevent resistance.
- Mixed infections (e.g., intra-abdominal and female pelvic infections) require broader coverage.
Thromboprophylaxis
- Deep vein thrombosis (DVT) occurs more often in surgical patients above 40. Postoperative platelet increase and venous trauma contribute. Patients without prophylaxis have a 30% chance of developing DVT and 0.1-0.2% risk of pulmonary embolism (PTE).
- Thromboprophylaxis includes mechanical devices (e.g., TED stockings) and drugs impacting the clotting cascade (e.g., heparin, low-molecular-weight heparin).
Regimen
- National protocols require assessment of all surgical patients for DVT risk factors upon admission.
- Risk factors include procedure duration, immobility, age, malignancies, inflammatory conditions, dehydration, obesity, diabetes, heart or respiratory issues, oral contraceptives, hormone therapy, and family history of blood clots.
- Risks of blood clots must be balanced against possible bleeding risks or other complications from prophylaxis.
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Description
Test your knowledge on surgical prophylaxis and antimicrobial selection with this quiz. Explore various aspects including the types of procedures, common pathogens, and considerations for antibiotic choice. Ensure you're well-versed in preventing infections during surgery.
