Tactical basics and drug selection
Preventing endogenous infection of surgical wounds requires a clear strategy. The main tactic in this case is perioperative antibiotic prophylaxis and therapy.
The key tool is the administration of antibacterial drugs (primarily antibiotics). It is important to note that specifically antibacterial agents are used to achieve this specific goal, whereas antifungal, antiviral, and antiprotozoal drugs are not included in the baseline regimen for preventing bacterial endogenous infection.
Dosing regimen
To ensure maximum patient protection, antibacterial therapy must be strictly synchronized with the surgical intervention. There are three mandatory stages of drug administration:
- Immediately before surgery — establishing an initial pool of the drug in the body.
- During surgery — ensuring protection at the moment of highest risk for bacteria entering the tissues.
- After surgery — consolidating the result and preventing delayed infectious complications.
Goals and pathogenetic rationale
The use of antibiotics in the perioperative period pursues three specific goals:
- Exercising a direct effect on the focus of infection.
- Maintaining a bactericidal concentration of the drug in the patient's blood throughout the entire intervention.
- Rapid and effective destruction of microbes that have already managed to penetrate the bloodstream from the inflammatory focus.
The pathogenetic rationale for this tactic is extremely logical: this approach ensures reliable blocking of the hematogenous pathway of infection, preventing bacteria from spreading through the body via the bloodstream.
Prevention of contact infection
In addition to hematogenous spread, there is a risk of direct tissue contamination. The indication for preventing contact infection is the presence of a focus of chronic infection directly in the area of the ongoing surgical intervention.
In such situations, the surgical team is required to take strict actions: implementing mandatory, regulated measures to prevent contact infection of surrounding healthy tissues directly during the surgery.
Briefly: answers to topical questions
How long before the skin incision must the first dose of antibiotic be administered for adequate prophylaxis?
The first dose of antibiotic should standardly be administered intravenously 30 to 60 minutes before the skin incision. An exception is vancomycin, the infusion of which should be started 2 hours before the incision. This timing ensures that an effective bactericidal concentration of the drug is achieved in tissues and blood serum strictly at the time of the skin incision.
Under what conditions is re-administration of the antibiotic dose required directly during surgery?
Intraoperative re-administration of the antibiotic dose is required during prolonged surgery and massive blood loss. An additional dose is indicated if the duration of surgery exceeds 3 hours, in case of massive blood loss, and also if the time elapsed since the first administration corresponds approximately to two half-lives of the drug. With blood loss exceeding 1500 ml, repeated administration of a systemic antibiotic is recommended.
What is the recommended maximum duration of antibiotic administration after elective surgery is completed?
In most cases, antibiotic prophylaxis is limited to a single preoperative dose, and its duration should not exceed 24 hours after the end of surgery. Extending prophylaxis after wound closure is usually inexpedient and does not increase its effectiveness; it increases the risk of selecting antibiotic-resistant strains and C. difficile-associated diarrhea. The source also indicates that in cases of high risk of complications, extending prophylaxis for 24–48 hours after surgery is permissible.
Which classes of antibiotics are the drugs of choice for perioperative prophylaxis in abdominal surgery?
The sources for abdominal surgery indicate regimens with cephalosporins and metronidazole: for mild acute appendicitis — metronidazole combined with 1st–2nd generation cephalosporins; for operations on the colon and rectum — cefuroxime or ceftriaxone combined with metronidazole.
Into what classes are surgical wounds divided according to the degree of microbial contamination to determine the prophylaxis strategy?
Surgical wounds are divided into four classes depending on the degree of microbial contamination:
- "Clean" wounds — prophylaxis is not required, except for cases involving the placement of orthopedic implants and metal hardware.
- Clean-contaminated wounds — antibiotic prophylaxis is indicated.
- Contaminated wounds — antibiotic prophylaxis is indicated.
- Infected ("dirty") wounds — prophylaxis is not indicated, as full therapeutic antibiotic therapy is required in this case.
What specific actions of the surgical team relate to measures for preventing contact tissue infection from a focus?
Measures to prevent contact tissue infection during surgery include: isolating wound edges with towels or drapes; exteriorizing the affected organ from the wound or thoroughly packing it with sponges deep within the wound; after placing the first row of sutures, mandatory replacement of the surrounding drapes and instruments, as well as treating or changing gloves.
The rule of three stages of prophylaxis: "BEFORE — DURING — AFTER". The antibiotic must protect the patient before the incision, during surgical manipulations, and after the completion of the intervention.
Class and exam questions
Which drug classes are used for perioperative prophylaxis?
Only antibacterial drugs (antibiotics) are used. Antiviral, antifungal, and antiprotozoal agents are not used for this purpose.
What is the pathogenetic rationale of antibiotic prophylaxis?
The main mechanism is maintaining a bactericidal concentration in the blood, which ensures reliable blocking of the hematogenous pathway of wound infection.
When does the need for contact infection prophylaxis arise?
Such a necessity (indication) arises if a focus of chronic infection is located directly in the area of the surgical intervention.
What else to study on this topic
- Specifics of maintaining a bactericidal concentration of the antibiotic in the blood
- Technical measures to prevent contact infection during surgery
- Mechanisms of microbial penetration into the bloodstream from the inflammatory focus
- Differences in tactics when a focus of chronic infection is present in the surgical area
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