Principle V: Use Shortest Antibiotic Exposure That Is Effective
For the antibiotic prophylaxis to be effective, the antibiotic must be given before the surgery begins, and adequate plasma levels must be maintained during the surgical procedure. Once the surgical procedure is completed, continued antibiotic administration produces no benefit. Therefore the final dose of the antibiotic is usually given after the surgical operation. If the procedure is a short operation, a single preoperative dose of antibiotics is adequate: If the surgery lasts for 1 to 2 hours, the surgeon should give a second dose of antibiotics before the patient leaves the office. A plethora of animal and human clinical data demonstrates that the use of prophylactic antibiotics is necessary only for the time of surgery; after closure of the wounds-and formation of the blood clots, migration of bacteria into the
wound and underlying tissues occurs at such a low level that additional antibiotics are not necessary.
Factors Necessary for Metastatic Infection,
.Distant susceptible site
• Hematogenous bacterial seeding
• Impaired local defenses