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Antibiotic Prophylaxis of Infection

Selection diac, vascular, or orthopedic patients who receive prostheses.

_ , ,,, , Catheters for dialysis or nutrition, pacemakers, and shunts of vari-Spectrum. The antibiotic chosen should be active against the most t ' ■ , t. ( t . ■ , , ... r ^ , m , ous sorts are prone to infection mostly for technical reasons, and pro-likely pathogens. Single-agent therapy is almost always effective ex- , , . . . ,, ■ . .. i , ■ ■ ,. u 4 , L, L- ,,, , , phylaxis is not usually required. Meta-analysis indicates, however, that cept in colorectal operations small-bowel procedures with sstesis antimicrobial prophylaxis reduces the infection rate in CSF shunts by emergency abdominal operations in the presence of polymicrobial flo, . , 50%.109 Beneficial results may also be achievable for other perma-

ra, and i penetrating trauma; in such cases, a combinati°n of antibiotics nently implanted shunts (e.g.,peritoneovenous) and device^ (e.g., is usually useed te^use anaera^ co^ra^ Is reared long-term venous access catheters and pacemakers); however, the Pharmacokinetics. The half-life of the antibiotic selected must be long . Z. , ,. ... , T. ... , , , studies needed to confirm this possibility will never be done, because enough to maintain adequate tissue levels throughout the operation. the infection rates are low and the sample sizes would have to be proAdministration . hibitively large. The placement of such foreign bodies is a clean oper, , ation, and the use of antibiotics should be based on local experience.

Dosage, route, and timing. A single preoperative dose that is of the same strength as a full therapeutic dose is adequate in most instanc- clean-contaminated cases es. The single dose should be given I.V. immediately before skin inci- , , , ■,■ , , ,

. , . . ... ... a,u .. . . . „ i rr . Abdominal procedures. In biliary tract procedures (open or laparo-sion. Administration by the anesthetist is most effective and efficient. . . , , ■ ■ , , , L, ■ , ■ , L,

, , . i -r .i i ,,, .. scopic), prophylaxis is required only for patients at high risk: those Duration. A second dose is warranted if the duration of the operation , , 1n i * , , , „ f

, .m ou 4 ■ iU . u ... .■ r , whose common bile duct is likely to be explored (because of laundice, exceeds either 3 hours or twice the half-life of the antibiotic. No addi- , -J , , L L, . . ,. ... , , . , , bile duct obstruction, stones in the common bile duct, or a reoperative tional benefit has been demonstrated in continuing prophylaxis beyond biliary procedure); those with acute cholecystitis; and those older than the day of the operation, and mounting data suggest that the preopera- __ . . , , ... . ' . '. , . . ... .

, ■ ,, ■ ..f u u j,. 70 years. A single dose of cefazolin is adequate. In hepatobiliary and tive dose is sufficient. When massive hemorrhage has occurred (i.e., ' a . L., . L. , , ■ ■ , /,, pancreatic procedures, antibiotic prophylaxis is always warranted be-

blood loss equal to or greater than blood volume), a second dose is cause these operations are clean-contaminated, because they are long, warranted. Even in emergency or trauma cases, prolonged courses of . ^ ,,

.. .. ^ , .. 771f1„ because they are abdominal, or for all of these reasons. Prophylaxis is antibiotics are not lustified unless they are therapeutic.'',108 . / .. ., ..' . . . , '

also warranted for therapeutic endoscopic retrograde cholangiopancre-

Indications atography. In gastroduodenal procedures, patients whose gastric acidity is normal or high and in whom bleeding, cancer, gastric ulcer, and obstruction are absent are at low risk for infection and require no Prophylactic antibiotics are not indicated in clean operations if the prophylaxis; all other patients are at high risk and require prophylaxis. patient has no host risk factors or if the operation does not involve Patients undergoing operation for morbid obesity should receive double placement of prosthetic materials. Open heart operation and opera- the usual prophylactic dose110; cefazolin is an effective agent. tions involving the aorta of the vessels in the groin require prophylaxis. Operations on the head and neck (including the esophagus). Pa-

Patients in whom host factors suggest the need for prophylaxis in- tients whose operation is of significance (i.e., involve entry into the oral clude those who have more than three concomitant diagnoses, those cavity, the pharynx, or the esophagus) require prophylaxis. whose operations are expected to last longer than 2 hours, and those Gynecologic procedures. Patients whose operation is either high-whose operations are abdominal.6 A patient who meets any two of risk cesarean section, abortion, or vaginal or abdominal hysterectomy these criteria is highly likely to benefit from prophylaxis. When host fac- will benefit from cefazolin. Aqueous penicillin G or doxycycline may be tors suggest that the probability of a surgical site infection is signifi- preferable for first-trimester abortions in patients with a history of pelvic cant, administration of cefazolin at induction of anesthesia is appropri- inflammatory disease. In patients with cephalosporin allergy, doxycy-ate prophylaxis. Vancomycin should be substituted in patients who are cline is effective for those having hysterectomies and metronidazole for allergic to cephalosporins or who are susceptible to major immediate those having cesarean sections. Women delivering by cesarean sec-hypersensitivity reactions to penicillin. tion should be given the antibiotic immediately after cord clamping.

When certain prostheses (e.g., heart valves, vascular grafts, and Urologic procedures. In principle, antibiotics are not required in pa-orthopedic hardware) are used, prophylaxis is justified when viewed tients with sterile urine. Patients with positive cultures should be treat-in the light of the cost of a surgical site infection to the patient's health. ed. If an operative procedure is performed, a single dose of the appro-Prophylaxis with either cefazolin or vancomycin is appropriate for car- priate antibiotic will suffice.

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