We studied risk factors for postoperative infections at the operative site after hysterectomies. Data were collected prospectively on all women undergoing vaginal hysterectomies (323 patients) or abdominal hysterectomies (1125 patients) at the Boston Hospital for Women between February 1976 and April 1978. Logistic-regression analysis indicated that factors significantly associated (P less than 0.05) with a higher risk of infection at the operative site were increased duration of operation, lack of antibiotic prophylaxis, younger age, being a clinic patient, and an abdominal approach. After these variables were accounted for, the variables of obesity, preoperative functional and anatomical diagnoses, postoperative anatomical and pathological diagnoses, estimated blood loss, menopausal status, and operation by a specific surgeon did not add predictive power. An increasing duration of operation was associated with a decreasing effect of antibiotic prophylaxis, the preventive fraction of which diminished from 80 per cent at one hour to an unmeasurable effect at 3.3 hours.

Risk Factors for Infection at the Operative Site after Abdominal or Vaginal Hysterectomy

Avoiding serious infections associated with abdominal hysterectomy: A meta-analysis of antibiotic prophylaxis

The use of prophylactic antibiotics in surgery is widespread and often inappropriate. The lack of well-designed clinical studies partially explains the present confusion regarding the subject. We reviewed the literature in English on antibiotic prophylaxis through June 1982. Antibiotic prophylaxis reduces the incidence of wound infection after colorectal surgery, vaginal hysterectomy, and laryngeal and oropharyngeal resection for carcinoma, and in high-risk patients undergoing gastroduodenal or biliary surgery. In clean operations such as cardiac surgery, vascular procedures, and orthopedic surgery with placement of prostheses, the high morbidity associated with an infection justifies the use of antibiotics even though the risk of infection is small. There are conflicting data on the usefulness of prophylaxis in abdominal hysterectomy, cesarean section, noncardiac thoracic procedures, and urologic surgery. The effectiveness of prophylaxis in neurosurgery cannot be evaluated at the present time.

Antibiotic prophylaxis in surgical procedures. A critical analysis of the literature.

Surgical infections are almost always polymicrobial, yet the critical importance of bacterial mixtures in these infections has received relatively little attention. The convincing data on the prevalence of mixed infections in surgery are reviewed. Both clinical and experimental evidence indicate that true synergy between certain aerobes and anaerobes may exist. Of the possible mechanisms of synergy, the most important seems to be the ability of anaerobes, their metabolic products, or their capsules to inhibit phagocytosis of aerobes by leukocytes. Other mechanisms of importance in special microbial combinations include provision of essential nutrients such as vitamin K, succinate, and various growth factors by one microbe to the other; alteration of local environment, including reduction of the oxygen tension and lowering of redox potential; and the provision of substances toxic to the host that permit species of bacteria to flourish concurrently. Further study of these interactions will shed light on the causes and correction of treatment failure.

Mechanisms of microbial synergy in polymicrobial surgical infections.

The Lancet: RANDOMISED CLINICAL TRIAL OF PERIOPERATIVE CEFAZOLIN IN PREVENTING INFECTION AFTER HYSTERECTOMY

The efficacy of a three-dose, perioperative regimen of cefazolin or placebo in reducing postoperative infectious morbidity was evaluated in a double-blind study in 206 patients undergoing elective vaginal or abdominal hysterectomy. Postoperative infectious morbidity was defined as: an oral temperature of 100.4 F (38 C) or greater on any two postoperative days (excluding the first day), positive bacteriologic cultures, or pus from a wound. In premenopausal patients, cefazolin significantly reduced the incidence of postoperative infectious morbidity; 19% of the cefazolin group who had abdominal hysterectomy had evidence of infection compared to 71% of the placebo group, and 10% of the cefazolin group who had vaginal hysterectomies had evidence of infection compared to 37% of the placebo group. In postmenopausal patients undergoing abdominal hysterectomy, cefazolin also reduced the incidence of postoperative infection compared to placebo, but the difference was not significant (20% compared to 37%).

John Thompson

Papers

Perioperative antibiotics in major elective gynecologic surgery.