Clean technique for prolonged nonsurvival cardiothoracic surgery in swine (Sus scrofa)

Laboratory animal regulations provide little guidance regarding duration of nonsurvival surgery requiring aseptic technique. We hypothesized that swine would experience no sepsis during nonsurvival cardiothoracic surgery accomplished by using clean technique and lasting 8 h or less. Incision sites of 5 male farm pigs (Sus scrofa) were shaved and then cleaned with alcohol and povidone-iodine. The surgeon wore sterile gloves, clean scrubs, and hair bonnet; assistants wore clean scrubs and nonsterile gloves; most instruments were autoclaved. A median sternotomy incision was used for thoracic cavity exposure, and the skull was exposed to allow induction of brain death. Heart rate, body temperature, and blood samples were obtained before surgery (0 h; baseline) and at 2, 4, 5 or 6, and 7 or 8 h thereafter. Statistical analysis by t-tests showed that heart rate was unchanged and body temperature increased after the 0-h (baseline) time point. Aerobic blood cultures were negative except for 2 samples that were positive for coagulase-negative Staphylococcus spp. at 4 h. RBC, Hgb, and Hct levels were decreased at 2 and 4 h, but WBC and platelets were unchanged. Other alterations included decreased glucose (at 7 or 8 h), increased BUN (at 5 or 6 h and 7 or 8 h) and creatinine (at 5 or 6 h), decreased Na(+) and Ca and increased K(+) (most time points), decreased total protein and albumin (most time points), and decreased globulin (at 7 or 8 h). Liver enzymes and bilirubin typically were unchanged, and cholesterol consistently was decreased. Together our results indicate a lack of sepsis for 8 h or less in pigs undergoing cardiothoracic surgery by using clean technique. These findings provide new and specific data regarding the use of aseptic technique during prolonged nonsurvival surgeries.