[Thyroidectomies: surgical site infection risk factors of using prophylactic antibiotics].

BACKGROUND: Surgical site infection is one of the most common types of nosocomial infection and an important factor in increased mortality and medical costs. The effectiveness of prophylactic antibiotics use on thyroidectomy wound sites merits further examination. PURPOSE: This study compared the influence of prophylactic antibiotics use or non-use on surgical site infection risk, average hospital stay length and average medical costs in thyroidectomy patients. METHODS: This cross-sectional study targeted patients undergoing thyroidectomies at the general surgery ward of a medical center during the period 2007 to 2008. Subjects were divided into two groups. The first comprised patients who received prophylactic antibiotics thirty minutes before receiving a thyroidectomy between January 1, 2007 and October 31, 2007. A retrospective review of patient charts and reports was conducted for this group. The second consisted of patients that did not receive prophylactic antibiotics 30 minutes before receiving a thyroidectomy between November 1, 2007 and October 31, 2008 in line with a new antibiotics policy enforced at the research hospital. RESULTS: A total of 310 subjects were enrolled in the study. All subjects were free of surgical site infection. Fifteen patients (4.8%) received a course in antibiotics after surgery and six (40.0%) of these showed surgical site swelling (x² = 120.33; p < .01). Statistically significant risk factors of post-surgery antibiotics use included diabetes mellitus (x² = 6.39; p = .03), a surgery duration in excess of 2 hours (x² = 4.40; p = .04), drainage tube remaining in place at the surgical site (x² = 4.58; p = .03) and drainage tube insertion for more than 2 days (x² = 6.24; p = .03). Significant reductions in average hospital stay length (3.65 days ± 1.04; p < .01) and medical costs (p < .01) were observed when prophylactic antibiotics were not used before surgery. The cost of post-operative antibiotics increased by $5,851 and medical costs increased from $32,436 to $63,895 when hospital stay length exceeded four days. If hospital stay length was kept within four days and post-operative antibiotics were used, this study found no significant difference in drug or medical costs. CONCLUSION: Not using prophylactic antibiotics before thyroidectomy does not increase surgical site infection risk.