Surgical Site Infection (SSI) is one of the most serious post-operative complications and therefore its prevention is extremely important. SSI risk factors were evaluated in 337 cardiac valvular surgical cases without concomitant CABG or the thoracic great vessels interventions which had been performed in our center between January 2008 and December 2010. The Center for Disease Control and Prevention definition of SSI was used for case determination. The SSI incidence was 4.7% (16 cases). Univariate analysis found statistical significance in history of cardiac surgery, LVEF, surgical procedures, operative time and morning glucose level on post-operative days (POD) 1 and 2. POD 1 morning glucose level higher than 150 mg/dl (odds ratio 4.2 ; 95% confidence interval 1.3-13.7) and operative time (odds ratio 2.0 ; 95% CI 1.2-3.5) were identified as independent factors by multiple logistic regression. According to SSI rate comparison by glucose-level, the incidence was higher when POD 2 morning glucose level exceeded 150 mg/dl as in the case of POD 1 (p<0.02). Longer operative time represented higher SSI rates in interquartile range-based comparison. This study suggested values of reducing surgical time and controlling POD 1 morning glucose level within 150 mg/dl.

Postoperative infections should be comprehensively controlled in the context of infection control, rather than as activities of individual surgeons. We started a surgical site infection (SSI) surveillance program in 2009 in which prophylactic measures for preventing SSIs were applied. These measures were as follows : 1) screening for nasal carriage of methicillin-resistant Staphylococcus aureus ; 2) dental checks and oral screening ; 3) antibiotic prophylaxis in the intra- and postoperative period ; 4) control of glucose levels to ≤160 mg/dl in the immediate postoperative period ; and 5) early removal of surgical drain. After the introduction of prophylactic measures, we reexamined SSI surveillance and added the following prophylactic measures at the beginning of 2011 : 6) data concerning SSI and compliance with prophylactic measures for all surgical and ward staff were published monthly, and the Infection Control Team (ICT) and surgeons performed weekly ward visits to assess SSIs ; 7) recommendations were made for wearing two pairs of gloves and surgical hoods to cover the hair, scalp, ears and neck ; and 8) collaboration with diabetologists was implemented to control glucose levels in diabetics. We compared incidences of SSI in cardiovascular surgery from the periods before (469 cases, Group B) and after (118 cases, Group A) introduction of the additional prophylactic measures. Clinical characteristics of patients in each group did not differ significantly. Operative time was significantly shorter in Group A (400±116 min) than in Group B (434±145 min). Compliance with antibiotic prophylaxis in the intraoperative period improved progressively from 93% in Group B to 99% in Group A. Compliance with control of glucose levels to ≤160 mg/dl on postoperative day 1 improved progressively from 71% in Group B to 81% in Group A. Duration of drain placement was significantly shorter in Group A (2.9±1.8 days) than in Group B (3.6±2.9 days). Incidence of SSI decreased significantly from 6.0% in Group B to 0.8% in Group A. Revision of preventive measures based on the results of surveillance and enhancement of cooperation between the ICT and surgeons could help to decrease the incidence of SSI.

Objective : Risk factors for SSI after open heart surgeries were evaluated in relation to a bundle of SSI preventive measures. Methods : Research design is a retrospective cohort study. The study population was 1,579 patients who had received open heart surgeries at Kobe City Medical Center General Hospital from January 2008 to December 2010 (Period I : when standard infection prevention measures were implemented) and from January 2014 to December 2016 (Period II : after a relocation of the hospital to a new campus and enhanced infection prevention measures were implemented). Factors associated with SSI were determined using univariate modelling analysis followed by multi-variate logistic regression analysis. The Center for Disease Control and Prevention definition of SSI was used for case determination. Results : Overall SSI incidence was 4.5%. SSI incidence decreased significantly from 6.6% in Period I to 2.9% in Period II (p＜0.001). Significant improvement in adherence to the recommended preventive measures was observed in Period II in selection of appropriate antibiotics, discontinuation of prophylactic antibiotics within 72 h after surgery and glucose control on post-operative Day 1 and 2 (p＜0.001). A univariate analysis showed statistical significance in surgical procedure, surgical period, surgical duration, post-operative day 2 morning glucose level, administration of prophylactic antibiotics within 1 h before incision, 100% compliance with the Bundle. Complex surgery (odds ratio 2.5 ; 95%CI 1.3～4.8) were identified as a risk factor by multiple logistic regression. Surgical period (Period II, odds ratio 0.41 ; 95%CI 0.28～30.71) and administration of prophylactic antibiotics within 1 h before incision (odds ratio 0.57 ; 95%CI 0.33～0.97) reduced SSI risks. Conclusion : The study demonstrated administration of prophylactic antibiotics within 1 h before incision was particularly important for SSI prevention. Higher compliance with SSI bundle and a special attention to patients receiving complex surgery were also warranted.