Risk Factors for SSI after Open Heart Surgery

Noriko Shinkai＊1,＊2)	Takeshi Morimoto＊3)	Hisako Yano＊2)
Tadaaki Koyama＊4)

（Department of Nursing, Department of Infection Control, Kobe City Medical Center General Hospital＊1), Kobe, Japan, Graduate School of Nursing, Nagoya City University＊2), Nagoya, Japan, Department of Clinical Epidemiology, Hyogo College of Medicine＊3), Nishinomiya, Japan, Clinical Research Promotion Center, Department of Research Support, Kobe City Medical Center General Hospital＊3), Kobe, Japan, and Cardiovascular Surgery, Kobe City Medical Center General Hospital＊4), Kobe, Japan）

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 72h 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 1h before incision（odds ratio 0.57;95%CI 0.33～0.97）reduced SSI risks. Conclusion:The study demonstrated administration of prophylactic antibiotics within 1h 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.

 

Jpn. J. Cardiovasc. Surg. 48:161-169（2019）

Keywords：open heart surgery;surgical site infection;risk factor;SSI bundle