This observational study investigates whether 3 paints are superior compared to 2 paints in reducing microbial skin counts in the disinfection area of cardiac and abdominal surgery patients.

Surgical site infection (SSI) remain the most common nosocomial infection in surgical departments. Preparation of the skin with disinfectants belongs to the standard of care prior to any surgical intervention but disinfection practices are heterogeneous across different hospitals and countries. Although the efficacy and effectiveness of preoperative surgical site preparation is dependent on both the antiseptic agent used and the application method, it is unclear how many paints of an antiseptic are needed to ensure adequate infection protection.

An adequately powered study including different standard antiseptic agents (i.e. chlorhexidine in alcohol (CHX) and povidone iodine in alcohol (PI)) is therefore required to compare the protective effect of different numbers of paints.

Inclusion Criteria:

• Adult patients undergoing elective cardiac surgery at the study site
• Adult patients undergoing elective abdominal surgery at the study site
• Provision of informed consent

Exclusion Criteria:

• Pregnancy reported by patient
• Emergency (non-elective) surgical interventions
• Contraindications to the use of either one of the compounds: Alcoholic CHX; Alcoholic PI
• Skin or other hypersensitivity reactions during the disinfection process

All patients undergoing cardiac or abdominal (colorectal surgery, cholecystectomy) interventions at the University Hospital of Basel will be eligible for this study unless meeting exclusion criteria