Evidence for a Standardized Preadmission Showering Regimen to Achieve Maximal Antiseptic Skin Surface Concentrations of Chlorhexidine Gluconate, 4%, in Surgical Patients

Importance
To reduce the amount of skin surface bacteria for patients undergoing elective surgery, selective health care facilities have instituted a preadmission antiseptic skin cleansing protocol using chlorhexidine gluconate. A Cochrane Collaborative review suggests that existing data do not justify preoperative skin cleansing as a strategy to reduce surgical site infection.

Objectives
To develop and evaluate the efficacy of a standardized preadmission showering protocol that optimizes skin surface concentrations of chlorhexidine gluconate and to compare the findings with the design and methods of published studies on preoperative skin preparation.

Design, Setting, and Participants
A randomized prospective analysis in 120 healthy volunteers was conducted at an academic tertiary care medical center from June 1, 2014, to September, 30, 2014. Data analysis was performed from October 13, 2014, to October 27, 2014. A standardized process of dose, duration, and timing was used to maximize antiseptic skin surface concentrations of chlorhexidine gluconate applied during preoperative showering. The volunteers were randomized to 2 chlorhexidine gluconate, 4%, showering groups (2 vs 3 showers), containing 60 participants each, and 3 subgroups (no pause, 1-minute pause, or 2-minute pause before rinsing), containing 20 participants each. Volunteers used 118 mL of chlorhexidine gluconate, 4%, for each shower. Skin surface concentrations of chlorhexidine gluconate were analyzed using colorimetric assay at 5 separate anatomic sites. Individual groups were analyzed using paired t test and analysis of variance.

Intervention
Preadmission showers using chlorhexidine gluconate, 4%.

Main Outcomes and Measures
The primary outcome was to develop a standardized approach for administering the preadmission shower with chlorhexidine gluconate, 4%, resulting in maximal, persistent skin antisepsis by delineating a precise dose (volume) of chlorhexidine gluconate, 4%; duration (number of showers); and timing (pause) before rinsing.Results The mean (SD) composite chlorhexidine gluconate concentrations were significantly higher (P < .001) in the 1- and 2-minute pause groups compared with the no-pause group in participants taking 2 (978.8 [234.6], 1042.2 [219.9], and 265.6 [113.3] µg/mL, respectively) or 3 (1067.2 [205.6], 1017.9 [227.8], and 387.1 [217.5] µg/mL, respectively) showers. There was no significant difference in concentrations between 2 and 3 showers or between the 1- and 2-minute pauses.

Conclusions and Relevance
A standardized preadmission shower regimen that includes 118 mL of aqueous chlorhexidine gluconate, 4%, per shower; a minimum of 2 sequential showers; and a 1-minute pause before rinsing results in maximal skin surface (16.5 µg/cm2) concentrations of chlorhexidine gluconate that are sufficient to inhibit or kill gram-positive or gram-negative surgical wound pathogens. This showering regimen corrects deficiencies present in current nonstandardized preadmission shower protocols for patients undergoing elective surgery.