Surgical hand rub: Influence of duration of application on the immediate and 3-hours effects of n-propanol and isopropanol

Background

The recommended duration for surgical hand treatment has been changed from 10 over 5 to 3 minutes and even shorter.

Objectives

Our objective was to study the impact of the length of surgical hand antisepsis with n-propanol 60% (vol/vol) or isopropanol 70% (vol/vol) applied for 1, 3, or 5 minutes on the reduction of resident hand flora in the setting of the microbiologic laboratory for experimental and applied testing of disinfectants and antiseptics at the Medical University Vienna, Austria, using a Latin Square design.

Methods

Our methods were according to the Austrian Guidelines for Testing Products for Surgical Hand Antisepsis. The release of bacterial hand flora of 21 subjects is assessed before and immediately after disinfection from one hand and 3 hours later from the other, meanwhile gloved, hand. Mean reduction factors (RF) are calculated.

Results

The immediate mean log₁₀ RFs with n-propanol or isopropanol were 1.05, 2.03, and 2.30 and 0.74, 1.48, and 2.12, respectively, when applied for 1, 3, or 5 minutes, respectively. After 3 hours, the respective mean log₁₀ RFs were 0.45, 1.01, and 1.60 and 0.19, 0.79, and 1.03. Thus, with increasing length of application, a highly significant trend (P < .001) toward higher log₁₀ reductions was demonstrated. At both sampling times, n-propanol was more effective than isopropanol at the corresponding treatments. Furthermore, a highly significant (P < .001) association was found between the individual volunteers and the effect of the antiseptics on their hands.

Conclusion

The efficacy of surgical antisepsis is significantly associated with the length of application.