There is a trend in some countries to recommend the use of surgical hand disinfectants at volumes as low as 4 ml per application. Kampf and Ostermeyer (2014) sought to determine whether the volume applied and hand size influence the efficacy of surgical hand disinfection.
Thirteen experiments, according to EN 12791, resulting in 269 datasets from 75 subjects were analyzed. Hands were first washed for one minute with soap. The pre-values were obtained by rubbing the finger tips in tryptic soy broth for one minute. Each subject treated his/her hands with n-propanol (60%, v/v), with as many portions as necessary to keep the hands wet for three minutes (6-12 ml). Bacterial post-values were taken from one hand (immediate effect); the other hand was gloved for three hours (sizes 7-9).
The second post-value was taken when the glove was removed (three-hour effect). The mean immediate log10 reduction of CFU was 2.56 +/- 1.12. The glove size had no significant effect on the efficacy of disinfection (p = 0.182; ANOVA). However, a volume of 6 ml was significantly less effective than 9 ml for glove sizes of 7.5-8 (p < 0.05; Tukey post hoc analysis). The mean log10 reduction after 3 h was 2.12 +/- 1.24. A volume of 6 ml was again significantly less effective than 12 ml for glove size 7 and than 9 ml for glove sizes 7.5-8 (p < 0.05).
The researchers concluded that application of small volumes of surgical hand disinfectant when using the EN 12791 reference procedure is likely to yield poor efficacy results, regardless of hand size. Their research was published in Antimicrobial Resistance and Infection Control.
Reference: Kampf G and Ostermeyer C. Small volumes of n-propanol (60%) applied for 3 minutes may be ineffective for surgical hand disinfection. Antimicrobial Resistance and Infection Control 2014, 3:15 doi:10.1186/2047-2994-3-15