Are nail brushes and nail picks used during the surgical hand scrub effective?

Nail brushes and nail picks are routinely used during the surgical scrub to remove dirt from the surface of the nail and underneath the nails. Though their use is recommended in various national guidelines (1,2,3) there is no evidence to demonstrate their effectiveness. This is important as they have a cost implication. A packet containing a disposable brush and pick is around 0.40 GBP. Though this is relatively cheap, the numbers of brushes and picks used is high. A UK study found 92% of operating room nurses used a brush every time they scrubbed (4). The aim of this study was to determine the effect of nail brushes and nail picks on the number of bacteria on operating room nurses hands following a surgical scrub.

Study design

The randomised trial was carried out in three hospitals in England. 164operating room nurses were randomised to one of three intervention groups; 4% chlorhexidine gluconate only, 4% chlorhexidine gluconate and a nail pick, 4% chlorhexidine gluconate and a nail brush. Bacterial counts were obtained using the glove juice test before the scrub and one hour after the scrub. The reductions in bacterial counts were compared for each of the three groups. 

After consenting to take part in the trial, the operating room nurses opened an opaque sequentially numbered envelope which contained a card randomising them to one of the three scrub groups. The randomisation sequence was generated by a computer programme. The scrubbing protocol for each intervention group is shown in Table 1. Each scrub was observed and timed by an observer who gave each participant two 2mL doses aqueous 4% chlorhexidine gluconate. Bacterial hand counts were taken using the glove juice method before the scrub (baseline) and one hour after the surgical scrub (post intervention). The glove juice method is the standardtest for measuring the effectiveness of hand antibacterial solutions (5). This involves each participant inserting their dominant hand into a large sterile glove is filled with 75 mL of sampling solution (phosphate buffered saline). The gloved hand is then uniformly massaged for one minute. After one minute the hand is removed and the sampling solution extracted aseptically and put into a sterile jar for transporting to the laboratory.

This process is repeated again using the same hand to collect the post intervention count. The post intervention sampling fluid contained a neutralising solution (25%Tween 80 and 3.75% soyal lecithin) to inactivate any chlorhexidine gluconate which may have come off the participants hand into the sampling solution. During the hour between the scrub and the post scrub sampling, the nurses wore sterile gloves and performed circulating duties only. It was not ethical for the nurses to take part in surgical operations at the operating table as participants who did not use a brush or pick would have performed a scrub which did not meet current recommended guidelines. Sample size calculations identified also collected the following baseline demographic details from each participant; gender, glove size and hand skin condition. The nail picks and brushes were manufactured by BD EZ scrub, Becton Dickinson and the 4% chlorhexidine gluconate was manufactured by Mölnlycke Health Care.

 

Laboratory testing

Before the trial started we tested the effectiveness of the sampling solution, the neutralising solution and the sterile gloves. We also conducted a pilot study with an additional 20 nurses. The samples were immediately transported to the laboratory in sterile containers where they were serially diluted, and poured into Petri dishes using tryptone soya agar. Duplicates were made of all plates. The plates were then incubated at 37oC for 24 hours. After 24 hours the colony forming units (CFUs) were counted and calculated to represent the number of CFUs per hand (see Image 2). Because the numbers were so large, they were presented as average log 10 values.

Statistical analysis

T-tests were used to test the effects of demographic variables (gender, glove size, skin condition) on baseline CFUs. Analysis of variance (ANOVA) and analysis of covariance (ANCOVA) were used to test post intervention CFUs across the three groups.

Results

164 operating room nurses took part in the study. The distribution of men, women and glove sizes were similar in all three groups. There were more participants in the nail pick only group with skin cuts or dry skin, but this did not affect the post intervention counts.
There was no statistically significant difference between any of the groups (significance level 5%):

• Chlorhexidine compared with chlorhexidine plus pick (p value 0.34)
• Chlorhexidine compared with chlorhexidine plus brush (p value 0.09)
• Chlorhexidine with pick compared with chlorhexidine plus brush (p value 0.45)
  
  

Discussion

The results show no statistically significant differences between any of three groups. This means that using brushes or picks does not provide any further reduction in bacterial counts on hands. In fact, the group which used brushes had a slightly higher bacterial count than the other two groups. This could mean that brushes traumatise the skin around the nails creating an environment where bacteria thrived. This is an interesting possibility as historically, brushes were used to scrub the hands and arms. This practice was discontinued when brushes were found to increase bacterial counts(6). However, in this study, the increase was not statistically significant and a larger sample size would be needed to confirm this theory.
  This study finds that nail brushes and nail picks are unnecessary and because of their associated costs would not recommend their use. However, changing practice can be difficult and staff will continue to want to clean under their nails. Therefore the most practical recommendation, which accommodates staffs desires, financial considerations and the findings from this study, is that a tub of cheap non-sterile nail picks is available in scrub rooms for staff to use to remove visible dirt from underneath their nails.

Conclusion

Nail brushes and nail picks used during the surgical scrub do not provide additional decontamination. Though they are relatively inexpensive, the large number used means that they have a considerable cost implication. This study recommends that nail brushes are withdrawn from operating theatres and only non-sterile nail picks are available to remove visible dirt from under nails.

Acknowledgement

The authors would like to thank the operating room nurses who took part in this study and The Association for Perioperative Practice and Mölnlycke Health Care for their financial contribution.
  A more detailed version of this study can be found elsewhere(7).

References

1. AORN Standards, Recommended Practices and Guidelines, Denver, Association of periOperative Registered Nurses Inc. 2006
2. AfPP Standards and Recommendations for Safe Perioperative Practice, Harrogate, Association for Perioperative Practice 2007
3. ACORN Standards, Australian College of Operating Room Nurses 2004
4. Tanner J, Blunsden C, Fakis A. National survey of hand antisepsis practices. J Periop Pract 2007; 17:27-37
5. ASTM. E1115-02 Standard test method for evaluation of surgical hand scrub formulations. Annual Book of ASTM Standards 2002, Philadelphia: American Society for Testing and Materials
6. Loeb M, Wilcox L, Smaill F, Walter S, Duff Z. A randomized trial of surgical scrubbing with a brush compared to antiseptic soap alone. Am J Infect Control 1997; 25:11-15
7. Tanner J, Khan D, Walsh S, Chernova J, Lamont S, Laurent T. Brushes and picks used on nails during the surgical scrub to reduce bacteria: a randomised trial. J Hosp Infect; 2009 71:234-238