Alcohol-only hand cleansers have been shown to decrease the spread of infections in hospitals and have been recommended in this country since 1986.1 Alcohol-only cleansers have been shown to be equivalent to washing with soap and water in preventing the spread of illnesses in school age children,2 and their use has increased handwashing compliance by health care providers in hospitals.3
Waterless antiseptic surgical hand scrub with 1% chlorhexidine gluconate and 61% ethyl alcohol (Avagard™; 3M Health Care, St. Paul, MN) has been found to be superior to the traditional surgical hand scrub in cost-effectiveness and time efficiency. It has been noted to provide comparable hand antisepsis as judged by the incidence of wound infection in a variety of pediatric urological procedures.4 However, failure to follow the manufacturer's directions for use of a waterless surgical scrub has been reported to be associated with a spike in surgical site infections.5
Currently, our hospital policy mandates that a traditional surgical scrub (5-minute scrub with 4% chlorhexidine soap using a sterile scrub brush with water) should occur before placement of a central venous line in the operating room (OR). Other institutions use a variety of methods to clean hands, including alcohol-only disinfectant, traditional surgical scrub, or waterless surgical scrub (Avagard).
We hypothesized that alcohol-only cleanser and waterless surgical scrub (Avagard) would be equivalent to traditional surgical scrub for hand cleansing before gowning and gloving for placement of a central venous line, and our objective was to determine whether these cleansing methods were equivalent to a traditional surgical scrub.
With the help of the Microbiology Department, we cultured the fingers of fellows, residents, and attending anesthesiologists to determine whether these methods were equivalent. This study is relevant because hand cleansing with alcohol-only disinfectant solutions or waterless surgical scrub (Avagard) may have several advantages over traditional surgical scrubbing, including decreased scrub time leading to increased OR efficiency, and consequent decreased need for health care providers to remain outside the OR to scrub during critical parts of the patient's care after induction of anesthesia.
This study involved cleansing hands using 5 different methods (Table 1). All methods were performed in an empty cardiac OR early in the morning before the start of any cases. No patients were involved in this study. Method 1 was a traditional surgical scrub (5-minute scrub with water, brush, and 4% chlorhexidine soap) followed by cultures (n = 49 plates). This involved use of a 4% chlorhexidine-impregnated scrub brush (BD E-Z scrub™ 107 surgical scrub brush/sponge with 4% chlorhexidine gluconate; Becton Dickinson & Co., Franklin Lakes, NJ). This brush package contains a nail stick; the participants were encouraged to use it and perform a 5-minute surgical scrub using the provided brush and water. All participants had experience placing central venous catheters (upper-level residents, fellows, and attending anesthesiologists) and were thus familiar with the traditional surgical scrub technique. Participants were roughly timed by the investigators and were monitored and instructed to scrub as if they were about to insert a central venous catheter.
After scrubbing, participants dried their hands with a sterile towel and then their fingers were cultured. Method 2 was a traditional surgical scrub followed by a 15-minute break, then use of an alcohol-only disinfectant (62% ethyl alcohol) (n = 49 plates). This method involved performing a surgical scrub as described for method 1, followed by a period of 15 minutes to allow for recontamination and then use of an alcohol-based disinfectant (alcohol-only disinfectant). During the 15-minute break, participants were encouraged to perform normal morning activities (such as preparing the ORs for anesthesia). Method 3 was an alcohol-only disinfectant (62% ethyl alcohol) alone (n = 49 plates). Participants placed 3 pumps (6 mL) of alcohol-based hand disinfectant on their hands and nails, which were then rubbed together vigorously; the solution was spread under the nails and up to the elbows in a manner similar to that described in method 5. The subjects allowed their hands to air-dry completely after application of this solution. Subjects were observed by the investigators during the drying period, which took approximately 2 minutes. Method 4 was an alcohol-only disinfectant (62% ethyl alcohol) followed by a 15-minute break, then use of a traditional surgical scrub (n = 49 plates). First, alcohol-only cleanser was used as described above for method 3, followed by a period of 15 minutes to allow for recontamination and then performance of a traditional surgical scrub as described above for method 1. During the 15-minute break, participants were encouraged to perform normal morning activities. Method 5 was a waterless surgical hand scrub with 1% chlorhexidine gluconate and 61% ethyl alcohol (Avagard) alone (n = 116 plates). A sufficient amount of the waterless surgical scrub (Avagard) was applied to coat dry hands and nails thoroughly and was subsequently allowed to dry according to the manufacturer's instructions, as follows: 1 pump (2 mL) was dispensed into the palm of the left hand and tips of the fingers of the right hand were dipped into the lotion, which was then worked under the nails. The remaining lotion was spread over the right hand and up to just above the elbow. Another pump (2 mL) was then placed into the palm of the opposite hand (right hand) and the process was repeated by dipping the fingers of the other hand (left hand) into the lotion followed by working the lotion under the nails and spreading it over the left hand and up to just below the elbow. Finally, another 2 mL of lotion was placed into either hand and reapplied to all aspects of both hands up to the wrists. This solution was then allowed to dry. This process took approximately 1 to 2 minutes. No nail stick was used, but participates were encouraged to work the lotion under their nails.
The 15-minute break, described in methods 2 and 4 above, was introduced to allow a short period of recontamination. This break was also given to test for any residual effects from prior cleansing. During this break, participants were allowed to set up the ORs and perform normal morning activities. All cultures were obtained before the start of the first surgical case, such that there was no direct patient contact during this break.
After 1 of the above 5 cleaning methods, the tips of the fingers (excluding the thumb) of the right hand were gently pulled across a blood agar plate in a sterile manner and the plates were cultured for 24 hours at 37°C. The plates were subsequently read by a bacteriologist blinded to the method of cleaning as “growth” or “no growth.” Participants who had hands with abrasions, eczema, or other skin lesions, or with artificial nails were excluded from the study. After each cleansing method, subjects had a washout period of ≥24 hours to allow for recontamination of their hands (Table 1).
Informed consent was obtained from all participants. Participants were initially randomly assigned by coin toss to participate in methods 1 and 2 (group A) or methods 3 and 4 (group B) (Table 1). After collection of these data, we also investigated the effects of the waterless surgical scrub (Avagard), and all participants were invited to perform method 5. The number of subjects performing each method of cleansing is as follows: 28 subjects were randomly assigned with a 1:1 allocation ratio by simple randomization (coin toss) to either group A or group B. Fourteen were randomized to traditional scrub followed by alcohol (group A) (methods 1 and 2). Another group of 14 different subjects was randomized to alcohol followed by scrub (group B) (methods 3 and 4). Fourteen subjects (group A) produced 49 culture plates with method 1 and 49 plates with method 2. Fourteen different subjects (group B) produced 49 culture plates with method 3 and 49 plates with method 4.
After collection of these data, all 28 participants in groups A and B as well as other recruits were invited to participate in method 5 (no randomization). Thirty-eight subjects in method 5 produced 116 culture plates. After each cleansing method, subjects had a washout period of ≥24 hours to allow for recontamination of their hands (Table 1).
Considering a traditional 5-minute surgical scrub (method 1) to be the gold standard (reference), we compared this method with other methods of hand cleansing. We used a repeated-measures generalized estimating equations approach with a binomial distribution, because the outcome was binary (growth versus no growth), and logit link function to account for the same subjects using different methods and multiple trials of the same method.6,7 A Bonferroni correction was applied in the generalized estimating equations analysis to account for multiple comparisons. Four multiple comparisons of methods 2 to 5 to the reference method (method 1) were made, and P values and confidence intervals were Bonferroni corrected. Two-sided Bonferroni-corrected values of P < 0.05 were considered statistically significant. Likelihood ratio–based 95% confidence intervals (CIs) were constructed around the observed growth rate for each hand cleansing method to provide a range that could be observed in practice.7 Statistical analysis was performed using the SPSS software package (version 18.0; SPSS, Inc./IBM, Chicago, IL).
Plate growth was observed significantly more often for method 3 (alcohol-only disinfectant [62% ethyl alcohol] alone) versus method 1 (traditional surgical scrub, 5-minute scrub with water, brush, and 4% chlorhexidine soap): 82% growth (95% CI: 70%–93%) versus 16% growth (95% CI: 4%–29%) (P < 0.001). Method 2 (traditional surgical scrub followed by a 15-minute break then alcohol-only disinfectant [62% ethyl alcohol]) (P = 0.49; 95% CI: 8%–37%), method 4 (alcohol-only disinfectant [62% ethyl alcohol] followed by a 15-minute break, then use of a traditional surgical scrub) (P = 0.99; 95% CI: 5%–28%), and method 5 (waterless surgical hand scrub with 1% chlorhexidine gluconate and 61% ethyl alcohol [Avagard] alone) (P = 0.99; 95% CI: 10%–25%) were not significantly different in % growth as compared with the traditional 5-minute scrub (method 1). The absolute % differences in growth among methods with the 95% CI for the absolute % differences relative to the reference method (method 1) are as follows8:
- Method 1 = reference
- Method 2 versus reference = 6% observed difference, 95% CI: −10% to 22%
- Method 3 versus reference = 66% observed difference, 95% CI: 48% to 84%
- Method 4 versus reference = 0% observed difference, 95% CI: −15% to 15%
- Method 5 versus reference = 0% observed difference, 95% CI: −14% to 11%
Based on the 95% CI for the difference, a minimum of a 48% difference between method 3 and method 1 can be expected.8 Results summarizing % growth with 95% CIs are shown in Table 1.
We found that an alcohol-only hand cleanser (method 3) was not as effective as a traditional surgical scrub (method 1). Therefore, using alcohol-only hand cleanser as the sole method of hand cleansing before placing a central line is not recommended. We also found that waterless surgical scrub (Avagard: 1% chlorhexidine + 61% alcohol) (method 5) had a 0% observed difference (95% CI: −14% to 11%) from the reference (method 1).
Interestingly, if a traditional surgical scrub was used first followed by a period of 15 minutes to allow recontamination, method 2 (performing a second surgical scrub) had a 6% observed difference from method 1 (95% CI: −10% to 22%) and method 4 (using an alcohol-only hand cleanser as the second method of cleansing) had a 0% observed difference from method 1 (95% CI: −15% to 15%). Therefore, clinicians may be able to perform a surgical scrub before starting a case, and then use an alcohol-only hand cleanser before gowning and gloving for central line placement after induction of anesthesia. This would enable anesthesia care providers to use the alcohol-only disinfectant, thus allowing them to remain in the OR with their critically ill patients after induction of anesthesia. Alternatively, waterless surgical scrub (Avagard) may be used rather than the traditional surgical scrub. The waterless surgical scrub has the advantage of being less time consuming (<3 minutes) versus the traditional scrub (5 minutes).
There are several limitations to this study. First, we assumed that there would be no carryover effects after the 24-hour period of recontamination. Therefore, we allowed participants to participate multiple times in the study as long as they had a ≥24-hour period of recontamination. Because all providers wash hands multiple times a day, our assumption that there are minimal, if any, carryover effects after a 24-hour period of recontamination is probably correct. However, future studies involving culturing fingers after a washout period and comparing this with cultures taken after ≥24 hours would better help answer this question. Additionally, although all plates were cultured in the same manner (tips of the 4 fingers dragged across the plate), it is conceivable that participants with longer nails did have more nail contact with the blood agar than people with shorter nails. It is also possible that female participants (n = 24) had longer nails than the male participants (n = 24). We did not specifically address gender difference because we had equal numbers of male and female participants. We also did not determine the species of bacteria cultured; therefore, we are unable to compare this study with others for the effects of background contamination. Nonetheless, despite these flaws, our study is likely representative of the actual clinical environment in which health care providers clean their hands multiple times a day. Additionally, because method 5 was an add-on after the study was initiated, we cannot exclude a selection bias in this method, because we included additional recruits without randomization. Lastly, this study investigated the cleansing process alone and did not address the effects of hand cleansing on the overall central venous line infection rate and its cost-effectiveness. Further data collection is needed to address these issues.
As the initial cleansing method, alcohol-only cleansers are significantly less effective than the traditional surgical scrub before inserting a central venous catheter (P < 0.001). However, when an initial surgical scrub is followed by a 15-minute interval to allow for recontamination, there is no significant difference between performing a second surgical scrub or using an alcohol-only hand cleanser as the second cleansing method (no difference between methods 2 and 4). A waterless surgical scrub (Avagard) is as effective as a surgical scrub for the initial cleansing method.
Supported by the Departments of Anesthesiology and Microbiology at Wake Forest University School of Medicine; Department of Anesthesiology at Brigham and Women's Hospital, Harvard Medical School; and Department of Anesthesiology at Children's Hospital Boston, Harvard Medical School. Most of the materials, supplies, equipment, and facilities were provided by the Departments of Anesthesiology and Microbiology at Wake Forest University School of Medicine. No outside funding was provided for this study. No funding was obtained from any manufacturer of any hand-cleaning substance.
Name: Thomas Michael Burch, MD.
Contribution: This author helped design the study, conduct the study, and write the manuscript.
Attestation: Thomas Michael Burch has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.
Name: Brett Stanger, MD.
Contribution: This author helped design the study, conduct the study, and write the manuscript.
Attestation: Brett Stanger has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: K. Annette Mizuguchi, MD, PhD.
Contribution: This author helped analyze the data and write the manuscript.
Attestation: K. Annette Mizuguchi has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: David Zurakowski, PhD.
Contribution: This author helped analyze the data and write the manuscript.
Attestation: David Zurakowski has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: Sean D. Reid, PhD.
Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.
Attestation: Sean D. Reid has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
This manuscript was handled by: Sorin J. Brull, MD.
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