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Bacterial Contamination of the Anesthesia Workplace and Efficiency of Routine Cleaning Procedures: A Prospective Cohort Study

Goebel, Ulrich MD, PhD; Gebele, Nicole Cand. Med.; Ebner, Winfried MD; Dettenkofer, Markus MD, PhD; Bürkle, Hartmut MD, PhD; Hauschke, Dieter PhD; Schulz-Stübner, Sebastian MD, PhD

doi: 10.1213/ANE.0000000000001220
Patient Safety: Brief Report

In this prospective cohort study, 200 decontamination (cleaning and disinfection) procedures of the anesthesia workplace either by anesthesia nurses or by specially trained housekeeping staff were monitored. Time used by housekeeping staff was shorter (1.2 ± 0.1 vs 2.6 ± 0.2 minutes on average, data are mean ± SEM; P < 0.0001) with less visible marker spots (14.4 ± 0.68 [55%] vs 17.3 ± 0.75 [66.7%] on average, data are mean ± SEM; P = 0.0041), and the bacterial load showed a decrease (≅67%, P < 0.0001) compared with anesthesia nurses. Specially trained housekeeping staff outperformed anesthesia nurses in cleaning the anesthesia workplace. Specific training for anesthesia workplace cleaning is supported by these findings.

From the *Department of Anesthesiology and Intensive Care Medicine, University Medical Center Freiburg, Freiburg, Germany; Institut für Umweltmedizin und Krankenhaushygiene am Universitätsklinikum Freiburg, Freiburg, Germany; Institut für Krankenhaushygiene & Infektionsprävention, Gesundheitsverbund Landkreis Konstanz, Konstanz, Germany; §Institute of Medical Biometry and Medical Informatics, University of Freiburg, Freiburg, Germany; and Deutsches Beratungszentrum für Hygiene (BZH GmbH), Freiburg, Germany.

Accepted for publication January 8, 2016.

Funding: Institutional.

Conflict of Interest: See Disclosures at the end of the article.

This report was presented in abstract form at Deutscher Anästhesiecongress (DAC) 2015, Düsseldorf, Germany, and Networking World Anesthesia Convention (NWAC) 2015, Vancouver, Canada.

Reprints will not be available from the authors.

Address correspondence to Sebastian Schulz-Stübner, MD, PhD, Deutsches Beratungszentrum für Hygiene (BZH GmbH), Schnewlinstr. 10, 79098 Freiburg im Breisgau, Germany. Address e-mail to Schulz-stuebner@bzh-freiburg.de.

The anesthesia workplace as a vector for bacterial transmission that might also play a role in causing health care–associated infections has been recognized in studies by Loftus et al.1–3, and decontamination (cleaning and disinfection) of hand-contact surfaces after every case is a standard operating procedure in German operating rooms (ORs). However, little is known about the effectiveness and the time needed and actually used for effective cleaning and disinfection and the related effectiveness in clinical routine.

We conducted this prospective observational cohort study to analyze and improve the cleaning and disinfection process and make it more efficient.

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METHODS

This quality assurance project was reviewed by the IRB of the Universitätsklinikum Freiburg (No. 52/15), and a waiver was issued to analyze patient data without informed written consent.

Two hundred cleaning and disinfection procedures were monitored after routine orthopedic procedures under general anesthesia in June and July of 2014. In 100 cases, the anesthesia nurse performed the cleaning and disinfection, and in 100 cases, specifically trained housekeeping staff performed this task. Both groups used commercially available disinfectant-soaked wipes from a special dispenser (Incidin Plus 0.5%; Ecolab GmbH & Co., Düsseldorf, Germany). ORs were assigned blockwise to each regimen and cases were scheduled by OR management without knowledge of the assigned regimen. Anesthesia nurses in Germany have a nursing degree and additional 2 years of subspecialty training in anesthesia including handling and cleaning of special medical equipment. They are not allowed to practice anesthesia independently and work under physician supervision only. Cleaning and disinfection of the anesthesia workplace is part of their usual work description and standard operating procedures, but no checklists are used. There was no specific instruction how much time should be used to complete the task or is allowed for cleaning the area. Housekeeping staff is normally not allowed to touch medical equipment such as anesthesia machines and had to be trained in the special handling of the anesthesia machine based on the manufacturers’ handbook by a licensed instructor according to German medical product law. The training session consisted of 2 parts; first, a theoretical briefing about the anesthesia machines used and second, a demonstration and hands-on session with the possibility of answering all questions concerning the handling and disinfection of the anesthesia machine.

Fourteen staff members of the housekeeping and maintenance department were on duty during the study period in the ORs analyzed. Moreover, 12 anesthesia nurses were on duty during the screening time. The largest percentage of the 100 cases performed by a single individual of each group was 10% for housekeeping staff and 11% for anesthesia nurses, respectively.

The anesthesia machines (Primus; Dräger, Lübeck, Germany, and Siemens monitoring system X9000; Siemens, München, Germany) were marked with 8 fluorescent marker spots (Glow Check®; Bode, Hamburg, Germany), and the anesthesia carts with 18 spots, giving a total of 26 marker spots at prominent hand-contact points or representative spots to cover the entire surface area. Primary outcome variables included the decontamination time, which was measured by an independent observer who also performed the spot check with ultraviolet light before the start of the next case. The specific role of the observer and the methods of the study were not disclosed to staff at the time of the study, and no immediate feedback was given. However, general information that an observer would be present for a scientific study was given to all people involved, and senior supervising staff was informed about the study and approved the protocol. We focused exclusively on the anesthesia machine and cart and not on additional items such as computer keyboards, etc.

As a secondary end point, microbiological testing using RODAC (Replicate Organism Detection and Counting)-plates was performed on 4 consecutive study days on the 2 most frequently touched spots (multifunction dial knob on the anesthesia machine and a drawer for stopcock covers on the anesthesia cart). During a baseline phase, 56 probes were taken in routine practice, followed by 24 probes with the anesthesia nurse performing the disinfection and 24 with the trained housekeeping staff during the study period.

RODAC-plates were used in a standardized manner and cultured at 36°C for 2 days and then at 22°C for 3 days. Grown bacteria were isolated on Columbia blood agar for species differentiation, and colony-forming units (CFU) were calculated per 16 cm2.

Three months after surgery, the patients’ electronic records were screened for any diagnosis indicating hospital-acquired infections (HAIs) such as surgical-site infection, pneumonia, or catheter-associated bloodstream infection.

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Statistics

The standardized effect size according to Cohen of 0.5 implies a moderate effect, which is assumed for this study. The power analysis assumes a 2-sided significance level of 5%, sample size of 100 per group, and thus resulting in a power of at least 90% (nQuery, study-planning software, Statistical Solutions Ltd., Cork, Ireland).

For the limited sample size of 12 nurses versus 14 housekeeping staff members, there is no sufficient power for testing normality. Hence, we did not perform a statistical test for assessing the assumption of the normal distribution.

Statistical calculation was performed using the GraphPad Prism 6.0f Software (La Jolla, CA). Statistical analyses for the items in Table 1 were performed using the unpaired t test with Welch correction for addressing heterogeneity. Data are expressed as mean ± SEM.

Table 1

Table 1

For the reduction in bacterial load (CFU), an unpaired t test was used. Data are mean ± SD.

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RESULTS

Table 1 shows a significantly shorter duration of cleaning in ORs where the cleaning was performed by housekeeping staff (group 1) compared with anesthesia nurses (group 2): 1.2 ± 0.1 vs 2.6 ± 0.2 minutes on average (data are mean ± SEM; <0.0001) and significantly less visible marker spots (14.4 ± 0.68 [55%] vs 17.3 ± 0.75 [66.5%]) on average (data are mean ± SEM; P = 0.0041). The bacterial load (CFU) showed a reduction (≅67%) in group 1 with an average of 17.58 ± 9.63 CFU per contact plate in group 1 vs 54.50 ± 39.89 CFU per contact plate in group 2 (data are mean ± SD; 95% confidence interval = [13.51–21.65] and [38.10–70.90]; P < 0.0001). Five plates in group 2 showed complete bacterial overgrowth and 2 grew molds.

HAIs in group 2 included 2 surgical-site infections, 2 urinary-tract infections, 1 pneumonia, and 1 unspecified infection. In contrast, no infection was identified in group 1.

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DISCUSSION

The extent of contamination of the anesthesia workplace has recently been demonstrated by Munoz-Price et al.4–6 who also showed the frequent interaction between surfaces and the anesthesiologists’ hands. A recent study demonstrated that contamination of the anesthesia work area was very quickly spread throughout the OR. Therefore, lack of adequate cleaning and disinfection of the anesthesia workplace could pose a threat to the current patient and subsequent patients in that OR.7 However, the clinical implications of environmental contamination as a contributing factor of infections remains unclear because the chain of infection should theoretically be interrupted by sufficient hand hygiene before aseptic procedures. Loftus et al. showed contamination of sterile stopcocks by organisms recovered from the anesthesia machine and that stopcock contamination was associated with an increased mortality (odds ratio, 58.5; confidence interval, 2.32–1477; P = 0.014). Intraoperative bacterial contamination of patients and provider hands was linked to 30-day postoperative infections.1 In another study by the same group, a reduction of contaminated IV tubing could be achieved by an increased intraoperative hand disinfection.8 Because less than optimal hand hygiene compliance, especially among anesthesiologists, is prevalent,9 routine disinfection of frequent hand-contact surfaces, which are generally considered to be potential spots for transmission of microorganisms, should be considered as an additional safety net as part of standard care.

The overall quality of cleaning in our study leaves room for improvement. Because turnover time is monitored as a management quality indicator, subjectively perceived time pressure might be a contributing factor to skip corners although the absolute time used is practically irrelevant.

Interestingly, trained housekeeping staff performed better and faster than anesthesia nursing staff. The bacterial load at the end of the disinfection process was also significantly lower when the decontamination was performed by trained housekeeping staff. A possible explanation for this finding is that they are not distracted by other tasks and identify themselves with the cleaning job rather than considering it a necessary nuisance. The idea that motivational factors rather than the amount or repetition of training or the time used to perform the task is a contributing factor to cleaning thoroughness is supported by studies by Rupp et al.10 They found no correlation between time and cleaning success in a hospital room setting and while evaluating the effectiveness and efficiency of 17 housekeepers in terminal cleaning of 292 hospital rooms through adenosine triphosphate detection, they identified a subgroup of housekeepers who were significantly more effective and efficient than their coworkers. They concluded that these optimum outliers may be used in performance improvement to optimize environmental cleaning.11

In the United States, cleaning of the anesthesia machine by environmental services and not by anesthesiologists or nurse anesthetists is practiced in many hospitals. Given the fact that German anesthesia nurses are highly qualified and receive comprehensive training in infection prevention, microbiology, and transmission pathways as well as training in the technology of anesthesia machines, we do not believe that the content or duration of the training session our housekeeping staff received can explain our findings. Future research should focus on the motivational aspect and dedication to the cleaning job.

To improve cleaning performance, visual aids such as fluorescent markers have been shown to be effective for staff education and process monitoring and have led to significant improvements in the disinfection cleaning process of ORs.12 We believe that such a feedback approach could be helpful to raise awareness and increase motivation independent of the primary qualification of the person performing the cleaning task.

Our study is limited because the observed time differences between the groups did not turn out to be practically relevant despite statistical significance. Our initial hypothesis that a time difference would be a distinctive factor is not supported by the data. However, the observed differences in cleaning quality are important to optimize a clean and safe OR environment.

Our observation of HAIs is clearly limited by the search criteria used and the low numbers because our study was not powered to detect significant differences in infectious complications. Therefore, our secondary findings are purely observational. However despite these limitations, the finding of no infection in the housekeeping group versus 6 infections in the anesthesia nurse group should trigger further research to elucidate the role of environmental contamination during anesthesia. Such a study would ideally incorporate microbiological sampling in the OR and a comparison of isolated microorganisms from the hands of anesthesiologists and anesthesia nurses, from the environment and from the patient himself with clinically obtained samples from the body site associated with a nosocomial infection by strain typing or whole genome analysis. These kinds of data for the OR environment are urgently needed because research so far has mainly focused on general hospital rooms and areas and transmission of specific organisms. In 2004, Dettenkofer et al.13 performed a systematic review of the impact of environmental surface disinfection interventions on occurrence of health care–associated infections. They concluded that the quality of the studies at that time was poor, and none provided convincing evidence that disinfection of surfaces reduced infections. In a 2013 review, Donsky et al.14 concluded that “that during the past decade a growing body of evidence has accumulated suggesting that improvements in environmental disinfection may prevent transmission of pathogens and reduce health care–associated infections. Although the quality of much of the evidence remains suboptimal, a number of high-quality investigations now support environmental disinfection as a control strategy. Based on these data, current guidelines for pathogens such as Clostridium difficile, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and norovirus emphasize the importance of environmental disinfection as a control measure.”

In conclusion, the cleaning of the anesthesia workplace after every use needs improvement. Specially trained housekeeping staff outperformed anesthesia nurses in cleaning the anesthesia workplace. Specific training for anesthesia workplace cleaning is supported by these findings. Future studies are needed to evaluate the motivational approaches for performance improvement and to clarify the role of environmental contamination of the anesthesia workplace for the development of postoperative infectious complications.

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DISCLOSURES

Name: Ulrich Goebel, MD, PhD.

Contribution: This author helped design the study and prepare the manuscript and attests to the integrity of the original data and the analysis reported in this manuscript and is the archival author who is responsible for maintaining the study records.

Attestation: Ulrich Goebel approved the final manuscript.

Conflicts of Interest: None.

Name: Nicole Gebele, Cand. Med.

Contribution: This author conducted the study and helped preparing the manuscript and attests to the integrity of the original data and the analysis reported in this manuscript. Data presented are part of the doctoral thesis of Nicole Gebele at the Albert Ludwigs-University, Freiburg, Germany.

Attestation: Nicole Gebele approved the final manuscript.

Conflicts of Interest: None.

Name: Winfried Ebner, MD.

Contribution: This author helped in conducting the study and preparation of the manuscript.

Attestation: Winfried Ebner approved the final manuscript.

Conflicts of Interest: None.

Name: Markus Dettenkofer, MD, PhD.

Contribution: This author helped design the study and prepare the manuscript.

Attestation: Markus Dettenkofer approved the final manuscript.

Conflicts of Interest: None.

Name: Hartmut Bürkle, MD, PhD.

Contribution: This author helped prepare the manuscript and attests to the integrity of the original data and the analysis reported in this manuscript.

Attestation: Hartmut Bürkle approved the final manuscript.

Conflicts of Interest: None.

Name: Dieter Hauschke, PhD.

Contribution: This author helped prepare the manuscript and attests to the integrity of the original data and the analysis reported in this manuscript.

Attestation: Dieter Hauschke approved the final manuscript.

Conflicts of Interest: None.

Name: Sebastian Schulz-Stübner, MD, PhD.

Contribution: This author helped design the study and prepare the manuscript.

Attestation: Sebastian Schulz-Stübner approved the final manuscript.

Conflicts of Interest: Sebastian Schulz-Stübner is co-owner of the Deutsches Beratungszentrum für Hygiene (BZH GmbH), Freiburg, Germany.

This manuscript was handled by: Sorin J. Brull, MD.

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ACKNOWLEDGMENTS

This report contains data from the doctoral thesis of Nicole Gebele at the Albert-Ludwigs-Universität, Freiburg, Germany.

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REFERENCES

1. Loftus RW, Brown JR, Koff MD, Reddy S, Heard SO, Patel HM, Fernandez PG, Beach ML, Corwin HL, Jensen JT, Kispert D, Huysman B, Dodds TM, Ruoff KL, Yeager MP. Multiple reservoirs contribute to intraoperative bacterial transmission. Anesth Analg. 2012;114:1236–48
2. Loftus RW, Koff MD, Burchman CC, Schwartzman JD, Thorum V, Read ME, Wood TA, Beach ML. Transmission of pathogenic bacterial organisms in the anesthesia work area. Anesthesiology. 2008;109:399–407
3. Loftus RW, Koff MD, Birnbach DJ. The dynamics and implications of bacterial transmission events arising from the anesthesia work area. Anesth Analg. 2015;120:853–60
4. Birnbach DJ, Rosen LF, Fitzpatrick M, Carling P, Munoz-Price LS. The use of a novel technology to study dynamics of pathogen transmission in the operating room. Anesth Analg. 2015;120:844–7
5. Munoz-Price LS, Riley B, Banks S, Eber S, Arheart K, Lubarsky DA, Birnbach DJ. Frequency of interactions and hand disinfections among anesthesiologists while providing anesthesia care in the operating room: induction versus maintenance. Infect Control Hosp Epidemiol. 2014;35:1056–9
6. Munoz-Price LS, Lubarsky DA, Arheart KL, Prado G, Cleary T, Fajardo-Aquino Y, Depascale D, Eber S, Carling P, Birnbach DJ. Interactions between anesthesiologists and the environment while providing anesthesia care in the operating room. Am J Infect Control. 2013;41:922–4
7. Birnbach DJ, Rosen LF, Fitzpatrick M, Carling P, Arheart KL, Munoz-Price LS. Double gloves: a randomized trial to evaluate a simple strategy to reduce contamination in the operating room. Anesth Analg. 2015;120:848–52
8. Koff MD, Loftus RW, Burchman CC, Schwartzman JD, Read ME, Henry ES, Beach ML. Reduction in intraoperative bacterial contamination of peripheral intravenous tubing through the use of a novel device. Anesthesiology. 2009;110:978–85
9. Munoz-Price LS, Patel Z, Banks S, Arheart K, Eber S, Lubarsky DA, Birnbach DJ. Randomized crossover study evaluating the effect of a hand sanitizer dispenser on the frequency of hand hygiene among anesthesiology staff in the operating room. Infect Control Hosp Epidemiol. 2014;35:717–20
10. Rupp ME, Adler A, Schellen M, Cassling K, Fitzgerald T, Sholtz L, Lyden E, Carling P. The time spent cleaning a hospital room does not correlate with the thoroughness of cleaning. Infect Control Hosp Epidemiol. 2013;34:100–2
11. Rupp ME, Huerta T, Cavalieri RJ, Lyden E, Van Schooneveld T, Carling P, Smith PW. Optimum outlier model for potential improvement of environmental cleaning and disinfection. Infect Control Hosp Epidemiol. 2014;35:721–3
12. Jefferson J, Whelan R, Dick B, Carling P. A novel technique for identifying opportunities to improve environmental hygiene in the operating room. AORN J. 2011;93:358–64
13. Dettenkofer M, Wenzler S, Amthor S, Antes G, Motschall E, Daschner FD. Does disinfection of environmental surfaces influence nosocomial infection rates? A systematic review. Am J Infect Control. 2004;32:84–9
14. Donskey CJ. Does improving surface cleaning and disinfection reduce health care-associated infections? Am J Infect Control. 2013;41:S12–9
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