Eliminating CLABSI: Is stethoscope hygiene the missing piece?

^*W. Frank Peacock, Kathleen Vollman, Cynthia Cadwell, Nicole Kupchik

¹Baylor College of Medicine

²ADVANCING NURSING LLC

³Hawaii Pacific Health Medical Group, Cloudwell Health, Cadwell Consulting

⁴Nicole Kupchik Consulting, Inc.

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Abstract

Like the hands, the stethoscope serially touches many patients throughout the clinical day. But unlike hands, mandatory hygiene is rare and potentially ineffective. Even when cleaned with an alcohol swab for 60 seconds, cultures from the stethoscope diaphragm still will demonstrate pathogens in 28% of cases. Central Line-Associated Bloodstream Infections (CLABSI) are a potentially fatal hospital associated infection (HAI), estimated to cause a >300% increase in death and result in multiple weeks longer hospitalization.  These challenges persist, despite being standard prevention targets. Intensive efforts, such as total body washing with chlorhexidine gluconate (CHG) swabs, and intravenous line antiseptic barrier capping, decrease but do not eliminate the occurrence of CLABSI. In 2025, data from a 17 bed ICU study of an intervention that combined the combination of CHG intravenous line dressing and the use of touch free aseptic disposable single use stethoscope diaphragm covers, was reported. This combination strategy resulted in CLABSI rates that declined to 0%, and which were sustained at 0% for more than 1 year. Failing to provide a clean contact with the hands is potentially fatal for selected patients. It is likely that is the same for the stethoscope for which the addition of a aseptic barrier may save thousands of lives.

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Introduction

Consistent with Koch’s postulates¹, in 1861 Ignaz Semmelweis recognized that our hands, by touching patient after patient, transferred pathogens between every contact². The publication of his seminal work resulted in a major improvement in public health. This critical insight remains today; anything with direct patient contact, that is used serially between patients, will result in a dangerous transfer of pathogens, just like hands. Somehow this concept, as applied to the stethoscope, has missed the memo for more than 164 years.

In current clinical practice any vehicle that sequentially touches more than 1 patient is to be cleaned (or eliminated from use), before coming in contact with another patient.  Included in this practice are endoscopes, speculums, otoscopes, laryngoscopes, etc. which, per Spaulding’s criteria, require high-level disinfection.  Consistent with these recommendations is that devices that touch a second patient should undergo at least low-level disinfection, or be discarded. Unfortunately, the CDC guidelines (updated in June 2024)³, define the stethoscope as a non-critical surface that should be washed, but without a frequency specification.  Spaulding’s criteria defines surfaces as non-critical, thus requiring low risk decontamination, for intact skin.  However, in the setting of a central line, the skin is not intact and reconsideration of the stethoscope is warranted.

Stethoscope Hygiene

It is curious that the stethoscope has not garnered the same degree of concern as the hands. Data clearly shows that when cultured, the stethoscope diaphragm has the EXACT same pathogens as the hands, and at times in even greater quantities^4,5,6. For these reasons, some have termed the stethoscope as the clinician’s 3^rd hand⁷. As such, it would be reasonable that the third hand undergo similar strategies to prevent pathogen transmission as the clinician’s anatomic hands.

Unfortunately, the performance of 3^rd hand hygiene does not match that of the anatomic hands.

Many hospitals have adopted hand hygiene audits and observers (secret shoppers) to ensure compliance with their hand hygiene policy and procedures.  Quality departments have implemented extensive processes to observe, record, and report measurements that confirm their institutions hand hygiene practice. However, the pathogen covered 3^rd hand, a tool that touches patient’s as frequently as the hands, is largely ignored and its hygiene performance rarely, if ever, measured or reported.

Strategies To Improve Pathogen Transmission by the Stethoscope

Some institutions have adopted a stethoscope pathogen transmission defense strategy of trying to wash their way out of the stethoscope challenge, similar to hand washing practice. But while a “washing the hands” strategy is effective for the hands, unfortunately this doesn’t work for the stethoscope.  Numerous studies with the intent to increase stethoscope hygiene have failed^7-13. In fact not a single study has ever demonstrated success in providing a clean stethoscope contact for the patient.  The cause of these failures are multifactorial.  Cleaning the stethoscope is a tremendous workflow challenge¹⁴. To diligently clean the stethoscope diaphragm for 60 seconds with an alcohol swab before and after every patient (the time required to provide maximal benefit) represents a significant work-flow challenge. Moreover, even if diligently cleaned with alcohol for 60 seconds, studies have shown that the best efforts at cleaning still leave a contaminated stethoscope diaphragm, as proven by diaphragm cultures, in 28% of cases (due to the challenge of cleaning the junction between the diaphragm and its retaining metal ring)¹⁵.

Many institutions have attempted to limit stethoscope pathogen transmission by the implementation of single patient use, disposable stethoscopes. However, the acoustic quality of disposable stethoscopes is so poor that it is proven to be potentially harmful to patients. One simulation mannequin study of 880 auscultations reported a 0% misdiagnosis rate when physicians used their personal stethoscope¹⁶. This misdiagnosis rate was unchanged with or without the touch free applied, disposable, diaphragm barrier (DiskCover©, Aseptiscope, Inc, San Diego, CA), which supports the fact that this disposable diaphragm barrier is acoustically invisible. However, the 0% misdiagnosis rate with the barrier protected personal stethoscope compares to a 10.9% misdiagnosis rate when the disposable stethoscope was used¹⁶. There is no practice standard in healthcare that would accept an avoidable 10.9%  misdiagnosis rate. 

Further challenges to the disposable stethoscope are studies demonstrating Multi-Drug-Resistant Organisms (MDROs) on the earpieces of shared, single patient, disposable stethoscopes¹⁷. Ultimately, shared disposable stethoscopes simply shift the pathogen risk  from that of the patient to that of the staff.  With its acoustic and infectious challenges, the disposable stethoscope is not a viable solution to address the spread of pathogens by stethoscopes.

New Options for Stethoscope Hygiene

Successful alternatives to disinfecting the stethoscope diaphragm have been reported, but resistance to adoption has been significant when it does not fit into clinician workflow. Quality improvement success is predicated upon solutions that do not complicate but instead simplify the process. The most successful strategy to date¹⁴ has been the hands-free application of a disposable stethoscope diaphragm cover, as mentioned above.  This inexpensive, disposable cover is applied in less than 2 seconds from a touch-free dispenser, does not alter the acoustic properties of the stethoscope, does not interfere with clinician workflow and provides an aseptic point of contact 100% of the time^{18, 19}. The fact that the most effective stethoscope cleaning requires 60 seconds of alcohol swab scrubbing (and yet even then pathogens commonly persist)²⁰, suggests the 2 second application of an aseptic barrier will represent a large improvement in clinical workflow. 

In the current clinical environment, it is obvious pathogen transmission between patients and staff continues at an egregious rate. As reported by the CDC²¹, there are estimated 687,000 HAIs, with 72,000 deaths in the US each year. Infections are most likely spread between staff, and from staff to patient, by the hands. It seems logical if the same pathogens on the hands are also on the stethoscope, the stethoscope is a mode of transmission as well. Extensive modeling data exists^22-24 identifying that pathogen transmission occurs by the stethoscope, but until recently, prospective clinical data demonstrating resulting infections was lacking.

HAIs are avoidable events, and of these, Central Line-Associated Blood Stream Infections (CLABSI) are particularly harmful and deadly. In fact, a recent meta-analysis of 16 CLABSI studies reported an odds ratio for acute mortality of 3.19 (95% confidence interval = 2.44-4.16) and a 16.14 day (95% CI: 9.27-23.01) increased length of hospitalization for CLABSI vs. uninfected controls²⁵. The ability to mitigate CLABSI rates and their consequences, would represent a major advance in infection prevention. Although decreasing the incidence of CLABSI’s has been demonstrated, the elimination of CLABSI has been challenging.

Eliminating Clabsi

Two strategies^{26, 27}, both evaluated in large meta-analyses, have shown partial efficacy in decreasing CLABSI rates. The first (26) used intravenous line antiseptic barrier caps (ABCs) containing either 70% isopropyl alcohol or chlorhexidine gluconate (CHG) vs. standard care, to decrease variation of central line hygiene time and techniques.  They reported that in 273,993 catheter days there were 391 CLABSIs with ABCs vs 620 CLABSIs with standard care (risk ratio = 0.65; 95%CI 0.55-0.76)²⁶. The second²⁷strategy used 2% CHG wipes for daily body bathing and found a CLABSI risk reduction of 48% vs. conventional bed bathing (risk ratio 0.52; 95% confidence interval, 0.37-0.73), although it did not significantly change ICU length of stay or mortality rates²⁷. While both interventions resulted in decreased CLABSI rates, neither resulted in the elimination of CLABSI.

Most recently, the results of a novel CLABSI prevention strategy were presented as an abstract at the American Association of Critical Care Nurses (AACN) National Teaching Institute (NTI) meeting in New Orleans, Louisiana, May 2025²⁸.In this study, the authors reported the results of a before and after evaluation in a 17 bed ICU of the use of a CHG intravenous line dressing combined by the implementation of a touch free, disposable, stethoscope diaphragm cover for all clinical contacts (a dispenser was placed in each patient’s room, see figure 1, Aseptiscope, San Diego, CA).

They reported a mean ICU CLABSI rate of 3.49 infections/1,000 line days at the beginning of the study, decreasing to a mean 0.97 infections/1,000 line days after the implementation, with a 0% rate over the subsequent 12 months. While these outstanding results require validation in other populations and environments, this is one of the first studies that has prospectively demonstrated the clinical impact of quality stethoscope hygiene when added to an intervention that already demonstrated an improvement in decreasing CLABSI rates.

It is reasonable to consider  if hand hygiene prevents the transmission of pathogens between patients, eliminating the serial patient contaminant of the stethoscope could have similar effect.

Why Clabsi Prevention Requires Antisepsis and Stethoscope Hygiene

It should also be considered that while CHG dressing, alone or in combination with CHG bathing, has not historically resulted in the complete elimination of CLABSI, could the addition of a touch free applied disposable aseptic stethoscope barrier be the important added component to this intervention bundle? It is likely that CLABSI elimination may require multiple sequential barriers; adding sterile diaphragms appears to close the gap.  Considering that in large studies neither CHG dressings, nor CHG bathing, alone resulted in the complete elimination of CLABSI, it is reasonable to consider that the addition of stethoscope hygiene may have been the missing strategy for the elimination of CLABSI.

An important consideration of this strategy is that the disposable aseptic stethoscope barrier is applied using a touch-free device, thus reducing potential barrier contamination during placement. While only recently available in the US, the touch-free application is likely an important aspect of this CLABSI prevention intervention.  This is because applying a cover on the stethoscope with the clinician’s hands would simply insure that hand pathogens were put on the stethoscope. Alternatively, if the hands were washed before applying the stethoscope diaphragm barrier, the hands would simply become contaminated by the pathogens on the stethoscope, during the application of the barrier. Finally, it is critical that the aseptic cover is used for a single patient contact, as prior studies of covers left on for up to a week found increased pathogens as compared to an uncovered diaphragm²⁹.

Limitations

Lastly, the above-mentioned CLABSI study is not without limitations. It was performed in a single ICU and only reported data for 18 months. However, a 0% CLABSI rate is not insignificant, especially when other strategies have been effective at decreasing, but not eliminating CLABSI rates.

With the increasing data on the clinical significance of stethoscope hygiene and its potential benefits to patient care, regulatory recommendations have begun to be published. The Association of Operating Room Nurses (AORN) recently published guidelines³⁰ stating stethoscopes should not be worn around the neck, should not have fabric covers, and should be cleaned before and after each use. Secondly, although not released in a final form at the time of this article, the draft format of the most recently updated CDC guidelines regarding stethoscope hygiene identifies that the stethoscope can be a pathogen vector that transmits via touch³¹. The CDC has updated their recommendations to indicate that all patients should receive a clean stethoscope contact with every usage.

Conclusions

Ultimately, the failure of stethoscope hygiene is likely to have negative consequences for patients. Unfortunately, simply washing it with alcohol pads does not work, especially against alcohol resistant microbes. It is promising that a bundled intervention including CHG dressing and aseptic diaphragm barriers dramatically reduced CLABSI.

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