Stethoscope diaphragms are contaminated with the same pathogens as the hands and they are capable of transmitting pathogens from patient to patient. The CDC should readdress its published guidelines.
In the United States, roughly 1.7 million healthcare-acquired infections (HAIs) occur annually in hospitals, resulting in total costs (direct, indirect, non-medical) estimated at up to $147 billion. Nearly 100,000 people die annually from HAIs in the acute care setting. Distressingly, when nursing homes are included, the number of annual deaths linked to HAIs soars to over 400,000. We appropriately employ tremendous effort to continually improve hand hygiene practices in hospitals, as hand hygiene is demonstrably the single most important practice to prevent and control HAIs—and, importantly, the effort has demonstrated a favorable impact. We also routinely use barriers to protect ourselves and our patients from infection—gloves for the hands, goggles for the eyes, gowns for the body, and covers for our shoes. In light of the persistent and stark reality of HAIs, however, opportunities to improve outcomes clearly exist, compelling us to address other fomites in the clinical setting.
The stethoscope, the most frequently used medical instrument with over 5.5 billion annual auscultations in the US alone, is commonly referred to as the “clinician’s third hand.” It is a ubiquitous, valuable clinical tool and an enduring symbol of the trust between healthcare providers and patients. Stethoscopes are a foundational tool in acute and clinic patient care settings. In addition to routine physical exams, various medical conditions demand thorough auscultation of the chest and abdomen for a comprehensive evaluation. Unfortunately, the stethoscope, carrying the same exact volume and diversity of pathogens as the clinician’s fingertips, is also a proven vector of disease transmission1.
Standard of Care Shortfall
It has become clear from the literature that the US Centers for Disease Control and Prevention (CDC) stethoscope cleaning guidelines are impractical and incompatible with the intensity of stethoscope use in the high-paced workflow characteristic of clinical settings. Recent observational studies reveal that stethoscopes are seldom cleaned between patients and, even when cleaning does occur, less than 4% of stethoscope diaphragms meet CDC cleanliness requirements2. Moreover, even in instances where cleaning techniques such as alcohol swabs are employed in accordance with the guidelines (60 seconds of continuous wiping), resistant and dangerous pathogens, such as c. difficile spores, frequently persist.
The CDC classifies the stethoscope as a non-critical surface, a characterization that does not reflect the severity of the transmission risk associated with its use. Additionally, the CDC states that weekly cleaning with alcohol is acceptable, unless the stethoscope diaphragm is visibly soiled. In light of the existing, and increasing, body of evidence demonstrating that stethoscope diaphragms are contaminated with the same pathogens as the hands and data showing that stethoscopes are capable of transmitting pathogens from patient to patient, the CDC should readdress its published guidelines on proper hygiene practices.
Disposable, “single-patient” stethoscope options, although increasingly popular in light of the COVID-19 pandemic, offer significantly compromised auscultation accuracy. An abstract presented at the American College of Emergency Physicians 2020 Annual Meeting showed that, in a study of >200 auscultations, nearly 11% of cardiac pathologies were misdiagnosed by clinicians using disposable stethoscopes3. Disposable stethoscopes also fail to address the fundamental risk of clinician-to-clinician infections from rotating use of a likely contaminated device4.
Alternative options for stethoscope hygiene have been limited. Individual patient stethoscope disk covers have been marketed but were not effective solutions because they required manually placing a clean disk cover on a contaminated stethoscope by hand, thereby contaminating the clinician’s clean hands. If clinicians, instead, placed the clean disk cover on the stethoscope before washing their hands, then the disk cover itself would become contaminated. Additionally, in both cases, the time required for this highly manual process proved to be incompatible with clinical workflow.
Although numerous interventions, educational programs, and attempts at improving stethoscope hygiene rates have been implemented over the years, none have proven successful. Each attempt to improve stethoscope hygiene has proven to be ineffectual, inconsistent, and almost never practiced. The roots of poor stethoscope hygiene practices are truly multifactorial in nature.
A 2012 study in the American Journal of Infection Control identified 6 factors behind poor stethoscope hygiene compliance across clinical settings5:
Effective, compliance-enhancing techniques are exemplified by routine, simple methods implemented in standard workflows. Best practices are those that are easily applied by multiple staff without workarounds.
Technologies to help eliminate human error are the most effective and ensure that providers do the right thing, each and every time. Hand sanitizer and gloves immediately visible at the entrance of patient rooms, for example, enhance their routine use. A solution designed to provide effective stethoscope hygiene between each patient examination must consider and address obstacles to compliance in the clinical setting. A system should be compact, allowing it to be installed in each hand hygiene station or patient room, and capable of holding a significant number of single use disk cover barriers before replacement is necessary. The system should be capable of displaying visual reminders of the benefit of effective hygiene to encourage compliance by clinical staff.
The aseptic single use disk covers that the system dispenses must be proven to prevent patient exposure to pathogens while not damaging the stethoscope diaphragm and not interfering with the acoustic quality of the auscultation. It must be easy to use—preferably with no formal training required—instantly and reliably applying disk covers to the diaphragms of professional stethoscopes on demand and fit into the regular workflow for healthcare providers. Lastly, such a system must be completely touch-free, ensuring the aseptic status of the disk cover for each patient examination. As patients are alarmingly and continually exposed to unclean stethoscopes, we now know that stethoscope transmission of pathogens from patient to patient can undermine the efforts of hand hygiene programs. Infection control professionals can partner with other clinical leaders (physicians, nurses) to educate and advocate for better stethoscope and hand washing hygienic practices. Effectively promoting “third hand” hygiene best practices could reduce infection rates. In turn, Infection control professionals can decrease healthcare costs (including reducing antibiotic use and complications) while improving the patient experience—the three cornerstones of the Institute for Healthcare Improvement’s “triple aim.”
ALPESH AMIN, MD, MBA, MACP, SFHM, FACC, FRCP (LOND), is a Professor of Medicine, Public Health, Nursing Science, and Biomedical Engineering and Executive Director of the Hospitalist Program at the University of California, Irvine. Dr. Amin also serves as a scientific advisor for AseptiScope (www.aseptiscope.com).