By Paul K. Reilley, BS-EMC, NRP and Steven L. Johnson, MHS, RN, NRP, CP-C, NCEE, CMTE
The stethoscope is the quintessential medical device and an essential tool in prehospital care, enabling EMS providers to quickly assess a patient’s cardiovascular, respiratory and gastrointestinal systems.
With the advent of in-hospital diagnostic imaging, the once-indispensable stethoscope has become a symbol more than a tool. However, prehospital clinicians rely daily on the stethoscope as a staple of their medical practice.
Proper usage, recognizing assessment discrepancies, and understanding factors influencing its effectiveness are crucial to providing quality patient care.
This article explores these facets while considering the unique needs of various patient populations.
In the deep, resonant tones that only Morgan Freeman can deliver, “In a world dominated by advanced in-hospital diagnostic imaging, the stethoscope has transcended its original purpose, evolving into a symbol of medical professionalism. Join us as we navigate this vital instrument’s role in the intricate tapestry of healthcare, reminding us that even in a world of technology, the art of listening remains a cornerstone of medicine.”
Appropriate Use of the Stethoscope
In the prehospital setting, the stethoscope serves primarily to auscultate heart, lung and bowel sounds and measure blood pressure. EMS providers use it during initial assessments and ongoing monitoring to detect abnormal sounds that may indicate conditions such as pneumonia, congestive heart failure, bowel obstruction, or types of shock.
Correctly diagnosing these disease processes means the difference between life and death for the patient. We will analyze the use of the stethoscope through three different components: The patient, the clinician, and the stethoscope, the humble tool that connects the first two.
The Patient
Anytime clinicians use a stethoscope, they must consider patient anatomy, which can significantly impact the function of the stethoscope. Standard stethoscopes suffice for most adults, as adults are the most common patient population.
However, infants and young children require pediatric stethoscopes for subtle sounds. At the same time, their age-inverted counterparts, geriatric patients, may present additional challenges due to decreased skin elasticity, thicker chest walls or spinal deformities.
Adjusting positioning and technique based on internal and external anatomical differences due to age ensures accurate assessments and is a hallmark of a high-quality clinician.1
Emergency patients often move or are uncooperative, either willingly or unwillingly, complicating auscultation. Providers must stabilize patients and adapt their techniques to obtain accurate findings. Quick, efficient positioning is vital in these scenarios.2
This may involve verbally calming your patients, pharmacological interventions, pain medications, or, in rare cases, restraining the patient until the necessary assessments can be performed.
The Clinician
The chest piece should contact bare skin for optimal sound quality.
Accurate auscultation begins with proper patient and stethoscope positioning. Assessment discrepancies often arise from improper technique, environmental noise or user auditory acuity.
For example, placing the stethoscope over clothing or failing to secure the chest piece tightly against bare skin can result in inaccurate readings, as clothing muffles sound and can obscure findings.
In addition, inexperienced providers may misinterpret normal anatomical variations, such as different lung sounds over different lung fields, as abnormalities. High-quality stethoscopes, regular training, and auscultating every patient to obtain experience can mitigate these challenges, ensuring accurate sound transmission.
Providers should know the best anatomical sites for auscultation based on suspected conditions, and educators should regularly review these sites.2 However, high-quality stethoscopes may be cost-prohibitive for the individual or the department. To optimize stethoscope use, see the stethoscope maintenance section below.
Ambient noise—from sirens, traffic, or bystanders—is a significant daily challenge in prehospital settings. Noise-reducing stethoscopes have improved in quality and effectiveness and are a great tool for improving sound quality.
When possible, positioning patients in quieter areas is highly recommended, as it can also improve sound quality. Similarly, unnecessary equipment noise should be reduced to aid auscultation.
Differentiating lung and heart sounds is difficult enough without ambient noise. For example, crackles, wheezes, and pleural rubs may sound similar, even to the trained ear.
In addition to reducing ambient noise as much as possible, a solid understanding of pathophysiology and sound characteristics is crucial for effective auscultation.2
The Stethoscope
Recall from our previous article that stethoscopes have two sides—the bell and the diaphragm—each suited for specific types of sounds (see our last article). The diaphragm is characterized by the plastic film covering the opening and is more effective for high-frequency sounds, like breath sounds and normal heart sounds.
On the flip side, the bell is open-bottomed (like a bell!) and is better for low-frequency sounds like heart murmurs and some bowel sounds. The key takeaway: use the diaphragm when assessing lung sounds for wheezes, crackles, or diminished breath sounds, and switch to the bell when listening for bruits or low-pitched heart murmurs.
Knowing when to switch between the two is required to achieve diagnostic precision.
A decontaminated stethoscope is a happy stethoscope. Regular cleaning and maintenance are prerequisites to a successful “stethoscopy.” First, non-sanitized stethoscopes can transmit pathogens like MRSA, posing risks to patients. Patients often battle pathogens that demand the attention of their immune systems.3
A non-sanitized stethoscope can quickly become a fomite for MRSA, a scarily common finding on ambulances and a potential death sentence for immunocompromised patients.4
Cleaning the stethoscope after every patient encounter can easily save patients and their families from physical, psychological, and financial suffering. To that end, another beneficial tool is disposable stethoscope covers.
These operate like gloves for a stethoscope, and a growing body of evidence suggests disposable covers do not reduce sound quality, even being described as “acoustically invisible.”5
Following every patient encounter, check for earwax blocking the earpieces, then decontaminate the diaphragm, bell, and earpieces to prevent contamination and ensure quality sound transmission.
Extra Credit: Provider Apathy
A disturbing trend in EMS is apathy towards improving one’s clinical practice. Focusing on proper stethoscope use common retorts trend toward the non-necessity of diagnosing many diseases in the prehospital setting and, even if diagnosed, there is a lack of prehospital interventions available for these diseases.
However, recognizing abnormalities shapes transport decisions, prompts earlier hospital alerts, and guides treatments within the clinician’s scope, such as the aggressiveness of airway management or giving the hospital time to prepare for a pericardiocentesis.
Even if auscultation does not lead directly to prehospital action, it enhances and provides key data points that benefit the patient and the entire healthcare continuum.
To address this, EMS agencies should foster a culture of ongoing education. This change begins with leadership. Agencies should select field training officers and supervisors who model high standards in assessment practices and hold accountable those who do not.
Apathy, directly translated from the original Greek, means “without feeling,” which perfectly captures this issue. Clinicians must remember the excitement and joy they felt when they first began their journey to becoming medical professionals.
This excitement and joy is easier said than done, but it is a necessary step toward improving EMS as a field of medicine.
Conclusion
Mastering the stethoscope is essential for providing preeminent patient care in prehospital settings. Paramedics should focus on selecting the appropriate side of the stethoscope (diaphragm or bell) based on the clinical situation, understanding potential discrepancies in auscultation findings, and accounting for anatomical (think pediatric vs. adult) and situational factors, such as environmental noise.
Routine training and consistent practice in stethoscope use will improve patient assessment and improve patient care decision-making.
Training and awareness of these nuances ensure that providers use their stethoscopes to their full potential, ultimately improving patient outcomes in emergency settings.
The last article in our three-part series will cover everyday stethoscope observations and their diagnostic significance.
About the Authors
Paul Reilley is a passionate EMS educator with over a decade of experience, currently serving as EMS Training Captain at Cy-Fair (TX) Fire Department. Known for his creativity and problem-solving skills, Paul has developed innovative educational content and redesigned competency testing processes, emphasizing systematic patient assessment and care.
Steve Johnson is a performance-driven leader with 35 years in fire, rescue, EMS and critical care transport (Air and Ground). He currently is full-time faculty member at Western Carolina University in the Emergency Medical Care program. Steve is an active member and community paramedic with the Skyland (NC) Fire Department.
References
1. Texas A&M International University Online. (2019, December 2). Patient assessments throughout the lifespan. Retrieved January 9, 2025, from https://online.tamiu.edu/programs/nursing/rn-to-bsn/patient-assessments-throughout-the-lifespan/
2. Bickley, L. S. (2021). Bates’ Guide to Physical Examination and History-taking (13th ed.). Wolters Kluwer.
3. Monegro, A. F., Muppidi, V., & Regunath, H. (2023, February 12). Hospital Acquired Infections. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK441857/
4. Obenza A, Cruz P, Buttner M, Woodard D. Microbial contamination on ambulance surfaces: a systematic literature review. J Hosp Infect. 2022 Apr;122:44-59. doi: 10.1016/j.jhin.2021.12.020. Epub 2022 Jan 12.
5. Kalra S, Garri RF, Shewale JB. Aseptic Disposable Stethoscope Barrier: Acoustically Invisible and Superior to Disposable Stethoscopes. Mayo Clin Proc. 2021 Jan;96(1):263-264. doi: 10.1016/j.mayocp.2020.10.029. PMID: 33413829.
