Use of Bell of Stethoscope in Neonates
The Bell is NOT Specifically Recommended for Neonates
The bell of the stethoscope is not specifically recommended for neonatal auscultation, and in fact, standard practice uses the diaphragm for routine cardiac and respiratory assessment in newborns. The question appears based on a misconception—there is no guideline evidence supporting preferential use of the bell in neonates.
Why the Diaphragm is Preferred in Neonates
The diaphragm is the standard choice for neonatal auscultation because it captures the higher-frequency sounds that predominate in newborn cardiorespiratory assessment 1, 2.
Neonatal breath sounds have a mean frequency of approximately 334 Hz at 1 minute of life, decreasing to 303 Hz by 2 hours—these are mid-to-high frequency sounds best detected with the diaphragm 2.
Heart sounds and pathologic murmurs in neonates are also effectively captured using diaphragm-based technology, as demonstrated by piezoelectric sensors and electronic stethoscopes that function similarly to diaphragms 3, 4.
When the Bell Might Be Considered (Adult Context)
The bell is traditionally used in adults for detecting low-frequency sounds like the S3 heart sound, which occurs during rapid ventricular filling and indicates volume overload 5. However:
The S3 is actually a normal physiologic finding in most pregnant patients due to increased blood volume and cardiac output 5.
In neonates, the clinical context differs entirely—there is no evidence base for routine bell use in this population.
Modern Alternatives to Traditional Stethoscopes
Digital stethoscopes with amplification have shown superior performance in neonatal resuscitation, improving time to first heart rate recording (p < 0.001), total number of heart rate recordings (p < 0.001), and earlier recognition of heart rate changes (p = 0.009) 4.
Esophageal stethoscopes provide continuous monitoring of both breath and heart sounds in intubated neonates during transport, with minimal interference from ambient noise 6.
Point-of-care ultrasound (POCUS) has emerged as "the new clinical tool" that has displaced the traditional stethoscope in many critical care scenarios, particularly for neonatal cardiac assessment and detection of conditions like intraventricular hemorrhage 7, 8.
Clinical Pitfall to Avoid
Do not assume that principles of adult cardiac auscultation (such as bell use for low-frequency sounds) automatically translate to neonatal practice. The acoustic characteristics of neonatal cardiorespiratory sounds, combined with the smaller chest wall surface area, make the diaphragm the appropriate choice for routine assessment 2, 3.