Where should bilateral breath sounds be assessed on an infant?

Assessment of Bilateral Breath Sounds in Infants

Bilateral breath sounds in infants should be assessed by listening over both axillae (armpits), as this location provides the most reliable assessment of equal air entry to both lungs. 1

Optimal Auscultation Location

• Listen specifically over the axillae bilaterally to assess for equal breath sounds, as recommended by the American Heart Association guidelines for pediatric advanced life support 1
• The axillary location minimizes transmitted sounds from the upper airway and provides the clearest assessment of actual lung aeration in each hemithorax 1

Complete Assessment Technique

When verifying proper ventilation or endotracheal tube placement in infants, perform the following systematic assessment:

• Look for bilateral chest movement as a visual indicator of symmetric lung expansion 1
• Auscultate over both axillae for equal breath sounds bilaterally 1
• Listen over the stomach to ensure gastric insufflation sounds are absent, which would indicate esophageal rather than tracheal positioning 1
• Observe for condensation in the endotracheal tube if intubated 1

Critical Pitfall to Avoid

Auscultation of bilateral breath sounds alone does not reliably rule out endobronchial (mainstem) intubation in children and infants. 2 Research demonstrates that:

• Endobronchial intubation occurred in 11.8% of pediatric patients despite auscultation confirming bilateral breath sounds 2
• This failure rate was particularly high in children under 10 years of age and infants under 12 months 2
• The Murphy eye on endotracheal tubes allows air entry even when the tube tip is in a mainstem bronchus, creating falsely reassuring bilateral sounds 2

Additional Confirmation Methods

Beyond axillary auscultation, use these adjunctive methods for complete assessment:

• Exhaled CO2 detection remains the most reliable method for confirming endotracheal tube placement in the trachea (versus esophagus) in neonates with adequate cardiac output 1
• Chest radiography should be performed in hospital settings to verify the tube is not in a bronchus and is positioned in the midtrachea 1
• Direct laryngoscopy can visualize tube position between the vocal cords if uncertainty persists 1
• Pulse oximetry provides assessment of oxygenation, though saturation may not decline for up to 3 minutes after hyperoxygenation even without effective ventilation 1