Reference — Fundamentals
Breath Sounds Quick Reference
The normal breath sounds and the adventitious ones layered on top of them — what each sounds like, when in the breath cycle it appears, and the conditions that produce it. Built to scan at the bedside.
Written by Apex Respiratory Editorial Team
Educational use only. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Overview
Auscultation answers two questions: is air moving normally, and is anything abnormal layered on top? Identify the expected normal sound for each location first, then listen for adventitious sounds — crackles, wheezes, rhonchi, stridor, or a rub. Compare side to side at matching levels, and listen through at least one full inspiration and expiration at each point.
Normal Breath Sounds
| Sound | Quality | Where It’s Normal | Notes |
|---|---|---|---|
| Vesicular | Soft, low-pitched | Over most of the peripheral lung fields | The normal sound over healthy lung; inspiration longer than expiration |
| Bronchovesicular | Medium pitch and intensity | 1st and 2nd intercostal spaces anteriorly and between the scapulae | Normal in these central locations; inspiratory and expiratory phases roughly equal |
| Bronchial / tracheal | Loud, high-pitched, hollow | Over the trachea and manubrium | Normal over the trachea; abnormal if heard over the lung periphery, where it suggests consolidation |
Adventitious Breath Sounds
| Sound | Timing | Quality | Common Causes |
|---|---|---|---|
| Fine crackles | Late inspiratory | Discontinuous, high-pitched; Velcro-like | Pulmonary fibrosis, early pulmonary edema, atelectasis |
| Coarse crackles | Inspiratory and expiratory | Discontinuous, low-pitched; bubbling | Airway secretions, pneumonia, pulmonary edema |
| Wheezes | Expiratory > inspiratory | Continuous, musical, high-pitched | Asthma, COPD, bronchospasm; a monophonic (single-tone) wheeze suggests focal obstruction |
| Rhonchi | Expiratory (may be both) | Continuous, low-pitched, snoring; clears with cough | Secretions in the large airways |
| Stridor | Inspiratory | Continuous, high-pitched; often audible without a stethoscope | Upper-airway obstruction (EMERGENCY): croup, epiglottitis, post-extubation edema, foreign body |
| Pleural friction rub | Inspiratory and expiratory | Grating, leathery; does not clear with cough | Pleuritis (inflamed pleural surfaces rubbing together) |
| Diminished / absent | Throughout | Reduced or absent air movement | Pneumothorax, pleural effusion, severe airflow obstruction, poor respiratory effort |
Stridor is an airway emergency. Inspiratory stridor signals upper-airway obstruction and demands immediate assessment — it is never a finding to chart and revisit later.
Clinical Notes
- Auscultate before and after therapy. Listen before and after a bronchodilator and before and after suctioning to gauge the response — clearing rhonchi after a cough or suction, or improved air movement after a bronchodilator, is the documentation that matters.
- A silent chest in asthma is ominous. Disappearing wheezes in a patient who is still working hard to breathe usually mean airflow has fallen too low to generate sound, not that the patient has improved.
- Stridor is an airway emergency. Croup, epiglottitis, post-extubation edema, and foreign-body aspiration all present with inspiratory stridor and call for urgent airway evaluation.
- Always compare side to side. Move the stethoscope symmetrically across matching levels; many findings — diminished sounds, a unilateral wheeze — are obvious only when the two lungs are compared directly.
Related Resources
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Bedside assessment of the patient.
- Bohadana A, Izbicki G, Kraman SS. Fundamentals of lung auscultation. N Engl J Med. 2014;370(8):744-751.