EMS Airway Management - Lungs Sounds

EMS Providers should have a solid understanding of normal lung sounds and be able to recognize those that are adventitious lung, as these can provide crucial information about a patient's respiratory status. 

Here’s an overview of the key points regarding lung sounds:

1. Normal Lung Sounds

• Vesicular Breath Sounds: These are the standard breath sounds heard over most of the lung fields. They are soft, low-pitched, and have a longer inspiratory phase than expiratory phase.
  • Characteristics: "Gentle rustling" sound, more prominent in the bases of the lungs.
  • Cause: Normal airflow through the large and small bronchi and alveoli.

2. Adventitious (Abnormal) Lung Sounds

Adventitious Sounds are additional lung sounds superimposed on normal breath sounds. They indicate an underlying pathology. They include:

Stridor

• Description: A high-pitched, harsh sound heard during inspiration.
• Cause: Caused by a partial obstruction of the upper airway (i.e., larynx).
• Common Conditions:
• Croup: Typically in children, caused by a viral infection that leads to inflammation.
• Epiglottitis: Life-threatening condition caused by bacterial infection.
• Airway Obstruction: Foreign body or severe anaphylaxis.
  
• Sound File: Stridor

Wheezing

• Description: High-pitched, musical sounds, typically heard during expiration (but can be heard on inspiration as well).
• Cause: Narrowing or obstruction of the lower airway (i.e., trachea)
• Common Conditions:
  • Asthma: Due to bronchospasm and inflammation.
  • COPD: From chronic airway obstruction.
  • Bronchiolitis: Inflammation of the small airways, common in infants.
• Sound File: Wheezing

Rhonchi

• Description: Low-pitched, snoring or gurgling sounds, often cleared with coughing.
• Cause: Secretions or mucus in the larger airways (i.e., bronchi; bronchioles)
• Common Conditions:
  • Chronic Bronchitis: Increased mucus production and obstruction.
  • Pneumonia: Accumulation of mucus and fluids.
  • Bronchiectasis: Chronic enlargement and inflammation of bronchi.
• Sound File: Rhonchi

Rales (Crackles)

• Description: Fine or coarse, popping or crackling sounds, more prominent during inspiration.
  • Fine Crackles: High-pitched, short, and intermittent.
  • Coarse Crackles: Low-pitched, bubbling or rattling.
• Cause: Fluid in the small airways (i.e., alveoli)
• Common Conditions:
  • Heart Failure (Pulmonary Edema): Fluid accumulation in the alveoli.
  • Pneumonia: Fluid or pus within alveoli due to infection.
  • Fibrosis: Stiffening of lung tissue.
• Sound File: Fine & Course

Pleural Friction Rub

• Description: Low-pitched, grating sound, like creaking leather, heard during both inspiration and expiration.
• Cause: Inflammation of the pleural layers causing them to rub together.
• Common Conditions:
  • Pleuritis: Inflammation of the pleura, often due to infection or autoimmune disorders.
  • Pulmonary Embolism: Can lead to pleuritic inflammation and pain.
• Sound File: Pleural Friction Rub

3. Other Abnormal Lung Findings

Pleural Effusion

• Description: Presence of fluid in the pleural space, usually causing a decrease in normal lung sounds over the affected area.

• Common Conditions:

  • Heart Failure: Increased hydrostatic pressure causes fluid leakage into the pleural space.
  • Infection (e.g., Pneumonia): Inflammatory fluid accumulation.
  • Cancer: Malignant pleural effusions.

• Physical Exam Findings:

  • Decreased breath sounds over the affected area.
  • Dullness to percussion due to fluid presence.

Key Points for EMS Providers

• Stridor is a red flag indicating upper airway obstruction — immediate airway assessment is critical.

• Wheezing typically suggests lower airway narrowing; listen carefully to both inspiratory and expiratory phases.

• Rhonchi may indicate the need for airway clearance (e.g., suctioning).

• Crackles (rales) suggest fluid in the lungs — think about causes like heart failure or infection.

• Pleural Friction Rub can indicate pleuritic pain and requires assessment for underlying conditions like pleuritis or PE.

• Assess for Patient Symptoms: Correlate lung sounds with symptoms (e.g., shortness of breath, cough, sputum production, chest pain) for a more complete clinical picture.

Recognizing and differentiating these sounds can help EMS providers make critical early decisions about management and transport.

Further Reading:

Alexander, M. & Belle, R. (2017) Advanced EMT: A Clinical Reasoning Approach (2nd Ed). Hoboken, New Jersey: Pearson Education

Bickley, L. S., & Szilagyi, P. G. (2020) Bates' Guide to Physical Examination & History Taking (13th Ed). Philadelphia, Pennsylvania: Wolters Kluwer.

Bohadana, A., Izbicki, G., & Kraman, S. S. (2014) Fundamentals of Lung Auscultation. New England Journal of Medicine, 370(8): 744-751. Accessed October 8, 2024

Brown, C. A. (2022) Walls Manual of Emergency Airway Management (5th Ed). Philadelphia, Pennsylvania: Lippincott, Williams & Wilkins.

Bledsoe, B. E., Cherry, R. A. & Porter, R. S (2023) Paramedic Care: Principles and Practice (6th Ed) Boston, Massachusetts: Pearson

Mistovich, J. J. & Karren, K. J. (2014) Prehospital Emergency Care (11th Ed). Hoboken, New Jersey: Pearson Education

Sarkar, M., Madabhavi, I., Niranjan, N., & Dogra, M. (2015) Auscultation of The Respiratory System. Annals of Thoracic Medicine 10(3):158-168. Accessed October 8, 2024