Respiratory Examination – Noisy Breathing


Definition: A short, explosive, moaning or crying sound heard on expiration (Child and neonates)

Cause: Any cause of respiratory distress

Mechanism: In attempt to increase FRC which helps to keep narrowed or collapsing airways open, creating a longer time for alveolar gas exchange

grunting mechanism


Definition: Non-musical, low pitched, snoring sound

Cause: Supra-laryngeal obstruction


Definition: Loud, intense, monophasic sound with constant pitch

Cause: Upper airway obstruction at and below level of vocal cord


  1. Inspiratory (Supra-glottic)
  2. Biphasic (Sub-glottic/glottic to tracheal ring)
  3. Expiratory (Tracheo-bronchial)


Definition: Continual, high-pitched musical sound heard at the end of inspiration or start of expiration

Cause: Asthma, RTI, COPD, Foreign Body aspiration, Cardiac asthma, Bronchiolitis

Mechanism: Vibration of airway wall due to increased velocity of air through narrowed airway

narrowed airway


  1. Monophonic: Fixed single pitch resulting from localized narrowing of a single airway (Bronchial tumor, Fixed Foreign Body)
  2. Polyphonic: Multiple simultaneous different pitched sound occurs during expiration and implies diffuse disease of different sized airways

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