Auscultation of Breath Sounds in IPF

Auscultation of Breath Sounds

Auscultation of the lungs is an important component of a physical examination because respiratory sounds provide vital information regarding the physiology and pathology of lungs and airways obstruction.1 The ability to distinguish normal breath sounds from various abnormal adventitious sounds is essential to make an accurate medical diagnosis.1 Breath sounds are generated by airflow in the respiratory tract and include normal and adventitious sounds.1 Adventitious sounds are additional respiratory sounds superimposed on normal breath sounds and usually indicate pulmonary disorders.1 For many years a complex, conflicting, and confusing body of terms was used to describe respiratory sounds.2 In order to establish a more objective naming system, in 1985 an ad hoc committee of the International Lung Sounds Association agreed on a nomenclature that divided adventitious sounds into 2 major categories: continuous sounds or wheezes, and discontinuous sounds or crackling noises (Table 1).2 These terms are defined acoustically (eg, frequency, duration, initial deflection width, etc) and do not assume a generating mechanism or location.34

Table 1.
Lung Sound Nomenclature. Adapted from Mikami R, et al. Chest. 1987;92:342-345.

Lung Sound Category Term
Discontinuous
FineHigh pitched, low amplitude, short duration Fine crackles
CoarseLow pitched, high amplitude, long duration Coarse crackles
Continuous
High pitched Wheezes
Low pitched Rhonchus