Pulmonary Concepts In Critical Care
Breath Sounds

I.  Ausculation
    A.  The best way to assess breath sounds.
    B.  Make environment as quite as possible before starting assessment.
    C.  If possible, place patient in setting position or on side of bed. 
    D.  Drape the patient.
    E.  The stethoscope should be warmed before use.
    F.  Ausculate in a symmetrical  manner. 
        1.  First listen to the left side, then listen to the right side in the same location to determine if there's any difference. 
        2.  It's a good idea to start with the apex of the lungs and then move from side aside as you approach the basis.    
        3.  Do it the same way, in the same sequence, every time. 
        4.  If you get abnormal breath sound it is best to  locate its exact extent and character.
II. Categories of  Breath Sounds
    A. Categorized according to their location; pitch, intensity, and inspiratory to expiretory ratio.    
        1.  As air travels through the bronchial tree and pulmonary branches breath  sounds are produced. 
        2.  This turbulence is created with each expiration as well as inspiration. 
        3.  When there are no obstructions to the airways normal air movement occurs, this is normal breath sounds. 
        4.  However, when there is an obstruction, by such things as constriction, fluid, or hyperexpansion, abnormal breath sounds will occur.   
    B. Tracheal Breath Sounds.
        1. Usually relatively high pitched and loud.   
        2.  Equal in length
        3.  Best heard in the neck over the trachea. 
    C.  Vesicular Breath Sounds
        1.  Major normal breath sound and is heard over most of the lungs.
        2.  They sound soft and low-pitched.
        3.  The inspiratory sounds are longer than the expiratory sounds.
        4.  Sounds may be harsher and slightly longer if there is rapid deep ventilation.
        5.  May be harsher and longer in children and frail, elderly obese or muscular.
    D. Bronchial Breath Sound
        1.  Sounds are very loud, high-pitched and sound close to the stethoscope.
        2.  There is a gap between the inspiratory and expiratory phases of respiration.
        3.  The expiratory sounds are longer than the inspiratory sounds.
        4.  If these sounds are heard anywhere other than over the manubrium, it is usually an indication that an area of consolidation exists (ie space that usually contains air now contains fluid or solid lung tissue).
    E, Bronchovesicular Breath Sounds
        1.  These are breath sounds of intermediate intensity and pitch.
        2.  The inspiratory and expiratory sounds are equal in length.
        3.  They are best heard in the 1st and 2nd ICS (anterior chest) and between the scapulae (posterior chest) - ie over the mainstem bronchi.
        4.  As with bronchial sounds, when these are heard anywhere other than over the mainstem bronchi, they usually indicate an area of consolidation.

III.  Abnormal Breath Sounds
    A.  Absent or Decreased Breath Sounds
        1. There are a number of common causes for abnormal breath sounds, including:
            a.  ARDS: decreased breath sounds in late stages
            b.  Asthma: decreased breath sounds
            c.  Atelectasis: If the bronchial obstruction persists, breath sounds are absent unless the atelectasis occurs in the RUL in which case adjacent tracheal sounds may be audible.
            d. Emphysema: decreased breath sounds
            e. Pleural Effusion: decreased or absent breath sounds. If the effusion is large, bronchial sounds may be heard.
            f. Pneumothorax: decreased or absent breath sounds
    B. Bronchial Breath Sounds in Abnormal Locations
        1.  Bronchial breath sounds occur over consolidated areas.
        2.  Further testing of egophony and whispered petroliloquy may confirm your suspicions.

IV.  Adventitious Breath Sounds
    A. Crackles (Rales)
        1.  Crackles are discontinuous, nonmusical, brief sounds heard more commonly on inspiration.
        2.  They can be classified as fine (high pitched, soft, very brief) or coarse (low pitched, louder, less brief).
        3.  Pay special attention to their loudness, pitch, duration, number, timing in the respiratory cycle, location, pattern from breath to breath, change after a cough or shift in position.
        4.  Crackles may sometimes be normally heard at the anterior lung bases after a maximal expiration or after prolonged recumbency.
        5.  The mechanical basis of crackles
            a.  Small airways open during inspiration and collapse during expiration causing the crackling sounds.
            b. Another explanation for crackles is that air bubbles through secreations or incompletely closed airways during expiration.
                - ARDS
               - chronic bronchiti
                - consolidation

                - early CHF

                - interstitial lung disease
                - pulmonary edema
    B. Wheeze

        1.  Wheezes: continuous, high pitched, hissing sounds heard normally on expiration also sometimes on inspiration.
        2.  Produced when air flows through airways narrowed by secretions, foreign bodies, or obstructive lesions.
        3.  Note when the wheezes occur and if there is a change after a deep breath or cough. Also note if the wheezes are monophonic (suggesting obstruction of one airway) or polyphonic (suggesting generalized obstruction of airways).

            -  Causes
            -  CHF
            -  chronic bronchitis
            -  COPD
            -  pulmonary edema
    C. Rhonchi
Rhonchi are low pitched, continous, musical sounds that are similar to wheezes.
        2. They usually imply obstruction of a larger airway by secretions.
    D. Stridor
        1.  Stridor is an inspiratory musical wheeze heard loudest over the trachea during inspiration.
        2.  Stridor suggests an obstructed trachea or larynx and therefore constitutes a medical emergency that requires immediate attention.
    E.  Pleural Rub
        1.  Pleural rubs are creaking or brushing sounds produced when the pleural surfaces are inflammed or roughened and rub against each other.
        2.  They may be discontinuous or continuous sounds.
        3.  They can usually be localized a particular place on the chest wall and are heard during both the inspiratory and expiratory phases.

               - Conditions:
            -  pleural effusion

            -  pneumothorax

      F.  Mediastinal Crunch (Hamman's Sign)
        1.  Mediastinal crunches are crackles that are synchronized with the heart beat and not respiration.
        2.  They are heard best with the patient in the left lateral decubitus postion.
        3.  As with stridor, mediastinal crunches should be treated as medical emergencies.

                -  Conditions:
                -  pneumomediastinum
Type Characteristic Intensity Pitch Description Location
Normal tracheal loud high harsh; not routinely auscultated over the trachea
vesicular soft low . most of the lungs
bronchial very loud high sound close to stethoscope; gap between insp & exp sounds over the manubrium (normal) or consolidated areas
bronchovesicular medium medium . normally in 1st & 2nd ICS anteriorly and between scapulae posteriorly; other locations indicate consolidation
Abnormal absent/decreased . . heard in ARDS, asthma, ateletasis, emphysema, pleural effusion, pneumothorax .
bronchial . . indicates areas of consolidation .
Adventitious crackles (rales) soft (fine crackles) or loud (coarse crackles) high (fine crackles ) or low (coarse crackles) discontinuous, nonmusical, brief; more commonly heard on inspiration; assoc. w/ ARDS, asthma, bronchiectasis, bronchitis, consolidation, early CHF, interstitial lung disease may sometimes be normally heard at ant. lung bases after max. expiration or after prolonged recumbency
wheeze high expiratory continuous sounds normally heard on expiration; note if monophonic (obstruction of 1 airway) or polyphonic (general obstruction); assoc. w/ asthma, CHF, chronic bronchitis, COPD, pulm. edema can be anywhere over the lungs; produced when there is obstruction
rhonchi low expiratory continuous musical sounds similar to wheezes; imply obstruction of larger airways by secretions .
stridor . inspiratory musical wheeze that suggests obstructed trachea or larynx; medical emergency heard loudest over trachea in inspiration
pleural rub . insp. & exp. creaking or brushing sounds; continuous or discontinuous; assoc. w/ pleural effusion or pneumothorax usually can be localized to particular place on chest wall
mediastinal crunch . not synchronized w/ respiration crackles synchronized w/ heart beat; medical emerg.; assoc. w/ pneumomediatstinum best heard w/ patient in left lateral decubitus position