Breath sounds part 1- crackles

#KYJ- knowing your jargon
Breath sounds, part 1.

Rattles, rales, crackles n creeps, Wheezes, and Rhonchi.

When I teach nurses about breath sounds, I always ask who does them, and who does them confident in the knowledge that they can name them.  In an average class of 25 nurses, 5-7 put up their hand indicating they auscultate chests, but only 1-2 of these (about 5-8% of all nurses) attending my nursing assessment classes, or respiratory nursing classes, agree they can identify different breath sounds.

Here is my simplified version of the terminology (our biggest hurdle).

Pitch (highs and lows)
Let's start with a beautiful pipe organ in a cathedral.  You know the ones I mean, huge gilded pipes arranged artistically around a dual layered keyboard and foot pedal system.  When a low note is struck, deep, chocolate vibrating sound emanates from the largest pipes.  When a high note is played, the tone bursts from the smallest pipes.

Lungs are similar.  As air rushes through them, the pipes (bronchi and bronchioles) vibrate producing noise audible with the diaphragm (flat surface) of the stethoscope.  Large airways towards the centre of the chest produce low pitch deep notes, and fine tubes on the outer periphery of the lung fields produce a higher pitch sound.... It's just like the pipe organ.

The first concept is this one of pitch. Low pitched sounds over the middle of a chest, high sounds in the outer reaches of the respiratory tree.

Next to master is the two major categories of abnormal sounds produced by diseased lungs.  Abnormal lung sounds are often called "Adventitious sounds".  They are lumped into two types.

Wet and squeezed.

1.  Wet sounds (crackles)
Wet sounds are produced as air moves through pipes filled with water and thin mucus. Typically heard in pulmonary oedema, wet sounds resemble that bubbly noise you made as a kid, sucking the last dregs of a milkshake through a straw.  Don't lie, I know you did.

Wet sounds are collectively called crackles, and depending on where in the lungs they are, they will produce a different pitch.

In smaller peripheral airways, the sounds are high pitched, so these crackles are called creps or fine crackles. Typical in pulmonary oedema, pneumonia, and chest infections.

In larger bronchioles and bronchi, the sound is lower pitch.  Still wet bubbling sounds, but lower in tone.  These crackles are commonly called Rales, or simply coarse crackles.  Typical of bronchitis.

If the wet sound is audible with no stethoscope, the gurgling sounds like comes from the back of the throat, it is fluid in the main bronchi, or trachea.  These sounds are called Rattles.  The gurgling death rattle common in an frail dying patient is a classic example.

Next episode we look at squeezy wheezes.
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