the following section the patterns of lung sounds presented will be illustrated
from actual tracings of patients with lung diseases who have been recorded
using a multichannel lung sound analyzer, Stethograph or STG for short.
This device collects data from 16 channels simultaneously. Microphones
can be placed on the patients chest in a variety of configurations,
but for simplicity the patterns seen in common lung diseases are presented
with the placement shown below.
electronic stethoscopes are incorporated in a foam back pad shown here.
A disposable, fluid impervious covering covers the pad during patient
application. One microphone is applied on the trachea and one on the heart.
Patients comfortably lie on the back pad during recording. Following the
recording the computer automatically calculates crackles and wheezes and
displays their location on the chest as well as their timing in the respiratory