The assessment technique of auscultation involves listening to the body. Although this is typically performed with a stethoscope, you can sometimes hear sounds from the body using just your ear. For example, you have probably heard your own or another person’s stomach growling; another example is heavy breathing after exercise.

You can perform auscultation on the body to hear several sounds including:

• High-pitched sounds like lung sounds, bowel sounds, and some heart sounds.
• Low-pitched sounds like some heart sounds, as well as sounds associated with abnormal vascular sounds of the carotid arteries and the aorta.

To perform auscultation, you need a high-quality stethoscope. See Figure 13 for an acoustic stethoscope with a separate diaphragm on one side and a bell on the other side. The diaphragm is used for auscultating high-pitched sounds, while the bell is used for auscultating low-pitched sounds. Another option is an acoustic stethoscope in which the diaphragm and bell are manufactured as one piece: using this type of stethoscope, you can alternate pressure to auscultate for high- or low-pitched sounds, using light pressure to accentuate low-pitched sounds and firmer pressure to accentuate high-pitched sounds. There are also electronic stethoscopes to help amplify sounds for people with hearing loss. Some advanced stethoscopes facilitate better ambient noise reduction, sound amplification, and capability to record sounds (Leng et al., 2015). Unlike electronic stethoscopes, an acoustic stethoscope does not amplify the body’s sounds; it simply reduces interference from extraneous noises around you.

Figure 13: Stethoscope with a separate diaphragm and bell

Use of the stethoscope

Proper use of a stethoscope involves several steps.

1. Begin by explaining the procedure and asking permission to touch.
2. Next, create a quiet environment. Turn off or mute the sound on cell phones, radios, or televisions. Ask the client to not speak or move while you are listening. Also, many clinical environments have ambient noise that you cannot control, particularly in hospitals, when beds are close together, or in an open concept unit such as an emergency room. You will need to focus your hearing; it may help to close your eyes when listening.
3. Third, cleanse the stethoscope. The stethoscope is a potential vector of transmission that can carry pathogenic bacteria (Horiuchi et al., 2018; Tschopp et al., 2016). Clean the entire stethoscope using an alcohol pad on the earpieces and the end piece immediately prior to use. Always clean the stethoscope from cleanest to dirtiest areas, therefore earpieces first and bell/diaphragm last.
4. Next, place the earpieces in your ears so that they are pointing toward your nose as per Figure 14. This positioning aligns with the angle of your ear canal and enhances your capacity to hear. You may need to wiggle them into place so that they are comfortable and angling down your ear canal.
5. Last, open or close the diaphragm or bell depending on which end piece you want to use. It is important to tap on the diaphragm to ensure sounds are heard if using the diaphragm or not heard if using the bell. See Film Clip 2 on how to open and close the diaphragm and bell.

Figure 14: Positioning in the ears

Film clip 2: Opening and closing the stethoscope

Make note of your findings when performing auscultation. For example, findings may include “clear air entry bilaterally in all lobes” or “high-pitched gurgling bowel sounds present in all four quadrants.”

Activity: Check Your Understanding