How Does It Work?
The diaphragm is basically a sealed membrane. It vibrates more or less like the eardrum. When it vibrates, it moves a column of air within the stethoscope down and up, which moves air into and out of the ear canal. The diaphragm’s surface area is significantly greater than the coinciding column of air moving in the tube. This therefore means that the air within the tube has to travel a greater distance than the diaphragm, which magnifies the pressure waves leaving the tip of the ear. It is the large pressure waves that make louder sounds. This is the mechanism of sound amplification in stethoscopes.
How to Wear a Stethoscope
Place the ear tips into your ears then twist them till they are slightly pointing forward and toward your nose. If done right, it makes a good seal and the sounds in the vicinity very faint.
How to Hold a Stethoscope
In most cases, you will have to hold the stethoscope’s chest piece in between the distal section of your middle and index finger on your dominant hand. This provides a better, firmer grip than when you use your fingertips at the edge of the bell or diaphragm, allowing you to press slightly and firmly against the patient but without letting your fingers rub it and create extra noise.
How to Place a Stethoscope on the Patient
For the best sound transmission, place the chest piece with the bell or diaphragm directly against the skin. If say you’re in a rush, try holding it against a very thin layer of clothing although it’s not recommended. Doing so could risk missing some nuances that could be very crucial in your examination.
What Can You Do With a Stethoscope?
Most clinicians tend to miss out on 80% of the tests they can perform on patients when using a stethoscope. A stethoscope can be used to measure blood pressure, assessing lung sounds, assessing heart sounds, assessing bowel sounds, detecting bruits and as a hearing aid.
What are the Functions of the Diaphragm and Bell in a Stethoscope?
The diaphragm is ideal for checking high-pitched sounds like normal heart sounds and breath sounds while the bell is better designed to detect lower-pitched sounds like some bowel sounds or heart murmurs. Essentially, the bell is used for detecting bruits and together with the diaphragm for heart sounds in a cardiac exam. When using the bell, hold it gently to the patient’s skin for the lowest sounds but more firmly for higher ones.
Some stethoscope such as the cardiology stethoscopes
only have a single sided head. This is because the diaphragm also acts as the bell. In single sided stethoscopes all you need to do is apply more pressure to zero down on the lower pitched sounds. So you can effectively zoom in and out to change the sound you want without have to flip the stethoscope head back and forth.
Stethoscope Infection Control
A stethoscope needs to be cleaned regularly. Stethoscopes have been found to be the frequent vectors of patient disease transmission. An easy way to keep all your patients from infections is to disinfect the chest piece surface with an antiseptic or alcohol prep pad.