Frequently Asked Questions About Littmann Stethoscopes
Q. I can’t hear anything out of my stethoscope. What is wrong with it?
A. If the acoustic performance seems to be lacking or absent, the following areas should be checked before assuming there is a problem with the stethoscope:
- Proper Headset Alignment - 3M™ Littmann® Stethoscopes have headsets which have been designed to be worn at an anatomically correct angle, oriented towards the user's ear canals. Wearing the stethoscope headset incorrectly can result in poor acoustic seal, and in some cases, complete sound blockage.
- Before placing the eartips in your ears, hold the stethoscope headset in front of you so that the eartubes point away from you. When the eartips are in your ears, the eartips should be pointed forwards.
- Not everyone's ear canals are the same. If after inserting the eartips in a proper manner, the fit does not seem comfortable and acoustic performance does not improve, grasp each of the eartubes, adjusting the headset for a custom fit.
- Proper Fit of Eartips - It is important that the proper sized eartips are used to achieve optimal acoustic performance. This is especially true when using the soft-sealing eartips. If the soft-sealing eartip is too large for the user, the compression of that eartip while in the ear could result in poor acoustic performance. This could also be true if the eartip is too small. Finding the correct size of the individual's ears results in the best acoustic performance.
- Obstruction - If the stethoscope is commonly carried in a pocket or hasn't routinely been cleaned, it is possible that somewhere in the sound pathway (chestpiece, tubing headset or eartips) there is something such as lint or dirt obstructing it.
- Complete Seal in the System - Stethoscopes rely on an airtight seal in order to transmit body sounds from the patient to the user's ear. Loose parts in the chestpiece, loose tubing or cracked tubing can prevent an airtight seal.
- Indexed Chestpiece - When using a doublesided stethoscope, the user needs to open, or index the bell or diaphragm by rotating the chestpiece. If the diaphragm is open, the bell will be closed, preventing sound from coming in through the bell, and vice versa.
- If all these issues have been addressed and it is still difficult to hear, your stethoscope will need to be returned for servicing or repair.
Q. Why does the tubing on my stethoscope become stiff and rigid?
A. The tubing used in all 3M™ Littmann® Stethoscopes is a PVC (polyvinylchloride) tubing that becomes hard when exposed for long periods of time to the lipids found in human skin. Wearing the stethoscope around the neck may cause stiffening of the tubing over time.
If worn around the neck, we recommend trying not to let it come in contact with skin by wearing it under a collar. It is also recommended that the tubing is treated with a vinyl protector such as Armor All® Protector once a month. This will not prevent stiffening, but may slow the process down.
Armor All® is a registered trademark of Armor All Products Corp, USA.
Q. Is there a difference in sound quality between long and short tubing?
A. Past publications have suggested that the shorter the tubing, the better the acoustic response. Laboratory testing has shown this to be true, but the average hearing person will only pick up a difference if there is an extreme increase in stethoscope tubing length. In fact, based on the manner in which sound waves travel, there is a slight advantage in low frequency sounds with longer tubing.
Most heart sounds are considered to be in the lower frequency range. Length of tubing seems to be a personal preference, based on physique and infection control issues viewed by the user.
Q. What is the sound difference (acoustic response) between one 3M™ Littmann® Stethoscope and another?
A. There are many factors that contribute to acoustic response, such as having a complete seal from the point of auscultation to the stethoscope user’s ear canal. External factors can also contribute. We can cite our laboratory test results, but these do not include factors like ambient noise, motion artefact and ear canal seal. Because of variables in each individual’s hearing, we recommend trying the stethoscopes before purchasing.
The price of the 3M™ Littmann® Stethoscope product range correlates to the laboratory test results in acoustic response. The 3M™ Littmann® Master Cardiology Stethoscope has the best acoustic response (5dB ‘louder’ than the 3M™ Littmann® Cardiology III Stethoscope. Keep in mind that these results are in the “low frequency” range (50-200 Hz) where one is listening to most heart sounds.
Q. How should I routinely clean my stethoscope? Can I sterilize it?
A. Avoid extreme heat, cold, solvent and oils. The stethoscope should never be immersed in any kind of liquid, or steam sterilized. If sterilization is required, it should be gas sterilized in a 3M™ Steri-Vac™ Sterilizer, followed by aeration for 36 hours in a 3M™ Steri-Vac™ Aeration Cabinet.
Q. Can I put a tunable diaphragm (like on the 3M™ Littmann® Cardiology III Stethoscope) on my old 3M™ Littmann® Cardiology II Stethoscope?
A. No. The new 3M™ Littmann® Cardiology III Stethoscope has an attenuating ring behind the diaphragm to make the tunable function possible. The old 3M™ Littmann® Cardiology II Stethoscope cannot be retrofitted to a 3M™ Littmann® Cardiology III Stethoscope.
Q. Can any of the 3M™ Littmann® Stethoscopes be used during an MRI?
A. No. All 3M™ Littmann® Stethoscopes contain metal.
Q. How do I know which type of replacement eartips to use on my stethoscope?
A. It is important to know whether your eartips are threaded or snap-tight. Older 3M™ Littmann® Stethoscopes have the threaded type. In early 1994, the more secure snap-tight eartips were introduced. Because of the design of the headset, snap-tight and threaded eartips are not interchangeable. If your stethoscope was made prior to mid-1994 and no other repairs have been made (ie: binaural replacement), the eartips should be threaded. These are available in soft-sealing, firm and hard white plastic and in both large and small sizes. If the stethoscope is newer than mid-1994, it uses snap-tight eartips, which are available in large and small, soft-sealing and firm. The white plastic eartips are not available in the newer stethoscopes. Most medical supply stores will know which eartips will fit on your stethoscope.