The tunable diaphragm is a 3M invention that allows you to listen to both low and high frequency sounds without the need to remove the chestpiece from the patient, turn it over, and reposition it.
By varying the pressure placed on the patient, a tunable diaphragm will adjust, or tune, the sounds to allow you to hear either low or high frequencies. When holding the tunable diaphragm on a patient and pressing lightly, low frequency sounds will be transmitted. When using the tunable diaphragm and pressing firmly, higher frequency sounds will be emphasized.
This convenience will save you time and allow you to focus on your patient instead of trying to determine if you should be listening to the bell or diaphragm side of the chestpiece.
First, it’s very important to wear the stethoscope properly. All Littmann stethoscopes have headsets that are angled and are designed to fit properly with your ear canals. Here’s the correct orientation: Hold the stethoscope with the eartubes vertical. When placing the eartips in your ears, be sure that the angled eartubes are pointing forward, toward your nose.
Once the stethoscope is correctly oriented, adjust the sound amplification by pressing the "+" and "-" buttons on the keypad. Make sure that the very center of the chestpiece is making good contact with the patient; this is the location of the sound sensor. If you still cannot hear any sound, contact 3M Technical Support at 1-800-228-3957 or use the Contact Us form
When using the 3M™ Littmann® Electronic Stethoscope Model 3100 and Model 3200, there are several techniques that are important to consider that can substantially improve your auscultation experience.
The sound sensor, where all sound acquisition occurs, is quite small and located in the very center of the chestpiece (for demonstration purposes, you can peel off the diaphragm and look for the indentation under the white sticker). The area around the sound sensor does not contribute to sound acquisition. Therefore, it is important to focus the point of contact with the patient on the very center of the chestpiece.
Only light contact is necessary with the Littmann electronic stethoscopes. This includes both the handling of the stethoscope and the contact on the patient. Excessive pressure on the patient may result in artifact sounds.
Contact with the patient must remain steady and consistent for optimal sound quality. Movement with the chestpiece will induce frictional noise. It is a best practice to start your auscultation exam at a lower amplification level. Then, if you are trying to listen to a difficult to hear sound, adjust the amplification upward. Using the amplification on an as needed basis will help reduce distracting noises during your exam.
Finally, it is important to recognize the difference in technique between non-electronic stethoscopes and the Littmann electronic stethoscopes. Holding the Littmann electronic stethoscopes lightly, making light contact with the patient, focusing the point of contact on the center of the chestpiece, and remaining steady will assure the highest sound quality auscultation experience.
A Littmann model 3100 or model 3200 stethoscope battery will last for approximately 60 hours of continuous use. (Depending on Bluetooth® usage, you may experience a shorter battery life with model 3200.) Before the battery is depleted completely, you will hear a warning tone that the battery has only two more hours of continuous use. The life of the battery is being conserved if you are seeing the Littmann® logo; you are in standby mode. To enter active mode, tap on the diaphragm or push a button. To turn off the stethoscope, either do nothing (the stethoscope will power off after a period of time that is based on the POWER setting) or push the power button for two seconds (preferred).
There are several options to maximize battery life:
1. Minimizing backlight display time will conserve battery life. Select Menu > BACKLITE and then select either DISABLE or ON DMND (on demand). DISABLE will completely disable the backlight at all times. With ON DMND, the backlight will only activate after pressing the power button. If you feel the backlight is necessary in order to read the display screen, simply select Menu > BACKLITE > ALWAYS. This will activate the backlight at half power to provide visual assistance, yet minimize power consumption.
2. Ensuring that the Auto On / Auto Off feature is enabled (should be by default) will preserve battery life. This feature can be customized to allow for different periods of time before entering standby mode. To optimize the battery life, select Menu > POWER > LOW. This will program the stethoscope to enter standby after 10 seconds of inactivity.
Sound quality remains constant even on low battery. The electronic stethoscope will not work without a battery.
For optimum wireless connection performance, it is important that the stethoscope chest piece and wireless dongle are in close proximity and that the path between them is free of any obstructions. Walls, furniture, and bodies will degrade the wireless signal.
The positioning of the stethoscope and wireless adapter is crucial to good wireless performance. In some cases, the use of a USB extension cable which elevates the adapter and/or changes its orientation can result in a marked improvement. 3M recommends using the StarTech Desktop USB Extension Cable, or similar device, that can be found online at many retailers or at your local electronics store.
During recording, it may help for the PC to be located next to the patient (rather than behind them) so that the patient's body does not block the signal path. Hold the chest piece firmly with fingertips (rather than a cupped hand) to allow the wireless antenna to function optimally. Minimize the distance between stethoscope and PC. Under typical conditions, a distance of 10 feet should be readily achievable.
Operating environment also plays a role in connection performance. Cordless phones, cellular phone accessories, microwave ovens, and computer Wi-Fi equipment may all degrade connection performance and should be considered if connection performance is less than desirable.
By default, the sound will be played directly back to the Littmann model 3200 stethoscope via Bluetooth. Listening to previously recorded sounds using the Littmann model 3200 stethoscope is recommended, as the sound quality will be identical to what you heard while recording. If the connection icon is green (on StethAssist™ or Cardioscan®), try increasing the audio volume by pressing the "+" on the stethoscope.
If the "play to PC" checkbox is checked, then the sound will be played via the PC speakers instead of the stethoscope. Because of the low frequency sounds involved in auscultation, computer speakers (especially native laptop speakers) may have very poor audio response giving the impression that sounds are not playing. If "play to PC" is selected, the use of headphones typically works well. Desktop speakers will allow you to hear the recording, but will typically distort the low frequency sounds. The best alternative for playing the recorded sounds to an audience is to use a speaker system with midlevel speakers and a subwoofer.
When trying to obtain the heart rate of a patient, it is important that the very center of the chestpiece is making good contact with the patient, as this is the location of the sound sensor. It takes five seconds of consistent heart sounds to compute the initial heart rate and updates are provided every two seconds. The heart rate will then be displayed for 10 seconds after removal of the chestpiece from the patient. Prior to the initial reading, the display shows two dashes (--).For heart rates outside a range of 30-199 bpm, the display will also show two dashes (--).
The acoustic-based heart rate display functions best when the Littmann model 3100 or model 3200 stethoscope is placed near the apex of the patient’s heart. It can be monitored while using any filter mode or volume level. If the heart rate changes from consistent to inconsistent, or if there is excessive ambient noise, patient movement, or lung sounds during auscultation, the heart rate will display two dashes (--). With practice, your ability to obtain a heart rate from your patient will improve. The heart rate feature was designed and validated for us on humans.