Choosing the Right Stethoscope

KaWe wooden Pinard stethoscope

They can be divided into two main types: mechanical and electronic.

1. Mechanical stethoscopes:

• A distinction is often made between adult and pediatric mechanical stethoscopes. The former are only used for listening to adults’ heart and lungs. The latter are used for the auscultation of children. Many models are versatile, however, and serve for both children and adults with the same precision. Some can be equipped with interchangeable heads making it easy to switch from one type of patient to another.

• Pinard stethoscopes (named after their creator) are obstetrical models, made of wood or aluminum, specially designed to listen to the heartbeat of the fetus in the mother’s womb. These specific stethoscopes, in the form of an elongated cone ending in a perforated cylindrical plate, make it possible to amplify the sound of the fetus’ heart rate, which is more difficult to hear when the patient is of large stature.

• Mechanical stethoscopes for cardiology have a very high acoustic sensitivity to help the doctor detect certain cardiac or pulmonary pathologies. Some models are suitable for both adults and children. These instruments are generally powerful and extremely complete tools.

2. Electronic stethoscopes:

• These models are very popular with pulmonologists and cardiologists and are particularly effective in reducing external sounds and amplifying sounds picked up without distorting them. The doctor has a perfect listening quality and high precision. The patient’s heart rate is displayed on an LCD screen. Some models are equipped with a Bluetooth connection allowing you to transmit heart and lung sounds to your PC in real time. This makes it possible to record sounds, view them, store them or send them to a colleague. Some models also have an idle listening mode. These stethoscopes are usually used by specialists who wish to carry out a thorough diagnosis of the patient or analyze their auscultations.

A traditional stethoscope is made up of three parts: the head, the chest piece and the tubing. Some stethoscopes with a particular configuration don’t include all three of these parts. This is the case, for example, for Pinard horns that have no chest piece or tubing.

• The chestpiece: this is the part in contact with the patient’s skin. It is what that picks up the sounds. The chestpiece itself consists of three elements:
  • The diaphragm: the flat part of the head that allows you to hear mid to high frequency sounds.
  • The bell: the most rounded part of the head that allows you to hear low frequency sounds. Stethoscopes composed of a diaphragm and a bell are called “dual head.” Simply flip the head over to listen alternately to low and high frequency sounds.
  • The base: the part that links the head and the tubing.

• The tubing is the tube that connects the head and chest piece. This is the part that carries the sound. Some models have double tubing, which allows sounds to travel better and reach the practitioner’s ear canal more clearly.

• The headset: this is the metal part of the stethoscope on which the tubing is fitted. It is made up of three elements:
  • The tension spring: it can be adjusted by moving the tubes apart or tightening them in order to adapt to the morphology of each individual.
  • The two ear (or aural) tubes: their angle can be chosen according to the anatomy of the user.
  • Two eartips: they can be of two types: flexible or rigid. Closely clipped on to the branches for safety reasons, they are generally difficult to remove. Some stethoscope models provide an additional set of soft ear tips and a pair of hard eartips.

A Spengler single-head stethoscope

Some small details can influence the quality of your diagnosis or simply increase your comfort. As such, it is helpful to ask yourself the following questions:

• Single head or dual head chestpiece?
  • The single head stethoscope does not allow you to alternate listening to low and high frequency sounds by simply turning over the chestpiece. However, if a single-head chestpiece is equipped with a double frequency diaphragm, you will be able to apply slight pressure in order to hear low-frequency sounds and a firmer pressure for high-frequency sounds. The single-head chestpiece also limits sound loss during auscultation; and is known for its perfect propagation of sound. On the other hand, this type of chestpiece is more suitable for blood pressure measurements as its shape allows it to fit more easily under the cuff.

   

  • The dual-head stethoscope first and foremost allows you to listen to different types of sounds, not only those coming from the heart and lungs but also from the carotid arteries and abdomen. By placing the bell on top of where the carotid artery passes, this gives you the opportunity to listen to the sounds that characterize stenosis. On the median part of the abdomen, the bell is used to detect a systolic heart murmur that might indicate an aortic aneurysm.
    The other advantage of the dual-head stethoscope is that it allows adult and pediatric patients to be examined with the same tool. The larger surface allows for the examination of adults and heavier patients, while the smaller surface is used on children or underweight adult patients. Some models have a double frequency diaphragm both on the large and small head in order to optimize auscultation of both adult and pediatric patients.

Littmann dual-head stethoscope

• Single or double tubing? Double tubing provides stereo listening (which is more accurate) to internal noise. Double tubing also prevents any loss of volume. We can therefore say that double tubing offers a higher sound quality than single tubing.

• What materials should you choose for the tubing? PVC, latex, rubber, etc. Some tubing does not contain any latex or natural resin in order to avoid potential allergies for the patient and the practitioner.

• Soft or rigid eartips? Soft eartips generally offer greater comfort than hard tips, with increased sound insulation and durability. Both types are available in small and large sizes.

• Should you have an anti-chill ring? These rings offer increased comfort for patients by preventing them being in direct contact with the cold metal of the head. They are especially useful for pediatric patients.

Each doctor will need a stethoscope best suited to their needs, depending on the type of patients they examine and diseases they treat. We can name six categories of practitioners who will need to be equipped with the appropriate stethoscope: general practitioners; pediatricians; pulmonologists and cardiologists; nurses; physiotherapists; and veterinarians.

• General practitioners:
  These doctors use their stethoscopes daily. They mainly use this tool for listening to cardiac and pulmonary functions in patients of all ages. Most general practitioners will choose a dual head model (interchangeable) to be able to examine both adults and children with the same instrument.

• Pediatricians:
  Unlike general practitioners, pediatricians only treat children. They will therefore use a specific model, differing from an adult model mainly by the size of the chestpiece. To reassure children during auscultation, some pediatric stethoscopes are available in different colors and some even have adjustible animal figures on the chestpiece that can easily be replaced. Most pediatric stethoscopes are single head with an anti-chill ring.

• Pulmonologists and cardiologists:
  These specialists generally choose to use an electronic stethoscope to benefit from high-precision acoustics and a display of pulmonary or cardiac sounds on their screen. This type of stethoscope is more expensive but allows the practitioner to hear high and low frequencies in order to detect possible pulmonary or cardiac pathologies. With electronic stethoscopes, it is possible to amplify a sound and hear up to 20 times louder than with a conventional stethoscope.

• Nurses:
  Nurses use stethoscopes mainly to measure blood pressure.

• Physiotherapists:
  Physiotherapists use stethoscopes for pulmonary auscultation before and after a session. Since their auscultation is essentially pulmonary, they generally choose a single head stethoscope.

• Veterinarians:
  They use stethoscopes similar to traditional mechanical stethoscopes that are only suitable for the auscultation of certain types of animals.