STETHOSCOPE

Typical Number in Hospital:

Cost Bands:

References: 9

Sounds from the heart, chest and peripheral circulation, which were originally detected by pressing an ear to the skin, are now detected using a stethoscope. This is normally a small bell- shaped end-piece pressed on to the skin and coupled to a flexible tube, splitting to feed two ear-pieces. The performance of this system is roughly equivalent to that achieved by direct application of the ear, with some amplification provided by standing waves within the system. Sound levels detected and the frequency response depend upon the pressure applied to the skin (low frequencies are lost by higher pressure) and by how well the ear-pieces fit into the ears.

The diagnostic accuracy achieved using a stethoscope depends to a large extent on the experience and skill of the clinician, since it is very hard to give a verbal description of the sounds. Electronic types exist to amplify and modify the sounds but these have not been generally accepted by clinicians, partly because the sounds generated are unfamiliar to them.

Stethoscopes also exist which detect the heart sounds from within the oesophagus. Ultrasonic foetal heart detectors are also sometimes (incorrectly) call stethoscopes.

MPCB

STIMULATOR r=3

This loose term is usually taken to mean an electrical stimulator for inducing muscle contraction during anaesthesia, physiotherapy, or during diagnostic procedures. It can of course apply to photostimulators, used during electroretinography, auditory stimulators used during electric response audiometry, or chemical stimulators (stimulants) used in therapy. More details can be found under the specific headings.