Sphygmo Health Dictionary

The traditional device for measuring blood pressure in clinical practice, devised by Riva-Rocci and Korotko? about a century ago. Measurement depends on accurate transmission and interpretation of the pulse wave to an artery. The sphygmomanometer is of two types, mercury and aneroid. The former is more accurate. Both have some features in common – an in?ation-de?ation system, an occluding bladder encased in a cu?, and the use of AUSCULTATION with a STETHOSCOPE. The mercury sphygmomanometer consists of a pneumatic armlet which is connected via a rubber tube with an air-pressure pump and a measuring gauge comprising a glass column containing mercury. The armlet is bound around the upper arm and pumped up su?ciently to obliterate the pulse felt at the wrist or heard by auscultation of the artery at the bend of the elbow. The pressure, measured in millimetres of mercury (mm Hg), registered at this point on the gauge is regarded as the pressure of the blood at each heartbeat (ventricular contraction). This is called the systolic pressure. The cu? is then slowly de?ated by releasing the valve on the air pump and the pressure at which the sound heard in the artery suddenly changes its character marks the diastolic pressure. Aneroid sphygmomanometers register pressure through an intricate bellows and lever system which is more susceptible than the mercury type to the bumps and jolts of everyday use which reduce its inaccuracy.

While mercury sphygmomanometers are simple, accurate and easily serviced, there is concern about possible mercury toxicity for users, those servicing the devices and the environment. Use of them has already been banned in some European hospitals. Although it may be a few years before they are widely replaced, automated blood-pressure-measuring devices will increasingly be in routine use. A wide variety of ambulatory blood-pressuremeasuring devices are already available and may be ?tted in general practice or hospital settings, where the patient is advised on the technique. Blood-pressure readings can be taken half-hourly – or more often, if required – with little disturbance of the patient’s daily activities or sleep. (See also BLOOD PRESSURE; HYPERTENSION.)... sphygmomanometer

An instrument for recording the PULSE.... sphygmograph

n. an apparatus for producing a continuous record of both the heartbeat and the subsequent pulse in one of the blood vessels. The recording can be shown on a moving tape or on an electronic screen.... sphygmocardiograph

n. a device to record the heartbeat or pulse in the form of amplified sound waves played through a loudspeaker or earphones.... sphygmophone

n. a device for showing the heartbeat or pulse as a visible signal, especially a continuous wave signal on a cathode-ray tube.... sphygmoscope