What kinds of manometers are available?
There are three types of blood pressure apparatus: the mercury-gravity manometer, the aneroid gauge and electronic devices. The mercury-gravity manometer consists of a calibrated glass tube with a reservoir containing mercury. The reservoir communicates with the compression cuff through a rubber tube. When pressure is exerted by inflating the cuff the mercury rises in the glass tube. “Once the mercury manometer is calibrated, recalibration is unnecessary. The mercury manometer is the most reliable recorder available for the clinical measurement of blood pressure.” (Pg. 49-50 Primer of Clinical Measurement of Blood Pressure, BURCH and DePASQUALE, Tulane University Medical School.) The aneroid gauge consists of a metal bellows and a watch-like movement connected to the compression cuff. Variations of pressure within the system cause the bellows to expand and contract. Movement of the bellows rotates a gear that turns a pointer pivoted on bearings, across a calibrated dial. Obviously the
