A mercury sphygmomanometer uses a column of mercury to display a blood pressure reading. According to ABCMonitor.com, the cuff of the device is placed around the arm of the person and inflated with a bulb attached to the cuff via a cord. The values of blood pressure are read on the column in units of millimeters of mercury, or "mmHg."
According to Europa.eu, the mercury sphygmomanometer is the first choice for blood pressure measurement, and when calibrated properly, it is considered to be more accurate than other methods. However, it is being gradually replaced with non-mercury pressure monitors in clinical settings. Aneroid, or liquid-free, auscultatory mercury-free devices are one such option. Mercury-free blood pressure reading devices have been shown to have no adverse effects on patient health when used. Due to the toxicity of mercury, the use of devices containing this element have been banned or are being phased out in some parts of the world. In 2009, the European Commission banned the sale of devices containing mercury, but this ban excluded devices that measured blood pressure. Blood pressure is a vital measurement needed in clinical settings to prevent, diagnose and treat disease. High blood pressure readings are associated with stroke, heart disease and kidney failure.