The mercury sphygmomanometer should be abandoned before it is proscribed

Both in clinical practice and medical research, blood pressure is still lar gely measured by auscultation using a mercury sphygmomanometer. Blood press ure is the most important predictor of life expectancy. Treatment of high b lood pressure reduces strokes, heart attack and heart failure. Accurate mea surement is therefore essential. At a large London teaching hospital, just under 500 mercury sphygmomanometers and their associated cuffs were examine d. More than half had serious problems that would have rendered them inaccu rate in measuring blood pressure. At the same time, assessment of the techn ical knowledge needed to measure blood pressure by the ausculatory techniqu e was also carried out amongst medical and nursing staff. This showed a con siderable level of ignorance. These results inevitably lead to inaccurate m easurement of blood pressure with serious consequences. In addition mercury is a non-degradable pollutant, eventually accumulating on the sea bed. The use of mercury in sphygmomanometers is already in the process of being eli minated in Scandinavia and Holland and other countries are likely to follow . Our results suggest that mercury sphygmomanometers are not adequately mai ntained and require expertise that is not available for accurate measuremen t of blood pressure. Their use should be dispensed with on these grounds be fore a ban for other and, perhaps less justifiable reasons. Validated autom atic devices, which are less liable to measurement and observer error shoul d be used instead. At the same time a concerted effort is needed to instruc t health care professionals on the importance of more accurate measurement of blood pressure.