What will replace the mercury sphygmomanometer?

Mercury sphygmomanometers are gradually being phased out, not because of any technological advances but because of environmental concerns. While mercury is still accepted as the 'gold standard' for routine clinical measurement, it suffers from two deficiencies: poor observer technique, and problems due to poor maintenance of the devices. At the same time, there is no generally accepted alternative; the most widely advocated candidates are aneroid or oscillometric devices. Oscillometric devices have the advantages of eliminating observer error and mechanical drift, but it is suggested that the inherent limitations of the oscillometric method mean that it cannot become the gold standard for clinical measurement in individual patients. Aneroid monitors have been found in practice to be frequently deficient, and are subject to the same deficiencies in observer technique as mercury devices. Two possible but so far untested techniques are a 'hybrid' sphygmomanometer, whereby the mercury column is replaced by an electronic transducer and display, and the wideband recording technique, which has the potential of using the same basic principle as the auscultatory technique, while eliminating the human observer.