A surrogate arm for evaluating the accuracy of instruments for indirect measurement of blood pressure.

A surrogate arm, containing an artificial artery, has been developed for evaluating the accuracy of automatic, non-invasive, blood-pressure measuring devices. The surrogate arm produces all of the events associated with the auscultatory and oscillometric methods of measuring blood pressure. The surrogate arm includes a flat artificial artery in a plastic cylindrical chamber, 30 cm in circumference and 25 cm long, that contains an air/water mixture that allows matching the compliance of the human arm. Linear regression lines were obtained to correlate the indirectly (y) and directly (x) measured pressures. For auscultatory systolic pressure y = 1.01x - 1.60, with a correlation coefficient of 0.99. For mean oscillometric pressure y = 1.00x + 0, with a correlation coefficient of 1.00. For phase IV auscultatory (diastolic) pressure, y = 1.02x - 1.40, with a correlation coefficient of 0.96. For phase V auscultatory (diastolic) pressure y = 0.79x + 10.9, with a correlation coefficient of 0.98.