[Measurement of arterial blood pressure using the sphygmomanometer-S and the direct method]

Sphygmomanometer--S is the microcomputer device measuring blood pressure (BP) by the noninvasive sphygmooscillographic method following standard algorithm. When compared sphygmomanometer--S with auscultatory method, this device overestimated systolic BP by 7 mm Hg, and underestimated diastolic BP by 9 mm Hg on the average. In other words, sphygmomanometer--S overestimated systolic pressure and lowers diastolic pressure in relation to auscultatory method in the same ratio and value, as the direct method in relation to the auscultatory method. In this study, we evaluated the accuracy of the results obtained by sphygmomanometer--S, with simultaneously recorded radial artery pressure by direct method. In 15 patients 27-60 years of age undergoing cardiac surgery BP was measured by sphygmomanometer--S and direct method simultaneously on the same left upper extremity. We measured direct radial artery pressure using AE 840 Nycotron transducer and Philips amplifier. BP by sphygmomanometer--S was obtained on the same left arm using cuffs of size 11 x 24 cm and 13 x 35 cm. In 15 patients 124 pairs of BP measurement were carried out with sphygmomanometer--S and direct method. The regression equation for systolic, diastolic and mean pressure demonstrated the coincidence of the BP results obtained by sphygmomanometer--S with direct method. The correlation coefficient (r) was 0.97 for systolic, 0.90 for diastolic and 0.92 for mean pressure. Systolic and diastolic pressure measured by the sphygmomanometer--S were 2 mm Hg and mean 0.6 mm Hg higher on the average, than the same pressures obtained by direct method (ryc. 1). These differences were statistically not significant.(ABSTRACT TRUNCATED AT 250 WORDS)