Clinical validation of aneroid sphygmomanometer.

Recent concerns about the mercury toxicity and its ill effects on the environment and health has led to widespread use of aneroid manometers. Present study was conducted to analyse whether this change would lead to any systematic shift in measured blood pressure or consistency of blood pressure measurement in clinical setting. The clinical accuracy of the Welch Allyn aneroid sphygmomanometer model 7670-04 was studied against the mercury sphygmomanometer on 83 volunteers from Dehradun. Two blood pressure reading of each study subject was recorded with pretested instruments (aneroid and mercury sphygmomanometer). Data analysis showed the difference of means between the reading of two devices against mean of the observer reading for both systolic (-3.62 +/- 4.88) and diastolic (-2.36 +/- 3.77) blood pressure were not statistically different. The corresponding values of the SBP and DBP from both the instruments showed significant correlation. Regression analysis of mercury versus aneroid showed regression line (Y = 9.52 + 0.95X for SBP, Y = 0.36 + 0.96X for DBP) significantly different from line of equality (P < 0.001). The study has demonstrated that the aneroid device (model: 7670-04) achieved grade B performance according to the British Hypertensive Society criteria.