Variation in blood pressure readings with mercury sphygmomanometer and automated device and to identify its impact on routine clinical practice: A comparative study

Background: Accurate measurement of blood pressure (BP) is helpful and inevitable for clinical diagnosis. Mercury sphygmomanometer is a gold standard non-invasive BP measurement instrument. Recently, there is an increasing trend toward the use of automated devices for various reasons. BP readings with automatic devices rely on built-in electronic algorithm for several standard validation protocols have been developed. Thus, it is important to look into the functioning of such devices vis-a-vis the mercury sphygmomanometer. Aims and Objectives: The aim of the study was to estimate and compare BP reading obtained by the automated device with mercury sphygmomanometer. Materials and Methods: The study was carried on 500 subjects divided equally into five age groups. BP readings from the automated device (NUTEC BP09, based on oscillometric technique) were compared to the readings of mercury sphygmomanometer. BP was recorded twice on the left arm in the sitting position with each instrument. Results: The mean BP by mercury sphygmomanometer (HgBP) was 120.1 ± 12.9/81.7 ± 9.8 mmHg and mean BP by automated device (ABP) was 118.5 ± 15.9/72.0 ± 11.6 mmHg. There is a difference of about 1.5 mmHg in systolic BP (SBP) while there is a difference of about 9.7 mmHg in the diastolic BP (DBP). Similarly, the mean arterial pressure (MAP) value with the automated device is 7 mmHg less than the mercury sphygmomanometer. Conclusion: The present study concludes that there is a significant difference for SBP, DBP, and MAP values between the automated device and mercury sphygmomanometer measurement methods and automated BP device underestimate all the BP variables except SBP with more preponderance of DBP. Thus, automated device should be used with caution.