Maintaining the normal blood pressure (BP) is challenging things after passing certain age. Most people don’t know to use the auscultatory method for BP measurement which needs stethoscope and sphygmomanometer. However most of them prefer to use automatic BP instrument in their home for their regular BP monitoring. How accurate automatic BP instrument measure the blood pressure compare to the auscultatory method use by health care professional? Can we really relay in automatic BP instrument?
Automatic BP instrument measure the blood pressure in same basic principal as that of the auscultatory method. In both methods, cuff is inflated at the arm temporarily to cut off the blood blow through the brachial artery. In auscultatory method, the cuff is slowly released and the point where the blood flow begins to release making the sound (turbulent flow) which is heard in stethoscope that is mark as systolic blood pressure. The pressure of cuff further decreases causing the blood flow as that of normal (laminar flow) and the sound heard in stethoscope will disappear that is mark as diastolic blood pressure. In an automatic cuff or automatic blood pressure instrument there is a sensor, called an oscillometer, is in place to sense the above activities and reflected on a digital screen as a blood pressure.
From the research done by the different researchers using different brands of automatic machines, most of them concluded that there was slightly lower BP recording measured by automatic devices. Some of them showed that there was around 75% difference within 5mmHg and around 90% difference within 10mmg in systolic and diastolic BP as that measured by the auscultatory method. While other researchers revealed that differences were not clinically significant, there was a 3-mmHg difference for systolic and a 5-mmHg difference for diastolic pressures, and it was, therefore, appropriate to use automated devices.
As, most of the findings are done by different brand BP machine, if you are buying the automatic machine and worried about its accuracy you can compare some of the recording of that device and by the health care professionals. It is easy way to know the how much difference is there. Moreover for the home use and to track your BP it is appropriate to use the automatic devices but it would be better if you verify your recording with some health care professional.
Despite there being a lot of concerns about the automatic devices for BP measurement it may not be realistic to suggest replacing the manual auscultatory readings in all situations. It is suggestive to use manual BP measurement for those who need to have a high degree of accuracies like patients with those cardiac arrhythmias (irregular heart rate), trauma, and cardiovascular accident (heart attack).
Reference: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2702.2010.03528.x
