Home Self-Monitoring of Blood Pressure Is Fully Automated Oscillometric Technique as Good as Conventional Stethoscopic Technique?

Abstract

Home blood pressure (HBP) measurement is becoming increasingly popular as an additional source of information for the practicing physician. Whether HBP measured with a fully automated oscillometric device (oHBP) is more reliable than HBP measured with an aneroid sphygmomanometer and a stethoscope (sHBP) remains unclear. We compared sHBP with oHBP using as a reference method daytime ambulatory blood pressure (ABP), as this is believed to be a better index of an individual's overall level of pressure. Forty-six hypertensive patients measuring HBP with aneroid devices were retrained by a standard 30 min protocol that included training in the technique of measurement, checking patients' devices, and testing patients' performance in stethoscopic measurement. Patients were randomized to measure for 2 weeks either sHBP using their own calibrated aneroid devices or oHBP using a validated fully automated oscillometric device (Omron HEM-705CP). Then 24 h ABP monitoring was performed (SpaceLabs 90207) and patients crossed over for a second 2 week period by using the alternative HBP measurement technique. Mean sHBP was not different from mean oHBP, and there was a close correlation between them (r = 0.82/0.76 for systolic/diastolic BP, P < .001). Daytime ABP was not different from oHBP or sHBP and was closely related to both of them (oHBP, r = 0.59/0.72 systolic/diastolic BP, P < .001; sHBP, 0.50/0.65, P < .001). Age was significantly related with diastolic ABP-sHBP difference (r = 0.33, P < .05). These results suggest that HBP measured with validated fully automated oscillometric devices is equally reliable in predicting average ABP as that measured with calibrated aneroid sphygmomanometers used by very carefully trained patients. In clinical practice, HBP monitoring by using reliable automated devices is probably more feasible than to achieve a high standard of stethoscopic HBP measuring technique.