Accuracy of Automated Blood Pressure Monitors

Abstract

Purpose. The purpose of this study is to determine if automated and aneroid manometers are as accurate a means of determining blood pressure as the mercury manometer. Obtaining vital signs for patients is considered standard of care, yet many dental offices do not routinely perform this health service because of technique inconsistencies and time constraints. The use of automatic blood pressure monitors addresses both concerns. The mercury column manometer, the control in this study, has long been considered the most accurate and preferred instrument for obtaining blood pressure measurements.

Methods. During this study, 94 participants (19 years of age and older) consented to having blood pressure taken by each of 4 different monitors. These included the mercury column manometer and stethoscope, the aneroid manometer and stethoscope, the automatic arm blood pressure monitor, and the automatic wrist blood pressure monitor. Each of 3 investigators was assigned to and calibrated for a specific monitoring device. All measurements were taken from the left arm with 5 minutes allowed between measurements. Identical stethoscopes were used with the manual monitors. Strict adherence to the manufacturers' directions and patient preparation was followed for all monitors. Investigators were not aware of readings obtained by other investigators during testing. Eighty-three subjects completed all tests.

Results. Review and analysis of data indicates little difference for pulse readings between the automated and digital methods. Systolic readings by automated wrist manometers were the most unreliable. Automated arm monitors tended to provide higher measures than the mercury standard on average, and demonstrated significantly different diastolic readings in one age group compared to the control. All monitors exhibited low reliability for participants over age 50 compared to the control.

Conclusion. This study demonstrates there is inaccuracy in the use of automated blood pressure monitors and traditional aneroid manometers when compared to the gold standard mercury column manometer for subjects of all ages and blood pressure ranges.