Interarm differences in blood pressure should be determined by measuring both arms simultaneously with an automatic oscillometric device.

Objective: To compare two methods for screening interarm difference (IAD) of blood pressure.

Material And Methods: This study compared two methods for double-arm measurements: (i) conventional measurement (CM) and (ii) simultaneous automatic measurement (SAM). A total of 118 patients with two or more cardiovascular risk factors and a mean age of 59±17 years were referred to two internal clinics. CM was taken with a validated aneroid manometer in sitting position on the right and left arm subsequently and vice versa. SAM was taken three times in sitting position using a validated automatic oscillometric device equipped with two cuffs for simultaneous double-arm measurements.

Results: The average absolute IAD of the conventional systolic value (4.9 mmHg) was significantly higher than the average absolute IAD of the SAM pressures averaged from two (3.7 mmHg; P<0.03) and three measurements (3.8 mmHg; P<0.05). The standard deviations of IADs were significantly higher (P<0.05) for the conventional systolic and diastolic measurements (4.1/3.1 mmHg) than for SAM averaged from two and three (3.0/2.3 and 3.2/2.6 mmHg, respectively) measurements. Differences of more than 20 mmHg for systolic pressure and/or 10 mmHg for diastolic pressures averaged from two CMs, two SAMs, and three SAMs were seen in 10 (9%), four (3%), and six (5%) patients, respectively.

Conclusion: SAM provides smaller and more reproducible IADs than CM and therefore, most likely better estimates a patient's true IAD.