JAMA Intern Med

When measuring blood pressure, arm position matters

October 10, 2024

Commonly used, nonstandard arm positions (e.g., arm resting on lap or unsupported at the patient’s side) during BP measurements can results in substantial overestimation of BP, leading to misdiagnosis and overestimation of hypertension. The findings highlight the need for standardizing positioning for BP measurement.

In the ARMS crossover randomized clinical trial, adults (ages 18-80 years) were randomly assigned to sets of triplicate BP measurements with arm positioned in 3 ways: (1) supported on a desk (desk 1; reference), (2) hand supported on lap (lap), and (3) arm unsupported at side (side). All participants also underwent a fourth set of BP measurements with the arm supported on a desk (desk 2) to account for intrinsic BP variability.

Of 133 total participants (mean age, 57 years; 53% female), 48 participants (36%) had SBP ≥130 mm Hg, and 55 participants (41%) had a BMI ≥30. BP readings were statistically significantly higher when measured in lap and side positions vs. desk positions. Difference in differences were as follows: lap, SBP 3.9 mm Hg and DBP 4.0 mm Hg; and side, SBP 6.5 mm Hg and DBP 4.4 mm Hg.

Source:

Liu H, et al. (2024, October 7). JAMA Intern Med. Arm Position and Blood Pressure Readings: The ARMS Crossover Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/39373998/