NEW RESEARCH has shown that nonstandard arm positions during blood pressure (BP) measurements significantly overestimates systolic and diastolic BP, compared to the recommended standard position.
Accurate BP measurement is crucial in clinical settings, as it directly impacts the diagnosis and management of hypertension. Current guidelines advocate for arm support on a desk with the midcuff at heart level to ensure precise readings. However, common practice often deviates from these recommendations, with many clinicians allowing patients to rest their arms on their laps or at their sides. Understanding how these positions affect BP readings is vital for improving clinical practices and outcomes.
In this trial conducted in Baltimore, Maryland, from August 9, 2022, to June 1, 2023, 133 adults aged 18 to 80 were randomly assigned to receive triplicate BP measurements using three different arm positions: supported on a desk, resting on the lap, and unsupported at the side. To control for individual variability in BP readings, participants also underwent a fourth set of measurements with the arm supported on a desk. Among the cohort, 48 participants (36%) had SBP of 130 mm Hg or higher, and 55 participants (41%) had a body mass index of 30 or higher. The primary outcomes analysed were the differences in mean systolic BP (SBP) and diastolic BP (DBP) between the reference position and the alternative positions.
The results indicated that the lap position overestimated SBP by 3.9 mm Hg (95% CI: 2.5-5.2) and DBP by 4.0 mm Hg (95% CI: 3.1-5.0). The side position showed an even greater overestimation, with SBP increasing by 6.5 mm Hg (95% CI: 5.1-7.9) and DBP by 4.4 mm Hg (95% CI: 3.4-5.4). These findings were consistent across various subgroups, including those with different hypertensive statuses and body mass indices.
In conclusion, the findings of this study emphasize the importance of adhering to standardized BP measurement protocols in clinical practice. The significant overestimations associated with resting the arm on the lap or at the side could lead to misdiagnosis of hypertension and inappropriate treatment plans. Future clinical practice should prioritise educating healthcare professionals about the impact of arm positioning on BP readings, ensuring that patients are placed in the recommended position to obtain accurate assessments. Implementing these guidelines could enhance patient outcomes by preventing the unnecessary escalation of treatment for falsely elevated BP readings.
Katrina Thornber
Reference
Liu H et al. Arm position and blood pressure readings: the ARMS crossover randomized clinical trial. JAMA Intern Med. 2024;DOI:10.1001/jamainternmed.2024.5213.
