Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyDecember 2024
Commonly used nonstandard arm positions resulted in clinically relevant overestimation of BP.
Clinical guidelines emphasise that proper technique is important when measuring blood pressure (BP), but in many practice settings, clinicians or staff take measurements that do not follow all the recommended steps. In this US trial of 133 adults, researchers assessed the effect of nonstandard arm positions on BP readings by measuring each patient’s BP in three different arm positions (order of measurement was determined by a randomisation protocol):
- arm supported on a desk, with cuff
- at heart level (reference position)
- hand supported in the lap
- arm unsupported at the side.
Investigators otherwise followed standard guidance for office BP measurements.
Lap and side positions led to significantly higher readings (by 4mmHg to 6mmHg for both systolic and diastolic measurements) than did the desk position. Results were consistent when patients were categorised by age range, obesity status, healthcare use and whether or not they had known hypertension.
Comment: This study replicated some of the ‘realworld’ shortcuts that often occur when we check BP, such as measuring BP while the patient is sitting up on an exam table. The recommended technique (arm fully resting at heart level) is worth following strictly, as incorrect arm positioning might lead to clinically significant BP overestimation that could misclassify patients as having hypertension or needing intensification of hypertension treatment. With home measurements being used increasingly to monitor hypertension, we should educate our patients on measurement technique, too.
Sarah E. Post, MD, Lecturer in Medicine, Harvard Medical School; primary care physician and medical educator, Atrius Health, Boston, USA.
Liu H, et al. Arm position and blood pressure readings: the ARMS crossoverrandomized clinical trial. JAMA Intern Med 2024 Oct 7; e-pub (https://doi. org/10.1001/jamainternmed.2024.5213).
This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine.