A new study by Johns Hopkins Medicine researchers has revealed that incorrect arm positioning during blood pressure checks can lead to inaccurate results.
The dysfunctional posture could cause some people to be wrongly diagnosed with high blood pressure.
Researchers found that when the arm was placed on the lap, systolic blood pressure (the top number of a reading) was overestimated by nearly four points. When the arm was left hanging without support, the systolic reading was almost seven points higher than it should be.
Impact of arm position in blood pressure readings
The study highlighted that proper arm support is essential for accurate blood pressure measurements. The ideal position is with the arm resting on a desk or table, ensuring the cuff is at heart level.
Incorrect positions, such as resting the arm on the lap or leaving it unsupported, not only affect systolic readings but also lead to higher diastolic measurements (the bottom number). Inaccurate readings can lead to over-diagnosis or hypertension, putting patients at risk of unnecessary treatment.
Dr. Tammy Brady, senior researcher and vice chair for clinical research at Johns Hopkins, emphasized the importance of adhering to guidelines for blood pressure measurement.
Brady said that proper arm positioning is crucial for ensuring accurate blood pressure readings. Even small overestimations can mean the difference between a normal reading and a diagnosis of stage two hypertension.
Sherry Liu, an epidemiology research coordinator at Johns Hopkins, added that the difference in readings caused by poor arm positioning could lead to a misclassification of blood pressure levels, potentially leading to inappropriate treatment plans.
The study in detail
The research involved 133 adults, aged 18 to 80, with most participants being Black women. The study tested blood pressure using three different arm positions during a single visit.
Before taking blood pressure measurements, participants walked for two minutes to simulate a typical clinic setting. They then rested for five minutes before taking three sets of readings using a digital blood pressure device.
Participants underwent these tests with their arms in three different positions: resting on a desk, on their lap, and hanging at their side. Between each set, participants walked for another two minutes and then rested for five minutes to ensure consistency.
The researchers noted that while the study focused on automated blood pressure devices, the findings are a reminder that proper technique is essential across all methods of measurement.
The results suggest that healthcare professionals must pay closer attention to ensuring correct arm support during blood pressure screenings.
