We have been measuring BP wrong, say Johns Hopkins doctors
A study by Johns Hopkins Medicine has found that the position of a patient's arm during routine blood pressure screenings, can greatly affect the results. The research found that the commonly used arm positions, like resting arm on the lap or leaving it unsupported at one's side, can inflate BP readings by up to 7mmHg in systolic pressure. This is especially important as almost half of US adults have elevated blood pressure, according to the American Heart Association (AHA).
Arm position's impact on BP readings
The study was led by Dr. Tammy Brady, the Vice Chair for Clinical Research in the Department of Pediatrics, at the Johns Hopkins University School of Medicine. The research tested three arm positions: resting the arm on a desk, resting it on the lap, and leaving it unsupported at the patient's side. The results showed that even small deviations from recommended guidelines could significantly impact patient diagnosis and treatment.
Incorrect arm positions can lead to hypertension misdiagnosis
The study found the lap support position overestimated systolic BP by an average of 3.9mmHg, and diastolic BP by 4.0mmHg. The unsupported arm at the side position was even more inaccurate, overestimating systolic BP by 6.5mmHg and diastolic BP by 4.4mmHg. These findings underscore the potential for misdiagnosis of hypertension due to faulty arm positioning during BP screening, especially when left unsupported at the side.
Need for proper BP measurement techniques
The researchers stressed their findings pertain to BP readings taken via automated devices, but may not be applicable to other BP measuring devices. They stressed clinicians should follow proper BP measurement steps and patients should ensure their arm is properly positioned during readings. Dr. Brady emphasized following clinical guidelines for accurate BP measurements, including using the right cuff size, back support for the patient, uncrossed legs with the feet flat on the floor, and proper arm support.
