— Important to educate patients conducting home measurements, says researcher
A randomized trial published in JAMA Internal Medicine opens in a new tab or window revealed that certain arm positions—supported on a lap or hanging by the side of the body—led to a significant overestimation of blood pressure readings compared with standardized positioning, raising concerns about misdiagnosis or overestimation of hypertension.
Researchers Tammy Brady, MD, PhD, of the Johns Hopkins University School of Medicine in Baltimore, addresses the results and their implications in this video interview.
The following is a transcript of her remarks:
Globally, cardiovascular disease is one of the main causes of death. Indeed, almost 800,000 fatalities annually in the US are attributed to cardiovascular disease. Accurate blood pressure measures are essential for conducting hypertension screening, which is a crucial step in preventing cardiovascular disease.
Now, a lot of individuals are unaware that the rules for measurement specify several patient positions and preparation steps. Many of these procedures take time and sometimes require extra resources. Actually, a number of studies have demonstrated that healthcare professionals don’t always follow these guidelines.
In light of this, my fellow researchers and I were particularly curious to find out how crucial arm support and posture are to the accuracy of blood pressure readings.
For background, according to the standards, to take a blood pressure reading, the arm must be supported by a desk or table, and it must be positioned so that the middle of the cuff is at the level of the middle of the heart. Since many workspaces lack a desk or other arm support, people frequently make do by hanging their arms by their sides or placing them in their laps. Thus, once more, we were interested in learning if the accuracy of blood pressure was affected by either of these two additional positions.
We enlisted 133 community-dwelling persons to participate in a crossover randomized clinical trial to find the answer to this query. Each of those individuals was randomly assigned to one of six groups, which were distinguished by the arrangement of the three seated arm postures. Once more: at the side, in their lap, or on the desk.
All other aspects of the blood pressure measurement were standardized. Specifically, before taking each measurement, we ensured that every participant had emptied their bladders. Afterward, we had them walk for two minutes, simulating a typical scenario in which they would enter a clinic or office before being screened. Following a 5-minute rest period during which they were required to sit with their backs and feet supported, each subject was fitted with an upper arm blood pressure cuff whose size was determined by the size of their upper arm.
A digital blood pressure monitor was used to take three sets of triplicate measures from [them] separated by 30 seconds. Following the completion of each set of three measurements, the cuff was taken off, and they walked for an additional two minutes to counteract any possible effects of embedded rest before resting for a further five minutes.
Now, with their arms supported on a desk, each participant conducted a fourth round of triplicate blood pressure measures because blood pressure varies from minute to minute B2B. After adjusting for those well-known fluctuations in blood pressure measurements, we used this information in our studies of differences in differences.
We discovered that blood pressure values were greatly affected by inadequate arm support and improper arm placement. Blood pressure readings with the arm hanging at the side and with the arm resting in the lap overestimated systolic blood pressure by 6.5 mm Hg and diastolic blood pressure by 4.4 mm Hg, respectively. The overestimation occurred during both of these blood pressure measurements.
It has been demonstrated that it is very important to make sure your arm is positioned correctly when screening for hypertension. You could mistakenly diagnose a patient and have an artificially increased blood pressure if you don’t do this.
This study, in my opinion, also emphasizes the significance of educating people who take their blood pressure at home to ensure that their arms are positioned correctly, in addition to healthcare professionals. One of the key points in our guidelines is that patients must get their blood pressure measured outside of the office before a diagnosis of hypertension can be made. Once more, our goal is to rule out the white-coat effect, which could inadvertently cause a blood pressure reading at a clinic to rise. Whether in a clinic or at home, the conclusions we made on arm position are applicable in both scenarios. Thus, patients may be giving their medical professionals false readings and aiding in a misdiagnosis if they are unaware of the necessity to support and appropriately place their arms.
I hope that our paper reaches patients for this very reason since I think so many rides on home blood pressure measurements.
Making sure the blood pressure measurement is set up correctly may require an initial time and resource investment, but I believe there could be a big return on investment in the form of time and cost savings as well as improved patient care with fewer misdiagnoses. Requiring patients to return for measures costs money, time, and resources because it necessitates scheduling follow-up sessions with medical personnel. Patients will have to miss work to undergo evaluations and take medication. Thus, once more, I believe that the initial investment will have a significant effect.
My goal is that this research will raise awareness about the significance of arm posture and support for measurement among patients and healthcare professionals. It’s not as simple as putting on a cuff and pressing a button, and if a patient’s blood pressure reading is ever elevated, I hope they will feel empowered to request a repeat test under optimum circumstances, which includes this arm support and alignment.
In order to ensure that there is no skill degradation, I also hope that healthcare professionals would realize how crucial it is to retrain and recertify blood pressure monitors every six months in addition to properly training and certifying those who currently hold the position. Furthermore, it’s crucial to ensure that you receive the correct diagnosis if you’re prescribing an out-of-office blood pressure measurement. Take the time to teach them the necessary procedures.
