Blood pressure cuffs come in many sizes, and if a clinician uses the wrong one, it matters. Pediatric nephrologist Tammy Brady presented on March 1, during the American Heart Association’s Epidemiology and Prevention, Lifestyle, and Cardiometabolic Health conference, about findings from her study that show using the wrong blood pressure cuff size, can cause an incorrect blood pressure measurement.
My name is tammy brady and I'm the vice chair for clinical research in the department of pediatrics and the medical director for the pediatric hypertension program at the johns Hopkins University School of Medicine. I was invited to present my research at the American Heart Association, the Epidemiology prevention, lifestyle and cardio metabolic health conference. Hypertension is the leading cause of cardiovascular disease morbidity and mortality worldwide. And over one billion people have a diagnosis of hypertension across the globe, accurate blood pressure measurement is essential to ensure people with hypertension are identified and appropriately treated. What many people may not appreciate is that accurate blood pressure measurement depends on many factors, including proper patient preparation and positioning and using a cuff that is appropriately sized for one's arm hypertension guidelines emphasize the importance of individualized blood pressure cuff selection for BP measurements. However many clinical settings, particularly those that have few resources often only have one blood pressure cuff size. Typically the regular adult cuff for measurement of all patients. So with this in mind we wanted to find out what the impact was when using a regular adult cup for all patients, regardless of arm size. To test this, we recruited 195 adults from the surrounding area to participate in our study. The average age was 54 years, 1/3 were male and 68% were self reported black race. At the beginning of the study, all participants had the middle of their upper arm measured so we could determine what blood pressure cuff size was appropriate for them. Was it the small adult, the regular adult, large adult or extra large adult. Each participant then underwent two sets of three blood pressure measurements. One set using the regular adult sized cup and another set using an appropriately sized cuff. The order of these measurements were randomized, meaning for some people, they have blood pressure is measured first with the regular adult cuff, then with the appropriately sized cup, and then for others, they had their blood pressure measured first with the appropriately sized cup and then with the regular adult cuff. So we found that a third of the participants had a systolic blood pressure that was at or above 130 of mercury. So that's the top number and consistent with the measurement and the hypertensive range Over a third of participants had a body mass index of 30 or greater, which met the criteria for obesity, and among the participants in whom a small adult cuff size was appropriate when using the regular adult size cuff. Their blood pressure readings were notably lower, on average, 3.5 millimeters of mercury lower systolic. In contrast among those who require a large cuff, A regular cuff size resulted in blood pressure readings that were almost five of mercury higher for the systolic reading and even more strikingly among those who required an extra large adult cuff, The regular sized cuff was associated with blood pressure readings that were almost 20 of mercury higher. So on average, those who required an extra large cuff based on their measurement arm circumference they had a blood pressure of 1 44/87. When using a regular adult cuff, That measurement is in the range of a diagnosis of stage two hypertension, But when using the appropriately sized cuff for those same participants, their blood pressure readings are on average 125 over 80, which is essentially in the normal range. So in our study, the overestimation of blood pressure due to using a cuff that was too small misclassified almost 40% of participants as being hypertensive. While the underestimation of blood pressure due to using a cuff that is too large is 22% of participants with hypertension. So we concluded that a renewed emphasis on cuff sizes warranted, particularly in populations with a high prevalence of obesity requiring large or extra large cuff sizes and patients should feel empowered to ask their providers to make sure the right cuff size was used when measuring your blood pressure. Thank you so much for your attention and thank you to the participants of our study