May is High Blood Pressure Awareness Month, the perfect time to share recent articles of interest related to blood pressure measurement and hypertension.
Third Time’s the Charm
Evaluation of blood pressure is recommended in all children older than three. While traditional auscultatory measurement (performed manually using a stethoscope and sphygmomanometer) continues to be the recommended technique, automated oscillometric devices are becoming increasingly popular.
A recent study published online in the Journal of the American Society of Hypertension compared readings obtained by noninvasive BP monitors to those obtained by manual measurement.
The study observed 9,870 participants in a school-based blood pressure screening program to determine if multiple oscillometric BP measurements are needed to approach true blood pressure.
The researchers found that there was a significant decrease in blood pressure values with repeated measurements, which is less pronounced after the third reading. They concluded that averaging the three replicates a single auscultatory measurement.
The study didn’t determine the reasons, but we have our own theories from years of manufacturing and selling some of the world’s most popular manual sphygs and NIBP instruments.
First, manual measurement is subject to human error. Assuming the instruments are properly calibrated (eliminating instrument error), hearing acuity, measurement technique, observer bias, and the rounding phenomenon all contribute to potentially significant error.
NIBP monitors, on the other hand, can be a bit intimidating, exacerbating white-coat hypertension. We’ve coined the phrase “first-reading spike.” It’s not that the BP measurement is wrong, it’s merely that at that moment the patient’s anxiety elevates BP. With multiple readings, patients typically relax, lowering blood pressure. We’re all in favor of using average readings regardless of measurement method as they eliminate spikes and provide a more reliable picture of BP values.
Many of ADC’s Advantage home BP monitors offer our proprietary MAM (average mode technology) and we are building it into our next generation Adview NIBP, which is due out later this year.
Lower Is Better
A new meta-analysis published in The Lancet confirms what most would agree is a logical conclusion: Lower blood pressure is better.
The study analyzed the findings of 123 large-scale randomized trials that compared different blood pressure targets involving 600,000 patients over nearly 50 years. Researchers concluded that blood pressure should be lowered below 130 mmHg in patients at high risk for cardiovascular disease and stroke regardless of their starting blood pressure, and all high-risk patients should be offered blood pressure-lowering drugs.
The researchers determined that, overall, a 10 mmHg reduction in systolic blood pressure reduces the risk of major cardiovascular disease events by 20%, coronary heart disease by 17%, stroke by 27%, heart failure by 28%, and all-cause mortality by 13%.
“The size of these proportional reductions was broadly consistent across several major high-risk groups of patients, suggesting that blood pressure lowering provides broadly generalisable benefits,” the authors wrote.
They also recommended a shift from rigid blood pressure targets to individualized risk-based targets, even when blood pressure is below 130 mmHg before treatment.
ADC is one of the world’s leading manufacturers of professional aneroid sphygmomanometers, NIBP, and home blood pressure monitors, under the Diagnostix, Prosphyg, Advantage, and Adview brands.
Xamayta Negroni-Balasquide, MD, Cynthia Bell, MS, Joyce Samuel, MD, MS, and Joshua A. Samuels, MD, MPH. “Is one measurement enough to evaluate blood pressure among adolescents?” Journal of the American Society of Hypertension. Published Online: December 14, 2015.
Dena Ettehad, MSc, Connor A. Emdin, HBSc, Amit Kiran, PhD, Simon G. Anderson, PhD, Thomas Callender, MB, ChB, Jonathan Emberson, PhD, Prof. John Chalmers, PhD, Prof. Anthony Rodgers, PhD, and Prof. Kazem Rahimi, DM, FRCP. “Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis.” The Lancet. Published Online: December 23, 2015.