Conference Coverage

Wrong cuff size throws off pediatric BP by 5 mm Hg


 

REPORTING FROM JOINT HYPERTENSION 2019

An arm cuff that’s one size too small in children will artificially elevate blood pressure 5 mm Hg, while one size too large will drop it 5 mm Hg, according to investigators from Columbia University in New York.

Dr. Ruchi Gupta Mahajan, pediatric nephrology fellow at Columbia University, New York M. Alexander Otto/MDedge News

Dr. Ruchi Gupta Mahajan

There are five cuff sizes in pediatrics, depending on a child’s arm circumference. Ideally, it’s measured beforehand so the right cuff size is used, but that doesn’t always happen in everyday practice.

Sometimes, clinicians just estimate arm size before choosing a cuff or opt for the medium-sized cuff in most kids; other times, the correct size has gone missing, said lead investigator Ruchi Gupta Mahajan, MD, a pediatric nephrology fellow at Columbia.

For those situations, she and her colleagues wanted to quantify how much the wrong cuff size throws off blood pressure readings in children, something that’s been done before in adult medicine, but not in pediatrics.

The idea was to give clinicians a decent estimate of true blood pressure even when the cuff isn’t quite right, something that’s particularly important with an increasing emphasis on catching hypertension as early as possible in children, she said.

After her subjects sat quietly for 10 minutes, Dr. Mahajan took automated blood pressure readings on 137 children; once with the right cuff size, once with a cuff one size too small, and once with a cuff one size too big, with a minute apart between readings.

The children were aged 4-12 years old and were in the office for wellness visits. None of them had heart or kidney disease, and none were on steroids or any other medications that affect blood pressure. There were a few more boys than girls, and almost all the children were Hispanic.

Overall, systolic blood pressure was an average of 5 mm Hg less with the larger cuff and 5 mm Hg more with the smaller cuff. The finding was the same in both girls and boys, and it held across age groups and in under, over, and normal weight children.

“I was really surprised there was no difference between ages, 4-12 years of age, its just a single number: 5. [Even] if [you] don’t have the appropriate cuff size,” the finding means that it’s still possible to have a good estimate of blood pressure, Dr. Mahajan said at the joint scientific sessions of the American Heart Association (AHA) Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension.

Meanwhile, cuff size didn’t have any statistically significant effect on diastolic pressure.

There was no outside funding for the study and Dr. Mahajan reported having no disclosures.

SOURCE: Mahajan RG et al. Joint Hypertension 2019, Abstract P182.

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