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Odds Are, They're Taking Your Blood Pressure All Wrong

Nov 20, 2017
Originally published on November 20, 2017 7:14 am

When was the last time you were asked to sit without saying a word for five minutes before your blood pressure was measured? If your answer was "I never remember doing that," you're in good company.

Yet that is one of the many rules that medical professionals are supposed to follow when measuring your blood pressure.

Paul Whelton, a cardiovascular specialist at the Tulane University School of Public Health, says airplane pilots always run down a safety checklist before taking off. "We would be shocked if a pilot told us he was in a rush and just didn't have time to do it."

Yet he says clinicians aren't taking enough care to make an important measurement when it comes to health: reading blood pressure values.

That is topical right now because Whelton is among a group of physicians who have just recommended new standards for blood pressure. Now, if your blood pressure tops 130 over 80, you are in unhealthy territory. Having an accurate measure is important because more people than ever may be keeping a close eye on their blood pressure and trying to keep it in a healthy range through diet, exercise and potentially medications.

The new guidelines from the American Heart Association and the American College of Cardiology, released Tuesday, which lowered the threshold for diagnosing high blood pressure from 140/90, mean that nearly half of the U.S. population will be considered as having high blood pressure, with the greatest impact on younger people.

So Whelton and his committee members rolled out a checklist for medical professionals to follow when they're taking your blood pressure. Here are the do's and don'ts from a patient's perspective, aimed at making it less likely that you'll get a reading that is falsely high, or low:

  • Do: Sit in a chair, feet flat on the ground, legs uncrossed, with your back supported and without talking, for at least five minutes before you get your blood pressure measured.
  • Don't: Exercise, consume caffeine or smoke within 30 minutes of your test.
  • Do: Empty your bladder before your blood pressure is taken.
  • Don't: Sit or lie on the exam table. Whelton says that can result in a falsely low blood pressure reading.
  • Do: Roll up your sleeve so the blood pressure cuff rests on bare skin, not clothing.
  • Don't: Let your arm dangle or rest in your lap during the reading. It should be supported on a surface such as a desk.

If your blood pressure appears high, your doctor's office should take a reading in both arms. And next time you come in, the reading should be from the arm that showed the higher blood pressure.

There is no single number that determines your blood pressure — it can vary throughout the day and be influenced by something as simple as being approached by a well-meaning nurse carrying a blood pressure cuff. So the new checklist says the diagnosis of high blood pressure requires at least two readings on separate occasions.

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Some people may wonder what family conflicts at the holidays do to their blood pressure. There's new guidance as to what counts as high blood pressure so it is important if you're measuring your blood pressure to get an accurate reading, which is surprisingly hard. NPR's Richard Harris reports that people who administer the test often do it wrong.

RICHARD HARRIS, BYLINE: Pilots run through a long checklist of safety checks before they're allowed to take off, notes Dr. Paul Whelton at Tulane University.

PAUL WHELTON: And we would be shocked if a pilot told us he knew we were in a rush and he was busy and just didn't have time to do it.

HARRIS: Unfortunately, he says, that's too often the case in busy medical offices when it comes to measuring blood pressure accurately. So Whelton and his colleagues, who developed the new blood pressure standards, also included a checklist of do's and don'ts for measuring it. We ran down the rules at a medical office, appropriately enough, not far from Dulles International Airport near Washington, D.C.

EMILY BLAIR: I'm going to bring you folks on down here to Room 2.

HARRIS: Medical assistant Emily Blair leads a client, Mary Ann Henderson, down the hall.

BLAIR: Before you get seated, I'm actually going to go ahead and get your weight.

MARY ANN HENDERSON: I wouldn't have had a big breakfast.

(LAUGHTER)

HARRIS: With that done, Blair steers her client away from the exam table, which is on the do-not list of places to have your blood pressure taken. If you are lying flat or your legs are dangling that can foul up the reading.

BLAIR: And if you would like to have a seat over here in one of these chairs.

HARRIS: Blair asks Henderson to put her feet flat on the ground and to uncross her legs, more steps on the checklist.

BLAIR: I'm just going to go ahead and get back into your chart, and we're just going to update some information.

HENDERSON: OK.

HARRIS: Henderson answers the medical assistant's questions for a few minutes before the actual test begins. The blood pressure cuff goes on Henderson's arm. Bare skin is the rule, no clothing under the cuff. And the patient's arm is supposed to rest on a surface during the test. That's not so easy where Henderson's sitting at the moment.

BLAIR: Since I don't have the table there, I'm going to go ahead and have you rest your hand right here, if you don't mind.

HARRIS: Henderson's hand rests on the medical assistant's knee as she gets down to the nitty gritty.

(SOUNDBITE OF BLOOD PRESSURE CUFF INFLATING)

HARRIS: The cuff is positioned at heart level, as the checklist specifies.

(SOUNDBITE OF BLOOD PRESSURE CUFF DEFLATING)

BLAIR: One-sixteen over 70. You're doing great.

HENDERSON: (Laughter).

HARRIS: So have you had coffee this morning?

HENDERSON: Yeah, at least three cups.

HARRIS: Oops. That's on the checklist, too. No coffee, exercise or smoking within half an hour of a proper blood pressure test.

HENDERSON: Uh oh. I think I blew it for you.

BLAIR: (Laughter).

HENDERSON: Well, no, actually not because with the traffic that was at least a half an hour. So I guess I'm within the parameter.

HARRIS: You're also supposed to sit quietly for five minutes before your blood pressure. So that check-box wasn't quite hit on this occasion.

HENDERSON: No, no. We kind of were chit chatting, weren't we?

HARRIS: That quiet time is supposed to help people calm down before the test, but it seems to be one of the most challenging rules to follow. I broach that with Jessica Gondi, a physician assistant in the office.

So I don't think I've ever been asked to sit quietly for five minutes before having my blood pressure taken. Have you?

JESSICA GANDHI: No, unfortunately. I wish that the timeline for seeing a patient allowed a patient to sit there for five minutes.

HARRIS: Patients and doctors alike are busy, she says. The office visit also didn't include a few other items on the checklist such as asking a patient to come in with an empty bladder or to take measurements on both arms. Those details become important when a doctor starts to suspect high blood pressure and the purpose of an exam is to make that diagnosis, and that's where the checklist can really make a difference.

Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.