Blood Pressure: Why It’s Never Accurate. The rest of the Story.
Did I tell you patients don’t do any better at home than Doctor’s Offices do??
And yes, that includes me!
If you missed it, you can review why blood pressure is never taken correctly in a doctor’s office here:
Blood Pressure: Why It’s Never Accurate.
But most people really don’t do any better at home. Referring to this handy-dandy WelchAllyn Quick Reference Guide your doctor’s office SHOULD be using), I’ll explain the ways you probably aren’t taking your own pressure properly at home, either. (Source)
Here’s the gist of it, with selected items highlighted and/or comments added by me:
Accurate Blood Pressure Tips:
· Use the proper size cuff. If two cuff sizes fit, use the larger one. (First tip: If it hurts your arm or is uncomfortable during inflation, it’s too tight! One of the problems at home is there are often two or more people with different sized arms. They seldom realize the importance of cuff size in accuracy of measurements. Even if they do, it’s just too inconvenient to change cuffs, or too expensive to buy two cuffs.) The second problem is, how many people at home really understand the importance of proper cuff size? I’ll give you a clue: None.
· Place the cuff on a bare arm. (FYI: Rolling up your sleeve is not the solution here. It actually puts MORE unnatural pressure on your arteries. You should remove the arm from your sleeve (even if a short sleeve). BTW, does your doctor ever do this?)
· Place the artery marker over the brachial artery. (BWAHAHAHA! How many of you know exactly where your brachial artery is? Or even what it is? Add to that the fact that many cuffs (including the Welch-Allyn) are applied one way to one arm but must be turned upside down on the other arm. I think. Frankly, It’s really confusing.
· Apply the cuff snugly, allowing room for no more than two fingers underneath. (Again, snug does NOT mean tight! See the first item! A small cuff is tight and causes inaccurately high readings. So does applying the cuff too snugly. There should be room for a couple of fingers between the cuff and your arm. It should be LOOSELY snug.)
· Have the patient sit quietly for a few minutes. (Actually, below it says 3 to 5 Minutes, and in reality, 10 minutes would be better. Now, the reason for this is so you are consistently relaxed when you take your pressure. But consider this: If you have the TV on, you are constantly being stimulated! I can tell you from personal observation of myself, that if an upsetting news story, ad, or exciting movie scene comes on while I’m taking my blood pressure reading, it results in a higher reading than the previous reading! It’s literally a shot of adrenalin.)
· Do not talk to the patient while taking a blood pressure. (See the item above. Also, have you ever had your spouse talk to you while you’re taking a blood pressure measurement? Asking for a friend…😊)
· Support the patient’s back and feet. (I don’t know about you, but I sit on the couch. While my back and feet ARE supported, I’m not exactly sitting straight up. And the supine position can, indeed, affect readings.)
· Keep legs uncrossed. (That would include before you start the first reading, as well as between readings. Might be more difficult for some people than others.)
· Keep the upper arm at heart level with the lower arm passively supported, i.e. resting on lap. Keep the arm still during the measurement cycle. (This is another one that, frankly, is difficult to determine. Do you know exactly where your heart level is? I’ll bet not. And yes, it matters in the accuracy of your measurements.) In your defense, your doctors office probably doesn’t know either.
Blood Pressure Variability. The following activities affect a blood pressure reading.
Activity Systolic (mmHg)
· Cuff too small 10 to 40 ⇑
· Cuff over clothing 0 to 40 ⇑ or ⇓
· Back/feet unsupported 5 to 15 ⇑
· Legs crossed 5 to 8 ⇑
· Not resting 3 to 5 minutes 10 to 20 ⇑
· Patient talking 10 to 15 ⇑
· Labored breathing 5 to 8 ⇑
· Full bladder 10 to 15 ⇑
· Pain 10 to 30 ⇑
· Arm below heart level 1.8 /inch ⇑ 4.6 /cm ⇑
· Arm above heart level 1.8 /inch ⇓ 4.6 /cm ⇓
These errors made at home for these measurement activities can increase systolic blood pressure readings by 79.6 to 195.6 mmHg!! OR, decrease systolic readings by14.6 to 44.6 mmHg. Or some combination of the two, just like in the doctor’s office.
Oh, and how many of you measure 3 times each, morning, noon, and evening (12 readings) and plug it into a spreadsheet for the average? What, no hands? I thought so.
Now, your readings at home will no doubt be lower than in the doctor’s office (mine always are), but frankly, your readings at home are probably still higher than if they were taken clinically for a study.
Again, the net result of both Doctor’s Office AND patient at-home readings is that our Medical System is routinely over-medicating patients for HBP and UNDER-Medicating patients that may have LOW blood pressure.
And as a final reminder, I repeat that I am not suggesting that blood pressure problems don’t exist and don’t need treated. Just with more emphasis on an accurate measurement and finding the root cause. And treating the root cause, not prescribing a drug for the SYMPTOM of high blood pressure. Did I mention that high blood pressure is a symptom of many disease states, but is not a disease itself?
We just desperately need either a method of measurement for blood pressure that is consistent, repeatable, and not as subject to human error as the one we have now, OR we need to do new studies to reset the Blood Pressure standards based on how we currently ACTUALLY take blood pressure in the clinical setting.
It’s important because our actual measurement practices do not match our diagnostic protocols. The diagnostic protocols were developed based on studies where they do take the blood pressure meticulously and accurately.
We are currently comparing apples to oranges and coming up with lemons.
Here's the studies again. It’s worth your time to read them.
Recommendations for Blood Pressure Measurement in Humans and Experimental Animals
Part 1: Blood Pressure Measurement in Humans: A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research
https://www.ahajournals.org/doi/full/10.1161/01.hyp.0000150859.47929.8e
Part 2: Blood Pressure Measurement in Experimental Animals: A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research
https://www.ahajournals.org/doi/10.1161/01.hyp.0000150857.39919.cb