Is your blood pressure being measured correctly? Accurate blood pressure measurements are essential for diagnosing and treating high blood pressure. A specific set of techniques and procedures have been developed for obtaining the most accurate blood pressure readings possible.
But research has shown that medical professionals often do not completely follow these guidelines. It is important for you as a patient to be able to identify when proper protocol is being followed, or not.
When to Measure
It is normal to see a small amount of blood pressure fluctuation during different times of the day. Taking multiple measurements corrects for these daytime fluctuations, but there are some special timing issues that should be addressed.
In general, blood pressure should be measured:
- Before taking any morning doses of high blood pressure medicine
- No less than 1 hour after exercising, smoking, or consuming caffeine
- After allowing for about 10 minutes to adjust to the temperature in the examining room
Choose the Proper Cuff Size
One of the most important factors that can influence the accuracy of blood pressure readings is the size of the blood pressure cuff that is used. There is a very specific set of guidelines for precise cuff sizing. But it can be difficult for patients to tell, just by looking, if their healthcare provider is using a correctly sized cuff.
If you are significantly above or below “average” height or weight, then the doctor or nurse should probably not be using the cuff that is already in the room. The “default” cuff that is usually kept in the examining room is meant to be used for average sized people, and will not produce an accurate reading if you are larger or smaller than average.
The official guidelines specify the following cuff sizes:
- Arm circumference 22 to 26 cm, ‘small adult’ cuff, 12 x 22 cm
- Arm circumference 27 to 34 cm, ‘adult’ cuff: 16 x 30 cm
- Arm circumference 35 to 44 cm, ‘large adult’ cuff: 16 x 36 cm
- Arm circumference 45 to 52 cm, ‘adult thigh’ cuff: 16 x 42
Proper positioning is vital in obtaining accurate blood pressure readings.
In general, blood pressure should be measured while you are seated comfortably. The arm being used should be relaxed, uncovered, and supported at the level of the heart. Only the part of the arm where the blood pressure cuff is fastened needs to be at heart level, not the entire arm.
Sometimes your doctor will take your blood pressure while you are reclined or while you are standing up. This is appropriate in certain cases, but he should also be measuring your blood pressure while you are positioned in the seated posture, as described above.
Multiple Readings Should Be Taken
One blood pressure reading is not enough to get an accurate measurement. While the specifics of how many readings are necessary can change based on many factors, the essential need for multiple measurements does not.
To ensure an accurate reading, your doctor should be checking your blood pressure over time, and watching the how the values change between office visits. More than this, though, he should actually be taking your blood pressure more than once during each office visit.
Because things like temperature and stress can change blood pressure, more than one reading in a single office visit allows the ability to correct for these variations. For example, your blood pressure is often higher at the beginning of an office visit than at the end. Taking a reading at both the beginning and the end gives a more accurate average reading.
Your doctor should be checking your blood pressure:
- In both arms, not just one
- At both the beginning and the end of your appointment
Expect Correct Technique
There is no reason for you to expect your doctor or nurse to use anything less than perfect technique when measuring your blood pressure. If you see your doctor making any mistakes or not following proper procedure, you should ask why. While variations on technique are sometimes necessary, he should be able to clearly explain these to you, or he should apologize for not following accepted procedure and start the measurement over.
You should also tell your doctor if you have taken any medicines prior to your appointment, or if you have smoked, exercised, or eaten anything in the past hour—even if he doesn’t ask.