Blood Pressure Measurement Should be Taken With The Arm Straight | The BMJ.
With the cuff on your bare arm, sit in an upright position with back supported, feet flat on the floor and your arm supported at heart level. Make sure the bottom of the cuff is directly above the bend of the elbow. Relax for about five minutes before taking a measurement.
Arm position
Dependency of the arm below heart level leads to an overestimation of systolic and diastolic pressures and raising the arm above heart level leads to underestimation. The magnitude of this error can be as great as 10 mm Hg for systolic and diastolic pressures.
Measuring blood pressure in the supine position shows lower blood pressure readings when compared with the seated position.
Acute meal ingestion, caffeine or nicotine use can all affect BP readings, leading to errors in measurement accuracy. If the patient has a full bladder, that can lead to an error in systolic BP of up to 33 mm Hg, and the white-coat effect can have an error of up to 26 mm Hg.
Incorrect patient positioning
Perhaps the most common mistake in blood pressure measurement is allowing patients to sit or lie with their arms hanging by their side, since when the upper arm is below the level of the right atrium, the readings will be too high.
A BP cuff that is too large will give falsely low readings, while an overly small cuff will provide readings that are falsely high.
The ideal resident body position for the most accurate blood pressure reading is seated with legs uncrossed, feet not dangling, back supported and the arm (or leg) where the cuff is applied supported on a chair or counter at mid-heart level.
Results: The blood pressure tended to drop in the standing position compared with the sitting, supine and supine with crossed legs. Systolic and diastolic blood pressure was the highest in supine position when compared the other positions.
The sensitivity for the detection of hypertension was 90.6% when BP was measured only at right arm, and 83.4% when measured only at left arm. Corresponding sensitivity were 87.9% and 87.1% in men, and 95.4% and 76.9% in women.
Call 911 or emergency medical services if your blood pressure is 180/120 mm Hg or greater and you have chest pain, shortness of breath, or symptoms of stroke. Stroke symptoms include numbness or tingling, trouble speaking, or changes in vision.
Don't measure your blood pressure right after you wake up.
You can prepare for the day, but don't eat breakfast or take medications before measuring your blood pressure. If you exercise after waking, take your blood pressure before exercising.
Blood pressure should be checked while seated after a few minutes of rest. Take at least two readings a minute apart each time. Wait at least 30 minutes after having caffeine, alcohol, smoking, or exercising before taking your blood pressure.
Everyone's blood pressure rises and falls many times during the course of a single day, sometimes even within minutes. Many factors contribute to these changes, including physical activity, emotion, body position, diet (especially salt and alcohol intake), and sleep deprivation.
Both the arms can be used for BP measurement and sometimes, your doctor might take two readings from two arms to check for any variations too. Generally, it's best to take your blood pressure from your left arm if you are right-handed.
The study found: Blood pressure readings taken at home were consistent with ABPM. Blood pressure readings based on follow-up clinic visits were significantly lower for the systolic measure, leading to over half of the people with hypertension based on ABPM being missed.
Dozens of at home blood pressure machines were tested in the study. According to the results, the participants' home blood pressure monitor readings were off by around 5 mmHg a shocking 70% of the time.
But home blood pressure monitors aren't always as accurate as they should be. "Home blood pressure monitors may be inaccurate in 5% to 15% of patients, depending on the threshold for accuracy used," according to Dr. Swapnil Hiremath, a kidney specialist at Ottawa Hospital in Canada.
Systolic pressure (the first number in a blood pressure reading) measures the force with which the heart pumps blood into the arteries. Diastolic pressure (the second, lower number) reflects the pressure in the arteries when the heart rests between beats.
Usually, blood pressure starts to rise a few hours before a person wakes up. It continues to rise during the day, peaking in midday. Blood pressure typically drops in the late afternoon and evening. Blood pressure is usually lower at night while sleeping.
Alcohol, Caffeine, and Tobacco
Consumption of alcohol, caffeine and tobacco cause your blood pressure to immediately rise. Avoid alcohol, caffeine and smoking at least 30 minutes before your blood pressure test to ensure an accurate measurement.
Stage 2 high blood pressure is 140/90 or higher. If you get a blood pressure reading of 180/110 or higher more than once, seek medical treatment right away. A reading this high is considered “hypertensive crisis.” Readings between 120/80 and 129/89 are considered pre-hypertension.