BP: improve accuracy of measurement to improve control.
Among the reasons for inaccurate blood pressure measurement are inadequate training, use of substandard equipment, improper use of equipment, and improper technique, said Dr. Grim, president of Shared Care Research & Education Consulting Inc., Milwaukee.
A quick poll of attendees at Dr. Grim's workshop revealed that most medical professionals received fewer than 30 minutes of training in blood pressure measurement. That's about average, he said, noting that such an important health measure deserves more time and attention.
Training should involve the use of a double stethoscope, so that a seasoned professional can evaluate the trainee's technique and ability to hear the sounds correctly and so the two can compare measurements, he said.
As for equipment, the mercury manometer remains the standard, and every facility should have at least one that can be used to calibrate automated machines. Proper cuff selection is also important for obtaining accurate measurement. Although many facilities have only one cuff size available, there are various sizes to choose from, and selection should be based on the circumference of the midpoint of the upper arm: For 22.0-26.9-cm circumference, use small adult size; for 27.0-32.9-cm, use adult size; and for 33.0-40.9-cm, use large adult size.
The arm cuff should be placed over the brachial artery and should fit snugly, with room for no more than two fingers' width beneath it. The lower edge should be 2 cm above the antecubital space.
Use the bell of the stethoscope, not the diaphragm, to listen for sounds, because the bell is designed to pick up low-pitched sounds and the diaphragm is designed to pick up high-pitched sounds; it should be placed over the brachial artery below but not touching the cuff, he said.
He also offered tips for proper measurement and patient preparation:
* Position the patient in a straight-back chair, seated with arm flexed and both feet on the floor. Never measure blood pressure while the patient is sitting on the examining table, because the contraction of muscles required for this position can increase blood pressure by 10/5 mm Hg.
* Always use the right arm for measuring BP, because the left, which many people use because it is closest to the heart, is also more prone to blockages and other problems that can lead to inaccurate readings.
* Inflate the cuff to 30 mm Hg above palpated systolic pressure, and deflate at 2 mm Hg per second or per beat, rather than at 10 mm Hg per second, which is commonly done.
* Measure systolic BP by the first of at least two regular sounds, not by the first loud sound, a common technique. Measure diastolic BP by the last sound heard.
BY SHARON WORCESTER
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|Title Annotation:||Cardiovascular Medicine; blood pressure|
|Publication:||Internal Medicine News|
|Date:||Aug 1, 2004|
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