Avoiding missteps in BP measurement

The American Heart Association (AHA) recommends that BP be measured in both arms at the initial evaluation, with the higher measurement used for monitoring BP. The AHA also recommends obtaining at least 2 readings at least 1 minute apart and averaging them as the patient’s BP.¹⁰ Other research recommends using a fully automated sphygmomanometer to take multiple readings with the patient resting quietly alone in either the exam room or the waiting room¹¹ as an effective and efficient method for accurate BP averaging.

The 2 principal noninvasive methods of BP measurement are the manual auscultatory technique and the oscillatory technique. Because of its simplicity and relative degree of accuracy (when correctly performed), the auscultatory measurement remains common in everyday medical practice. Remarkably, it is one of only a few techniques for clinical examination of patients that has remained relatively unchanged since it was introduced by the Russian physician and scientist Nikolai Sergeevich Korotkoff in 1905.¹² However, accurate performance of the auscultatory method requires adequate training and experience.

In contrast, automated oscillometric BP measurement is easily performed and requires minimal training. However, it is important to note that any condition altering oscillation amplitude or regularity (eg, arterial wall stiffness or cardiac arrhythmia) will produce erroneous results, and the reading must be confirmed by auscultatory measurement.^{13, 14}

Auscultatory methods of BP ­measurement

The mainstay of clinical BP measurement has been auscultatory methods to detect the Korotkoff sounds, using a stethoscope and either mercury, aneroid, or “hybrid” sphygmomanometers. Traditionally, the mercury device was the “gold standard,” but the widespread ban of mercury in health care settings has now all but eliminated its use.

Aneroid gauge sphygmomanometers have a metallic spring and a metal membrane that flexes elastically to translate pressure signals from the cuff and operate a needle in the gauge. Owing to their complexity, these devices require regular recalibration, since inaccurate results may occur anytime the needle does not rest on 0 before use.

Contine to: The newer hybrid sphygmomanometers...