Advice from the BP Measurement Experts
As a manufacturer of blood pressure (BP) cuffs, we are often asked: “What is the difference between an Adult BP cuff (or “standard” cuff) and an Adult Long BP cuff?”
Simply put, a “long” cuff has the same range indicators and bladder size as a “standard” cuff, but the actual length is longer than that of a “standard” cuff. Therefore, a “long” cuff is able to fit on a larger patient population than a “standard” cuff.
You are probably asking yourself, “If the range and the bladder size is the same on both a “standard cuff” and a “long cuff”, do they both give accurate readings?”
To answer this question, you need to understand the “80/40” rule. The “80/40” rule states that in order to obtain an accurate blood pressure measurement, the cuff bladder length should be approximately 80% of the circumference of the upper arm and the cuff bladder width should be optimally 40% of the circumference of the upper arm. The basic reasoning behind this rule is that the cuff bladder must be able to occlude the brachial artery (obstruct the flow of blood through the artery) when the bladder is inflated. If the brachial artery is not completely occluded before you start to deflate the bladder, then you will hear the Korotkoff sounds earlier which will result in false high readings. On the other hand, if the bladder size is too big for the arm, then it will take longer to hear the Korotkoff sounds which will result in false low readings.
So if a “long cuff’ is used on a patient with an arm circumference that fits in the intended range of the cuff, then an accurate blood pressure measurement can be expected. However, if a “long cuff” is used on a patient with an arm circumference outside the intended range of the cuff, even if the cuff fits the arm of the patient, you risk obtaining inaccurate blood pressure measurements.
While we have kept customer demand in mind by making the long sized cuff available, we recommend always using best practices for obtaining an accurate blood pressure reading. You can read “10 Steps to Accurate Manual BP Measurement” for a detailed guide for obtaining a high quality reading. In addition, we highly recommend the following video tutorial for proper cuff sizing.
If you have experiences using "long" versions of blood pressure cuffs, we invite you to share your thoughts with us.