Cuff(SZ): The Cuff Size Blood Pressure Measurement Trial

Johns Hopkins University


To determine the impact of overcuffing (using a too-large cuff) and undercuffing (using a too-small cuff) on initial BP and average BP measurements when using an automated BP device, overall and stratified by appropriate cuff size

To determine if the impact over- or under-cuffing differs based on the following patient characteristics:

  1. Hypertensive (≥140/90 based on triplicate measures using appropriately sized cuff) vs. non-hypertensive.

  2. Arm circumference (continuous)

  3. Obesity status

For the Cuff Size Blood Pressure Measurement trial, 195 adults recruited from the community underwent 2 to 3 sets of 3 BP readings, 30 seconds apart, with an automated and validated device (Welch Allyn ProB 2000) using a BP cuff that was appropriated sized, one size lower, and one size higher. The order of cuff sizes was randomized. Before each set, patients walked for 2 minutes, followed by 5 minutes of rest to eliminate the potential effect of longer resting periods between tests on the results. The room was also kept quiet and participants were asked not to speak or use a smart phone.

Participants had a mean age of 54 years, 34% were male, 68% were Black, and 36% had a body mass index of at least 30 kg/m2, meeting the criteria for obesity.

Roughly one-half had a self-reported hypertension diagnosis, 31% had a systolic BP of 130 mm Hg or greater, and 26% had a diastolic BP of 80 mm Hg or greater.

Based on arm circumference (mean, 34 cm), the appropriate adult cuff size was small (20-25 cm) in 18%, regular (25.1-32 cm) in 28%, large (32.1-40 cm) in 34%, and extra-large (40.1-55 cm) in 21%.

This study shows that an inappropriate cuff can be off by 5-20 mmHg.

A 2019 AHA scientific statement on the measurement of blood pressure stresses the importance of cuff size, and last year, the American Medical Association launched a new initiative to standardize training in BP measurement for future physicians and health care professionals.

Previous work also showed that children as young as 3 to 5 years of age often require an adult cuff size, and those in the 12- to 15-year age group may need an extra-large cuff, or what is often referred to as a thigh cuff. Please note the following measurements and the frequency in the population.

  • Small (20-25 cm) (18%)

  • Regular (25.1-32 cm) (28%)

  • Large (32.1-40 cm) (34%)

  • Extra-large (40.1-55 cm) (21%)

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