Standard Blood Pressure Cuffs May Produce Inaccurate High Readings In Obese Persons
posted 08/28/03
Using a standard blood pressure (BP) cuff in obese subjects may result in overestimation of BP.

Commercially available sphygmomanometers generally consist of only a standard cuff, with a 12.5 cm bladder. A large adult cuff, with a 15.5 cm bladder, is rarely available. However, some researchers have found higher BP values in obese individuals when the standard cuff is used.

To evaluate this issue further, Salvador Fonseca-Reyes, MD, PhD, with Instituto de Investigacion, at the Cardiovascular, Hospital Civil de Guadalajara, Mexico and colleagues measured BP in 120 subjects with an arm circumference greater than 33 cm. They also determined the prevalence of large arm circumference in 244 patients from a family health unit, and in 216 patients from a hypertension clinic.

The researchers first measured the BP of 60 patients with a large cuff, followed by a standard cuff; and applied the opposite sequence for another 60 patients. They then calculated the difference in BP with each measurement.

Both systolic and diastolic BPs were significantly greater when the standard cuff was used (all p<0.05). For every 5 cm increase in arm circumference, starting at 35 cm, a 2 to 5 mmHg increase in systolic BP and a 1 to 3 mmHg increase in diastolic BP were seen. They also found that about 42% of patients in the family medicine unit and hypertension clinic had an arm circumference greater than 33 cm.

"Our results showed that the BP readings taken with a standard cuff in the two study groups were consistently higher and similar, and independent of the sequence of the cuffs used, " the researchers conclude.

They suggest that this difference could have important consequences in daily practice, "especially in those subjects with obese arms and with BP values within the range known as high normotensive (130 to 139 mmHg and 85 to 89 mmHg respectively for the systolic and diastolic blood pressures)."

According to the researchers, their findings "should obligate practitioners and clinics to have larger cuffs available in order to take BP readings under more appropriate conditions."

Source: Diabetes In Control Dot Com: Blood Press Monit 2003;8:3:101-106.

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