Photo Credit: Bernard Bodo
Using a one-size-fits-all blood pressure cuff for patients with varying arm sizes can result in significantly inaccurate blood pressure readings.
Although clinical practice guidelines recommend using an individualized cuff size to measure blood pressure (BP), healthcare providers typically use a standard BP cuff regardless of a patient’s arm size. However, a standard size cuff can produce inaccurate BP readings because patients’ mid-upper arm circumference varies.
“When physicians review BP reports, they should be aware of how BP readings were obtained. Our data suggests that using a BP cuff that is either too small or too large may result in overestimation or underestimation of BP readings,” according to Junichi Ishigami, MD, PhD, who conducted a study with a team of colleagues to evaluate the effect of using a regular BP cuff versus an appropriately sized BP cuff on automated BP readings.
How Does Overcuffing & Undercuffing Affect BP Readings?
The researchers conducted a randomized crossover trial that included 186 adults with a wide range of mid-upper arm circumference to evaluate whether using a too-large BP cuff (overcuffing) would result in lower BP readings and using a too-small BP cuff (undercuffing) would result in higher BP readings. They measured the difference in the mean systolic BP (SBP) and diastolic BP (DBP) obtained with a regular BP cuff compared with an appropriately sized BP cuff. In addition, they measured the difference in the mean SBP and DBP using too-small, or too-large BP cuffs compared with an appropriate BP cuff across all cuff sizes.
The average age of patients was 54 years, 67 (34%) were male, 132 (68%) were Black, 100 (51%) had hypertension, 39 (20%) had diabetes, and the mean BMI was 28.8. After measuring midarm circumference, researchers determined a small BP cuff (20-25 cm) was appropriate for 35 participants, a regular BP cuff (25.1-32 cm) was appropriate for 54 participants, a large BP cuff (32.1-40 cm) was appropriate for 66 participants, and an extra-large BP cuff (40.1-55 cm) was appropriate for 40 participants.
After triplicate measurements, Dr. Ishigami reported that “the magnitude of errors is substantial and clinically significant. For instance, using a regular BP cuff led to a 3.6 mm Hg lower SBP reading in individuals requiring a small cuff. In contrast, for those needing a large or extra-large cuff, a regular BP cuff resulted in 4.8 mm Hg and 19.5 mm Hg higher SBP readings, respectively.” These findings were also consistent, although less substantial, for DBP readings. When a regular BP cuff was 1 size too large, 1 size too small, and 2 sizes too small, DBP readings were 1.3, 1.8, and 7.4 mm Hg lower, respectively (Table).
Implications of Using Standard BP Cuffs
The study revealed that using a regular BP cuff size for all individuals regardless of arm size resulted in strikingly inaccurate BP readings; therefore, there is a need for renewed attention to individualized BP cuff selection. Dr. Ishigami cautions that “inaccurate BP readings will not only lead to over- and underdiagnosis of hypertension but also result in financial consequences. For instance, undertreatment of hypertension may escalate the costs associated with treating preventable cardiovascular complications. Conversely, overtreatment can lead to unnecessary side effects of medical interventions and increased expenditure on medications. Thus, stakeholders at every level, including healthcare providers, health system managers, and policymakers, should make every effort to ensure proper BP cuff sizes are available for every occasion of BP measurement.”
Although individualized BP cuff selection may not be consistently implemented in every setting, it is crucial to recognize the importance of using the right BP cuff and the potential consequences of using an inappropriate size. Dr. Ishigami suggests that “it is worthwhile to review the BP measurement procedure within each clinic, assessing the availability of various cuff sizes and staff awareness and practice in measuring arm circumference to select an appropriately sized BP cuff. Staff training and educational opportunities to enhance adherence to BP measurement procedure guidelines may also be important.”
