Key points What is the effect of using a regular-sized blood pressure (BP) cuff, regardless of a person’s mid-upper arm circumference, on BP readings when using an automated device ? Findings In this randomized crossover trial of 195 community-dwelling adults with a wide range of mid-arm circumferences, use of a normal BP cuff resulted in a 3.6 mm Hg lower systolic BP reading among people who required a small BP cuff. In contrast, among people requiring a large or extra-large BP cuff, use of a regular BP cuff resulted in 4.8 mm Hg and 19.5 mm Hg higher systolic BP readings , respectively. Meaning Using a regular BP cuff for all people, regardless of arm size, resulted in surprisingly inaccurate BP readings with an automated device; A renewed emphasis on individualized blood pressure cuff selection is warranted, particularly in individuals with larger arm sizes. |
Importance
Clinical practice guidelines recommend selecting an appropriately sized cuff based on mid-arm circumference before measuring blood pressure (BP). To our knowledge, the effect of error on BP measurement when using an automatic BP device has not been quantified.
Aim
To determine the effect of using a regular BP cuff versus an appropriately sized BP cuff on automatic BP readings.
Design, environment and participants
This randomized crossover trial of community-dwelling adults with a wide range of mid-arm circumferences was conducted between March 16 and October 25, 2021 in Baltimore, Maryland. Participants were recruited through BP screening events at a public food market and a senior living facility, targeted mailings to participants from previous research, placement of study flyers in hypertension clinics at Johns Hopkins University, and referrals from physicians who provide hypertension care to adults.
Interventions
Participants underwent 4 sets of BP measurements in triplicate, with the initial 3 sets using an appropriate, too small, or too large BP cuff in random order; the fourth set of triplicate measurements was always completed with an appropriate BP cuff.
Main results and measures
The primary outcome was the difference in mean BP when measured with a normal BP cuff compared with an appropriate BP cuff . The secondary outcome was the difference in BP when using too small or too large BP cuffs versus an adequate BP cuff across all cuff sizes.
Results were also stratified by systolic BP (≥130 mm Hg vs <130 mm Hg) and body mass index (calculated as weight in kilograms divided by height in meters squared; ≥30 vs <30).
Results
A total of 195 adults (mean [SD] age, 54 [16] years; 67 [34%] men; 132 [68%] blacks; 100 [51%] with hypertension) were randomized for inclusion.
Among people requiring a small BP cuff, use of a regular BP cuff resulted in a statistically significant lower BP reading (mean systolic BP difference, −3.6 [95% CI, −5.6 to −1.7] mm Hg).
In contrast, among people requiring a large or extra-large BP cuff, use of a regular BP cuff resulted in a statistically significant higher BP reading (mean systolic BP difference, 4.8 [95% CI]. % 3.0-6.6] mm Hg and 19.5 [95% CI, 16.1-22.9] mm Hg, respectively).
For the secondary outcome, BP differences with cuffs above and below 1 and 2 cuff sizes were greatest among those requiring larger BP cuffs. Results were consistent in analyzes stratified by systolic BP and body mass index.
Conclusions and relevance
In this randomized crossover trial, use of incorrect cuffs resulted in strikingly inaccurate BP measurements . This is particularly concerning for settings where a normal BP cuff size is routinely used in all individuals, regardless of arm size. A renewed emphasis on individualized PA cuff selection is warranted.
Final message This randomized crossover trial of community-dwelling adults using an automated BP device reports that BP readings obtained with a regular BP cuff instead of an appropriately sized cuff resulted in strikingly inaccurate BP measurements. Specifically, measurements obtained when the regular BP cuff was too large or too small resulted in clinically and statistically significant lower and higher BP readings, respectively. Accurate BP measurement is crucial to reducing the prevalence of cardiovascular disease and these data suggest the need for renewed emphasis on individualized BP cuff selection, particularly in individuals with larger arms. These data further support the American Heart Association guideline recommendation that arm circumference measurement be used to select a cuff with corresponding bladder length and width. |
ClinicalTrials.gov Trial Registration Identifier: NCT04610775
