BACKGROUND AND PURPOSE:

• The effect of incorrect cuff size has not been systematically measured
• Ishigami et al. (JAMA Internal Medicine, 2023) determined the effect of using a regular BP cuff vs an appropriately sized BP cuff on automated BP readings

METHODS:

• Randomized crossover trial
  • Baltimore, MD
• Participants
  • Adults in the community
• Interventions
  • 4 sets of triplicate BP measurements
    • Initial 3 sets used an appropriate, too-small, or too-large BP cuff in random order
    • The fourth set always used repeated measurements obtained with an appropriate BP cuff (to determine reproducibility of the reference measurement)
• Study design
  • 4 cuff sizes: Small | Regular | Large | Extra large
  • Automated BP devices
  • All participants had ≥1 set of BP measurements with the regular cuff regardless of whether size was appropriate based on arm circumference
  • Results were stratified by
    • Systolic BP: ≥130 mm Hg vs <130 mm Hg
    • BMI: ≥30 vs <30
• Primary outcome
  • The difference in mean BP when measured with a regular BP cuff compared with an appropriate BP cuff
• Secondary outcome
  • The difference in BP when using too-small or too-large BP cuffs vs an appropriate BP cuff across all cuff sizes

RESULTS:

• 195 adults
  • Mean age: 54 (SD, 16) years | Male: 34% | Black: 68% | With hypertension: 51%
• Patients who require a small BP cuff
  • Use of a regular BP cuff resulted in a significant lower BP reading
  • Mean systolic BP difference −3.6 (95% CI, −5.6 to −1.7) mm Hg
• Patients who require a large or extra-large BP cuff
  • Use of a regular BP cuff resulted in a significant higher BP reading
    • Large: Mean systolic BP difference 4.8 mm Hg (95% CI, 3.0 to 6.6)
    • Extra-large: Mean systolic BP difference 19.5 mm Hg (95% CI, 16.1 to 22.9)
• BP differences were greater among those requiring larger BP cuffs
• These results were consistent when stratified by systolic BP and BMI

CONCLUSION:

• Using the wrong BP cuff size resulted in significantly inaccurate BP readings especially among patients requiring a large or extra-large BP cuff size
• The authors state

…using a regular BP cuff size for all individuals regardless of arm size resulted in strikingly inaccurate BP readings. A renewed emphasis on individualized BP cuff selection is warranted, particularly in individuals with larger arm sizes 

Learn More – Primary Sources:

Effects of Cuff Size on the Accuracy of Blood Pressure Readings: The Cuff(SZ) Randomized Crossover Trial