Assessing the Accuracy of the A&D TM-2657W Oscillometric Device

Methods and Analysis

Study methodology will follow the ISO protocol:

• 85 adult (age 18 years or greater) subjects will be included (it is estimated that approximately 140 subjects will need to be screened as some will be ineligible). 85 is the recommended sample size for validation studies using the ISO protocol.
• Subjects will be recruited via an existing registry of over 250 individuals that have participated in past measurement studies, through advertisements, and from the University of Alberta Hypertension Clinic.
• Specific requirements for a certain percentage of subjects with specific age, sex, upper arm circumference, and baseline blood pressure levels will be observed to ensure that a representative sample is studied (according to the ISO standards).
• Subjects that are pregnant or with atrial fibrillation will be excluded. Blood pressure measurements will be taken using recommended, optimal technique.
• Nine measurements will be taken in each subject, alternating between blinded two-observer auscultation with a mercury-based sphygmomanometer (the reference standard) and the TM-2657. Careful attention will be paid to ensuring proper cuffing. The first two measurements will be discarded and the latter seven measurements (4 auscultatory and TM-2657 measurements) will be used in the analysis, which will be conducted according to ISO standards.
• Accuracy will be assessed according to Criterion 1 and 2 of the ISO standard. Bland-Altman plots will be generated. A plot of measurement error versus arm circumference will be generated as well.