Table 4.

Summary list of issues for consideration in development of an internationally accepted central blood pressure (BP) validation protocol

Validation protocol features	Comments
Reference method
Non-invasive reference standard	What criteria needed to satisfy for an acceptable non-invasive alternative to the invasive method which restricts study sample characteristics?
Error
Minimum standard	What is the magnitude of the minimum acceptable error and its frequency based on the invasive reference standard?
Study sample
Definition of general population sample	Which populations should be considered as special as there may be different device measurement accuracy from the general population, and therefore require separate validation?
Minimum sample size for a general population study	Based on the reference method for an acceptable statistical risk of false positive and negative results
Sample size for validations in special groups	To be defined after a successful study in the general population has been completed
Sex and age distribution	Representation of males and females, adolescents, young and middle aged adults and elderly
BP and heart rate range criteria	Based on reference central BP measurements and heart rate during the procedure?
Cuff size	Minimum number of subjects investigated per different cuff size, or number of different cuffs to be studied in a single study?
Exclusion criteria	On the basis of increased reference BP variation within individual validation procedures or clinical conditions
Procedural
Number of measurements	Procedure for the number of reference and test BP measurements in a validation session
Comparison with reference	How to compare when operating characteristics differ between reference (i.e. beat-to-beat) and non-invasive test devices (i.e. averaging over seconds to minutes) and influence of respiratory variation and arrhythmias?
Reporting
Data and pass criteria	What data, statistics and study features to be reported? What pass/fail criteria?