Validation of the A&D UA-651 Plus/UA-651SL Plus automated sphygmomanometer according to the ISO 81060-2, 2018 and ISO 81060-2 Amendment 1, 2020, which resulted in the currently pending Amendment to Amendment 1

In 2020 the ANSI/AAMI/ISO published Amendment 1 to the 81060-2 Standard. The purpose was to try to address issues relating to the distribution of subjects with respect to limb size ranges. It also required a new plot showing the limb circumferences on the x-axis and the device minus reference errors on the y-axis (Alpert plot). The study reported here showed inadequacies of the Amendment if significantly overlapping cuffs were to be tested. The innovative approach led to the testing of 135 subjects. Requirements for blood pressure (BP), arm circumference, and gender were fulfilled. The standard same arm sequential protocol was used. Criterion 1 calculations gave a mean +/- standard deviation (SD) device minus manual BP values of 0.22 +/- 7.90 mmHg for systolic BP and -0.68 +/- 7.36 mmHg for diastolic BP. The maximum allowed mean value for either measurement is 5.0 mmHg. The SD values for Criterion 2 were 6.03 mmHg for systolic BP (maximum allowed 6.95) and 6.47 mmHg for diastolic BP (maximum allowed 6.90). All results passed the Standard requirements. This study demonstrated inadequacies of Amendment 1 and led to the development of an Amendment 2, still in the process of finalization. The new Amendment corrects the issues with significantly overlapping cuffs and "wide-range" cuffs. The A&D UA-651 Plus/UA-651SL Plus BP monitors and the five cuffs not only passed the requirements of 81060-2:2018 and Amendment 1 but also a revised and more rigorous protocol with more subjects involved. These devices and cuffs can be used with confidence.