Evaluation of the A&D UA-767 and Welch Allyn Spot Vital Signs noninvasive blood pressure monitors using a blood pressure simulator

The performance of five units of the A&D UA-767 NIBP monitor and five units of the Welch Allyn Spot Vital Signs noninvasive blood pressure monitor was evaluated with the Biotek BP Pump blood pressure simulator under a variety of conditions. Using the simulator to provide a normal blood pressure waveform at 80 bpm over a range of pressures, it was found that the mean bias for the combined results from the A&D monitors was 1.9+/-2.8 mmHg and from the Welch Allyn monitors was 0.7+/-2.4 mmHg. No individual measurement showed a bias greater than 10 mmHg. A bias of greater than 5 mmHg was present in 28 out of 150 measurements for the A&D monitor and 10 out of 150 measurements for the Welch Allyn monitor. These results are comparable with ratings achieved by the instruments when tested previously according to the British Hypertension Society protocol, but testing with a simulator allowed assessment of aspects of performance which were not included in the British Hypertension Society protocol.