Use of patient simulators to characterize the repeatability and reproducibility of automated oscillometric blood pressure monitors.

OBJECTIVES: Automated oscillometric blood pressure (BP) monitors can be critical health assessment tools if they are accurate and can provide repeatable and reproducible readings. Commercial patient simulators are capable of screening for poorly performing oscillometric BP monitors. A valid screening bench test method to identify unreliable and underperforming BP monitors could advance surveillance of these devices and support regulatory decision making. METHODS: Two simulators were used to characterize a total of 19 legally marketed upper arm, wrist, hospital-grade, and public-use BP monitors. These oscillometric BP monitors were tested for repeatability and reproducibility across different simulated patient populations. The metrics for evaluating these devices were the difference between the simulated pressure and the BP monitor output, and the variability from repeated measurements. RESULTS: All but one of the BP monitors tested provided repeatable readings (<3 mmHg). The mean error between the simulated pressure and the BP monitor output was largest for the wrist devices, whereas hospital-grade BP monitors most closely estimated the target BP waveforms. In general, device error and measurement variability increased at elevated BPs. CONCLUSION: Patient simulators are more suitable for repeatability analysis as opposed to assessing device accuracy. Despite their limitations, patient simulators can be used as effective tools to screen and improve the quality of BP monitors.

Interlaboratory Evaluation of Ultraviolet Radiation Emissions from Compact Fluorescent Lamps.

There have been many recent reports regarding the potential risks of UV emissions from compact fluorescent lamps (CFLs). In some of these reports, the robustness of the measurements was difficult to discern. We conducted round-robin measurements, involving three lamp manufacturers and two government research laboratories to gather reliable data on the UV emissions from commercially available CFLs. The initial sample of lamps consisted of 71 spiral-shaped CFLs purchased from local retailers. From the initial sample, 14 "high UV emitting" CFLs were chosen for further evaluation. We compared the UV emissions at a distance of 20 cm with the UV exposure limits (ELs) published by the International Commission on Non-ionizing Radiation Protection (ICNIRP). We found that the allowable exposure time for measured lamps ranged from 21 to 415 h. This indicates that the emissions would not exceed the short-term ELs that have been established by the ICNIRP for healthy individuals. We also evaluated the potential long-term risk and found it to be insignificant. There was a large variation in the UV emissions found, even for lamps from a single package, indicating that it is impossible to predict the UV output of a CFL based on its physical appearance and model designation.