Background
Current blood pressure (BP) measurement guidelines specify patient requirements, including being still. Some populations of patients cannot comply. A new International Organization for Standards is being developed to test devices that claim tolerance to transport-induced motion artifacts. This study proposes the first protocol to assess BP device accuracy in the presence of patient-induced motion.
Participants and methods
Forty healthy volunteers (23 males) participated. The device tested was the Welch Allyn Connex Spot Monitor (CSM) using the SureBP algorithm. A reusable cuff was placed on the left arm. During inflation/deflation cycles the participant performed pronation/supination movements of the left forearm every 5 s. The CSM readings during motion were compared to the average of manual resting auscultatory estimations immediately before and after each motion cycle (bracketing).
Results
The CSM recorded a BP reading on the first cycle in 37 participants. It displayed a reading in all 40 participants with one repeat cycle in the other three. The mean±SD for the device minus the manual BP values was 0.9±7.3 mmHg for systolic BP and −3.4±7.9 mmHg for diastolic BP.
Conclusion
This study represents a proposal for an automated BP device assessment in the presence of patient-induced motion. The CSM device, which uses an inflation-based algorithm, routinely produced BP values that closely matched auscultatory values bracketed immediately before and after the motion-associated cycle. The CSM should be of significant clinical value in populations in whom resting ‘still’ readings are not usually feasible, such as pediatric and geriatric patients, and patients in pain from injury or illness.
We derive the 1 -limit of trimmed sums of order statistics from location-scale distributions satisfying certain assumptions. Based on this limit, an approximation to the asymptotic variance of a Best-Asymptotic-Normal (BAN) estimator for the location parameter is developed. Associated formulae are derived for four locationscale distributions commonly used in lifetime data analysis. The approximation is analyzed via the properties of the approximating function and by comparison to the exact values for a special case. Applications are illustrated by applying the approximation to comparing location parameters and to selecting the population with the largest location parameter, using censored samples from location-scale populations.
We consider the problem of selecting the best from k lognormal i 2 i populations using type-II censored samples. The selection parameter is taken to be a linear combination, a + b 2 , since many quantities of interest associated with lognormal can be expressed as exp a + b 2 . Since the known 2 i case has been dealt with elsewhere, the case of unknown 2 i is the focus of this paper. Two-stage procedures are proposed, one for the equal case and the other for the unequal case. The procedure for the equal case, with a simple modification for the subcase when there is no censoring, is comparable to the procedure of Bechhofer et al. (1954), and the comparison is discussed. A discussion on the optimality of the procedures is also included.
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