Studies of the quality of blood pressure measurements the muscatine study
Clarke, W.R.; Lauer, R.M.
Pediatric Research 12(4 Part 2): 422
ISSN/ISBN: 0031-3998 DOI: 10.1203/00006450-197804001-00358
To study blood pressure (BP) changes during maturation in children it was necessary to monitor the performance of those taking BP's. The Muscatine study, using standard mercury manometers, has measured 8910 children. These have been repeated at two year intervals since 1970, and 2652 children have been measured 3 or 4 times. A training and evaluation program has been maintained for 5 observers. Periodic evaluation consisted of (1) simultaneous recording of BP's from movie film or video tapes, (2) repeated blind measurement of a sample of children, (3) remeasuring by the same observer of a random sample from each day's screening, (4) comparing the distributions of Bp values obtained for each observer and (5) monitoring digit preference for each observer. Films yielded an optimistic estimate of reproducibility (r=0.99 for systolic Bp and r=0.88 for diastolic BP). Repeated blind measurements on a sample of children yielded lower estimates (r=0.80 for Sbp and r=0.43 for DBP). Rescreening a random sample from each day yielded the most accurate estimate of reproducibility (r=0.92 for Sbp and r=0.83 for DBP). On examining the distribution of BP's taken by each observer, only small biases were noted. While all observers were instructed to measure to the closest 2 mm of Hg, digit preference for zero's and four's was evident. Continued monitoring of observer performance showed highly reproducible and consistent results, thus allowing the study of blood pressures with time.