Differences in blood pressure levels obtained by auscultatory and oscillometric methods
M. G. Weaver, M. K. Park and D. H. Lee
Department of Pediatrics, University of Texas Health Science Center, San Antonio 78284.
Levels of blood pressure measured by the conventional auscultatory method
were compared with those measured by the Dinamap Monitor (Dinamap Monitor
1846 SX, Critikon Inc, Tampa, Fla), an oscillometric device. Triplicate
measurements were obtained by the two methods 10 to 15 minutes apart in 381
seated fifth-grade children, ages 10 to 13 years. The width of the air
bladder of the blood pressure cuff was selected to be 40% to 50% of the
circumference of the upper arm. The mean systolic and diastolic pressures
(at the fourth phase of Korotkoff sounds) by the auscultatory method were
6.4 mm Hg lower and 8.7 mm Hg higher than the oscillometric systolic and
diastolic blood pressures, respectively. The findings of this study suggest
that published normative levels of auscultatory blood pressure may be
inappropriate as a standard when blood pressure measurement is obtained by
the Dinamap Monitor. Until a new set of normative Dinamap blood pressure
levels becomes available, one should use equations (A = 12.8 + 0.82D for
systolic, and A = 34.3 + 0.54D for diastolic blood pressures at the fourth
phase of Korotkoff sounds, where A is auscultatory blood pressure and D is
Dinamap blood pressure) to predict auscultatory blood pressures before
Dinamap blood pressures are compared with normative auscultatory blood
pressure levels.
