Biases in the measurement of arterial pressure.

Journal Article (Journal Article)

We compared cuff to simultaneous direct intra-arterial pressure in 26 seriously ill patients, in order to: test the accuracy of oscillometric and auscultatory estimates of direct systolic pressure; test muffling and disappearance of sound as indices of direct diastolic pressure; gain insight into the timing of the different phases of Korotkoff sounds; and assess the local and general effects of cuff inflation on blood pressure. We found that conventional estimation of systolic blood pressure by auscultation of the first Korotkoff sound (K1) underestimates direct systolic pressure by an average of 16 to 17 mm Hg. Oscillometric pressure measurement provides a significantly better estimate than K1 but still underestimates by 7 to 8 mm Hg. These systolic cuff measurements are biased downward from direct values because of local cuff effect and cuff error. Diastolic cuff measurements deviate from direct values primarily because of a local cuff effect which produces an upward bias of 5 mm Hg at the point of sound muffling (K4), and 3 mm Hg at the point where sounds disappear (K5). We recommend oscillometric measurement of systolic pressure and K5 measurement of diastolic pressure as the best indirect estimates of blood pressure in critically ill patients.

Full Text

Duke Authors

Cited Authors

  • Finnie, KJ; Watts, DG; Armstrong, PW

Published Date

  • November 1, 1984

Published In

Volume / Issue

  • 12 / 11

Start / End Page

  • 965 - 968

PubMed ID

  • 6499482

International Standard Serial Number (ISSN)

  • 0090-3493

Digital Object Identifier (DOI)

  • 10.1097/00003246-198411000-00009


  • eng

Conference Location

  • United States