Comparison of indirect and direct methods of measuring arterial blood pressure

Direct and indirect determinations of blood pressure have been recorded in 70 human subjects. Statistical analysis of the results is presented. A frequent discrepancy between direct and indirect readings is evident with the drift of the latter falling increasingly below the direct measurement as blood pressure rises. The greatest discrepancy is found in the young hypertensive subject and the possible clinical implications of this finding are discussed. An attempt is made to explain some of the factors contributing to the variable error by which auscultatory readings underestimate the true intraarterial pressure.