Measurement of Blood-pressure: Comparison of Intra-arterial and Cuff Values

In recent years numerous reports have appeared?for example, Pickering (1955)?of discrepancies between arterial blood pressure measured by an intra-arterial method and by the usual cuff and sphygmomanometer. Part of this discrepancy has been attributed to the effect of arm circumference on arterial pressure measured with a cuff. Corrections based on measurements made by Ragan and Bordley (1941) have been published by Pickering, Roberts and Sowry (1954). While several workers report good agreement between systolic blood-pressure determined by the intra-arterial and that by the cuff method, there is disagreement over which of the two phases (phase 4, muffling, or phase 5, disappearance) represents the true diastolic pressure.