Traditionally, the palpation of the return of the brachial pulse and the disappearance of Korotkoff sounds is used to record the systolic and diastolic blood pressures, respectively. We noticed that the sharp (phase 4) Korotkoff sounds could be palpated by a thumb kept lightly over the brachial artery. Felt as sharp knocks, the "sounds" appear a little before the diastolic reading, increase slightly in their sharpness, and suddenly disappear; then the normal brachial pulse can be felt.
We tested whether the disappearance of knocks accurately indicated the diastolic blood pressure in 50 adult inpatients. Using a sphygmomanometer, one of us recorded the diastolic pressure by the new palpatory method; the other, blinded to the first reading, recorded it using a stethoscope. Irrespective of age (range, 35 to 74 years; median, 52 years), sex (male-female ratio, 3:2), or diastolic pressure reading (78 to 102 mm Hg; median, 84 mm Hg), the