Raising the arm before cuff inflation increases the loudness of Korotkoff sounds

Recent guidelines suggest that Korotkoff sounds can be enhanced by elevating the arm overhead for 30 s before inflating the cuff, and then bringing the arm to the usual position to continue the blood pressure measurement.

We evaluated the effect of this manoeuvre on the loudness of the Korotkoff sound and on the accuracy of Riva-Rocci-Korotkoff (RRK) measurements. Using an electronic stethoscope, we compared the amplitudes of Korotkoff sounds between both arm positions. To determine the accuracy of blood pressure measurements, which are performed after raising the arm first, we validated this 'new method' of blood pressure measurement according to the British Hypertension Society protocol.

The amplitude of the first Korotkoff sound with the arm elevated overhead for 30 s first, was 1.82+/-1.75 times greater (P<0.01) than the amplitude of the first Korotkoff sound with the arm in the usual position. Second and third Korotkoff sounds were also louder. RRK blood pressure measurements that were performed after raising the arm overhead for 30 s did pass the validation procedure according to the British Hypertension Society protocol. The nonsignificant difference (RRK after raising the arm first-normal RRK measurements) was 0.33+/-2.85 mmHg for systolic and -1.17+/-2.63 mmHg for diastolic measurements.

Korotkoff sounds can be enhanced by elevating the arm overhead for 30 s before inflating the cuff, and then bringing the arm to the usual position to continue in the blood pressure measurement. This manoeuvre leads to louder systolic Korotkoff sounds and does not have an effect on measured blood pressure levels.