Reliability of palpation of the radial artery compared with auscultation of the brachial artery in measuring SBP

BACKGROUND: Systolic blood pressure contributes more to cardiovascular disease than DBP, especially in elderly persons. Palpation of the radial artery to assess SBP - Riva-Rocci's technique - may be an attractive alternative for auscultatory SBP in these patients. Therefore, we investigated the difference between SBP determined by palpation of the radial artery (pSBP) and SBP assessed by auscultation of the brachial artery (aSBP). METHODS: Patients were included from the waiting room of a hypertension outpatient clinic. In each patient eight simultaneous pSBP and aSBP measurements were assessed by two observers in the same arm. After every two readings the observers switched between pSBP and aSBP. RESULTS: Forty patients were included, 25 men (62.5%), mean age 55.3 years (range 24-78). From a total of 320 measurements, mean difference between pSBP and aSBP was -5.2 mmHg (range -12-26 mmHg) (P < 0.01). This difference correlated significantly with BMI (r = 0.51, P < 0.01), but not with age (r = 0.15, P = 0.35), pulse rate (r = 0.29, P = 0.09) or mean SBP (r = 0.03, P = 0.85). After averaging the first three comparisons, reproducibility did not improve when increasing the number of comparisons. When correcting for the underestimation of 6 mmHg over the first three comparisons, Riva-Rocci's technique estimates SBP with an acceptable accuracy. CONCLUSION: In clinical practice, Riva-Rocci's palpatory technique offers an acceptable alternative for auscultatory SBP measurement. It is recommended to take three measurements and then correct for the average underestimation of 6 mmHg.