THE ACCURACY OF AUSCULTATORY MEASUREMENT OF ARM BLOOD PRESSURE IN VERY OBESE SUBJECTS

Abstract

Abstract. In 28 very obese subjects with arm circumference equal to or greater than 35 cm (mean 41.8, range 35–49) intraarterial measurements of arm blood pressure (BP) were performed simultaneously with auscultatory measurements using a standard cuff (12 × 23 cm) and a big cuff (14 × 45 cm). The mean difference between auscultatory and intraarterial measurements using the standard cuff was +6.8 mmHg (S.D. 14.3) for systolic and + 14.3 mmHg(S.D. 9.7) for dia‐stolic BP (phase V). Using the big cuff these mean differences were reduced to ‐5.8 mmHg (S.D. 11.2) and +7.1 mmHg (S.D. 7.1), respectively. Neither arm circumference nor BP correlated significantly with the difference between auscultatory and intraarterial measurement. It is emphasized that with the standard cuff the measurement of arm BP in these obese subjects is inaccurate. Using the big cuff the accuracy is better, similar to that of indirect measurements in normal subjects. But big interindividual differences nevertheless exist which cannot be predicted from the BP nor the circumference of the arm. Therefore, in patients in whom “cuff hypertension” is suspected, intraarterial measurements are indicated before prolonged antihypertensive treatment is initiated.