Should blood pressure be measured with the cuff on a bare arm?

Abstract

To establish whether the results of blood pressure (BP) measurements are affected by wearing clothing underneath the BP cuff during measurement. Normotensive and hypertensive patients (n=133; 65 men) of an outpatient clinic participated in this study. BP was measured according to a rigorous protocol with a validated oscillometric device under three conditions: with one layer of own clothing (OC) underneath the cuff, with one layer of standardized clothing (SC) underneath the cuff, and with the cuff on a bare arm (BA), in a randomized order. Patients were seated on a chair with their right arm on the table and their feet flat on the floor during BP measurement. The mean BP values (±SEM) measured during BA, OC, and SC were, respectively, 132.8±1.3, 132.3±1.4, and 133.2±1.4 mmHg for systolic blood pressure (SBP), 78.3±0.9, 78.3±0.9, and 78.5±0.9 mmHg for diastolic blood pressure (DBP), and 90.3±1.0, 90.0±1.0, and 91.5±1.0 mmHg for mean arterial blood pressure (MAP). The differences in SBP, DBP, and MAP between BA, OC, and SC measurements were not statistically significant, but there was considerable intraindividual variation in SBP deviations of more than 5 mmHg between BA versus OC and SC. There was no significant order effect of the three conditions. The absence of differences between BA, OC, and SC was not determined by age, sex, BMI, and arm circumference. We could not find differences in MAP, SBP, and DBP between the bare and clothed arms, but intraindividual variation of SBP between the three conditions is not negligible. Despite this caveat, these data suggest that in an outpatient clinic, BP can be measured reliably with one layer of clothing underneath the cuff. This is timesaving and more comfortable for patients.