Cuff bladder width and blood pressure measurement in children and adolescents.

Abstract

To estimate the independent contribution of the blood pressure cuff bladder width: mid-upper arm circumference (CW:AC) ratio to the variability in systolic blood pressure (SBP), diastolic blood pressure phase 4 (DBP4) and diastolic blood pressure phase 5 (DBP5) in children and adolescents, and its impact upon the estimate of prevalence of high blood pressure derived at screening. Use of cuffs with a CW:AC ratio below 40% causes overestimation of the true blood pressure level. With higher CW:AC ratios the level is underestimated. National recommendations for adults state that the CW:AC ratio is optimal at approximately 40%, but no consistent recommendations exist for children. We measured SBP and diastolic blood pressure phases 4 and 5 in 811 boys and 771 girls aged 10-17 years (93% participation rate). In each subject the blood pressure was measured with a cuff conforming to the 40% rule (recommended cuff), with one smaller (mean decrease in the CW:AC ratio:7.4%), and with one larger (mean increase in the CW:AC ratio:10.2%). Cuffs were used in random order. Smaller cuffs gave significantly higher blood pressure readings. With the larger cuff there were significant mean decreases. The differences were independent of the blood pressure level obtained with the recommended cuff. The impact upon the estimate of the prevalence of high blood pressure was substantial. Selection of the proper cuff size is important for children and adolescents, in order to avoid both over- and underdiagnosis of hypertension.