Calf Blood Pressure: Clinical Implications and Correlations With Arm Blood Pressure in Infants and Young Children

Abstract

Objective. Indirect measurement of lower extremity blood pressure is often used in the clinical setting, although normative data after the newborn period are not readily available. Methods. Indirect blood pressure (BP) measurement was obtained in the right arms and right calves of 148 healthy infants and young children 2 weeks to 3 years of age. All measurements were made using an oscillometric device. The infants and children were quiet or asleep and in the supine position. A BP cuff of proper size was chosen. Three measurements were made in both extremities; the average of the second and third measurements was used for all analyses. Results. Age correlated better with calf systolic blood pressure (SBPc) than with arm SBP (SBPa) (r = .52 vs .17). Calf diastolic blood pressure (DBPc) and calf mean blood pressure (MBPc) correlated moderately poorly with age (r = .37 and .39, respectively). There was no order effect. SBPc correlated best with height (r .53), then age (r = .52), and, finally, weight (r = .51). The correlation between BPc and BPa was moderately low. The correlation of SBPc with SBPa was r = .46; that of DBPc with DBPa was r = .37; and that of MBPc with MBPa was r = .41. From birth to 6 months, SBPc was slightly lower than SBPa (1 to 3 mm Hg). SBPc increased linearly relative to SBPa and began to exceed SBPa at 6 months of age. The pattern of DBP and MBP was similar. Wide variability of blood pressure parameters was noted between the infants and children at all ages. Conclusions. Reference data are presented for BPc and the difference between BPc and BPa in healthy infants and children from 2 weeks to 3 years of age. BPc is not equivalent to BPa and should not be arbitrarily substituted. Because of the wide variability among healthy infants and children, SBPc measurements should be interpreted with caution when evaluating for coarctation of the aorta.