Orthostatic heart rate and arterial blood pressure changes in normovolemic children

Orthostatic heart rate and blood pressure changes were determined in 112 normovolemic children from two to 12 years of age. In normal children, two to eight years of age, and nine to 12 years of age, the heart rate may increase as much as 30 and 40 beats per minute, respectively, upon standing. The orthostatic systolic blood pressure change is independent of age and may, in normal children, fall as much as 27 mm Hg. The orthostatic diastolic blood pressure change, as determined by the fourth or fifth Korotkoff sounds, showed great variability, and probably will not be useful in the assessment of a child's intravascular volume status. Orthostatic changes in heart rate and blood pressure, within the above limits, cannot be used as evidence of hypovolemia, since these changes can occur in normovolemic children.