Quantitative studies of the human neonatal circulation. 3. Observations on the newborn infants central circulatory responses to moderate hypovolemia.

Abstract

Summary Twelve newborn infants, 1 1/2 to 58 hours old have been investigated with respect to the consequences of graded hemorrhage on peripheral circulation and plasma volume. It has been demonstrated that the newborn infant responds to a hypovolemia corresponding to 15 per cent of predicted total blood volume with a twofold increase of resistance to blood flow in the calf. Peripheral vasomotor tone is adequately controlling the systemic blood pressure by decreasing perfusion of the vascular compartments in the calf muscle, whereas no indications of a change in the cutaneous blood flow occurred. A rapid decrease of the arterial hematocrit reflects efforts to restore the plasma volume.