Arterial blood pressure and blood flow velocity in major cerebral and visceral arteries. II. Effects of colloid infusion.

To compare the effects of acute changes in blood pressure on arterial blood flow velocity in various regional circulations, Doppler ultrasound measurements of blood flow velocity were recorded from the anterior cerebral artery (ACA), superior mesenteric artery, coeliac axis and left renal artery. Measurements were obtained from 10 ventilated very low birth weight infants before and after plasma infusions given to treat systemic hypotension on the first day of postnatal life. Blood pressure increased in 8/10 infants, and in this group there was a significant increase in ACA and coeliac axis blood flow velocity. For the ACA only, there was a significant association between the change in blood flow velocity and the magnitude of the change in blood pressure (r = 0.73, P < 0.02). Mesenteric and renal artery velocity did not increase after the infusion. For ventilated VLBW infants on the first day of life, arterial blood flow velocity was affected by acute changes in blood pressure in the cerebral circulation only.