Propofol-induced alterations in the microcirculation of hamster striated muscle.

To investigate the effects of propofol on small vessels, we have measured changes in diameter and blood flow in microcirculatory venules and arterioles. Studies were carried out in the dorsal skinfold chamber of hamsters by intravital fluorescence microscopy. A bolus injection of propofol 25 mg kg-1 dilated small and collecting venules by a mean value of 18% and arterioles by 13%. Blood flow in venules increased by up to 69%. Intralipid dilated arterioles and post-capillary venules by 26% and 30%, respectively. After 4 h of continuous infusion (0.2-0.8 mg kg-1), only blood flow in post-capillary venules increased (66% propofol and 92% Intralipid). Post-capillary and collecting venules dilated in both groups. Therefore, propofol and Intralipid induced venodilatation and enhanced blood flow after bolus administration. After 4 h, despite dilatation in both groups, only post-capillary venules showed enhanced blood flow. These observations suggest redistribution of blood flow after prolonged administration of propofol.