The effect of dobutamine on middle cerebral artery blood velocity in volunteers: a preliminary study.

Five volunteers given dobutamine up to 4 micrograms/kg/min had significant increases in mean arterial blood pressure, systolic blood pressure, and stroke volume (P less than 0.05). Heart rate did not increase significantly. Pulsatility index, an index of middle cerebral artery maximum blood velocity waveform shape increased significantly in the dobutamine group (P less than 0.05). Time-averaged mean velocity did increase during the dobutamine infusion but the change was not statistically significant. Dobutamine significantly alters the blood velocity profile of the middle cerebral artery in volunteers even in low doses of 4 micrograms/kg/min. Transcranial Doppler may be a useful technique to monitor changes in cerebral artery blood velocity dynamics induced by dobutamine. These measurements can be performed easily and repeatedly at the bedside.