Key result
Low-dose dopamine boosts mean renal artery flow velocity and reduces pulsatility unlike dobutamine.
Why the study?
The utility of Doppler ultrasound in assessing renal hemodynamics during vasoactive agent infusion needed to be examined.
Doppler may differentiate renal vascular effects of dopamine vs dobutamine; leaves open translation to patients with renal impairment.
To examine the utility of Doppler ultrasound in assessing renal hemodynamics, we investigated the effects of dopamine and dobutamine on renal blood flow using Doppler ultrasound technique and conventional clearance tests in 7 healthy volunteers. After visualization of arterial blood flow in the right renal hilus by two-dimensional color flow mapping, the phasic blood flow velocity in the vessel was obtained by a pulsed Doppler method. Intravenous infusion of dopamine at a low dose increased the velocity and decreased the waveform pulsatility of renal artery blood flow without causing any significant changes in blood pressure, heart rate, or cardiac index. In contrast, dobutamine infusion increased the peak systolic velocity in a dose-dependent manner, but did not increase the mean velocity or decrease the waveform pulsatility. Percent changes of renal blood flow during infusions of both agents correlated well with those of the mean velocity. Furthermore, the degrees of changes of the waveform pulsatility were consistent with those of renal vascular resistance obtained from clearance tests and blood pressure. Our results suggest that mean velocity reflects renal blood flow and the pulsatility of blood flow waveform represents renal vascular resistance. We conclude that the effects of vasoactive agents on renal blood flow and renal vascular resistance can be estimated noninvasively, directly, and repeatedly using Doppler ultrasound.
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Yura et al. (2008) studied Healthy volunteers (n=7). Intravenous dopamine and dobutamine vs. Baseline / conventional clearance tests was evaluated on Renal artery blood flow velocity and waveform pulsatility assessed by pulsed Doppler ultrasound. Low-dose dopamine increased mean renal artery blood flow velocity and decreased waveform pulsatility, whereas dobutamine increased only peak systolic velocity in 7 healthy volunteers.
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