Role for Doppler Ultrasound in the Assessment of Renal Circulation: Effects of Dopamine and Dobutamine on Renal Hemodynamics in Humans

Abstract

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.

Nocturnal blood pressure reduction: effect on retrobulbar hemodynamics in glaucoma

“…The posterior ciliary artery peak systolic and/or end-diastolic velocity at baseline was lower in patients than in controls, and this may imply reduced baseline bulk flow in these vessels in glaucoma patients [22,24]. Because the posterior ciliary arteries are responsible for part of the optic nerve head perfusion, this result provides indirect evidence for reduced perfusion of the nerve head and nearby structures in these patients.…”

“…Analysis is guided by comparisons with standard measurements of blood flow both in mechanical models and in vivo [22,24]. These comparisons show that reductions in vascular bulk flow are consistently associated with simultaneous reductions in both the peak systolic and the end-diastolic velocity [22,24]. It is possible, therefore, that CDI changes are an accurate proxy for flow changes.…”

Changes in peripheral perfusion relate to visceral organ perfusion in early septic shock: A pilot study

“…The pulsatility index is a validated measure closely correlated with organ vascular resistance and blood flow in visceral organs [19][20][21]. Despite of this and its widespread use to assess visceral organ vascular tone, it does not directly measure blood flow.…”

“…It is a dimensionless figure, with low values indicating low and high values indicating high vascular tone [19][20][21]. Using a standard sonography machine (Vivid S6; GE Healthcare, Vienna, Austria) and a convex sector transducer (2-6 MHz), we measured the pulsatility index in the kidneys, liver, spleen, and intestines (Fig.…”

Ultrasound Evaluation of Valsartan Therapy for Renal Cortical Perfusion

“…Baseline CEHU data were obtained before subject tests of p-aminohippurate clearance (CPAH) for renal plasma flow (RPF) and thiosulfate clearance (Cthio) for glomerular filtration rate (GFR), performed with a single-injection technique described previously (7,8). Briefly, subjects drank 500 ml of water to enhance urinary volume during the test.…”