Practical use of duplex Doppler analysis of the renal vasculature in critically ill patients.

Duplex doppler examination of blood flow in renal interlobar arteries was analysed in twelve critically ill patients before and during low-dose dopamine infusion (2 micrograms/kg/min). Renal vasodilatation and increased blood flow were observed with dopamine, confirming results with indirect or invasive techniques. The doppler ultrasound technique is entirely non-invasive, is simple and quick to carry out, provides instant results, and will allow tailoring of inotropic support in critically ill patients to provide optimum renal blood flow.