Acute renal failure in critically ill patients: evaluation of an ultrasound contrast agent

The purpose of the present paper was to evaluate an ultrasound contrast agent (Levovist) in patients with oliguric acute renal failure (ARF) in order to assess renal vascularity, differentiate acute tubular from cortical necrosis and predict prognosis. Ten intensive care unit (ICU) patients with oliguric ARF were prospectively investigated by ultrasound including colour, power and pulsed Doppler before and after injection of Levovist. Doppler signals were graded as absent, equivocal or present from the inner and outer portions of the renal parenchyma, and these findings were correlated with clinical parameters and outcome. Only one patient had findings in keeping with acute cortical necrosis. All patients who survived had parenchymal vascularity while only three of six (50%) who died had parenchymal vascularity after Levovist. The ultrasound contrast caused no side effects and additional information was provided which improved diagnostic confidence, enabled appropriate classification of patients as having tubular or cortical necrosis and therefore added prognostic information.