Influence of mean arterial pressure and cardiac output on renal vascular tone reflected by the renal Doppler resistive index in critically ill patients
© de Oliveira et al. 2015
Published: 28 September 2015
The renal Doppler resistive index (RI) is a non-invasive tool used to predict acute kidney injury (AKI) and evaluate renal vascular tone in the ICU setting. However, the real impact of hemodynamic parameter variations on RI in critically ill patients is unknown.
To evaluate the influence of mean arterial pressure (MAP) and cardiac output (CO) on RI in critically ill patients.
Prospective observational study performed in the medical-surgical ICU from August 2014 to December 2014. RI was performed daily until ICU discharge, death or need for renal replacement therapy (RRT). Transthoracic echocardiography was performed immediately after RI analysis to estimate cardiac output using the velocity-time integral (VTI) at the left ventricular outflow tract. All clinical and laboratorial data were obtained routinely during daily ultrasound examinations. Patients with chronic renal disease or on dialysis were excluded. Transient AKI was defined by normalization of renal function within 48 hours of AKI onset. Persistent AKI was defined by nonresolution of AKI within 48 hours of onset or need for RRT.
We observed a negative correlation between RI and MAP in patients with AKI. No correlation was observed between RI and CO in the different groups.
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