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Table 1 Formulae for calculation of renal variables

From: Renal function and oxygenation are impaired early after liver transplantation despite hyperdynamic systemic circulation

Variable Formulae
Renal blood flow (RBF) (Unilateral renal vein blood flow × 2) + urine flow
Renal plasma flow (RPF) RBF × (1 – hematocrit)
Filtration fraction (FF) (RPF × [51Cr-EDTA arterial] – (RPF – urine flow) × [51Cr-EDTA renal vein])/(RPF × [51Cr-EDTA arterial])
Glomerular filtration rate (GFR) FF x RPF
Renal vascular resistance (RVR) (MAP-CVP)/RBF
Arterial-renal vein (rv) oxygen content difference (RAVO2-diff) (CaO2-CrvO2)
Renal oxygen consumption (RVO2) RBF × (CaO2-CrvO2)
Renal oxygen extraction (CaO2-CrvO2/CaO2)
Renal sodium filtration GFR × [Na+]s
Renal sodium excretion Urine flow × [Na+]s
Renal sodium reabsorption (GFR × [Na+]s) – (urine flow × [Na+]u)
  1. 51 Cr-EDTA, chromium ethylenediaminetetraaceticacid, MAP mean arterial pressure, CVP central venous pressure, CaO 2 arterial oxygen content, CrvO2 renal vein oxygen content, [Na + ] s serum sodium concentration, [Na + ] u urine sodium concentration