Cerebral effect of acute normovolemic hemodilution during brain tumor resection

Acute normovolemic hemodilution (ANH) is used in major surgery expected to be accompanied by excessive blood loss. Reducing the hemoglobin content may disturb cerebral oxygen balance. The aim of this study was to assess the effect of ANH on cerebral oxygen balance in patients subjected to brain tumor resection. Forty patients were randomly allocated into 2 groups (hemodilution and control). In the hemodilution group (HG), 1000 mL of blood was drawn and replaced with the same volume of HES 130/0.4 (6%, Voluven) colloid. In the control group (CG), no blood was drawn, and hemodynamics were stabilized using normal saline until allogenic blood was needed. Arterial and jugular bulb blood samples obtained after induction (basal, sample 1), 40 minutes after induction (or on completion of hemodilution, sample 2), after surgical hemostasis (sample 3), and just before extubation (sample 4) were used for the calculation of arterial-jugular oxygen content difference "Ca-jO(2)," cerebral oxygen extraction "CEO(2)," estimated cerebral metabolic rate for oxygen "eCMRO(2)," cerebral blood flow equivalent "CBFe," and jugular-arterial lactate difference "J-ALD" in both groups. Jugular oxygen saturation "SjvO(2)", CEO(2), and J-ALD showed no significant difference when the 2 groups were compared at the corresponding time points and when the values obtained at different time points were compared with the basal value in the same group. In CG, "Ca-jO(2)" significantly decreased at the end of surgery and before tracheal extubation (P