Changes in Arterial and Cerebral Venous Blood Lactate during Neuroanesthesia

Changes in arterial and cerebral venous blood lactate (A-Lac, CV-Lac)and colloid oncotic pressure (A-COP, CV-COP) were studied in 36 patients who underwent craniotomy. A-Lac increased with time. Ten hours later the induction of anesthesia, A-Lac increased significantly to 47.0±2.1mg/dl. Postoperative shiverings occurred in 6 patients at the time of emergence. No significant differences were found between A-COP and CV-COP, nor between A-Lac and CV-Lac before shiverings. There were no significant differences between A-COP and CV-COP during shiverings, but A-Lac and CV-Lac increased significantly during shiverings, and A-Lac was significantly domi-nant than CV-Lac. This suggests that lactate moves from the blood into the brain tissue probably due to the significant increase in A-Lac during shiverings. Convulsions were observed in 5 patients during recovery from anesthesia. There were no significant differences between A-COP and CV-COP, nor between A-Lac and CV-Lac before convulsions. During convulsions no significant differences were found between A-COP and CV-COP, but CV-Lac and A-Lac increased significantly during convulsions, and CV-Lac was significantly dominant than A-Lac. This suggests that during convulsions, lactate moves from the brain tissure into the blood probably due to the increased production of lactic acid in the brain tissue.