Analysis of difference in activation or inhibition of cerebral cortex during induction of and emergence from general anesthesia: functional near-infrared spectroscopy

Objective To investigate the brain mechanism of anesthesia-related loss of consciousness and awakening though measuring activation or inhibition of cerebral cortex during induction of and emergence from general anesthesia using functional near-infrared spectroscopy. Methods Twenty-two American Society of Anesthesiologists physical status Ⅰor Ⅱ patients of both sexes, aged 40-80 yr, undergoing thoracoscopic partial lung resection, were selected. The functional near-infrared spectroscopy was used to determine the level of oxyhemoglobin in cerebral cortex before and after anesthesia induction and before and after emergence from anesthesia, and a positive number was considered as activation and a negative number as inhibition. Results Compared with the baseline before anesthesia induction, the level of oxyhemoglobin in the premotor cortex was significantly decreased (P 0.05). Conclusion Frontopolar area is activated, and premotor cortex is inhibited during induction of general anesthesia, indicating that induction of anesthesia may first affect the integrated function of management and execution of the brain, and the motor regulation ability is weakened. Individual difference in brain areas activated during emergence from anesthesia is larger, and activated and inhibited brain regions are not found. Key words: Anesthesia, general; Cerebral cortex; Spectroscopy, near-infrared