Comparison of the effect of different methods of anesthesia on cerebral autoregulation in patients undergoing neurosurgery

Objective To compare the effect of different methods of anesthesia on cerebral autoregulation in patients undergoing neurosurgery.Methods Sixty-nine ASA Ⅱ orⅢ patients with brain tumor, aged 23-62 yr, scheduled for neurosurgery under general anesthesia, were randomly divided into 3 groups ( n = 23 each) : propofol-remifentanil group (group PR), sevoflurane-remifentanil group (group SR) and propofol-sevoflurane-remifentanil group (group PSR) . Anesthesia was induced with target-controlled infusion (TCI) of propofol (target plasma concentration3 μg/ml, PR and PSR groups) or inhalation of 8% sevoflurane (group SR) and iv injection of remifentanil 1 mg/kg and atracurium 0.5 mg/kg. The patients were mechanically ventilated after tracheal intubation. PETCO2 was maintained at 32-35 mm Hg. Anesthesia was maintained with TCI of propofol (target plasma concentration 2.0-3.5 μg/ml) in group PR, with inhalation of 1.5%-2.5% sevoflurane in group SR, with TCI of propofol (target plasma concentration 1.5-3.0 μg/ml) and inhalation of 1% sevoflurane in group PSR, and with TCI of remifentanil (target plasma concentration 2.0-4.5 ng/ml) and iv infusion of atracurium at 6 μg · kg-1 · min-1 in all groups. Auditory evoked potential index was maintained between 40-45. The middle cerebral artery time-average peak flow velocity was recorded before induction (baseline) , immediately after intubation, immediately before craniotomy and at the beginning of skin suture. The unilateral carotid artery was compressed for 7 s at the corresponding time points mentioned above. The transient hyperemic response ratio (THRR) was calculated to reflect cerebral autoregulation. Results Compared with the baseline value at T0, THRR was significantly increased at T2in group PR and decreased at T2,3 in group SR (P 0.05). The THRR was significantly lower in SR and PSR groups than in group PR, and higher in group PSR than in group SR ( P < 0.05). Conclusion Propofol-remifentanil anesthesia can improve cerebral autoregulation, sevoflurane-remifentanil anesthesia can reduce cerebral autoregulation, and propofol-sevofluraneremifentanil anesthesia exerts no effect on cerebral autoregulation in patients undergoing neurosurgery. Key words: Propofol;  Piperidines;  Neurosurgical procedures;  Cerebrovascular circulation; Sevoflurane