Esmolol blunts the cerebral blood flow velocity increase during emergence from anesthesia in neurosurgical patients

Cerebral hyperemia has been demonstrated during emergence from anesthesia in neurosurgical patients, but its mechanism is speculative. We performed this study to test the hypothesis that this could be attributed to sympathetic overactivity. Thirty neurosurgical patients were included in a prospective, randomized, double-blinded study comparing esmolol, a short-acting beta-blocker, and a placebo. Esmolol (0.3 mg. kg(-1). min(-1)) was infused from the end of anesthesia to 15 min after extubation. Cerebral blood flow velocity (CBFV), mean arterial blood pressure, and heart rate were recorded before anesthesia, during anesthesia after surgery, at extubation, and 5-60 min after extubation. Cardiac output (COe) was estimated by using an esophageal Doppler from anesthesia to 60 min after extubation. CBFV, COe, and heart rate were significantly lower in the esmolol group. Mean arterial blood pressure was comparable between the groups. There was no correlation between CBFV and COe at any time point during the study. In conclusion, esmolol blunted the CBFV increase during emergence, confirming that sympathetic overactivity contributes to cerebral hyperemia during neurosurgical recovery.

Esmolol blunted the postoperative increase in cerebral blood flow velocity in neurosurgical patients. The origin of sympathetic hyperactivity and its potential deleterious consequences require further study.