Hemodynamic effects of dexmedetomidine during intra-operative electrocorticography for epilepsy surgery

Dexmedetomidine, a predominant alpha-2-adrenergic agonist has been used in anesthetic practice to provide good sedation. The drug is being recently used in neuroanesthesia during awake surgery for brain tumors and in functional neurosurgery.

This prospective study analyzed the hemodynamic effects of dexmedetomidine infusion during electrocorticography in patients undergoing surgery for mesial temporal sclerosis. Dexmedetomidine infusion was administered during intra-operative electrocorticography recording, 15 minutes after the end tidal MAC of N2O and isoflurane were decreased to zero. Anesthesia was maintained with O2 : air mixture = 50:50, vecuronium and fentanyl. Heart rate (HR), mean arterial pressure (MAP) and end tidal carbon dioxide (ETCO2) were recorded across at induction, 2 min prior to dexmedetomidine (PreDEX), 5 min during dexmedetomidine infusion (DEX; 1 μg/kg), 5 min after stopping dexmedetomidine and 10 minutes after stopping dexmedetomidine.

Forty patients with mesial temporal sclerosis (M: F = 27:13, mean age = 28.15 ± 10.9 years; duration of epilepsy = 12.0 ± 7.9 years) underwent anterior temporal lobe resection with amygdalohippocampectomy for drug-resistant epilepsy. Infusion of dexmedetomidine caused a transient fall in HR in 87.5% of patients and an increase in MAP in 62.5% of patients, which showed a tendency to revert back towards PreDEX values within 10 min after stopping the infusion. Sixty-five percent of the patients showed ≤25% reduction and 10% of them showed >25% reduction in HR. 47.5% of the patients showed ≤25% increase and 15% of them showed >25% increase in MAP. These changes were over a narrow range and within physiological limits.

The infusion of dexmedetomidine for a short period causes reduction of HR and increase in MAP in patients, however the variations are within acceptable range.