Group A: Neuroanaesthesia
Introduction: Anaesthetic techniques for awake craniotomy include local anaesthesia and sedation or asleep-awake-asleep techniques [1,2]. The advantage of awake techniques is the ability to assess the patient's neurological status during surgery, although this benefit has to be balanced against the loss of control of ventilation and assurance of immobility. In this prospective study, we evaluated the effects of different anaesthetic combinations on providing haemodynamic stable, safe airway, and awake patient for neurological tests during awake craniotomy.
Methods: After obtaining ethics committee approval and informed consent, patients scheduled for awake craniotomy were randomly assigned to three groups. Group PF (n = 17) received propofol infusion (2 mg kg−1 h−1) with bolus fentanyl (1 μgkg−1) and repeated as needed; group PR (n = 17) received propofol (2mgkg−1 h−1) with remifentanil (0.05 μg kg−1 min−1) infusions; group DF (n = 17) received dexmedetomidine infusion (initial dose 1 μg kg−1 over 10 min fallow by of 0.1 μgkg−1 h−1) and bolus fentanyl (1 μg kg−1) administared as needed. The target level of sedation was 3 of the Modified Observer's Assessment of Alertness/Sedation scale at which patient responds after name is called. Mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2), endexpiratory carbon dioxide (ETCO2) were assessed before (T1) and after drug infusion (T2), after scalp infiltration with prilocaine (T3), at skin incision (T4), bone flap removal (T5), dura incision (T6), tumour resection (T7), dura closure (T8), bone flap closure (T9), skin closure (T10), and at the end of surgery (T11). The incidence of complications, infusion rates of drugs, and total dose of local anaesthetic were recorded. Statistical analysis included Wilcoxon signed ranks test, Mann-Whitney U-test and Chi-Square test.
Results: There were no statistically significant differences between the groups regarding the quality of anaesthesia. Total dose of local anaesthetic was lower in group D than in group PR (p < 0.05). The total dose of propofol was similar in group PF and PR. The total dose of fentanyl was lower in group DF than in group PF (p < 0.001). Peroperative complications such as nausea and vomiting were similar among the groups but the incidence of seizure was higher in group PF (p < 0.05, p < 0.05). RR was lower in group PR than in group D at T4 and T10 (p < 0.05, p < 0.05). ETCO2 concentration in group PR was higher at T4, T10 than in group D and at T2 than in group PF (p < 0.05, p < 0.05, p < 0.05). SpO2 was lower in group PF at T4 than in group D (p < 0.05). MAP was lower in group PR at T7 than in group PF (p < 0.05).
Conclusions: Requirements of opioid and local anaesthetic are decreased by dexmedetomidine. Dexmedetomidine infusion provides sedation without the loss of control of ventilation. We conclude that the use of dexmedetomidine in patients undergoing awake craniotomy is safe, comfortable, and easy technique.
1 Danks RA et al.
Patient tolerance of craniotomy performed with the patient under local anesthesia and monitored conscious sedation. Neurosurgery
2 Simon G, Osborn I. Scalpblock and the laryngeal mask hand in hand for awake craniotomies. J Neurosurg Anesthesiol