Anaesthesia for awake craniotomy - evolution of a technique that facilitates awake neurological testing

Background. There is an increasing trend towards performing craniotomy awake. The challenge for the anaesthetist is to provide adequate analgesia and sedation, haemodynamic stability, and a safe airway, with an awake, cooperative patient for neurological testing. Methods. The records of all patients who had awake craniotomy at our institution were reviewed. Patients were divided into three groups according to anaesthetic technique. Patients in Group I were sedated throughout the procedure. Patients in Groups 2 and 3 had an asleep-awake-asleep technique. Those in Group 2 were anaesthetized with a propofol infusion and fentanyl, and breathed spontaneously through a laryngeal mask airway (LMAdagger). Patients in Group 3 had total i.v. anaesthesia with propofol and remifentanil, and ventilation was controlled using an LMA. We noted the incidence of complications in each group. Results. There were 99 procedures carried out between 1989 and 2002. Group 3 had the fewest complications. No patients in Group 3 developed hypercapnia (E'(CO2) >6 kPa), compared with all of the patients in Group 2. Patients in Group I had no E, (CO2) monitoring, but 7% developed airway obstruction. No patients in Group 3 required additional analgesia for pain, compared with 70% of patients in Group 2. Conclusions. We have developed a technique for craniotomy, which facilitates awake neurological testing, is safe, and has good patient satisfaction.