[Comparison between TCI-TIVA, manual TIVA and balanced anaesthesia for stereotactic biopsy of the brain]

Total intravenous anaesthesia (TIVA) is increasingly used in diagnostic surgery such as stereotactic biopsy of the brain. TIVA could lead to a faster recovery of cerebral function, which may lead to a better behavior and advantages in the postoperative management. The aim of this prospective, single-blind study was to compare the hemodynamics, the postoperative recovery period, the side-effects and the need for additional cardiovascular medication during and after the operation between the three study groups.

After giving informed consent and approval by the ethical committee of our hospital, 51 patients (ASA I and II) undergoing stereotactic biopsy of a brain tumor were randomized to receive either propofol via the TCI-system (group 1: TCI-TIVA), propofol by a manual technique (group 2: MAN-TIVA) or methohexitone-sevoflurane (group 3: BAL-SEVO). Remifentanil was used as the analgetic component in all groups. Systolic and diastolic blood pressure, heart rate und transcutaneous oxygen saturation were noted before and after induction and before and after the end of anaesthesia. The time until return of complete orientation relative to person, location and time were measured. The patients' ranking of their satisfaction with the anaesthesia was questioned 60 min and 24 hours after the end of the procedure (VAS). Undesirable side-effects (i. e. PONV, shivering, pain, dysphoria, tiredness) were noted, whenever they occurred. The number of hemodynamic interventions by the anaesthesiologist was counted, and the total doses of remifentanil and propofol were quoted. Depth of anaesthesia was monitored by using a BIS-system, a range between 40 and 50 was thought to be adequate. Besides this, the total doses of remifentanil, propofol and sevoflurane were ruled out and the costs of the three regimens were ranked.

Heart rate dropped markedly in all groups with a maximum in the TIVA-collective. Systolic and diastolic pressure also fell in the groups. In the SEVO-group, the difference was statistically significant only at the end of anaesthesia. After extubation, the three groups reached their hemodynamic starting-point with a slight overshoot in the SEVO-group. The number of required hemodynamic interventions was two (TCI-TIVA) vs. 7 (MAN-TIVA) vs. 8 (BAL-SEVO) in each group, respectively. The difference scarcely failed to get significance. The remifentanil requirements were similar between the collectives, group 1 needed more propofol per time than group 2. The number of side-effects was very little after the different regimens. There were no differences with regard to the other measured parameters between the groups. The use of TCI-TIVA was more expensive than manual TIVA (18,85 euro vs. 12,50 euro). Surprisingly, balanced anaesthesia using Sevoflurane was the most expensive method during the first hour, mainly due to the use of methohexitone as the induction agent (23,90 euro).

Each of the three techniques compared in our study is suitable for anaesthesia in diagnostic neurosurgery. Since fast recovery of vigilance is important to justify the neurological outcome, none of the methods seems to be superior to the others. The hemodynamics were largely stable with a strong trend towards minor necessity for hemodynamic intervention in the TCI-TIVA group. This is also the best method from the subjective point of view of the anaesthesiologist due to the easy handling and the low number of interventions. The use of newer TCI-systems (e. g. fm-controller, Braun, Melsungen) not operating with special application syringes will cheapen TCI-TIVA.