The technology of bispectral index monitoring is based on an algorithm developed from adults. This study was conducted to investigate the difference in bispectral index monitoring between paediatric and adult patients under intravenous anaesthesia.

In all, 68 patients undergoing elective surgery were divided into three groups as follows: Group A (younger children, n = 20, 3 yr ⩽yr ⩽ 5 yr), Group B (older children, n = 20, 6 yr ⩽yr ⩽12 yr), Group C (adults, n = 28, 25 yr ⩽yr ⩽50 yr). All patients were induced by plasma target-controlled infusion of propofol till loss of consciousness (loss of response to verbal commands and eyelash reflex). The plasma concentration (Cppropofol) and effect-site concentration (Cepropofol) of propofol and bispectral index values were compared at loss of consciousness and regaining of consciousness. During the operation, remifentanil was infused at a fixed rate of 0.25μg kg−1 min−1, and the minute average bispectral index values of three groups were also compared at different stable concentrations of propofol (Cepropofol = Cppropofol = 2, 3, 4 and 5 μg mL−1, respectively).

At loss of consciousness and regaining of consciousness, the bispectral index values in Group A (loss of consciousness: 74.7 ± 6.3, regaining of consciousness: 81.1 ± 10.5) were significantly higher than those in Group C (loss of consciousness: 68.6 ± 9.4, regaining of consciousness: 74.5 ± 6.0) (P < 0.01). There was no statistical difference between Cppropofol in all groups at loss of consciousness and regaining of consciousness. The Cepropofol at loss of consciousness in Group A (3.57 ± 0.60 μg mL−1) and B (3.25 ± 0.44 μg mL−1) were significantly higher than those in Group C (2.15 ± 0.86 μg mL−1) (P < 0.01). At the same stable concentrations of propofol, the bispectral index values in Group A and B were significantly higher than those in Group C, and the bispectral index values in Group A were also significantly higher than those in Group B (P < 0.01). The Cepropofol when bispectral index ⩽ 40 in Group A, B, C were approximately at 6, 5 and 3 μg mL−1, respectively.

At loss of consciousness and regaining of consciousness, the bispectral index values of younger children group are significantly higher than those of adults. At the same stable concentrations of propofol, the bispectral index values are significantly different between children and adults. This study suggests that there is deviation when the adult algorithm of bispectral index monitoring is applied in paediatric patients under intravenous anaesthesia.

A randomized and prospective study was performed to compare anaesthetic characteristics and stress hormone responses of two anaesthetic techniques.

Forty-two patients undergoing day case excisional biopsy of breast mass were randomly assigned to receive propofol–remifentanil or sevoflurane–N2O. Anaesthesia was induced and maintained either with sevoflurane and 50% N2O in oxygen or with target-controlled remifentanil and propofol in 50% oxygen and air. Anaesthetic depth was monitored by the bispectral index.

The times for induction (2.9 vs. 1.7 min) and for laryngeal mask insertion (5.7 vs. 3.3 min) were longer in the sevoflurane–N2O group than in the propofol–remifentanil group. However, apnoea (57.1% vs. 9.5%) and bradycardia (23.8% vs. 0%) were more prevalent with propofol–remifentanil. In the sevoflurane–N2O group, the emergence times to a verbal response (10.6 vs. 3.7 min), to extubation (11.8 vs. 4.0 min) and to orientation (14.7 vs. 4.8 min) were longer than in the propofol–remifentanil group. There were significantly more nausea (38.1% vs. 4.8%) and vomiting (19.2% vs. 0%) in the sevoflurane–N2O group than in the propofol–remifentanil group. The time to discharge was similar although there was less postoperative pain in the sevoflurane–N2O group. There were no differences in the perioperative cortisol responses in the two groups.

Smoother induction of anaesthesia was seen with sevoflurane–N2O. Propofol–remifentanil showed a quicker emergence with less nausea/vomiting. There were similar perioperative cortisol responses in the two anaesthetic techniques.

Medialization thyroplasty is a surgical technique for improving voice quality, cough effort and laryngeal competence in patients with unilateral vocal fold paralysis. Precision surgery is enabled by operating under total intravenous anaesthesia with controlled ventilation and by using a laryngoscopic video-assisted technique. The anaesthetic challenge is to manage the shared airway with the surgeon, provide a stable operative field and ensure patient safety throughout the procedure. The objective of this case series was to evaluate the use of a modified general anaesthetic technique using the laryngeal mask airway, total intravenous anaesthesia with controlled ventilation.

In all, 29 patients underwent medialization thyroplasty using a disposable laryngeal mask airway, total intravenous anaesthesia and controlled ventilation. Standard anaesthetic monitoring including capnography was used intraoperatively. Total intravenous anaesthesia was achieved using effect site target-controlled infusions of propofol and remifentanil.

The technique proved safe with stable haemodynamic observations and only two minor complications. It also provided the surgeon with stable view of the vocal folds in order to perform this precision surgery under an operating microscope.

The objectives of this study were, firstly, to characterize the inter-patient variability in the dose of propofol required to achieve a bispectral index <70 and ‘time to eye opening’ following propofol infusion and, secondly, to determine if the pharmacodynamic parameter ‘time to achieve bispectral index <70’ was influenced by genotype of the sex-linked drug receptor gene GABRE or if pharmacokinetic parameters such as clearance and ‘time to eye opening’ were influenced by the genotype of the metabolizing enzyme CYP2B6.

One hundred and fifty patients received a standardized anaesthetic. Apparent systemic clearance values were estimated. Correlation was sought between carriers of different CYP2B6 and GABRE genotypes and apparent systemic clearance, ‘time to achieve bispectral index <70’ and ‘time to eye opening’.

Propofol induction/emergence characteristics varied, with slow recovery times in a subset of males. Time to loss of verbal contact and time to bispectral index <70 varied 6.6- and 4.3-fold, respectively. At emergence, there was a 15.5- to 111-fold variability in the measured time intervals. Clearance varied from 9.1 to 55.8 mL min−1 kg−1. The CYP2B6 C1459T (R487C) genotype frequencies were TT 1%, TC 22% and CC 67%. The three major haplotypes of CYP2B6 (R487C, K262R and Q172H variants) were not significantly associated with time to eye opening or clearance. Clearance was similar in 487C carriers and 487RR genotypes. There was no statistically significant correlation between the four major haplotypes of GABRE variants investigated ([mRNA358]G/T, 20118C/T, 20326C/T and 20502 A/T) and the observed anaesthesia induction time.

Great inter-patient variability exists in the dose of propofol required to achieve bispectral index <70, apparent systemic propofol clearance and time to eye opening. Common haplotypic differences at the CYP2B6 and GABRE genes do not appear to account for the majority of the observed inter-patient variability.

Target-controlled infusion, via the calculated effect compartment concentrations, may help anaesthesiologists to titrate anaesthetic depth and to shorten recovery from anaesthesia.

In this prospective, randomized clinical study, we compared the performance of six inexperienced anaesthesiologists with <1 yr of training when using target- or manually controlled infusion of propofol, combined with manual dosing of fentanyl. Ninety-two premedicated ASA I–III patients undergoing minor elective urological or gynaecological surgery were assigned to the manual- or target-controlled infusion group. Bispectral index was recorded in a blinded manner. Subjective assessment of anaesthetic depth on a 10 point numerical scale (1 = very deep anaesthesia, 10 = awake) was asked at regular intervals and the correlation with the blinded bispectral index was analysed using the prediction probability, PK. The propofol concentration profile was calculated post hoc.

Propofol administration was similar in both groups with no significant difference for the administered amount and concentrations of propofol. Recovery times were also not different. In both groups, a large percentage of the bispectral index data points recorded during surgery showed bispectral index values below the recommended value of 40, but in the target-controlled infusion group there were significantly less bispectral index values above the recommended upper limit of 60 (2.5% vs. 5.1%).

A target-controlled infusion system does not help inexperienced anaesthesiologists to assess anaesthetic depth or to shorten recovery times, but may reduce episodes of overly light anaesthesia and thus help to prevent awareness.

We compared heart rate dynamics during surgical levels of propofol and sevoflurane anaesthesia in a highly standardized setting.

We recorded electrocardiography from 24 anaesthetized healthy male subjects. In the first parallel part of the study, the subjects were anaesthetized either with sevoflurane (n = 8) or propofol (n = 8) targeted to match 1.0, 1.5 and 2.0 minimal alveolar concentration/effective concentration 50. In the second part, a separate group (n = 8) underwent four different anaesthetic regimens targeted to bispectral index 40: sevoflurane alone, sevoflurane + 70% nitrous oxide, propofol alone and propofol + 70% nitrous oxide. The electrocardiography data were analysed using conventional time and frequency domain methods, and the approximate entropy method, which estimates the complexity of the data.

The induction of anaesthesia was followed by an overall reduction of heart rate variability, evident in all frequency bands in the spectral analysis, and also in the time domain measures. Approximate entropy decreased at 1 effective concentration 50 with propofol and at 2 minimal alveolar concentration with sevoflurane. In the second part of the study, the time domain variables and high-frequency spectral power were all similarly reduced by sevoflurane and propofol anaesthesia, with and without nitrous oxide. Approximate entropy tended to decrease during propofol anaesthesia.

Hypnotic levels of sevoflurane and propofol anaesthesia suppressed the heart rate variability measured using conventional analysis methods. Deeper surgical levels of anaesthesia also reduce the complexity of heart rate variability.

Endoscopic endonasal transphenoidal surgery has been recently proposed as a minimally invasive procedure for the treatment of pituitary adenomas. The main objective of the anaesthesiologist is to induce sufficient haemodynamic control together with rapid recovery at the end of surgery. The aim of this study was to examine recovery profile, surgical operative conditions and haemodynamic differences using remifentanil infusion with either propofol target controlled infusion system or sevoflurane.

Forty-four adult patients were enrolled in a prospective, randomized, single-blind, two-group study: Group P received propofol target controlled infusion system and remifentanil; Group S received sevoflurane and remifentanil for maintenance of anaesthesia.

No statistically significant differences between the two groups with regards to the haemodynamic changes, operative conditions as assessed by a four-step bleeding score (0–3), were obtained. Recovery times were considerably shorter after remifentanil–sevoflurane in comparison with remifentanil–propofol target controlled infusion system group (7.4 vs. 12.8 min, P < 0.01).

This study demonstrates that sevoflurane–remifentanil gives a faster recovery and equivalent intraoperative status compared with propofol target controlled infusion system with remifentanil for the endoscopic endonasal transphenoidal approach.