Postoperative impairment of neurocognitive function was observed in a substantial proportion of elderly patients even 30 days after treatment. Xenon-based anesthesia was not associated with decreased incidence of POCD in comparison to propofol.

Our results demonstrate that finger pulse oximeter SpO(2) measurements can be affected by peripheral vascular tone independent of temperature. The mechanism for this effect remains speculative and unproven.

There are limited data on the effect of dexmedetomidine on epileptiform electroencephalogram (EEG). The aim of this study was to investigate if dexmedetomidine will abolish epileptiform discharges in patients with medically refractory seizure disorders who were candidates for surgery to resect foci of epileptic activity. With approval from the Institutional Review Board and written informed consent, we enrolled 5 patients with medically intractable seizures who were undergoing continuous video/EEG monitoring. EEG and hemodynamic values were recorded from 15 minutes before, during, and for 60 minutes after a 60-minute dexmedetomidine infusion. Epileptiform discharges were counted for each 15-minute epoch during the study. Two of the 5 patients had a discrete spike focus in each hemisphere. Thus, we analyzed the activity of 7 distinct foci. Epileptiform activity did not decrease in any individual focus during dexmedetomidine infusion. Although dexmedetomidine did not have a statistically significant effect on interictal epileptiform activity for the group as a whole, the activity of 4 foci increased during dexmedetomidine infusion. Dexmedetomidine did not reduce seizure focus activity and thus may be a suitable anesthetic adjunct during seizure surgery.

The results of this study confirm the alpha2 agonist induced vasomotor and hemodynamic effects in peripheral vasculature. However, the results do not support the hypothesis that alpha2B-adrenoceptor polymorphism has an effect on peripheral vasoconstriction in humans.

SummaryWe enrolled 114 patients, aged 65-83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy. Assessment of the hypnotic component of anaesthesia is commonly performed using EEG-derived numeric indices such as bispectral index (BIS) or spectral entropy including state (SE) and response entropy (RE). Monitoring of these EEG-based indices has been demonstrated to reduce drug consumption, to improve haemodynamic stability, to decrease the incidence of awareness, and to shorten recovery from anaesthesia [9][10][11]. Calculation of these indices is based on different methods and algorithms transforming the raw EEG signal (obtained from cutaneous forehead electrodes) into an arbtitrary value between 0 and 100 (0-91 for SE [12,13]) and the recommended target for surgical anaesthesia is 40)60 for all monitors.Previous studies have revealed that BIS and spectral entropy may not equally reflect effects of different anaesthetics, in particular those drugs that target the NMDA receptor [14]. There appears to be only one study investigating BIS and spectral entropy during xenon anaesthesia, in 17 healthy men [15]. Therefore, to assess if these monitors performed equally for all agents, we performed a randomised prospective study to characterise the agreement and performance of BIS, spectral entropy and haemodynamics during xenon versus propofol anaesthesia.