The PSI, based upon derived features of brain electrical activity in the anterior/posterior dimension, significantly co-varies with changes in state under general anaesthesia and can significantly predict the level of arousal in varying stages of anaesthetic delivery.

BackgroundReduced motor and sensory nerve amplitudes in critical illness polyneuropathy (CIP) are characteristic features described in electrophysiological studies and due to dysfunction of voltage-gated sodium channels. Yet, faulty membrane depolarization as reported in various tissues of critically ill patients may cause reduced membrane excitability as well. The aim of this study was to compare the pathophysiological differences in motor nerve membrane polarization and voltage-gated sodium channel function between CIP patients and critically ill patients not developing CIP during their ICU stay (ICU controls).MethodsICU patients underwent electrophysiological nerve conduction studies and were categorized as either ICU controls or CIP patients. Subsequently, excitability parameters were recorded as current-threshold relationship, stimulus-response behavior, threshold electrotonus, and recovery of excitability from the abductor pollicis brevis following median nerve stimulation.ResultsTwenty-six critically ill patients were enrolled and categorized as 12 ICU controls and 14 CIP patients. When compared to 31 healthy subjects, the ICU controls exhibited signs of membrane depolarization as shown by reduced superexcitability (p = 0.003), depolarized threshold electrotonus (p = 0.007), increased current-threshold relationship (p = 0.03), and slightly prolonged strength-duration time constant. In contrast, the CIP patients displayed a significantly reduced strength-duration time constant (p < 0.0001), which indicates an increased inactivation of voltage-gated sodium channels.ConclusionsAbnormal motor nerve membrane depolarization is a general finding in critically ill patients whereas voltage-gated sodium channel dysfunction is a characteristic of CIP patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-016-0083-4) contains supplementary material, which is available to authorized users.

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We performed rapid opioid detoxification under propofol anaesthesia in 30 opioid addicts, using the opioid receptor antagonist naltrexone. Two strategies to obtain a sufficient depth of anaesthesia and to avoid anaesthetic overdose were evaluated. Patients were allocated randomly to one of two groups. In group 1, the effects of propofol were monitored by observing clinical signs, and in group 2, depth of anaesthesia was controlled using an EEG threshold method. Withdrawal symptoms and post-anaesthetic recovery time were assessed. All patients remained stable and no anaesthetic complications were noted. There were significant differences in the total dose of propofol given (group 1, mean 72 (SD 9) mg kg-1; group 2, 63 (8) mg kg-1; P < 0.01), duration of anaesthesia (318 (53) min vs 309 (42) min; P < 0.05), duration of recovery time (49 (13) min vs 40 (12) min; P < 0.01) and frequency of withdrawal symptoms between groups. In addition, the incidence of side effects was different between groups (62 vs 29 points on a withdrawal symptom scale; P < 0.01). To obtain a sufficient depth of anaesthesia but to avoid inappropriately large doses of anaesthetic, we consider that EEG monitoring is valuable during rapid opioid detoxification.

Introduction Selective dorsal rhizotomy (SDR) consists of microsurgical partial deafferentation of sensory nerve roots (L1-S2). It is primarily used today in decreasing spasticity in young cerebral palsy (CP) patients. Intraoperative monitoring (IOM) is an essential part of the surgical decision-making process, aimed at improving functional results. The role played by SDR-IOM is examined, while realizing that connections between complex EMG responses to nerve-root stimulation and a patient's individual motor ability remain to be clarified. Methods We conducted this retrospective study, analyzing EMG responses in 146 patients evoked by dorsal-root and rootlet stimulation, applying an objective response-classification system, and investigating the prevalence and distribution of the assessed grades. Part1 describes the clinical setting and SDR procedure, reintroduced in Germany by the senior author in 2007. Results Stimulation-evoked EMG response patterns revealed significant differences along the segmental levels. More specifically, a comparison of grade 3+4 prevalence showed that higher-graded rootlets were more noticeable at lower nerve root levels (L5, S1), resulting in a typical rostro-caudal anatomical distribution. Conclusions In view of its prophylactic potential, SDR should be carried out at an early stage in all CP patients suffering from severe spasticity. It is particularly effective when used as an integral part of a coordinated, comprehensive spasticity program in which a team of experts pool their information. The IOM findings pertaining to the anatomical grouping of grades could be of potential importance in adjusting the SDR-IOM intervention to suit the specific individual constellation, pending further validation. Trial registration ClinicalTrials.gov ID: NCT03079362