A new approach for quantifying the relationship between brain activity patterns and depth of anesthesia (DOA) is presented by analyzing spatio-temporal in electroencephalogram (EEG) using Lempel-Ziv complexity analysis. Twenty-seven patients undergoing vascular surgery were studied under general with sevoflurane, isoflurane, propofol, or desflurane. The EEG was recorded continuously during procedure patients' states assessed according to responsiveness component observer's assessment...

Background Autoregressive modeling with exogenous input of middle-latency auditory evoked potential (A-Line autoregressive index [AAI]) has been proposed for monitoring anesthetic depth. The aim the current study was to compare accuracy this new Bispectral Index (BIS), predicted effect-site concentration propofol, and hemodynamic measures. Methods Twenty female patients scheduled ambulatory gynecologic surgery received effect compartment controlled infusion propofol. Target started at 1.5...

Background This study was conducted to compare the performance accuracy of independent variables Bispectral Index (BIS), A-Line ARX index (AAI), and predicted propofol effect-site concentration (CePROP) measure dependent loss responses different stimulation defined as response verbal command (LORverbal), eyelash reflex (LORlash), noxious stimulus (LORnoxious) during stepwise increased levels infusion with without remifentanil. Methods Forty-five patients were randomly allocated one three...

The objective of the present study was to validate qCON index hypnotic effect and qNOX nociception. Both indices are derived from frontal electroencephalogram (EEG) implemented in 2000 monitor (Quantium Medical, Barcelona, Spain).The approved by local ethics committee, including data 60 patients scheduled for ambulatory surgery undergoing general anaesthesia with propofol remifentanil, using TCI. Bis (Covidien, Boulder, CO, USA) recorded simultaneously qCON. Loss eyelash reflex [loss...

Double burst stimulation (DBS) is a new mode of developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists two short bursts 50 Hz tetanic stimulation, separated by 750 ms, and the response muscle contractions. Fade in results from as with train-of-four (TOF). authors compared sensitivity DBS TOF detection during anaesthesia. Fifty-two healthy patients undergoing surgery were studied. For both patterns frequencies manually detectable fade determined...

Obtaining an adequate depth of anesthesia is a continuous challenge to the anesthetist. With introduction muscle-relaxing agents traditional signs awareness are often obscured, or difficult interpret. These include blood pressure, heart rate, pupil size, etc. However, these factors do not describe (DA) in cerebral activity sense. Hence, better measure DA required. It has been suggested that Auditory-Evoked Potentials (AEP) can provide additional information about DA. The general method...

The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation response train-of-four (TOF) nerve stimulation. A total 80 patients were divided into four groups 20 each. For two (one given vecuronium and one pancuronium), anesthetists assessed degree neuromuscular blockade during operation recovery from by TOF In other groups, which received pancuronium, evaluated solely criteria. use stimulator was found have no effect on dose...

Background The objective of this study was to prospectively test the Cerebral State Index designed for measuring depth anesthesia. is calculated using a fuzzy logic combination four subparameters electroencephalographic signal. performance compared with that Bispectral and A-Line ARX Index. Methods This applied raw data from two previously published clinical protocols. patients in protocol 1 were given continuous propofol infusion, 300 ml/h, until 80% burst suppression occurred. In 2,...

The extraction of the middle latency auditory evoked potentials (MLAEP) is usually done by moving time averaging (MTA) over many sweeps (often 250-1,000), which could produce a delay more than 1 min. This problem was addressed applying an autoregressive model with exogenous input (ARX) that enables (AEP) within 15 sweeps. objective this study to show AEP be extracted faster ARX MTA and same reliability.The methods were compared Modified Observer's Assessment Alertness Sedation Scale (MOAAS)...

The objective of the study was to examine changes in central nervous system (CNS) activity and physical behaviour during induction awakening from CO 2 anaesthesia. Two studies, each using pigs immersed into 90% gas for a period 60 s were performed. In 1, we monitored middle latency auditory evoked potentials (changes latencies, amplitudes depth anaesthesia index), electroencephalographic parameters (delta, theta, alpha beta power 95% spectral edge frequency) heart rate; 2, body movements...

Background: Extraction of the middle latency auditory evoked potentials (AEP) by an auto regressive model with exogenous input (ARX) enables extraction AEP within 1.7 s. In this way, depth hypnosis can be monitored at almost real‐time. However, identification and interpretation appropriate signals could difficult to perform during anesthesia procedure. This problem was addressed defining index which reflected peak amplitudes latencies AEP, developed improve clinical AEP. defined as A‐line...

In Brief BACKGROUND: The increasing demand for anesthetic procedures in the gastrointestinal endoscopy area has not been followed by a similar increase methods to provide and control sedation analgesia these patients. this study, we evaluated different combinations of propofol remifentanil, administered through target-controlled infusion system, estimate optimal concentrations as well best way sedative effects induced drugs patients undergoing ultrasonographic endoscopy. METHODS: One hundred...

This study investigates the accuracy of a composite index, A-Line(R) auditory evoked potentials index version 1.6 (AAI1.6; Danmeter A/S, Odense, Denmark), as measure cerebral anesthetic drug effect in model for predicting calculated site concentration propofol (CePROP). The AAI1.6 algorithm extracts information from midlatency potentials, spontaneous electroencephalographic activity, and detection burst suppression. former this monitor, A-Line potential 1.5, is only based on fast extracted...

The purpose of this study was to identify optimal target propofol and remifentanil concentrations avoid a gag reflex in response insertion an upper gastrointestinal endoscope.Patients presenting for endoscopy received target-controlled infusions (TCI) both sedation-analgesia. Patients were randomized 4 groups fixed effect-site concentrations: 1 ng•mL (REMI 1) or 2 2) μg•mL (PROP 3 3). For each group, the other drug (propofol REMI vice versa) increased decreased using "up-down" method based...

Background: In 2004, the cerebral state monitor, CSM, was launched as a low‐cost alternative to bispectral index, BIS, for monitoring depth of sleep during anaesthesia. We tested whether two monitors would reflect hypnosis equally propofol/remifentanil Methods: During laparoscopy or breast/surface surgery, 55 non‐paralyzed patients were monitored simultaneously with BIS and CSM. Trend curves indexes [BIS index (CSI)] compared congruence. The difference between entire course quantified,...

Respiratory depression is a common adverse effect of propofol and remifentanil. We aimed to develop model for respiratory depressant effects with remifentanil in patients undergoing endoscopy sedation. Data were available 136 Participants randomly received infusions Predicted plasma concentrations, outputted by infusion pumps, available. Transcutaneous arterial pressure carbon dioxide (pCO₂) was measured. analyzed using nonlinear mixed-effects modeling methods. Covariate...

Objective Rheoencephalography is a simple and inexpensive technique for cerebral blood flow assessment, however, it not used in clinical practice since its correlation to conditions has yet been extensively proved. The present study investigates the ability of Poincaré Plot descriptors from rheoencephalography signals detect apneas volunteers. Methods A group 16 subjects participated study. data baseline apnea periods were recorded extracted reconstructed attractors with different time lags...

Background: Mid‐latency auditory evoked potentials (MLAEP) are widely suppressed during general anesthesia and may therefore be useful for assessment of the depth anesthesia. However, interpretation amplitudes latencies in AEP signal is time consuming. A new monitor (A‐line™) that quantifies MLAEP into an index has been developed. The present study aimed to assess precision a prototype test hypothesis shows graded response with changing steady‐state end‐expiratory concentrations sevoflurane....

Abstract Background: The presence of the A118G single nucleotide polymorphism in OPRM1 gene as well noxious stimulation might affect requirements remifentanil for patients undergoing ultrasonographic endoscopy under sedation-analgesia with propofol and remifentanil. Bispectral index (BIS) was used a surrogate measure effect. Methods: A total 207 were screened randomly received different combinations remifentanil, changed depending on nausea response to tube introduction. Nonlinear mixed...

Background: One of the problems encountered in assessment hypnotic level during anesthesia is extraction a consistent and reliable measure online close to real time. Hemodynamic parameters such as heart rate blood pressure are not, at least with traditional single parameter versus time presentation, adequate for ensuring an optimal anesthesia, especially when using neuromuscular blocking agents (NMBA). In literature, it has been demonstrated that auditory evoked potentials (AEP) able provide...

The level of sedation in patients undergoing medical procedures evolves continuously, affected by the interaction between effect anesthetic and analgesic agents pain stimuli. monitors depth anesthesia, based on analysis electroencephalogram (EEG), have been progressively introduced into daily practice to provide additional information about state patient. However, quantification analgesia still remains an open problem. purpose this work is improve prediction nociceptive responses with linear...