To "be aware" or to "be un-aware" of the BIS

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Bispectral index detects period of cerebral hypoperfusion during cardiopulmonary bypass.

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Searching for the ideal endobronchial blocker

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Tracheal rupture after intubation and placement of an endotracheal balloon catheter (A-view(R)) in cardiac surgery

Contains fulltext : 171832.pdf (publisher's version ) (Closed access)The endotracheal balloon catheter (A-view(R)) is a device developed to locate atherosclerotic plaques of the ascending aorta (AA) in cardiac surgery to prevent stroke. The saline-filled balloon is located in the trachea and combines the advantages of transoesophageal echocardiography (e.g. used before performing the sternotomy) and intraoperative epiaortic ultrasound scanning (e.g. complete view of the AA). We report the first severe complication after the use of A-view(R). This is a case of a 66-year old woman who underwent elective myocardial revascularization complicated by an intraoperative iatrogenic tracheal rupture of 6 cm, after uncomplicated intubation and the use of an endotracheal balloon catheter (A-view(R)), which required direct surgical repair with a posterolateral thoracotomy after the myocardial revascularization was completed, weaning from bypass and closure of the median sternotomy

Decoding motor responses from the EEG during altered states of consciousness induced by propofol

Contains fulltext : 157484.pdf (publisher's version ) (Open Access)Objective. Patients undergoing general anesthesia may awaken and become aware of the surgical procedure. Due to neuromuscular blocking agents, patients could be conscious yet unable to move. Using brain–computer interface (BCI) technology, it may be possible to detect movement attempts from the EEG. However, it is unknown how an anesthetic influences the brain response to motor tasks. Approach. We tested the offline classification performance of a movement-based BCI in 12 healthy subjects at two effect-site concentrations of propofol. For each subject a second classifier was trained on the subject’s data obtained before sedation, then tested on the data obtained during sedation (‘transfer classification’). Main results. At concentration 0.5 μ g ml -1 , despite an overall propofol EEG effect, the mean single trial classification accuracy was 85% (95% CI 81%- 89%), and 83% (79%-88%) for the transfer classification. At 1.0 μ g ml -1 , the accuracies were 81% (76%-86%), and 72% (66%-79%), respectively. At the highest propofol concentration for four subjects, unlike the remaining subjects, the movement-related brain response had been largely diminished, and the transfer classification accuracy was not significantly above chance. These subjects showed a slower and more erratic task response, indicating an altered state of consciousness distinct from that of the other subjects. Significance. The results show the potential of using a BCI to detect intra-operative awareness and justify further development of this paradigm. At the same time, the relationship between motor responses and consciousness and its clinical relevance for intraoperative awareness requires further investigation.9 p

Electromyographic assessment of blink and corneal reflexes during midazolam administration: useful methods for assessing depth of anesthesia?

Item does not contain fulltextBACKGROUND: There are at least three components of the anesthetic state: loss of consciousness, amnesia and obtundation of reflex responses to noxious stimuli. To investigate the third component, we used a standard electrical stimulus to evoke a blink reflex, which was electromyographically recorded. These data may give information on the anesthetic state. METHODS: The relation between the electrically evoked blink and corneal reflexes and the depth of sedation and anesthesia induced with intravenous midazolam was investigated. Ten patients received i.v. increments of midazolam (1 mg, 2 mg, 3 mg, 3 mg, 3 mg, etc., until a 21-mg total dose) to create a step-wise deepening of sedation and anesthesia. Depth of anesthesia was assessed by the Observer's Assessment of Alertness/Sedation (OAAS) scale, ranging from 5 ( = awake and alert) to 0 ( = no motor response to tetanic stimulation). RESULTS: Latency of the first (R1) and second (R2) blink components and the corneal (C) reflex component increased, whereas duration and area decreased with increasing depth of sedation and anesthesia. R1 was last seen at an OAAS score [mean (SD)] of 1.8 (0.8), R2 at a score of 3.1 (1.1), C at a score of 3.8 (0.8), and R3 at 4.8 (0.5). These end-points were all statistically different from each other, except R2 vs. C. CONCLUSIONS: Our results suggest that the differential sensitivity of the components of the blink reflex could be useful to monitor depth of sedation and light levels of anesthesia during the administration of midazolam