View clinical trials related to Unconsciousness.
Filter by:Propofol in combination with remifentanil or midazolam can result in synergistic or additive effect. The patients who are scheduled to undergo general anesthesia are enrolled in this study. 120 patients will be randomly allocated to 3 groups(P, PR, PMR). The patients in group P will receive general anesthesia only with propofol and group PR and PMR will receive 0.25 mcg/kg/min remifentanil infusion prior to propofol. The patients in group PMR will receive 0.03 mg/kg bolus dose of midazolam 1 min after start of the remifentanil infusion. 'Success' is defined as loss of both verbal response and eyelash reflex in 2 min after propofol administration. When 'success', the next patient will receive the same dose(in 18/19 probability) or 0.25 mg/kg lower dose(in 1/19 probability) of propofol. When 'failure', the next patient will receive 0.25 mg/kg higher dose of propofol at induction period.
213 patients undergoing elective on-pump coronary artery bypass grafting (CABG) were enrolled into this prospective-clinical trial.After hundred and sixty three patients were excluded due to various reasons, 50 patients were randomized to BIS (bispectral index) and MAC (minimum alveolar concentration) groups. In BIS group (Group B, n=25), desflurane was titrated within 40 to 60 BIS values and in MAC group (Group M, n=25) within 0.7 to 1.3 MAC. Primary end point of the study was to investigate the difference of desflurane consumption between groups.
Until today there is no standard-monitoring to specifically reflect the analgesic component of general anesthesia. Quality and safety of general anesthesia are of major clinical importance and can be improved by limiting the administration of opioid analgesics to the minimum dose needed. This study therefore examines the quality of three different monitoring techniques (PhysioDoloris, MetroDoloris, Lille, France, SPI (Surgical Plethysmographic Index), GE Healthcare, Helsinki, Finland and AlgiScan, IDMed, Marseille, France) in assessing the level of analgesia during general anesthesia. Therefore a standardized painful stimulus is applied under different levels of analgesic drugs. The monitor's indices are compared to clinical signs such as an increase in heart rate and blood pressure.
Iatrogenic hypoglycemia is the most frequent acute complication of insulin therapy in people with type 1 diabetes (T1DM). Recurrent hypoglycemic events initiate a process of habituation, characterized by suppression of hypoglycemic symptoms, eventually leading to hypoglycemia unawareness, which creates a particularly high risk of severe hypoglycemia. Recent evidence suggest a pivotal role for (brain) lactate in the pathogenesis of hypoglycemia unawareness. Indeed, exogenous lactate administration may preserve brain function and attenuate counterregulatory responses to and symptomatic awareness of hypoglycemia. It is unknown whether endogenous elevation of plasma lactate produces the same effects and whether such effects differ between patients with T1DM with and without hypoglycemia unawareness and healthy controls. Objective: To investigate the effect of elevated levels of endogenous lactate on brain lactate accumulation and on counterregulatory responses to, symptomatic awareness of and cognitive function during hypoglycemia in patients with T1DM with and without hypoglycemia unawareness and normal controls. Hypothesis: The investigators hypothesize first that endogenous lactate, when raised through high intensity exercise, preserves neuronal metabolism during subsequent hypoglycemia, which in turn will attenuate counterregulatory hormone responses, appearance of symptoms and deterioration of cognitive function. Second, the investigators posit that these effects will be augmented in patients with hypoglycemia unawareness compared to healthy subjects and T1DM patients with normal awareness as a consequence of greater transport capacity of lactate into the brain.
A prospective, randomised, phase IV trial including 150 patients. To evaluate the effects of varied concentrations of remifentanil on the proposal requirements for the loss of consciousness and response to pain and to evaluate the haemodynamic changes and processed EEG (BIS) during induction of anaesthesia.
Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. A dual-hormone closed-loop strategy would regulate glucose levels through the infusion of two hormones: insulin and glucagon. The main objective of this project is to compare the efficacy of single-hormone and dual-hormone closed-loop strategy to regulate overnight glucose levels in a in-patient study in type 1 diabetes adults with hypoglycemia unawareness and documented nocturnal hypoglycemia. The investigators hypothesized that dual-hormone closed-loop strategy is more effective in regulating overnight glucose levels compared to single-hormone closed-loop strategy.
This is a single center, double blind randomized cross over design trial that will compare the impact of N-acetyl cysteine (200 mg) vs. saline infusion during experimental hypoglycemia on day one on the responses to experimental hypoglycemia on day two. 18 participants will be studied twice, 8 weeks apart. On each occasion they will undergo a 2 hour hypoglycemic clamp (target 50 mg/dl) in the morning and in the afternoon on day one and then again on the morning of day 2 and day 3. During the morning clamps, samples will be collected for later measurement of serum epinephrine levels, plasma and red blood cell NAC, cysteine, and glutathione concentrations and GSH/GSSG ratios (redox status), and participants will be asked to complete a hypoglycemia symptom questionnaire
Iatrogenic hypoglycemia is the most frequent acute complication of insulin therapy in people with type 1 diabetes (T1DM). Recurrent hypoglycemic events initiate a process of habituation, characterized by suppression of hypoglycemic symptoms and lead to hypoglycemia unawareness, which in itself defines a particularly high risk of severe hypoglycemia. Recent evidence suggest a pivotal role for increased brain lactate transport capacity in the pathogenesis of hypoglycemia unawareness. However, there is uncertainty about the magnitude of this effect and whether such excess brain lactate is oxidizes as a glucose-sparing alternative energy source or acts as a metabolic regulator controlling brain glucose metabolism, oxygen consumption and cerebral blood flow. Objective: The primary objective of this study is to investigate the effect of hypoglycemia on brain lactate accumulation and regional cerebral blood perfusion in humans. The secondary objective is to assess whether this effect is a related to hypoglycemia unawareness or a consequence of T1DM per se. Hypothesis: The investigators hypothesize that hypoglycemia stimulates lactate transport over the blood-brain barrier leading to cerebral lactate accumulation and that this lactate accumulation is a function of prior hypoglycemic exposure frequency contributing to clinical hypoglycemia unawareness. Furthermore, the investigators expect that this effect of hypoglycemia on brain lactate accumulation is related to changes in cerebral blood flow (CBF).
Temporal dynamics of the EEG microstates show scale-free monofractal properties. This means that information is encoded in the same way at different scales. It may be postulated that these monofractal properties of the EEG microstate sequences constitute a necessary prerequisite of consciousness. We postulate that clinical variations of consciousness may also be linked to alterations of fractal properties of EEG microstates.
Loss and recovery of consciousness during propofol anesthesia seem to be mediated by different mechanisms beyond the actual effect-site concentration of anesthetic drug. This eventual difference between dose response curves for loss of consciousness (LOC) and for recovery of consciousness (ROC) beyond hysteresis has received the name of neuronal inertia. We performed a volunteer-study comparing LOC and ROC curves during a slow, steady-sate, stepped target controlled infusion of Propofol. Our hypothesis is that, at steady-state conditions between plasma an effect-site concentration, there is still going to exist a difference between LOC and ROC, demonstrating the existence of neuronal inertia.