Der Anaesthesist
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Randomized Controlled Trial Comparative Study Clinical Trial
[Acoustic evoked potentials of medium latency. Anesthesia induction with S-(+)-ketamine versus ketamine racemate].
Mid-latency auditory evoked potentials (MLAEP) reflect the primary cortical processing of auditory stimuli. They are widely suppressed during general anaesthesia with volatile anaesthetics. Under ketamine, in contrast, they seem to be preserved, which has been interpreted as indicating insufficient suppression of consciousness during ketamine anaesthesia. ⋯ MLAEP do not change in amplitude or latency during induction of general anesthesia with S-(+)-ketamine or ketamine-racemat. Primary cortical processing of auditory stimuli seems to preserved under S-(+)-ketamine and ketamine-racemat. This must be viewed in connection with dreams and hallucinations and could be interpreted as inadequate suppression of auditory information processing during general anaesthesia with S-(+)-ketamine and ketamine-racemat.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Respiratory gas exchange. Anesthesia with enflurane or isoflurane in nitrous oxide during spontaneous and controlled ventilation].
The estimation of oxygen consumption and carbon dioxide elimination is essential for predicting the metabolic activity and needs of any patient having anaesthesia. During anaesthesia oxygen consumption can be measured and compared to a predicted value. However, oxygen uptake is affected by anaesthetic agents, which complicates the interpretation of measured oxygen uptake rate. ⋯ The mean oxygen uptake rate at 10 min was between 2.0 and 2.2 ml.kg-1 x min-1 in all groups. At 30 min the mean oxygen uptake rates were 2.6 to 2.8 ml.kg-1 x min-1. Carbon dioxide elimination was closely associated with expired minute ventilation, with a carbon dioxide excretion of about 30 ml per litre gas exhaled, irrespective of ventilatory mode employed.