Anesthesiology
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Post-operative residual paralysis is common.
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Comparative Study
Neural mechanism of propofol anesthesia in severe depression: a positron emission tomographic study.
The precise neural mechanisms of propofol anesthesia in humans are still unknown. The authors examined the acute effects of propofol on regional cerebral blood flow (rCBF) using positron emission tomography in patients with severe depression. ⋯ As in earlier studies using normal subjects, pronounced suppression in rCBF in the brain stem reticular formation, the thalamus, and the parietal association cortex occurred even in severely depressed patients. However, previously reported decreases in rCBF in the basal frontal lobe were absent in depressed patients.
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Comparative Study
Spinal adrenergic and cholinergic receptor interactions activated by clonidine in postincisional pain.
Previous pharmacologic and molecular studies suggest that the alpha(2)-adrenoceptor subtype A is the target for spinally administered alpha(2)-adrenergic agonists, i.e., clonidine, for pain relief. However, intrathecally administered alpha(2) C antisense oligodeoxynucleotide was recently reported to decrease antinociception induced by clonidine in the rat, suggesting non-A sites may be important as well. The current study sought to determine the subtype of alpha(2) adrenoceptors activated by clonidine in a rodent model for human postoperative pain, and to examine its interaction with spinal cholinergic receptors. ⋯ Both alpha(2) A and alpha(2) non-A adrenoceptors, as well as spinal cholinergic activation, are important to the antihypersensitivity effect of clonidine after surgery. ST91 is more efficacious in this model than clonidine and relies entirely on alpha(2) non-A adrenoceptors.
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Comment Biography Historical Article Classical Article
Criteria of adequate clinical recovery from neuromuscular block.
This study was undertaken to compare the sensitivities of the train-of-four response (2 Hz for 2 s), the single twitch (0.15 Hz), and the tetanic response (50 Hz for 5 s) as indices of residual nondepolarizing block. Spontaneous or induced recovery of evoked thumb adduction in response to ulnar nerve stimulation was studied. One hundred and seven adult surgical patients were divided according to the relaxant used, into six groups. ⋯ Analysis of variance indicated similar train-of-four ratios among the six groups at complete recovery of the single twitch irrespective of the relaxant technique used (P < 0.1). It is concluded that a train-of-four ratio of 0.7 or higher reliably indicates the recovery of the single twitch to control height and a sustained response to tetanic stimulation at 50 Hz for 5 s. The clinical significance of this study is as follows: the train-of-four response provides the same indication of clinical recovery from nondepolarizing block as obtained from tetanic stimulation at a physiological frequency; and reliance on the recovery of the single twitch to control height as a criterion of spontaneous return to normal clinical neuromuscular function may be misleading.