ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The effects of ketamine on CNS electrical activities (EEC and multiple-unit activity of the brain-stem core) and gross behavior were studied in cats with chronically implanted electrodes. Ketamine induced three distinct patterns, related to dose An initial CNS excitation coupled with catatonic behavior was followed by disorganized excitation characterized by a catatonie-anesthetic state and finally, electrographic seizures without clinical correlates. During the initial period multiple-unit activity increased. Following this, the basal level of multiple-unit activity decreased, but the level increased phasically in synchrony with EEG hypersynchrony. During the stage of generalized seizures, the basal level decreased further, while phasic enhancement was not much affected. Comparison of polygraphic findings in the ketamine-induced anesthetic state and during control paradoxical (dream) sleep revealed that there is little or no possibility that ketamine induces dream sleep in the cat. Comparison of ketamine anesthesia and states induced by other hallucinogenic and convulsant drugs, including anesthetics, indicated some possibility that ketamine induces hallucinations. It was concluded that the ketamine-induced anesthetic state is a result of functional disorganization of the CNS rather than CNS depression.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The effects of lidocaine on optic evoked potentials (OEP) of the cat's visual cortex in response to electrical stimulation of the optic nerve in light and in darkness were investigated. EEC, ECG, and blood pressure were recorded simultaneously in barbiturate-anesthetized as well as in immobilized cats. In light, less than 1 mg/kg had no effect in anesthetized cats, but 1 mg/kg facilitated OEP, whereas in darkness, with OEP at naturally lower levels, both 0.5 and 1 mg/kg facilitated OEP, and the magnitude of facilitation was greater than that in light. In light, as much as 8 mg/kg was necessary for facilitation of OEP in immobilized cats, but twice that dose had no detectable effect. In darkness, with OEP naturally lower, 8 mg/kg lidocaine not only facilitated OEP in immobilized cats, but the magnitude of facilitation was greater than that in light, and 16 nig/kg also facilitated OEP. In darkness, the difference between 8 and 16 mg/kg was that with the latter dose facilitation was more predictable and longer-lasting. Facilitation of OEP by lidocaine was unrelated to its effects on blood pressure, ECG, or EEG. It is suggested that lidocaine-induced convulsions arc due to a dissociation in neuronal integration that results from depression of the active inhibitory inputs of the neuronal circuitry, that darkness induced depression of OEP is an active inhibition and that barbiturate anesthetization spares quantitatively greater inhibitory processes and thereby alters the process of homeostasis.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Dogs anesthetized with halothane were subjected to stress by increased depth of anesthesia, arterial hypoxemia, or hemorrhagic hypotension in stages leading ultimately to death. Excess lactate (XL) in the whole body, splanchnic circulation, and skeletal muscle did not change significantly until the final period just preceding death. At this time XL for the whole body and the splanchnic circulation increased. Muscle XL did not increase in any circumstance tested despite compromise of O2delivery sufficient to decrease muscle μo2. Overall, changes in arterial blood pH, buffer base, lactate, and Iactate/pyruvate ratio were small, metabolic acidosis was minimal to absent, and XL was insensitive and fallible as an index of regional and whole-body hypoxia. These findings are believed to be directly related to the relative suppression of activity of the sympathetic nervous system during halothane anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Uptake and excretion of a new inhaled anesthetic, Forane,in vivoare consistent with its measured blood-gas partition coefficient of 1.4. The rate of alveolar change is similar to that of fluroxene and somewhat more rapid than that of halothane. Washin curves of volunteers exposed to a subanesthetic concentration and washout curves of volunteers exposed to an anesthetic concentration for six to seven hours (complete equilibration) are similar. Small, but significant, differences between the curves can be explained by differences in muscle blood flow and ventilation, or by the occurrence of ventilation—perfusion abnormalities.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The mechanisms underlying pathologic pain states such as phantom limb pain remain a mystery. Observations that 1) pain may persist indefinitely; 2) trigger zones may spread to healthy parts of the body; and 3) pain may be abolished by either decreasing or increasing the sensory input cannot be explained solely in terms of peripheral causes or abnormal activity restricted to the spinal cord. This paper proposes that a portion of the brainstem reticular formation exerts a tonic inhibitory effect on transmission at all levels of the somatic projection system. The loss of sensory input after amputation would decrease the tonic inhibition and increase the probability of self-sustaining neural activity. The self-sustaining activity, its capacity to recruit adjacent neurons, and its occurrence at several transmission levels would underlie prolonged pain and spread of trigger zones. Modulation of the sensory input by anesthetic blocks or intense stimulation would abolish the self-sustaining activity and produce pain relief.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

A nomogram was constructed for quick and accurate derivation of the &OV0312;A/&OV0312;Eratio, VD/VTratio, &OV0312;A, &OV0312;co2, and &OV0312;o2from measured Paco2, F&OV0312;CO2and &OV0312;Evalues. The use of the nomogram is described and exemplified.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID