Articles: anesthetics.
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Comparative Study
General anesthesia during excision of a mouse tumor accelerates postsurgical growth of metastases by suppression of natural killer cell activity.
Our previous studies indicated that anesthetic drugs cause acceleration of postoperative metastasis of mouse tumors. We tested whether this augmentation could be attributed to a decrease in natural killer (NK) activity. ⋯ Treatment of mice with poly I:C abolished the accelerated growth of metastases following excision of the tumor under ketamine or halothane anesthesia. On the other hand, treatment with poly I:C seemed to have no effect on acceleration of postoperative metastasis in mice anesthetized with N2O or thiopental sodium.
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In general, the cardiovascular system is more resistant to the toxic actions of local anaesthetics than is the central nervous system. However, if sufficient doses and blood levels of local anaesthetics are achieved, signs of profound cardiovascular depression may be observed. Differences exist between local anaesthetics in terms of their relative potential for cardiotoxicity. ⋯ However, large dosages of chloroprocaine solutions administered intrathecally have been associated with prolonged sensory-motor deficits in a few patients due probably to the low pH and presence of sodium bisulfite in the chloroprocaine solutions. In general, the incidence of toxic reactions to local anaesthetic agents is extremely low. However, as with any class of pharmacological agents, local anaesthetics may cause severe toxic reactions, due usually to the improper use of these drugs.
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Two studies were carried out on 609 fit, unpremedicated patients to assess the influence of patient age on the response to the rapidly-acting hindered phenol, propofol, which is being evaluated for induction of anaesthesia. In the first study, 1.25 mg/kg was injected over 20 seconds followed by 10-mg increments every 15 seconds until loss of verbal contact. This showed a great individual variation in response to the drug. ⋯ Doses of 2.25-2.5 mg/kg were required to induce anaesthesia in patients under 60 years, whilst 1.5-1.75 mg/kg was adequate in those over 60 years. Side effects were more marked with the rapid injection and doses in excess of 1.75 mg/kg caused significant hypotension and apnoea in the elderly. These studies reveal marked sensitivity to propofol in the elderly with respect to both induction dose and acute toxicity.