ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Alveolar anesthetic concentrations at the first response to command and those concentrations just preventing the response were determined in man during recovery from methoxyflurane, halothane, ether and fluroxene anesthesia. The authors assumed equilibration of cerebral anesthetic concentration with alveolar concentration after alveolar concentration had been kept constant for at least 15 minutes. The anesthetic concentration midway between the value permitting the response and that just preventing the response was defined as “MAC awake.” MAC awake values were 0.081 ± 0.021 (SD) per cent methoxyflurane, 0.41 ± 0.05 per cent halothane, 1.41 ± 0.22 per cent ether, and 2.20 ± 0.49 per cent fluroxene. MAC awake-to-MAC ratios were fairly close for the four agents, being 0.52, 0.52, 0.67, and 0.60 for methoxyflurane, halothane, ether, and fluroxene, respectively. When the alveolar concentrations were allowed to fall spontaneously, falsely low MAC awake values were obtained for halothane and fluroxene, while MAC awake for methoxyflurane was unchanged from that found at constant alveolar concentration.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The effects of two short-acting barbiturates (thiopental and methohexital) on arterial blood pressure, cervical preganglionic sympathetic activity, and barostatic reflexes have been studied in cats anesthetized with nitrous oxide. Both barbiturates reduced sympathetic nervous activity while failing to extinguish the reflex responses to electrical stimulation of the aortic depressor nerve. In decerebrated animals the same response was seen. Baroreceptor-denervated animals had a similar but exaggerated reaction. Spinal animals developed arterial hypotension without depression of sympathetic activity. It is concluded that the barbiturates inhibit sympathetic nervous activity by inhibiting “pressor” neurons in the medulla oblongata. The medullary “depressor” neurons are relatively unaffected and the barostatic reflexes consequently remain, although they are weakened. The preservation of these reflexes accounts, in part, for the circulatory stability observed during barbiturate anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The optimum site for insertion of the needle into the epidural space for epidural anesthesia is controversial because understanding of the behavior of the catheter in the space is incomplete. This paper reports the results of roentgenographic analysis of the positions of catheters inserted into the epidural spaces of 151 patients. About 50 per cent of the catheters inserted by a conventional technique curled up or doubled back on themselves. Significant differences between the lumbar and thoracic regions were observed, in both length of catheter directly inserted and distance of the catheter tip from the puncture site. In the lumbar region, the probability that the catheter tip was situated three segments beyond the intervertebral space of insertion was only about 0.5 per cent; in the thoracic region it was about 50 per cent.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

During hypotension resulting from conduction anesthesia in gravid ewes, uterine blood flow (UBF) decreased roughly in proportion to the decrease in maternal blood pressure. Ephedrine or mephentermine significantly increased UBF over that accomplished by metaraminol. Presumably, the preferential effects of these agents were the result of increased cardiac output owing to inotropic and chronotropic actions. However, UBF never exceeded 90 per cent of prespinal levels with any vasoactive agent and, for a given maternal system, the UBF response was variable, generally increasing but frequently remaining constant or decreasing. For these reasons, all other methods of combating hypotension should be used initially. If vasopressors are still required, agents of choice are those whose principal mode of action lies in cardiac stimulation rather than peripheral vasoconstriction.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

The suitability of fentanyl, meperidine or alphaprodine for the production of neuroleptanesthesia in conjunction with droperidol and nitrous oxide–oxygen was investigated in a double-blind study of 527 surgical patients. Because of the greater stability of the circulatory and respiratory systems associated with their use, fentanyl and meperidine were found to be preferable to alphaprodine for the production of neuroleptanesthesia. Except for a lower incidence of apnea and more rapid recovery of consciousness, fentanyl does not seem to offer any significant advantages over meperidine as a component of neuroleptanesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID