ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Regional cerebral blood flow (rCBF) was measured by the123Xe intra-arterial injection method with 14 external scintillation detectors in 21 operations for stenosis of the internal carotid artery. rCBF and internal carotid arterial pressure distal to the stenosis were measured simultaneously before and after endarterectomy and during two test occlusions of the earotid artery at different Paco2values. In one group measurements during test occlusion were made at hypo- and hypercap-nia; in the other, at normo- and hypercapnia. During hypocapnia (mean Paco230 mm Hg) and normocapnia (mean Paco238 mm Hg) autorgu-lation was partially preserved, while during hypercapnia (mean Paco257 mm Hg) rCBF was linearly related to internal earotid arterial pressure. In both groups hypercapnia decreased internal erotid arterial occlusion pressures, but average mean rCBF values increased. In five patients, however, paradoxical rCBF responses to elevation of Paco2were observed, either focally or in the whole hemisphere. It is concluded that hypercapnia may reduce flow to poorly perfused regions.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Ninety-four sets of inspired, end-tidal and arterial samples were drawn from 17 human subjects anesthetized with halothane in oxygen or halothane in nitrous oxide. The arterial halothane partial pressure was less than the end-tidal pressure which, in turn, was less than that inspired. The difference between the arterial and end-tidal partial pressures was a fifth of the difference between end-tidal and inspired partial pressures.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The effects of halothane and sueeinylcholine (SCh) on Vo, and blood flow of the canine graci-lis muscle were determined and compared with previous findings for the gastrocnemius muscle. Because halothane decreased and SCh increased the Vo2's of the two muscles to approximately the same extent, the responses of the two muscles were averaged and used to estimate the contribution of change in skeletal muscle Vo, to change in whole-body Vo,. These projections suggested that increasing halothane from 0.1 to 0.8 per cent would reduce skeletal muscle Vo, approximately 12 per cent and comprise a decrease of 4 per cent in whole-body Vo,. Infusion of SCh, 0.3 mg/kg/min, was estimated to increase skeletal muscle Vo, approximately 30 and 14 per cent during the first and second hours, respectively, and to contribute increases in whole-body Vo, of 11 and 5 per cent, respectively. The accuracy of the latter estimates was supported by previous direct determinations of the effects of SCh on whole-body Vo,. Whereas the gracilis and gastrocaemius muscles were similar in these responses, actual resting Vo, and blood flow were significantly less for the gracilis muscle, as were cytochreme e concentration, succinic dehydrogenase activity, and Vo,in citro.

ISSN:0003-3022    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

A Clark-type oxygen electrode mounted on a scleral contact lens was used to measure palpebral conjunctival tissue oxygen tensions continuously in adult rabbits. The palpebral conjunctiva sup-plies oxygen to the cornea when the eyelids are shut, thus providing a unique opportunity to separate, atraumatically, a capillary bed with a high oxygen tension from its oxygen-consuming tissue. When the anesthetized rabbits inspired room air, tissue oxygen tensions of 60 to 100 torr were obtained. These values were elese to the predicted and measured arterial oxygen tensions for respiration of room air. At inspired oxygen mixtures varying from 10 to 100 per cent oxygen, continuous, steady-state, reproducible tissue oxygen tensions from 35 to 520 torr were recorded. Tissue and arterial oxygen tensions rose and fell as the inspired oxygen concentrations were increased and decreased in normovoleinic, normo-tensive animals. This technique is suggested as an aid in monitoring patients when knowledge of the state of oxygenation is vital.

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

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

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