摘要:

We have found that anesthetic technique modifies the neurological and pathological sequelae of unilateral middle cerebral artery and internal carotid artery occlusion in dogs. Occlusion was performed in seven groups of six dogs during each of the following anesthetic regimens: light (0.8%) halothane, “awake,” deep (1.9%) halothane, deep halothane with mean arterial pressure reduced to 55 torr, pentobarbital (56 mg per kilogram), light halothane plus 40 mg per kilogram thiopental begun just before cerebral artery occlusion, and light halothane plus 40 mg per kilogram thiopental begun 15 minutes after occlusion. Body temperature, arterial Pco2Po2pH, and blood pressure (except as noted above) were maintained normal. Neurological examinations were performed daily. On the seventh day the dogs were killed and their brains removed for pathological study. Hemiparesis occurred in five of six dogs under light halothane and five of six awake dogs; a mean of 10.8% and 9.6%, respectively, of their right hemispheres were infarcted. In the deep halothane groups, all of the normotensive and five of the six hypotensive dogs became severely hemiplegic; mean infarction size was 28.2% and 34.1%, respectively. Only one of the 18 dogs who received a barbiturate sustained a neurological deficit — a transient unilateral weakness. Means of 1.4%, 2.7%, and 0.1% of the right hemisphere were infarcted in the barbiturate animals. The protective action of barbiturates in canine acute focal cerebral ischemia suggests that they should be considered for anesthesia in surgery requiring cerebral vessel occlusion and perhaps even for treatment of acute stroke.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The133Xenon inhalation method of measuring regional cerebral blood flow was applied in serial studies comprising 100 measurements in 57 cases of acute hemiparesis and hemiplegia presumed due to arterial occlusion. Satisfactory data for analysis were obtained in over 95% of the cases studied. Significant flow reductions in the ischemic hemisphere were demonstrated in the cases with more severe clinical disability. This study demonstrates the feasibility of applying this method for serial regional cerebral blood flow measurements in most cases of acute stroke. The expected clinical usefulness and limitations of the method are discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The responsiveness of cerebral blood flow to changes in arterial carbon dioxide tension was determined in six monkeys following bilateral superior cervical ganglionectomy. Experiments were conducted 10 to 14 days following the removal of both ganglions using phencyclidine hydrochloride as the anesthetic agent. Following the initial acute experiments, the animals were placed in a sealed environmental chamber for five days at an inspired carbon dioxide level of 6%. The responsiveness to carbon dioxide was repeated following the chronic exposure to carbon dioxide. The animal was killed immediately and the brain removed. The major vessels of the circle of Willis were examined histochemically for the presence of sympathetic nerve fibers. The results of the study demonstrated that: (1) autoregulation was still present, (2) acute exposure to increased levels of carbon dioxide increased flow, and (3) some adaptation of flow occurred following a chronic exposure to 6% carbon dioxide. The carbon dioxide sensitivity of this group of animals was found to be 0.37 cm per second mm Hg-1as compared to a value of 0.94 cm per second mm Hg-1for normal animals. The difference in these two values was significant. It is concluded that the sympathetic nervous system is necessary for the normal responsiveness to changes in arterial carbon dioxide.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

In 50 patients with internal carotid artery occlusion and 40 patients with internal carotid artery stenosis hemispheric and regional cerebral blood flow (rCBF) was measured by the133Xenon clearance method, rCBF was evaluated according to the presence of ischemic or hyperemic foci and to the level of regional perfusion alteration. The degree of collateral circula tion and diameter of stenosis were determined from the angiograms. The clinical symptoms were expressed in a score of motor deficiencies. In internal carotid artery occlusion no correla tion of motor deficiency index with angiographically demonstrable collateral circulation was detectable, but there was good correlation with hemispheric CBF and an excellent correlation (P < 0.001) with the rCBF parameters. In internal carotid artery stenosis no correlation existed between motor deficiency and the degree of stenosis or hemispheric CBF, but good correlation was observed between motor deficiency and the rCBF parameters (P < 0.01).According to these findings, angiographical demonstration of collateral circulation and of stenosis does not provide as accurate information on impending or already developed tissue in farction as does rCBF measurement. Presence of hyperemic foci and lack of ischemic foci were related to lesser motor disturbances. Borderlines of 30 ml/100 gm per minute for threatening tissue ischemia and of 25 ml/100 gm per minute for present tissue ischemia are established. Some points favor the thromboembolic theory of infarction in internal carotid artery stenosis.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

A variety of experimental models for cerebral ischemia are currently available, but none are entirely satisfactory. We are reporting a model which combines hypotension, produced by intravenous Arfonad, with hypoxia, produced by respiring 4% oxygen. Rabbits used are awake but paralyzed with succinylcholine and ventilated mechanically. The electroencephalogram (EEG) is monitored with durally implanted electrodes. Onset of an isoelectric EEG ensues 4.5 ± 0.7 minutes in 17 rabbits studied and is used to measure the degree of ischemic insult. After three minutes of an isoelectric EEG, circulatory restoration is followed by complete functional recovery. After five minutes of an isoelectric EEG, rabbits do not recover or show neurological deficits such as limb weakness. The potential effects of systemic ischemia on these animals are minimized because of the rapid onset of ischemic brain damage. Examination of arterial blood gases, pH, platelets, various organs histologically, and the distribution of carbon-particles in the intracerebral circulation reveals that systemic factors are minimal. Moderately delayed onset of cortical EEG activity and the presence of motor impairment or an inability to respire satisfactorily after extubation indicates that the brunt of ischemic insult is upon brain. Our model has the advantages of simplicity and predictability and offers the opportunity to assess functional impairment after graded degrees of cerebral ischemia. We conclude that our model of cerebral ischemia produced by hypotension and hypoxia is a reasonable alternative to existing methods.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

An error appeared in the abstract of the article “The Relationship of Regional Cerebrovascular CO2Reactivity to Blood Pressure and Regional Resting Flow” by Robert H. Ackerman, M.D., which appeared in STROKE, volume 4, page 725 (September-October) 1973. The following is the corrected abstract.Cerebrovascular CO2reactivity (the change in cerebral blood flow per mm Hg change in PaCO2) is shown to be directly related to resting flow and inversely related to blood pressure for regional as well as for mean CBF data. Both regional and mean CO2reactivity therefore are proportional to the ratio resting flow/blood pressure. This ratio is the reciprocal of resistance and may be calledconductance. When regional CO2reactivity for 428 cerebral areas is plotted against an approximation of regional conductance, the data describe positive linear relationships similar to those found when mean CO2reactivity is plotted against mean conductance. These relationships can be demonstrated whether CO2reactivity is calculated with specific or percent change in flow. The data suggest that under physiological conditions CO2reactivity is related to the basal tone of the cerebrovascular bed. The way in which CO2reactivity relates to conductance, therefore, may be a more reliable index of the integrity of the cerebrovascular CO2response than the CBF change per se. Analysis of CO2reactivity as a function of conductance may facilitate the interpretation of mean and regional CO2reactivity and may provide a more meaningful basis for comparison of the CO2response between individuals.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The activities toward stroke prevention and improving stroke care at Good Samaritan Hospital and Medical Center of Portland, Oregon, for the past ten years are described. The program was multifaceted and included a stroke clinic, a stroke care unit, a course for nurses from throughout the state of Oregon and southwestern Washington, panel discussions and exhibits about stroke care, an educational program for families of stroke patients and satellite clinics at two small communities in Oregon.The presence of this program changed the percentage of patients with strokes of equal severity going home from 13% to 58% at Good Samaritan Hospital and Medical Center and no similar trend could be detected in five other hospitals in Portland during a comparable period.The evaluation of the program revealed that a team approach to stroke care in a special unit improved the care of stroke patients throughout the hospital and was effective in bringing the family into an active role in rehabilitation and patient care. The program also achieved educational goals.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Entry into CSF and consumption by brain of blood-borne lactate (La) was quantified in pentobarbital-anesthetized, normocapnic dogs loaded and infused with NaLa and HLa to hold constant, in arterial blood, both the La concentration at about 8 mM (normal = 1 mM) and the pH at 7.4. In four dogs studied hourly over six hours, the arteriosagittal sinus blood concentration difference (δA-V La) was 0.41 ± 0.14 (SE) mM (P <0.05) and was time independent. CSF La rose slowly over four hours to about 0.6 of blood La while cisternal CSF pH remained nearly constant. Four acetate loaded controls showed no changes of δA-V La, CSF La, CSF, or arterial pH. Brain uptake of La was quantitated in eight dogs during insulin-induced hypoglycemia, to minimize possible competition by glucose. Cerebral blood flow (CBF) and δA-V for La, glucose, and O2were determined at 30-minute intervals. CBF and cerebral metabolic rate of O2(CMRO2) both fell about 17% during two hours of hypoglycemia and returned to control with La loading although blood glucose continued to fall to 1.5 mM. In the two hour La loaded period δA-V La was 0.27 ± 0.10 mM (n = 32) and CSF La rose to 0.7 of arterial La without altering CSF pH. CMRO2averaged 1.61 ± 0.14 μ mol/(min.gm brain), of which CMR glucose (×6 to give O2, equivalents) provided 75% or 1.18 ± 0.13 μ O2eq/(min.gm). CMR La × 3 was 28% of CMRO2or 0.45 ± 0.15 μ eq/(min.gm). The results suggest that blood-borne La can stoichiometrically replace about one-fourth of the glucose used as brain substrate during hypoglycemia, and probably during normoglycemia. Uptake may be limited by saturation of carriers facilitating passage of La across the blood-brain barrier and into brain cells.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

This study was undertaken to compare care and cost outcomes of stroke patients who received home care with those who did not receive home care at St. Luke's Hospital Medical Center, New York, New York.Twenty-five home care stroke patients were matched by age and sex with 25 comparable stroke patients receiving no home care during 1971.After nine months' follow-up, stroke patients who received home care had shorter hospital stays (average, ten days less), overall costs greatly reduced (average, $3,450 for home care patients versus $8,300 for comparison group), fewer readmissions for recurring strokes, and fewer deaths (two versus nine). At the end of nine months, home care patients were located as follows: 20 at home, two on home care, one in a nursing home, and two were dead. The comparison group showed: eight at home, one at an extended-care facility, seven in nursing homes, and nine were dead. The differences in care and cost outcomes between these two groups have considerable implications for patients, hospitals, physicians, and third party payers.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Utilizing the Doppler flowmeter catheter, right carotid blood velocity was measured during episodes of catheter-evoked and pacemaker-induced ventricular tachycardias. Such tachyarrhythmias uniformly diminished peak carotid blood velocity, which in the case of catheter-evoked episodes reduced phasic blood velocity by 50%. At driving rates greater than 140 per minute, the average peak carotid blood velocity was 25% to 50% lower during ventricular when compared with atrial pacing. There was a direct correlation between the ventricular pacing rates and the percent decline of peak carotid blood velocity. Such arrhythmia-related carotid blood velocity deficits may account for syncopal episodes in subjects so affected.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID