Cerebral blood flow measurements and electroencephalograms during carotid endarterectomy

1974 ◽  
Vol 41 (3) ◽  
pp. 310-320 ◽  
Author(s):  
Thoralf M. Sundt ◽  
Frank W. Sharbrough ◽  
Robert E. Anderson ◽  
John D. Michenfelder
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Endarterectomy ◽  
Carbon Dioxide Tension ◽  
Initial Slope ◽  
Flow Measurements ◽  
Content Type ◽  
Blood Flow Measurements ◽  
Electroencephalogram Eeg ◽  
Fine Print

✓ Ninety-three endarterectomies for carotid stenosis were monitored with cerebral blood flow (CBF) measurements, and 113 with both CBF measurements and a continuous electroencephalogram (EEG). Significant CBF increase occurred only when carotid endarterectomy was for a stenosis greater than 90%. A high correlation between CBF and EEG indicated when a shunt was required. To sustain a normal EEG, the CBF ascertained by the initial slope technique must be 18 ml/100 gm/min at an arterial carbon dioxide tension (PaCO2) of 40 torr. The degree of EEG change below this level during occlusion reflected the severity of reduced blood flow and was reversible with replacement of a shunt. The value and limitations of these monitoring techniques and a concept of ischemic tolerance and critical CBF are discussed.

Cerebral blood flow measurements and electroencephalograms during carotid endarterectomy.

2007 ◽  
Vol 107 (4) ◽  
pp. 887-897 ◽  
Author(s):  
Thoralf M. Sundt ◽  
Frank W. Sharbrough ◽  
Robert E. Anderson ◽  
John D. Michenfelder
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Endarterectomy ◽  
Carbon Dioxide Tension ◽  
Initial Slope ◽  
Arterial Carbon Dioxide Tension ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Electroencephalogram Eeg

✓ Ninety-three endarterectomies for carotid stenosis were monitored with cerebral blood flow (CBF) measurements, and 113 with both CBF measurements and a continuous electroencephalogram (EEG). Significant CBF increase occurred only when carotid endarterectomy was for a stenosis greater than 90%. A high correlation between CBF and EEG indicated when a shunt was required. To sustain a normal EEG, the CBF ascertained by the initial slope technique must be 18 ml/100 gm/min at an arterial carbon dioxide tension (PaCO2) of 40 torr. The degree of EEG change below this level during occlusion reflected the severity of reduced blood flow and was reversible with replacement of a shunt. The value and limitations of these monitoring techniques and a concept of ischemic tolerance and critical CBF are discussed.

An experimental study of the acute stage of subarachnoid hemorrhage

1983 ◽  
Vol 59 (6) ◽  
pp. 917-924 ◽  
Author(s):  
Ken Kamiya ◽  
Hideyuki Kuyama ◽  
Lindsay Symon
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Acute Stage ◽  
Flow Measurements ◽  
Content Type ◽  
Baboon Model ◽  
Differential Increase ◽  
Blood Flow Measurements ◽  
Fine Print ◽  
Made In

✓ A baboon model of subarachnoid hemorrhage (SAH) has been developed to study the changes in cerebral blood flow (CBF), intracranial pressure (ICP), and cerebral edema associated with the acute stage of SAH. In this model, hemorrhage was caused by avulsion of the posterior communicating artery via a periorbital approach, with the orbit sealed and ICP restored to normal before SAH was produced. Local CBF was measured in six sites in the two hemispheres, and ICP monitored by an implanted extradural transducer. Following sacrifice of the animal, the effect of the induced SAH on ICP, CBF, autoregulation, and CO2 reactivity in the two hemispheres was assessed. Brain water measurements were also made in areas of gray and white matter corresponding to areas of blood flow measurements, and also in the deep nuclei. Two principal patterns of ICP change were found following SAH; one group of animals showed a return to baseline ICP quite quickly and the other maintained high ICP for over an hour. The CBF was reduced after SAH to nearly 20% of control values in all areas, and all areas showed impaired autoregulation. Variable changes in CO2 reactivity were evident, but on the side of the hemorrhage CO2 reactivity was predominantly reduced. Differential increase in pressure lasting for over 7 minutes was evident soon after SAH on the side of the ruptured vessel. There was a significant increase of water in all areas, and in cortex and deep nuclei as compared to control animals.

Relationship between hemispheric cerebral blood flow, central conduction time, and clinical grade in aneurysmal subarachnoid hemorrhage

1985 ◽  
Vol 62 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Jacob Rosenstein ◽  
Alexander Dah-Jium Wang ◽  
Lindsay Symon ◽  
Mikio Suzuki
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Initial Slope ◽  
Conduction Time ◽  
Clinical Grade ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print

✓ The relationship between central conduction time (CCT) and hemispheric cerebral blood flow (CBF) has been examined in 20 patients presenting with subarachnoid hemorrhage. A total of 63 combined CCT/CBF recordings were performed at various times throughout the hospital course of these patients, and the findings were correlated to clinical status. The initial-slope index of the CBF (CBFisi) was found to correlate well with clinical grade, and a gradation in flow was noted between the different neurological grades. Patients in Grades I and II (Hunt and Hess classification) had the highest flows (mean CBFisi = 47.2 ± 8.1); Grade III patients had intermediate flows (mean CBFisi = 39.6 ± 7.8); and Grade IV patients had the lowest flows (mean CBFisi = 32.0 ± 6.4). While CCT tended to become increasingly prolonged with worsening grade, a significant difference could not be demonstrated between Grade I, II, and III patients. Only when Grade IV status was reached was the CCT significantly prolonged. When CBFisi and CCT were examined, a threshold relationship was noted between CBFisi and CCT prolongation. At flow values above 30, little change was noted in CCT, and CCT remained in the normal range. However, at flow values below 30, CCT became increasingly prolonged as blood flow diminished. The degree of CCT prolongation appeared to be directly proportional to the degree of blood flow diminution at flows below threshold.

Pulsatile cerebral echo in diagnosis of brain death

1978 ◽  
Vol 48 (6) ◽  
pp. 866-875 ◽  
Author(s):  
Sumio Uematsu ◽  
Thomas D. Smith ◽  
A. Earl Walker
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Death ◽  
Simple Method ◽  
Cerebral Angiogram ◽  
Content Type ◽  
Cerebral Pathology ◽  
Conclusive Diagnosis ◽  
Electroencephalogram Eeg ◽  
Fine Print

✓ Conclusive diagnosis of brain death can be made by the demonstration of prolonged cessation of cerebral blood flow. This report describes a simple method to determine the presence or absence of the blood flow in the brain by recording the pulsatile midline echo on one channel of the electroencephalogram (EEG) or on any four-channel monitoring system in the intensive care unit. A firm transducer holder has been developed to eliminate artifacts caused by transducer motion. The pulsations of the midline echo are assumed to be the result of displacement of the midline structures by the arterial injection of each cardiac systole. Thus, the absence of these midline pulsatile echoes correlates with the absence of cerebral blood flow and, if the absence persists over 30 minutes in the presence of normal blood pressure, then the result is brain death. Twenty-eight cases of clinical brain death with electrocerebral silence of EEG and 18 obtunded patients with various types of cerebral pathology were examined by the echo-pulsation technique. Twenty-six of the 28 cases showed no pulsation of the midline echo. The validity of the technique was documented in four cases by four-vessel cerebral angiogram.

Spinal Cord Blood Flow in Experimental Transient Traumatic Paraplegia

1980 ◽  
Vol 52 (3) ◽  
pp. 335-345 ◽  
Author(s):  
Dean C. Lohse ◽  
Howard J. Senter ◽  
John S. Kauer ◽  
Richard Wohns
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
White Matter ◽  
Cord Blood ◽  
Spinal Cord Blood Flow ◽  
Flow Measurements ◽  
Content Type ◽  
The Mean ◽  
Blood Flow Measurements ◽  
Fine Print

✓ Blood flow in the lateral funiculus of the thoracic spinal cord was measured in 24 anesthetized cats using the hydrogen clearance method. In a control series of eight nontraumatized animals, blood flow measurements were taken from the T-5 and T-6 segments for 6 consecutive hours. The mean spinal cord blood flow (SCBF) in the control group was 12.8 ± 3.51 (SD) ml/min/100 gm on the basis of 107 measurements over 6 hours. In the experimental groups, 16 animals were similarly prepared. The spinal cords of these animals were then traumatized by dropping a 20-gm weight 5 cm (100 gm-cm trauma) or 13 cm (260 gm-cm trauma) onto the T-5 segment. Previous experiments have shown that these trauma levels lead to a transient paraplegia of less than 10 and 30 days' duration, respectively. Two hundred blood flow measurements from T-5 and T-6 were taken over the 6 hours following trauma. In the seven animals of the 100 gm-cm group, mean SCBF after trauma from the T-5 segment was 12.6 ± 3.45 (SD) ml/min/100 gm on the basis of 50 measurements taken over 6 hours; not significantly different from the controls (p > 0.70). In the 260 gm-cm group, mean SCBF from T-5 for 6 hours after trauma was 17.3 ± 6.60 (SD) ml/min/100 gm; significantly higher than controls (p < 0.001). Mean SCBF 3 to 6 hours after trauma was significantly elevated over controls (p < 0.05). The mean hyperemia in the 260 gm-cm group was found to be due to marked hyperemia in only four animals of the series, while five animals maintained blood flows in the normal range. This experiment provides quantitative evidence that white matter ischemia does not occur in spinal cord injuries that can be expected to produce only transient paraplegia. The data support the concept that white matter ischemia in the acute phase of severe spinal cord trauma may be related to secondary injury and subsequent permanent paraplegia.

Red cerebral veins and the cerebral steal syndrome

1971 ◽  
Vol 35 (2) ◽  
pp. 167-179 ◽  
Author(s):  
William Feindel ◽  
Y. Lucas Yamamoto ◽  
Charles P. Hodge
Keyword(s):  
Blood Flow ◽  
Cerebral Veins ◽  
Flow Measurements ◽  
Content Type ◽  
Perfusion Flow ◽  
Flow Through ◽  
Cerebral Steal ◽  
Blood Flow Measurements ◽  
Steal Syndrome ◽  
Fine Print

✓ The circulation through an arteriovenous malformation and the microcirculation of the surrounding brain were examined during craniotomy by fluorescein angiography and by microregional blood flow measurements using xenon133 and Neohydrin-Hg197. The evidence indicates that occluding the arterial supply to the angioma obliterated the cerebral steal by reducing the shunt or non-nutritional flow and improving the perfusion flow through the cortical microcirculation. The features characterizing the cerebral steal syndrome are described.

Differences in critical cerebral blood flow with age in swine

1991 ◽  
Vol 75 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Jun Harada ◽  
Akira Takaku ◽  
Shunro Endo ◽  
Naoya Kuwayama ◽  
Osamu Fukuda
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Ischemia ◽  
Content Type ◽  
Neonatal Pigs ◽  
S 100 ◽  
Newborn Pigs ◽  
Electroencephalogram Eeg ◽  
The Brain ◽  
Fine Print

✓ Normal cerebral blood flow (CBF), critical CBF at a flat reading of the electroencephalogram (EEG), and reversibility of the flat EEG after reperfusion were investigated in a total of 59 pigs, including seven newborns (1 to 3 days of age), 38 juveniles (1 month old), and 14 adults (7 months old). The CBF was determined by the hydrogen clearance method; the EEG was recorded continuously and a power spectrum analysis was performed. Cerebral ischemia was produced by occlusion of both common carotid arteries and induction of hypotension (approximately 50 mm Hg). The flat EEG reversibility was investigated for 3 hours after reperfusion. As parameters of brain development, the neuronal density and the time at which the S-100 protein appeared in the brain were examined. Normal CBF was highest in neonatal pigs and decreased with age. The critical CBF at a flat EEG was lowest in newborn pigs and was elevated with development of the brain. Tolerance against cerebral ischemia was greatest in newborn pigs.

Reproducibility of regional cerebral blood flow measurements in acute severe head injury

1978 ◽  
Vol 49 (3) ◽  
pp. 366-377 ◽  
Author(s):  
Erna M. Enevoldsen ◽  
Finn T. Jensen
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Head Injuries ◽  
Initial Slope ◽  
Regional Cerebral Blood ◽  
Flow Measurements ◽  
Content Type ◽  
Flow Parameters ◽  
The Brain

✓ In order to evaluate the reproducibility of regional cerebral blood flow (rCBF) measurements in pathological brain tissue, serial measurements were carried out in 13 determinations performed in patients who were comatose after severe head injuries within the first 2 weeks after the head trauma. The xenon-133 intra-arterial method was used for the flow measurements, and the flow was studied separately in 16 areas of the brain, producing 197 regional double determinations. The patients were maintained in a steady state during and between the measurements, and only differences of less than 2 mm Hg in the arterial CO2 pressure and less than 5 mm Hg in the perfusion pressure were tolerated. The reproducibility was found to be reasonably good as regards initial slope-flow indices and height/area flow values, whereas that of the compartmentally calculated flow parameters was poorer. On dividing the series into severely and moderately pathological areas, it could be shown that the reproducibility of the flow values in the moderately pathological brain areas was acceptable and similar to the results reported by others, whereas the reproducibility in the most severely pathological areas of the brain was rather poor, as regards the flow in the fast compartments. The correlation between the various flow parameters was found to be fairly good.

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