Outcome in Children With Significantly Abnormal Cerebral Blood Flow Detected by Doppler Ultrasonography: Focus on the Survivors

BACKGROUND AND PURPOSE: The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. PATIENTS AND METHODS: Forty-seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. RESULTS: Forty-two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. CONCLUSIONS: Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients.     

Acute cerebral infarction: pathophysiology and modern treatment concepts

Summary This review focuses on the pathophysiological changes in acute cerebral ischemia, with special emphasis on disturbances of the cerebral blood flow (CBF) and the associated penumbra concept. Alternatively, the model of peri-infarct depolarization is demonstrated. Metabolic and molecular changes caused by cerebral ischemia and reperfusion are discussed, namely energy failure, release of glutamate with an excitatoric burst, calcium influx in neurons, generation of free radicals, activation of different proteases, disturbances of protein synthesis, induction of gene expression and apoptosis, loss of membrane integrity, edema formation and microvascular disturbances. In summary, the pathophysiological changes after focal cerebral ischemia and reperfusion are most adequately described by a network of interacting different mechanisms of tissue alterations. The simple concept of a cascade of ischemic effects which would be easy to block seems to be less applicable. A time window of approximately 6 h for the acute stroke therapy is postulated on the base of the above mentioned pathophysiological changes. The recently introduced treatment regimen with optimized basic treatment, recanalization using thrombolysis and neuroprotection by different agents is presented. Different modes of a possible intervention are discussed. Modern concepts of stroke therapy including stroke-unit care and thrombolysis with add-on neuroprotection seem to have potential for improving the outcome of acute stroke patients.      

Early Stroke Recognition: Developing an Out-of-hospital NIH Stroke Scale

Objective : To develop an abbreviated and practical neurologic scale that could assist emergency medical services or triage personnel in identifying patients with stroke.
Methods : A prospective, observational, cohort study was performed at university-based EDs. Participants were 74 patients treated in a thrombolytic stroke trial and 225 consecutive non-stroke patients evaluated during 4 random 12-hour shifts in the ED. Scores on the NIH Stroke Scale were obtained for all patients by physicians. Items of this scale were modified and recoded to a binomial (normal or abnormal) scale. Serial univariate analyses using χ² were performed to rank items. Recursive partitioning was then performed to develop the decision rule for predicting the presence of stroke.
Results : Three items identified 100% of patients with stroke: facial palsy, motor arm, and dysarthria. An Abbreviated NIH Stroke Scale based on these items had a sensitivity of 100% and a specificity of 92%. A proposed Out-of-hospital NIH Stroke Scale consisting of facial palsy, motor arm, and a combination of dysarthria and best language items (abnormal speech) had a sensitivity of 100% and a specificity of 88%.
Conclusion : Using the derivation data set, a proposed Out-of-hospital NIH Stroke Scale had a high sensitivity and specificity for identifying patients with stroke when performed by physicians in this group of 299 ED patients. Prospective studies of other health care professionals using the scale in the out-of-hospital arena are needed.     

Cerebral blood flow, cerebral metabolic rate of oxygen and relative CO2 reactivity during neurolept anaesthesia in patients subjected to craniotomy for supratentorial cerebral tumours

In 10 patients subjected to craniotomy for supratentorial cerebral tumours in neurolept anaesthesia, cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured twice peroperatively by a modification of the Kety & Schmidt technique, using 133Xe. The relative CO2 reactivity was assessed indirectly as the % change of the arteriovenous oxygen difference (AVDO2) per mm change in PaCO2. The patients were premedicated with diazepam 10-15 mg perorally. For induction, thiopentone 4-6 mg/kg, droperidol 0.2 mg/kg and fentanyl 5 micrograms/kg were used, and for maintenance N2O 67% and fentanyl 4 micrograms/kg/h. During the first flow measurement the median and range of CBF was 30 ml/100 g/min (range 17-45), of AVDO2 8.0 vol % (range 4.1-9.5), and of CMRO2 2.28 ml O2/100 g/min (range 1.57-2.84). During the second CBF study, AVDO2 increased to 9.3 vol % (range 3.4-11) (P less than 0.05), and CMRO2 increased to 2.51 ml O2/100 g/min (range 1.88-3.00) P less than 0.05, while CBF was unchanged. The CO2 reactivity was present in all studies, median 1.8%/mmHg (range 0.5-15.1). The correlation coefficients between jugular venous oxygen tension/saturation, respectively, and CBF were high at tensions/saturations exceeding 4.0 kPa and 55%, indicating that hyperperfusion is easily unveiled by venous samples from the jugular vein during this anaesthesia.     

Dynamic aspects of expanding cava septi pellucidi et Vergae

Summary Two paediatric patients with expanding cysts of the cava Vergae et septi pellucidi are presented. In the first patient, consecutive CT scans showed agrowing cavum thought to be responsible for his dramatic increase in head circumference. In the other patient, the expanding cavum was discovered because a routine skull X-ray after minor head trauma revealed marked impressiones digitatae.Both patients were successfully treated with stereotactically placed internal shunts from the cysts via the lateral ventricle to the subarachnoid space. During this procedure, contrast medium was instilled, and the cysts were visualized on postoperative CT scans.Some dynamic aspects of such expanding cava are discussed.     

Channges in regional cerebral blood flow after hyperventilation in the pig with an induced focal cerebral contusion

Summary Changes in regional cerebral blood flow in anaesthetized pigs with an induced focal cerebral contusion were studied before and after two grades of hyperventilation. A reduction in arterial tension of CO₂ with 0.70mmHg and a further reduction of 0.55mmHg did not change the CO₂ reactivity. Reactivity in both injured and macroscopically normal regions was the same, revealing an average of 39.3% flow change per kPa change in CO₂ tension. Regions with low flow after the contusion had an equally big reduction apparently leading to hypoxia because global metabolic rate was unchanged.     

缺血性脑血管病患者载脂蛋白B基因多态性与血脂关系探讨

应用聚合酶链反应（ＰＣＲ），检测了１０６例正常汉族人及５５例缺血性脑血管病（ＩＣＶＤ）病人的ａｐｏＢ基因ｘｂａⅠ酶切位点限制性片段长度多态性（ＲＦＬＰｓ）及其与血脂的关系。结果表明ＩＣＶＤ组ｘｂａⅠ酶切位点上Ｘ＋的等位基因频率明显高于正常对照组（Ｐ＜０．００５）；ＩＣＶＤ组中具Ｘ＋Ｘ－基因型者的血浆ＨＤＬ－Ｃ较Ｘ－Ｘ－基因型者明显降低（Ｐ＜０．０５），而ＬＰ（ａ）和ＴＣ明显增高（Ｐ＜０．０５～０．００５）。提示ａｐｏＢ基因多态分析结合血浆脂蛋白测定更能有效地检测ＩＣＶＤ易患人群。     

Hyperaemia prior to acute cerebral swelling in severe head injuries: The role of transcranial doppler monitoring

Summary Acute cerebrovascular congestion after a closed head injury is significantly related to intracranial hypertension. As an indirect method of cerebral blood flow measurement, transcranial doppler sonography (TCD) provides a rapid and noninvasive assessment of cerebral haemodynamics, including hyperaemic conditions.TCD examinations was serially performed in 35 patients with severe head injury with intact cerebral circulation; i.e. the mean flow velocity (MFV) patterns of the middle cerebral artery (MCA) did not show signs of cerebral circulatory arrest such as systolic spike, to and fro, or no flow. The results showed that the MFV of the MCAs and ipsilateral extracranial internal carotid arteries (ICAs) in 9 of these patients increased sharply and pulsatility index (PI) decreased during 48–96 hours after the injury. This was soon followed by patterns of high intracranial resistance, consistent with elevated intracranial pressure (ICP) in monitored patients and acute brain swelling on repeated computed tomographic (CT) scans. The correlation between increased MFVs, decreased PIs, and cerebral haemodynamic changes leading to acute brain swelling is discussed.The number of patients who ended with severe disability, vegetative state, or death was 66% in this group of 9 patients, compared to only 34% for the 35 patients overall with severe head injury. Though the morbidity and mortality rates largely depend on the primary injury, the presence of acute cerebral swelling aggravate the grave course in these patients. And the ability of TCD to monitor the hyperaemic state prior to oedema should lead us to adjust the therapy in order to minimize the secondary insult related to intracranial hypertension.     

Cerebral blood flow changes in normal aging: Spect measurements

Global and regional cerebral blood flow (CBF) were evaluated with single photon emission computerized tomography (SPECT) utilizing both ¹³³Xenon (¹³³Xe) (47 subjects, 47–82 years old) and ⁹⁹Tc-hexamethylpropyleneamine oxime (⁹⁹Tc-HMPAO) (27 subjects, 47–80 years old). The ¹³³Xe results showed: among total subjects, no age-related decline in global CBF, but a significant regional decline in the occipital lobe (p < 0.05); among men, significant age-related declines in global, frontal, temporal, occipital and right hemisphere CBF (all p < 0.05); among women, no age-related decline in global or regional CBF. The ⁹⁹Tc-HMPAO results showed no age-related decline in either global or regional perfusion among total subjects, men or women. These results suggest that age-related global and regional (including frontal lobe) CBF declines do not occur in healthy control subjects after the age of 45 years. However, gender differences in age-related CBF changes warrant further study.     

电针对沙鼠急性脑缺血再灌注后神经原损伤的保护作用

本实验利用沙鼠急性脑缺血再灌注模型，研究电针对脑缺血及再灌注各期脑电活动的影响及组织病理学的改变。结果表明：缺血１０ｍｌｎ，脑电幅度受到严重抑制，甚至变平坦，总功率大大下降，再灌注后总功率难以恢复，在１２０ｍｉｎ时仅恢复到缺血前的２７．３９±１１．３１％，以后即不再进一步恢复，电针组动物缺血１０ｍｉｎ再灌注后，脑电的恢复明显比对照组快，１２０ｍｉｎ时恢复至缺血前的７１．４５±１６．４６％（Ｐ＜０．０１），２４０ｍｉｎ时继续恢复至缺血前的７５．２７±１８．４３％。同时电针能明显减轻缺血１０ｍｉｎ后再灌注２４小时的神经原缺血性损伤。结果提示：电针对急性脑缺血引起的神经原损伤具有保护作用，并能促进脑功能的恢复。