Hemodynamics of stroke patients under therapy with low molecular weight hydroxyethyl starch

Abstract

In stroke penumbra perfusion depends passively on hemodynamics. So far hemodynamic effects of low molecular weight hydroxyethylstarch (HES) has not been investigated. Ten stroke patients received hypervolemic HES therapy. Cardiac output and heart rate were monitored using the bioimpedance method, blood pressure by conventional measurement. The Scandinavian Stroke Scale assessed clinical outcome. Circadian cardiac output changes were measured in 20 controls. Patients' cardiac output increased after the loading dose (5.3± 1.41 min^-1 to 6.5± 1.71 min^-1, p < 0.01), fluctuating then between 5 and 71 min-I without nocturnal decrease. Beside an initial increase, the heart rate showed, like blood pressure, no remarkable changes. The Scandinavian Stroke Scale score did not change significantly. The controls showed a circadian cardiac output fluctuation (2.00 am, 5.3 ± 0.31 min^-1; 8.30 am, 8.7 ± 0.61 min^-1). Our patients showed a hemodynamic and clinical stabilization under therapy with low molecular weight HES. rhe physiological nocturnal decrease ofcardiac output and blood, which might cause clinical deterioration in stroke patients, was avoided. [Neural Res 1998; 20: 231-234]     

中分子羟乙基淀粉注射液治疗急性脑分水岭梗死的疗效观察

目的 观察中分子羟乙基淀粉注射液治疗急性脑分水岭梗死(CWI)的疗效.方法 随机将100例CWI患者分为中分子羟乙基淀粉注射液治疗组和对照组(每组50例).两组患者均给予改善脑供血、抗血小板等脑梗死常规治疗,治疗组再予以中分子羟乙基淀粉注射液500 ml静脉滴注,每天1次,连续14 d.在治疗前、治疗后第7 d、14 ...     

Haemodilution with dextran 40 and hydroxyethyl starch and its effect on cerebral microcirculation

Summary The effect of haemodilution with Ringer's solution, hydroxyethyl starch (HAES) 200/0.5 10% and dextran 40 on cerebral blood flow (CBF) was measured in ten cats by means of the hydrogen clearance technique. As expected from theoretical considerations the haemodilution effect was short and not significant with Ringer's solution, but was 25% with HAES and 35% with dextrane 40. The corresponding rise in CBF was significant in both the latter but not with Ringer's solution. CBF was similarly highly correlated with diminution of haematocrit (Hct). The different effects of the substances on CBF could all be explained by their different effects on the Hct. Data analysis, together with recent literature, suggests that the dominating factor determining CBF was the O₂-transport capacity, which in these experiments was in close relation to Hct. The results support the assumption that the increase of CBF by haemodilution is caused by a regulatory mechanism and not by a change of rheological parameters.     

Xenon-enhanced computed tomography compared with [14C]iodoantipyrine for normal and low cerebral blood flow states in baboons

The correlation between the acute, invasive diffusible [14C]iodoantipyrine technique for cerebral blood flow and the noninvasive xenon-enhanced computed tomographic method has been assessed by simultaneous measurements in the baboon. Blood flows in small tissue volumes (about 0.125 cm3) were directly compared in normal and low flow states. These studies demonstrate a statistically significant association between the two methods (p less than 0.001). Similar correlations were obtained by both the Kendall (tau) and the Spearman (r) methods (r = 0.67 to 0.92, n greater than or equal to 19 for each study). The problems and limitations of such correlations are discussed.     

60 g/L中分子羟乙基淀粉（130/0.4）高容量血液稀释对老年患者血液流变学的影响

背景：新型60 g/L羟乙基淀粉是目前容量治疗的血浆代用品,用其扩容对组织氧合更有利,更能改善微循环并减少内皮细胞肿胀。 目的：观察先后输注乳酸钠林格液和新型60 g/L中分子羟乙基淀粉(130/0.4)急性高容量血液稀释后对老年患者血液流变学的影响。 设计、时间及地点：随机对照临床观察,于2007-03/12在天津医科大学总医院完成。 对象：择期腹部手术患者20例,ASAⅠ~Ⅱ级,随机分为平衡液组10例和60 g/L中分子羟乙基淀粉组10例。 方法：建立通畅静脉通路行急性高容量血液稀释,平衡液组以15 mL/(kg•h)速度输入乳酸钠林格液1 000 mL;60 g/L中分子羟乙基淀粉组先以同样速度给予乳酸钠林格液500 mL,继之等速输入羟乙基淀粉(130/0.4)氯化钠注射液500 mL,术中维持输液用乳酸钠林格液。 主要观察指标：测定急性高容量血液稀释前后患者全血黏度高切变率、低切变率、血浆黏度、血细胞比容、红细胞聚集指数、红细胞刚性指数等指标。 结果：①急性高容量血液稀释后,平衡液组全血高切黏度明显降低(P < 0.05);60 g/L中分子羟乙基淀粉组全血高切黏度和低切黏度均明显降低(P < 0.01);两组比较差异无显著性意义 (P > 0.05)。②急性高容量血液稀释前后两组血浆黏度和全血还原黏度均无明显变化(P > 0.05)。两组比较差异无显著性意义 (P > 0.05)。③急性高容量血液稀释后两组红细胞聚集指数和红细胞刚性指数均降低,60 g/L中分子羟乙基淀粉组降低显著(P < 0.05)。两组比较差异无显著性意义 (P > 0.05)。 结论：先后输注乳酸钠林格液和60 g/L羟乙基淀粉(130/0.4)氯化钠注射液能够优化血液流变学状态。     

Effect of stable xenon in room air on regional cerebral blood flow and electroencephalogram in normal baboons

Measurement of regional cerebral blood flow (rCBF) was performed in 6 healthy baboons during ventilation with 35% stable xenon in artificial air. rCBF was measured with the intraarterial xenon-133 method. EEG was recorded continuously. All CBF areas of interest over one hemisphere reacted in the same way. Mean flow increased during short-term exposure to stable xenon and decreased if stable xenon inhalation was continued for at least 24 minutes. EEG showed a decrease of alpha- and beta-wave patterns a short time after the start of stable xenon inhalation without further changes over the period when rCBF finally decreased. CO2 reactivity increased in most animals, and autoregulation to mild arterial hypotension was significantly impaired with increased flow. It is concluded that 35% stable xenon in artificial air increases rCBF after short-term exposure and decreases rCBF after longer exposure. EEG changes were noted after short-term exposure. rCBF and EEG recovered rapidly after the end of stable xenon inhalation.     

Effect of flunarizine on cerebral blood flow in baboons with or without focal cerebral ischaemia

In baboons with or without regional cerebral ischaemia (achieved by transorbital clip of the middle cerebral artery), cerebral blood flow (CBF) was measured using the intra-arterial Xenon-133 technique during steady-state, slight hypotension, and hypocapnia before and after administration of various doses of the calcium antagonist flunarizine (0.5 mg kg^–1, 1.0 mg kg^–1, or 10 μg kg^–1 min^–1 over 30 min). In normal baboons flunarizine did not alter CBF significantly, but at reduced blood pressure it increased CBF by 19.9% owing to exaggerated vasodilatory autoregulation. During hypocapnia flunarizine impaired the physiological reduction in CBF owing to reduced vasoconstriction. In baboons with cerebral ischaemia, CBF measurements were stable and comparable with those in a control group using an arterial clip unless flunarizine was added. In a group of five flunarizine-treated animals, mean CBF after positioning of the clip was higher than in the control group. However, the increase in mean CBF varied significantly between animals, indicating that a secondary reduction in CBF due to postischaemic pathophysiological processes was not prevented consistently.     

Effect of flunarizine on cerebral blood flow in baboons with or without focal cerebral ischaemia

In baboons with or without regional cerebral ischaemia (achieved by transorbital clip of the middle cerebral artery), cerebral blood flow (CBF) was measured using the intra-arterial Xenon-133 technique during steady-state, slight hypotension, and hypocapnia before and after administration of various doses of the calcium antagonist flunarizine (0.5 mg kg-1, 1.0 mg kg-1, or 10 micrograms kg-1 min-1 over 30 min). In normal baboons flunarizine did not alter CBF significantly, but at reduced blood pressure it increased CBF by 19.9% owing to exaggerated vasodilatory autoregulation. During hypocapnia flunarizine impaired the physiological reduction in CBF owing to reduced vasoconstriction. In baboons with cerebral ischaemia, CBF measurements were stable and comparable with those in a control group using an arterial clip unless flunarizine was added. In a group of five flunarizine-treated animals, mean CBF after positioning of the clip was higher than in the control group. However, the increase in mean CBF varied significantly between animals, indicating that a secondary reduction in CBF due to postischaemic pathophysiological processes was not prevented consistently.     

Autoregulation of cerebral blood flow during controlled hypotension in baboons

The effect of graded, progressive hypotension on the autoregulation of cerebral blood flow was studied in anaesthetised baboons. Progressive hypotension was produced over a period of four to five hours, either by graded haemorrhage or by the administration of increasing concentrations of hypotensive drugs. During haemorrhagic hypotension autoregulation was maintained until the mean arterial pressure had decreased to 65% of its baseline value, below which cerebral blood flow was pressure passive. In those animals subjected to drug-induced hypotension, autoregulation persisted to lower levels of mean arterial pressure (35-40% of baseline). It is postulated that under conditions of haemorrhagic hypotension, constriction of the extraparenchymal cerebral vessels in response to sympathetic stimulation decreases the possible range of autoregulation in the anaesthetised baboon.     

Comparison of regional cerebral blood flow in patients with anorexia nervosa before and after weight gain

We investigated changes in regional cerebral blood flow (rCBF) before and after weight gain in patients with restrictive anorexia nervosa (AN-R) in comparison with findings in normal subjects. We assessed resting rCBF using single photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime in 12 AN-R patients and 11 controls. Each patient was examined at two time points, at the beginning of treatment and after weight gain (average examination interval = 88 ± 26 days). Control subjects were examined only once. Before treatment, the AN-R group had lower rCBF in the bilateral anterior lobes, including the anterior cingulate cortex (ACC), and in the right parietal lobe, the insula, and the occipital lobes. After weight gain, the patients showed significant increases in the right parietal lobe and decreases in the basal ganglia and cerebellum in accordance with significant improvement in body weight and eating attitudes. However, they showed persistent decreases in the ACC area even after weight gain compared with findings in the controls. A significant positive correlation was observed between body mass index and rCBF in the occipital lobes in the patients. These results suggest that weight gain is associated with a normalization of rCBF in a number of brain areas, but that the low level of rCBF in the ACC at baseline is unaffected by treatment in AN-R.     

Comparison of the effects of intravenous papaverine hydrochloride and oral pavabid HP capsulets on regional cerebral blood flow in normal individuals

A single-blind study was conducted in 13 right-handed normal male subjects to compare the effects of oral and i.v. papaverine on regional cerebral blood flow (rCBF). Six xenon-133 inhalation rCBF measurements were performed on each subject; three tests--baseline, placebo, and drug evaluations--were carried out on each of two separate days. The oral and i.v. drugs were randomized for first-day administration. rCBF, measured as flow gray (FG), increased significantly (p less than or equal to 0.001) from baseline with both drug forms. Increases of 10.53% and 13.94% (left and right hemispheres, respectively) were demonstrated 90 min after a single 600-mg dose of oral papaverine. Increases of 5.09% and 8.69%, respectively, were recorded immediately after a single 100-mg dose of i.v. papaverine. FG also increased significantly (p less than or equal to 0.001) for both drug forms when compared to that of placebo. Placebo produced only a slight increase (not significant) with both the oral and i.v. groups. The data show increasing rCBF in normal subjects.     

Decreases in regional cerebral blood flow with normal aging

Positron emission tomographic (PET) images of regional cerebral blood flow (rCBF) from 30 normal, resting volunteers aged 30 to 85 years were analysed to identify areas where rCBF fell with age. Images were anatomically normalised, and a pixel-by-pixel linear regression was performed to remove differences in global CBF between subjects. Pixels at which rCBF then showed a significant (p less than 0.01) negative correlation with age were identified. They were displayed as a statistical parametric map (SPM) of correlations. We demonstrate an age-related decrease in adjusted rCBF in the cingulate, parahippocampal, superior temporal, medial frontal, and posterior parietal cortices bilaterally, and in the left insular and left posterior prefrontal cortices (omnibus significance, chi 2 = 2,291, p less than 0.0001, df = 1). Decreases in rCBF suggest a regionally specific loss of cerebral function with age. The affected areas were all limbic, or association, cortices. Therefore, these decreases may constitute the cerebral substrate of the cognitive changes that occur during normal aging.     

The effects of high dose mannitol on cerebral blood flow in dogs with normal intracranial pressure

In normal dogs, bolus administration of a very high dose of mannitol (2 gm/kg) resulted in a small, transient increase in cerebral blood flow (CBF) of approximately 8 percent lasting less than 10 minutes followed by a significant reduction in CBF of approximately 20 percent lasting at least three hours. The increase in CBF may in part be related to changes in cardiovascular and hematological parameters. No explanation is available for the reduction below control values but, since urine losses were not replace in these animals, changes in the state of hydration may have been responsible. It appears that the increase in CBF resulting from mannitol administered by bolus infusion are of neither sufficient magnitude nor duration to explain the protective effect observed in other studies where cerebral blood flow was reduced below ischemic levels. This suggests then, that either the effect of mannitol on CBF is quantitatively different when flow is reduced to critical levels or that the protective effect observed when the cerebral circulation is compromised is based upon a different mechanism than augmentation of flow. Further studies on the effect of mannitol on CBF in ischemic situations, where the cerebral circulation is compromised, are required.     

中分子羟乙基淀粉注射液治疗急性脑分水岭梗死的疗效观察

目的 观察中分子羟乙基淀粉注射液治疗急性脑分水岭梗死的疗效。方法利用日常生活活动能力量表（Barthel index,BI）和治疗后90d改良Rankin量表评价中分子羟乙基淀粉注射液治疗患者（治疗组）和常规治疗患者（对照组）的临床疗效。结果治疗后7,14d,治疗组BI上升,日常生活能力明显高于对照组。治疗后90d,治疗组的致残程度明显轻于对照组。结论中分子羟乙基淀粉注射液治疗急性脑分水岭梗死,可以改善患者日常生活能力、90d的残疾程度。     

Comparison of the effects of risperidone and haloperidol on regional cerebral blood flow in schizophrenia.

BACKGROUND: Atypical antipsychotics, such as risperidone, have been shown to be more effective for the treatment of the symptoms of schizophrenia and have a greater beneficial effect on neurocognition compared to the conventional antipsychotics. The present study used [(15)O]H(2)O positron emission tomography imaging of regional cerebral blood flow to examine and compare the effects of haloperidol and risperidone on brain function. METHODS: Thirty-two subjects with schizophrenia participated in the study. Each subject was scanned in a medication-free state, and after being on a stable clinically assigned dose of either risperidone or haloperidol for 3 weeks. The off-medication scan was subtracted from the on-medication scan, using a within-subjects design. A randomization analysis was used to determine differences between the effects of haloperidol and risperidone on regional cerebral blood flow. RESULTS: Haloperidol was associated with a significantly greater increase in regional cerebral blood flow in the left putamen and posterior cingulate, and a significantly greater decrease in regional cerebral blood flow in frontal regions compared to risperidone. Risperidone was associated with a significantly greater decrease in regional cerebral blood flow in the cerebellum bilaterally compared to haloperidol. CONCLUSIONS: The results show that risperidone and haloperidol have significantly different effects on brain function, which may be related to their differences in efficacy and side effects. Further work is required to more precisely determine the mechanisms by which different antipsychotic medications exert their therapeutic effects on the clinical symptoms and cognition in schizophrenia. These findings emphasize the importance of controlling for both medication status and the individual antipsychotic in neuroimaging studies.     

Effect of intracarotid bradykinin infusion on cerebral blood flow in dogs

Abstract

We examined whether intracarotid infusion of bradykinin altered circulation in the normal canine brain. Twenty-four anesthetized dogs were divided into four groups receiving different doses of bradykinin (1, 2.5, 5, and 10 μg kg^–1 min^–1). Regional cerebral blood flow (rCBF) was measured continuously using laser Doppler flowmetry through a burr hole in the frontal bone. Systemic blood pressure (SBP) and heart rate (HR) were monitored simultaneously. Higher doses of bradykinin significantly but temporarily decreased rCBF and SBP immediately after the start of infusion; these parameters rapidly recovered and then were stable through the rest of the infusion. During this period, percent change in rCBF and SBP was small, and differences between groups were not significant. On the other hand, HR increased during infusion and remained high. SBP, rCBF, and HR returned to pre-infusion levels after bradykinin was stopped. The results suggest that intracarotid infusion of bradykinin for treatment of brain tumors would be safe in terms of circulation to the uninvolved brain. [Neurol Res 1999; 21: 791-795]     

Effect of intracarotid bradykinin infusion on cerebral blood flow in dogs

We examined whether intracarotid infusion of bradykinin altered circulation in the normal canine brain. Twenty-four anesthetized dogs were divided into four groups receiving different doses of bradykinin (1, 2.5, 5, and 10 micrograms kg-1 min-1). Regional cerebral blood flow (rCBF) was measured continuously using laser Doppler flowmetry through a burr hole in the frontal bone. Systemic blood pressure (SBP) and heart rate (HR) were monitored simultaneously. Higher doses of bradykinin significantly but temporarily decreased rCBF and SBP immediately after the start of infusion; these parameters rapidly recovered and then were stable through the rest of the infusion. During this period, percent change in rCBF and SBP was small, and differences between groups were not significant. On the other hand, HR increased during infusion and remained high. SBP, rCBF, and HR returned to pre-infusion levels after bradykinin was stopped. The results suggest that intracarotid infusion of bradykinin for treatment of brain tumors would be safe in terms of circulation to the uninvolved brain.