Temporary trigeminal disorder as a result of pneumocephalus after subarachnoid block.
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A patient was scheduled for inguinal herniorrhaphy under subarachnoid block. Lumbar puncture was difficult and several attempts were needed before it could be achieved. During the immediate postoperative period, the patient developed paraesthesia and anaesthesia on the right side of the face, mostly in the nose, cheek and upper lip areas. A CT scan showed a small pneumocephalus at the level of the brainstem. The symptoms persisted for approximately 70 min, after which they disappeared. (+info)
Effect of thoracic epidural blockade on plasma fibrinogen levels in patients with dilated cardiomyopathy.
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OBJECTIVE: To investigate the effects of thoracic epidural blockade (TEB) on plasma fibrinogen (FIB) levels. METHODS: Thirty cases of dilated cardiomyopathy (DCM) were selected randomly into a TEB group and a control group. TEB patients were subjected to a persistent TEB (T1 - 5), and injected with 0.5% lidocaine 3 - 5 ml every two or four hours for four weeks in addition to routine medicine, while patients in the control group were given routine medicine only. Plasma concentrations of FIB were measured using the micro-capillary assay. Doppler echocardiography was performed before and after the treatment. RESULTS: Plasma concentrations of FIB in two groups were greater than the normal value before the treatment. There was a significant decrease of plasma concentrations of FIB in the TEB group after the treatment (4.2 +/- 1.3 g/L vs 3.6 +/- 0.9 g/L, P < 0.05), but there was no significant change in the control group (4.2 +/- 1.2 g/L vs 4.3 +/- 1.9 g/L, P > 0.05). After four weeks of treatment, the left ventricular end diastolic diameters (LVEDD) of TEB patients were reduced (72 +/- 10 mm vs 69 +/- 10 mm, P < 0.05) and the left ventricular ejection fraction (LVEF) of TEB patients increased significantly (33% +/- 13% vs 44% +/- 14%, P < 0.05). In contrast, LVEDD (73 +/- 11 mm vs 73 +/- 12 mm, P > 0.05) and LVEF (32% +/- 14% vs 33% +/- 12%, P > 0.05) did not change significantly in the control group. CONCLUSIONS: The results suggest that plasma FIB levels in patients with DCM were decreased by performing a TEB, in addition to a reduction of the enlarged cardiac cavity and an improvement in cardiac systolic dysfunction. TEB might contribute to lowering the occurrence of thrombus and thromboembolism in patients with DCM. TEB might be a promising therapeutic method to improve the prognosis of DCM patients. (+info)
THE EFFECTS OF BETHANIDINE ON THE PERIPHERAL CIRCULATION IN MAN.
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Bethanidine has been administered intra-arterially and intravenously into normotensive subjects and its effects on the limb blood vessels, arterial blood pressure, vascular sensitivity to noradrenaline and the degree and time course of sympathetic nerve blockade have been studied. The drug caused an initial constriction of hand and forearm vessels which is attributed to release of catechol amines since it is abolished by the prior administration of phenoxybenzamine. The constriction was followed by a sustained vasodilatation lasting between 5 and 20 hr. Sympathetic blockade of hand vessels commenced immediately on infusion and was complete within 1 hr of administration. Recovery occurred in about 5 hr. Sensitivity to intra-arterial noradrenaline was increased within 10 to 15 min of infusion and before sympathetic blockade was complete. Intravenous administration caused a slight rise in blood pressure of supine subjects. Baroreceptor reflex responses of heart and of limb vessels elicited by tilting the subject feet downwards were abolished by bethanidine and postural hypotension occurred. Bethanidine is a potent sympathetic blocking agent in man with properties intermediate between those of bretylium and guanethidine. (+info)
THE SYMPATHETIC POSTGANGLIONIC FIBRE AND THE BLOCK BY BRETYLIUM; THE BLOCK PREVENTED BY HEXAMETHONIUM AND IMITATED BY MECAMYLAMINE.
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Acetylcholine, in the presence of atropine, has an action like that of sympathetic stimulation. When injected into the splenic artery it causes contraction of the spleen, but this action is blocked by hexamethonium; stimulation of the splenic nerves, however, is still effective. Thus hexamethonium distinguishes between sympathetic nerve stimulation and the action of acetylcholine. If bretylium is used instead of hexamethonium, there is no such distinction, for bretylium blocks the response to nerve stimulation as well as that to acetylcholine. It appeared that hexamethonium might block the action of acetylcholine by preventing its entry into the sympathetic fibre. Acetylcholine has some structural similarity to bretylium, since acetylcholine is a derivative of trimethylammonium and bretylium is a derivative of dimethylethylammonium. It has been found that hexamethonium, pentolinium and hemicholinium (HC-3), which are all bis-quaternary compounds, block the action of bretylium, presumably by preventing its entry into the fibre. Consistent with the view that ability to enter the fibre is important is the observation that mecamylamine and pempidine, which are ganglion-blocking agents, but not either mono- or bis-quaternary compounds, often abolish the response to stimulation of the sympathetic postganglionic fibre. (+info)
THE ADRENERGIC-NEURONE BLOCKING ACTION OF SOME COUMARAN COMPOUNDS.
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Ethyldimethyl(7-methylcoumaran-3-yl)ammonium iodide (SK&F 90,109) and its guanidine analogue [N-(7-methylcoumaran-3-yl)guanidine nitrate] (SK&F 90,238) abolish the effects of adrenergic nerve stimulation in cats, as do xylocholine and bretylium. SK&F 90,109 has slight sympathomimetic actions; these are less marked than in SK&F 90,238. Large doses of SK&F 90,109 have an action, dependent on local noradrenaline stores, that delays the appearance of adrenergic-neurone blockade in conscious cats. Responses to adrenaline are, in general, enhanced by each drug, but SK&F 90,238 transiently antagonizes tachycardia induced by adrenaline and isoprenaline. Both drugs inhibit the release of noradrenaline from the spleen during splenic nerve stimulation, but the release of catechol amines from the adrenal glands, in response to electrical or chemical stimulation, is unimpaired. In contrast to the prolonged adrenergic-neurone blocking action, any inhibition of the effects of cholinergic nerve stimulation is transient. Large intravenous doses produce neuromuscular blockade. The compounds have a slight central depressant action. In contrast to reserpine and guanethidine the noradrenaline content of rat hearts is not appreciably lowered 24 hr after a single dose of either drug. Unlike xylocholine they are not local anaesthetics. Related compounds also block the effects of adrenergic-nerve stimulation. The possible modes of action of these drugs are discussed. (+info)
Persistence of pain induced by startle and forehead cooling after sympathetic blockade in patients with complex regional pain syndrome.
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BACKGROUND: Stimuli arousing sympathetic activity can increase ratings of clinical pain in patients with complex regional pain syndrome (CRPS). OBJECTIVE: To determine whether the increase in pain is mediated by peripheral sympathetic activity. METHODS: The effect of sympathetic ganglion blockade on pain evoked by a startle stimulus and cooling the forehead was investigated in 36 CRPS patients. RESULTS: Loss of vasoconstrictor reflexes and warming of the limb indicated that sympathetic blockade was effective in 26 cases. Before sympathetic blockade, pain increased in 12 of these 26 patients when they were startled. Pain increased in seven of the 12 patients and in another five cases when their forehead was cooled. As expected, pain that increased during sympathetic arousal generally subsided in patients with signs of sympathetic blockade. However, pain still increased in three of 12 of patients after the startle stimulus and in six of 12 of patients during forehead cooling, despite indisputable sympathetic blockade. CONCLUSIONS: These findings suggest that stimuli arousing sympathetic activity act by a central process to exacerbate pain in some patients, independent of the peripheral sympathetic nervous system. This may account for the lack of effect of peripheral sympathetic blockade on pain in some CRPS patients. (+info)
Autonomic control of cardiovascular functions during neonatal development and in adult sheep.
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We studied the autonomic control of resting heart rate of systemic and pulmonary vascular blood pressures (BP) in chronically instrumented neonatal lambs 1-8 weeks of age. The maximum response to ganglionic blockade and sympathetic and parasympathetic antagonists was taken as an index of the magnitude of the total neural, adrenergic, and cholinergic tones. The reactivity of the circulatory parameters to adrenergic and cholinergic agonists also was investigated. All findings were compared with those in adult nonpregnant sheep studied concomitantly and with data previously obtained from term fetal lambs. The results of our studies show: (1) resting heart rate declines spontaneously throughout the 8 weeks of neonatal life approaching that of adult sheep; (2) the progressive bradycardia is not related to changes in the parasympathetic or sympathetic tone; (3) resting systemic BP is under strong neurohumoral control during the first two to three weeks of neonatal life; the control decreases progressively, becoming similar to that of adult sheep; (4) resting pulmonary artery pressure of neonatal and adult sheep has no neurohumoral control; (5) the systemic BP response of the neonate to autonomic agonists is greater than that of the term fetus and is similar to that of the adult; (6) in neonatal and adult sheep, compared to the term fetus, the pressor response to norepinephrine is accompanied by a baroreceptor-mediated bradycardia, and acetylcholine-induced systemci hypotension is accompanied by a "paradoxical" tachycardia mediated through beta-adrenergic stimulation; (7) in contrast to our finding for the fetus, the pulmonary vascular pressure of neonatal and adult sheep is unresponsive to autonomic agonists. (+info)
Characteristics of autonomic nervous function in Zucker-fatty rats: investigation by power spectral analysis of heart rate variability.
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We investigated the characteristics of autonomic nervous function in Zucker-fatty and Zucker-lean rats. For this purpose, a long-term electrocardiogram (ECG) was recorded from conscious and unrestrained rats using a telemetry system, and the autonomic nervous function was investigated by power spectral analysis of heart rate variability (HRV). Although heart rate (HR) in Zucker-fatty rats was lower than that in Zucker-lean rats throughout 24 h, apparent diurnal variation in HR was observed in both strains and HR during the dark period was significantly higher than that in light period. Diurnal variation in locomotor activity (LA) in Zucker-fatty rats was also observed, but LA was lower than that in Zucker lean rats, especially during the dark period. There were no significant differences, however, in high-frequency (HF) power, low-frequency (LF) power, and the LF/HF ratio between Zucker-fatty and Zucker-lean rats. The circadian rhythm of these parameters was mostly preserved in both strains of rats. Moreover, the effect of autonomic blockades on HRV was nearly the same in Zucker-fatty and Zucker-lean rats. These results suggest that the autonomic nervous function of insulin-resistant Zucker-fatty rats remain normal, from the aspect of power spectral analysis of HRV. (+info)