Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jan 1999
Effect of inhalational anesthesia on cerebral circulation in Moyamoya disease.
To clarify the effects of inhalational anesthesia on cerebral circulation in patients with Moyamoya disease, the authors measured regional cortical blood flow (CoBF), jugular bulb oxygen saturation (SjO2), and frontal regional oxygen saturation (rSO2) by near infra-red spectroscopy under total intravenous and inhalational anesthesia in 13 patients undergoing revascularization procedures. Cortical blood flow decreased in some regions under inhaled anesthesia in all cases, and the mean value decreased significantly (p<0.01). ⋯ Regional CoBF levels may be decreased by inhaled anesthesia in patients with Moyamoya disease, and such anesthesia may provoke intracerebral steal. Total intravenous anesthesia, however, lacked these effects.
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J Neurosurg Anesthesiol · Jan 1999
Comparative StudyEffects of postischemic halothane administration on outcome from transient focal cerebral ischemia in the rat.
This study examined the effect of prolonged postischemic halothane administration on outcome from transient focal cerebral ischemia in rats. Conscious normothermic rats were subjected to 75 minutes of filament middle cerebral artery occlusion (MCAO). Animals were then divided into two groups. ⋯ Cortical (Awake = 76+/-57 mm3; Halothane = 90+/-57 mm3; p = 0.494, mean +/- standard deviation), subcortical (Awake = 71+/-33 mm3; Halothane = 80+/-35 mm3; p = 0.472), and total (Awake = 147+/-88 mm3; Halothane = 171+/-91 mm3; p = 0.477) infarct volumes were not significantly different between groups. The data indicate that postischemic halothane administration offers no benefit in ameliorating damage from focal cerebral ischemia. This suggests that the neuroprotective effect of halothane observed in other studies is consistent with influences on intra-ischemic pathophysiology only.
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J Neurosurg Anesthesiol · Oct 1998
Clinical TrialVascular effects of etomidate administered for electroencephalographic burst suppression in humans.
Although its status as a neuroprotectant is controversial, etomidate is often employed for pharmacologic cerebral protection in aneurysm surgery. One purported advantage of etomidate over thiopental is its hemodynamic stability. This study examined the cardiovascular effects of etomidate given for electroencephalographic (EEG) burst suppression during cerebral aneurysm clipping in humans and the direct effects of etomidate on arteries in vitro. ⋯ Etomidate in vitro produced dose-dependent relaxation of human internal mammary arterial rings that had been preconstricted by potassium or norepinephrine. Etomidate, in EEG burst suppression doses, decreases mean arterial pressure in anesthetized patients undergoing cerebral aneurysm surgery. One mechanism of etomidate-induced hypotension may be direct relaxation of vascular smooth muscle, because etomidate directly dilates preconstricted human arteries in vitro.
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J Neurosurg Anesthesiol · Oct 1998
Cerebrovascular effects of high intracranial pressure after moderate hemorrhage.
Patients with head injuries often develop increased intracranial pressure after hemorrhage. The authors studied the effect of moderate hemorrhage followed by elevated intracranial pressure on cerebrovascular variables. Cerebral blood flow in 13 pigs was measured with laser Doppler flowmetry, and cerebral venous blood gases were taken from the sagittal sinus. ⋯ High intracranial pressure after hemorrhage decreased cerebral blood flow to 14% of baseline values. Sagittal sinus oxygen saturation decreased to 22%, cerebral perfusion pressure decreased to 30%, and the cerebrovascular resistance increased by 355%. The moderate hypotension after hemorrhage caused a considerable enhancement of the effects of high intracranial pressure on cerebral hemodynamics.
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J Neurosurg Anesthesiol · Oct 1998
Randomized Controlled Trial Clinical TrialModulation of somatosensory evoked potentials under various concentrations of desflurane with and without nitrous oxide.
Continuous measurement of somatosensory evoked potentials (SEP) by means of characteristic changes in the signal pattern makes it possible to identify cerebral or spinal cord ischemia during critical phases of the operative procedure. A correct interpretation of the measurements is only possible, however, if the influence of drugs acting on the central nervous system is known. The authors were able to show that inhaled anesthetics have an impact on latencies and response amplitudes. ⋯ When nitrous oxide is added, there were marked reductions in amplitude (p<0.01) of the cortical stimulus response (1.5 MAC = 2.4 +/- 0.9; 1.5 MAC/N2O = 1.1 +/- 1). It can therefore be recommended that supplementation with N2O should be avoided in the presence of low initial amplitudes. Based on the study's results, the use of desflurane (up to 1.0 MAC) seems to be compatible with intraoperative monitoring of median somatosensory evoked potentials.