Koukichi Kurehara

Postoperative neurological deterioration following the revascularization surgery in children with moyamoya disease.

We describe four children with moyamoya disease who developed neurologic deterioration following revascularization surgery. In all cases, anesthesia was smoothly induced and the intraoperative course was uneventful. Emergence from anesthesia was prompt and no new neurological deficit was observed. However, the children suffered strokes on 2, 4, 5, and 10 days, postoperatively, respectively. Dehydration and crying were thought to be closely associated with the stroke in each case. This report suggests that attention should be paid during entire the perioperative period to avoid stroke in patients with moyamoya disease.

Cortical blood flow response to hypercapnia during anaesthesia in Moyamoya disease

Cortical blood flow (CoBF) was measured continuously by the laser-Doppler method to evaluate the effect of hypercapnia on cortical blood flow during ten surgical procedures in ten young patients (mean ± SD 9.3 ± 6.4 yr) with Moyamoya disease. The CoBF was 42.8 ± 13.4 (ml·100 g−1. min−1) during normocapnia (PaCO2 = 39.0 ± 2.4 mmHg), and 38.7 ± 14.4 during hypercapnia (PaCO2 = 47.1 ± 2.5 mmHg). There was a decrease in CoBF with hypercapnia (P < 0.05) so that the normal CoBF response to hypercapnia was impaired during surgery in the patients with Moyamoya disease. He concluded that patients with Moyamoya disease have a precarious cerebral circulation and hypercapnia may be detrimental to the cortical circulation. This suggests that normocapnia is preferable to hypercapnia in patients with Moyamoya disease during anaesthesia.RésuméPendant dix interventions chirurgicales pratiquées chez dix jeunes patients (âge moyen 9,3 ± 6,4 ans) souffrant de la maladie de Moyamoya, le débit sanguin cortical (DSCo) est mesuré continuellement par la méthode Laser-Doppler dans le but d’évaluer les effets de l’hypercapnie sur le débit sanguin cortical. Le DSCo (ml·100 g−1· min−1) est de 42,8 ± 13,4 pendant la normocapnie (PaCO2 = 39,0 ± 2,4 mmHg) et de 38,7 ± 14,4 pendant l’hypercapnie (PaCO2 = 47,1 ± 2,5 mmHg). La baisse du débit pendant hypercapnie est significative (P < 0,05). Ce qui démontre que la réponse du débit sanguin cérébral est perturbée pendant la chirurgie de la maladie de Moyamoya. On conclut que cette maladie a une influence néfaste sur la circulation cérébrale pendant l’hypercapnie. Ceci suggère que dans la maladie de Moyamoya, la normocapnie est préférable à l’hypercapnie.

Effects of nicardipine on cerebral vascular responses to hypocapnia and blood flow velocity in the middle cerebral artery.

We noninvasively evaluated the effects of nicardipine on cerebral vascular responses to hypocapnia and blood flow velocity in the middle cerebral artery of 10 patients aged 17-60 (mean +/- SD 46.1 +/- 11.8) years. During fentanyl/diazepam/nitrous oxide anesthesia, mean blood flow velocity in the middle cerebral artery was measured and cerebral vascular reactivity to hypocapnia induced by hyperventilation was assessed before and during the administration of nicardipine. Mean blood flow velocity was measured using transcranial Doppler ultrasonography, and the cerebral vascular reactivity was expressed as the percentage change in mean blood flow velocity per unit change in end-tidal PCO2. During the administration of 5.1 +/- 1.3 micrograms/kg/min nicardipine, which caused a 26% reduction in mean arterial blood pressure, mean blood flow velocity increased significantly from 57.2 +/- 19.2 to 64.2 +/- 21.6 cm/sec (p less than 0.01, paired t test), whereas cerebral vascular reactivity showed no significant change (4.0 +/- 1.2% and 4.9 +/- 2.5%, respectively). In conclusion, during fentanyl/diazepam/nitrous oxide anesthesia in patients, cerebral vascular reactivity to hypocapnia was maintained and nicardipine-induced hypotension resulted in increased middle cerebral artery blood flow velocity with maintenance of carbon dioxide reactivity to hypocapnia.

Mild hypothermia can attenuate nitroglycerin-induced vasodilation of pial arterioles in the cat.

The purpose of the present study was to investigate the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels. The cranial window technique, combined with microscopic video recording, was used in an experiment involving 26 cats anesthetized with isoflurane. Animals were randomly assigned to either a normothermic or a mildly hypothermic group (33[degree sign]C). We administered three different concentrations of nitroglycerin (10-6, 10-5, 10-4 M) under the window and measured the diameter of small (<100 [micro sign]m) and large (100-200 [micro sign]m) pial arterioles. In the normothermic group (n = 13), nitroglycerin produced a significant dilation of both small and large arterioles in a dose-dependent manner. In the hypothermic group (n = 13), a significant dilation of arterioles was observed only after topical application of nitroglycerin at a concentration of 10-4 M. The percent increase in diameter of small and large arterioles was less in the hypothermic group than the normothermic group. Our in vivo study demonstrates that topically applied nitroglycerin produces a dose-dependent dilation of pial arterioles in normothermic cats anesthetized with isoflurane, but the reduction of temperature to 33[degree sign]C significantly attenuates nitroglycerin-induced vasodilation of pial arterioles. Implications: Although nitroglycerin may be used in hypothermic patients, the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels is unknown. In this study, we investigated the effects of nitroglycerin on pial arteriolar diameter in normothermic and hyperthermic cats. Hypothermia was found to attenuate nitroglycerin-induced vasodilation. (Anesth Analg 1998;86:546-51)

Evaluation of relatively low dose of oral transmucosal ketamine premedication in children: a comparison with oral midazolam

Background : Oral Transmucosal ketamine (lollipop) has been shown to be an effective, harmless preoperative medication for children. However, its efficacy was not compared with commonly used premedication drugs. We, therefore, compared the efficacy of oral transmucosal ketamine with oral midazolam for premedication in children.

Mild hypothermia can enhance pial arteriolar vasodilation induced by isoflurane and sevoflurane in cats.

ObjectiveVolatile anesthetics have been shown to dilate cerebral vessels. Recent evidence suggests that mild hypothermia can alter vascular reactivity of the cerebral vessels. However, the effect of mild hypothermia on volatile anesthetic-induced vasodilation of cerebral vessels is unknown. In the present study, we investigated the effect of mild hypothermia on pial arteriolar vasodilation induced by isoflurane and sevoflurane in cats. DesignProspective, randomized, experimental study with repeated measures. SettingInvestigational animal laboratory. SubjectsForty cats were used for the study of systemic administration of volatile anesthetics, and 22 cats were used for the study of topical administration of volatile anesthetics. InterventionsThis study was approved by the Animal Experiment Committee of Nara Medical University. Animals were anesthetized with pentobarbital to maintain suppressive electroencephalographic patterns, which were introduced to measure direct effects of anesthetic agents after removing metabolic effects. The cranial window technique, combined with microscopic video recording, was used for the measurement of small (50–100 &mgr;m) and large (100–200 &mgr;m) pial arteriolar diameter in an experiment. Animals were randomly assigned to either a normothermic (37°C) or a hypothermic group (33°C). Desired temperatures were maintained by using a water blanket. In the first phase of the study, the effect of hypothermia on pial arteriolar vasodilation induced by systemic administration of isoflurane or sevoflurane was assessed. Each cat received isoflurane or sevoflurane at 0.5, 1.0, 1.5, and 2.0 minimum alveolar anesthetic concentrations, and the diameter of pial arterioles was measured. In the second group of animals, the direct effect of isoflurane and sevoflurane on pial vessels was evaluated. The artificial cerebrospinal fluid bubbled with isoflurane or sevoflurane (minimum alveolar anesthetic concentrations of 1 or 3) was topically administered in the cranial window. Measurements and Main ResultsSystemic and topical administration of isoflurane and sevoflurane produced significant dilation of both small and large pial arterioles in a dose-dependent manner during normothermia. In the hypothermic group, vasodilation of small pial arterioles by systemic administration of isoflurane and sevoflurane at a high concentration was significantly larger than in the normothermic group (p < .05). Vasodilation of both small and large pial arterioles by topical administration of isoflurane and sevoflurane was significantly greater in the hypothermic group than in the normothermic group (p < .05). ConclusionsThese results suggest that pial arteriolar vasodilation induced by isoflurane and sevoflurane can be enhanced by mild hypothermia in cats anesthetized with pentobarbital.

Effect of mild hypothermia on nicorandil-induced vasodilation of pial arterioles in cats

Objective Nicorandil is characterized as hybrid between nitrates and potassium channel activators. Recent evidence suggested that mild hypothermia may alter cerebral vasodilation induced by a nitrate agent and potassium channel opener. However, the effect of mild hypothermia on nicorandil-induced vasodilation is not known. The present study was conducted to investigate whether mild hypothermia could alter nicorandil-induced cerebral vasodilation. In addition, the effects of mild hypothermia on cerebral vasodilation induced by nitroglycerin, a nitrate agent, and cromakalim, a selective adenosine 5′-triphosphate-sensitive potassium channel opener, were assessed in the same model. Design Prospective, randomized, experimental study with repeated measures. Setting Investigational animal laboratory. Subjects Twenty-four cats. Interventions Animals were anesthetized with pentobarbital. The cranial window technique, combined with microscopic video recording, was used to measure small (50–100 &mgr;m) and large (100–200 &mgr;m) pial arteriolar diameter in an experiment. Animals were assigned randomly to either a normothermic (37°C) or a hypothermic (33°C) group. Nicorandil, nitroglycerin, or cromakalim at concentrations of 10−8, 10−6, or 10−4 mol/L was applied topically in the cranial window, and the diameter of pial arterioles was measured. Measurements and Main Results Topical administration of nicorandil, nitroglycerin, and cromakalim significantly dilated both small and large pial arterioles in a dose-dependent manner during normothermia. Nicorandil-induced vasodilation of either large or small pial arterioles was not affected by hypothermia. However, hypothermia significantly attenuated nitroglycerine-induced vasodilation in both large and small pial arterioles and enhanced cromakalim-induced vasodilation in both large and small pial arterioles. Conclusions Nicorandil-induced vasodilation of cerebral pial arterioles was not affected by mild hypothermia. By contrast, mild hypothermia significantly attenuated nitroglycerin-induced vasodilation and enhanced cromakalim-induced vasodilation.

Use of transesophageal echocardiography probe imaging to guide internal jugular vein cannulation

T ransesophageal echocardiography (TEE) is widely used during cardiac or other surgeries for the evaluation of cardiac structure and function. Central venous catheterization is also an essential part of patient management in many of these cases. Cannulation through the internal jugular vein (IJV) is preferred for central venous access, and it is usually achieved by using a blind, external landmark-guided technique (1). Many reports indicate the use of percutaneous ultrasound-assisted IJV cannulation (2-4). However, there have been no reports using TEE during IJV cannulation. In this report, we present three cases in which TEE probe imaging was effective in guiding IJV cannulation.