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K Kitaguchi

Publications and source records attributed to K Kitaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Hypothermia attenuates the vasodilatory response of pial arterioles to hemorrhagic hypotension in the cat.

UNLABELLED: We investigated the effect of hypothermia on the vasodilatory response of pial arterioles to hemorrhagic hypotension. The cranial window technique was combined with microscopic video recording in an experiment involving 20 cats anesthetized with pentobarbital. The animals were randomly assigned to either a normothermic or a hypothermic group (32 degrees C). Mean arterial pressure (MAP) was reduced in stepwise increments of 10 mm Hg (from 100 to 50 mm Hg) by blood withdrawal. The diameter of small (50-100 microm) and large (100-200 microm) pial arterioles was measured. In the normothermic group (n = 9), small and large arterioles dilated at a MAP of 60 and 50 mm Hg, and at a MAP of 70, 60, and 50 mm Hg, respectively, compared with baseline values obtained at a MAP of 100 mm Hg. In contrast, in the hypothermic group (n = 11), vasodilation of either small or large arterioles was absent. The percentage diameter of small and large arterioles (percentage of control) was significantly lower at a MAP of 70, 60, and 50 mm Hg in the hypothermic group than the normothermic group. Our in vivo study demonstrates that hypothermia impairs autoregulatory vasodilation of pial arterioles in response to hemorrhagic hypotension. IMPLICATIONS: Deliberate mild hypothermia has been proposed as a means of providing cerebral protection during neurosurgical procedures. Our results suggest that cerebral blood flow autoregulation in response to hemorrhagic hypotension may be impaired during hypothermic conditions, indicating the importance of maintaining perfusion pressure during hypothermic therapy to prevent cerebral ischemia.

Animals↗
PubMed2000

[Optimal dose of indocyanine-green injected from the peripheral vein in cardiac output measurement by pulse dye-densitometry].

Cardiac output is measured by pulse dye-densitometry using indocyanine-green (ICG). This cardiac output is estimated by correlating with the cardiac output measured by pulmonary artery catheter using thermodilution method. Twenty-four patients scheduled for elective cardiovascular surgeries under general anesthesia were studied. The pulse dye-densitometry monitoring system used was DDG-2001 (Nihon Kohden, Japan). In group A (13 patients: 19 times), ICG was administered from the peripheral vein as bolus doses of 5, 10 or 20 mg (5 mg.ml-1 water solution). In group B (11 patients: 12 times), ICG was administered from the peripheral vein as bolus doses of 20, 10 or 5 mg (5 mg.ml-1 water solution). The correlation (Pearson's correlation coefficient) and precision (the method proposed by Bland and Altman) compared with cardiac output measured by pulmonary artery catheter were examined. Better correlation and precision were recognized after 20 mg ICG injection than 5 or 10 mg ICG injection. In conclusion, the measurement of cardiac output by pulse dye-densitometry with peripheral vein ICG injection was useful using a bolus dose of ICG 20 mg.

Aged↗
PubMed2000

[Intraoperative motor evoked potential monitoring: a review of 115 cases].

We reviewed our experiences of intraoperative motor evoked potentials (MEPs) monitoring for 115 operations on the spine or spinal cord. We observed compound muscle action potentials from bilateral anterior tibial muscles by electrical transcranial stimulation of the motor cortex under general anesthesia induced and maintained with intravenous anesthetics (ketamine, propofol, or droperidol), fentanyl, and 50% nitrous oxide. Partial neuromuscular blockade was obtained with continuous infusion of vecuronium. MEPs were recorded bilaterally in 91 cases (79%) and laterally in 18 cases (16%). Postoperative deterioration of motor function was observed in 2 cases and amplitude of MEPs decreased more than 50% of control values in both cases. Intraoperative monitoring of MEPs might be a reliable indicator of spinal cord motor function.

Adult↗
PubMed2000

[Monitoring of motor evoked potentials during insertion of iliosacral screws for reconstruction of pelvic fracture in two patients].

Monitoring of myogenic motor evoked potentials (MEPs) induced by transcranial electrical stimulation has become a promising tool for intraoperative monitoring. We described 2 patients who had developed significant decrease in MEP during the insertion of iliosacral screws for reconstruction of pelvic fractures. In both patients, MEPs were successfully obtained prior to the insertion under general anesthesia and partial neuromuscular blockade (propofol, ketamine, fentanyl, and nitrous oxide in oxygen: vecuronium), but reduced in association with the insertion. In one patient, they were restored by the re-insertion of screw and no new neurological deficits were observed postoperatively. However, in another patient, the decrease was not normalized and he suffered from paresis of the lower extremities after the surgery. We consider that intraoperative changes in MEPs could precisely predict postoperative motor function.

Aged↗
PubMed2000

[Relationship between changes in estimated and measured blood concentrations of propofol and serum albumin concentration during propofol anesthesia: effects of intraoperative bleeding (a case report)].

We investigated the effect of intraoperative bleeding on the changes in estimated and measured blood concentrations of propofol, and the relationship between anesthetic effect of propofol and serum albumin concentration in a patient undergoing prostatectomy during propofol/epidural anesthesia. The rate of propofol infusion was titrated to keep the BIS value about 50. The estimated blood concentration of propofol calculated by ConGrase, a program for on-line simulation of blood propofol concentration, was monitored during anesthesia. Blood samples were obtained at nine points during surgery and the blood concentrations of propofol and albumin were measured postoperatively. When the amount of bleeding reached about 2000 mg, the difference between estimated and measured blood concentrations of propofol did not increase. As the serum albumin concentration decreased, the concentration of propofol to keep bispectral index about 50 decreased. This study suggests that the change in serum albumin concentration following intraoperative bleeding is an important factor in the anesthetic effect of propofol.

Aged↗
PubMed2000

[Differences in hemodynamic effects of amrinone, milrinone and olprinon after cardiopulmonary bypass in valvular cardiac surgery].

The differences in hemodynamic effects of amrinone, milrinone and olprinone were evaluated in 46 patients for valvular cardiac surgery after cardiopulmonary bypass (CPB). Patients were randomly allocated to three groups; group A with amrinone infusion (17 patients); group M with milrinone infusion (15 patients); and group O with olprinone infusion (14 patients). Each drug was administrated as a single dose into the venous reservoir of the CPB circuit 15 min prior to the end of emergence from CPB, followed by continuous infusion. Hemodynamic parameters were measured at the time of preCPB (C0), just after the end of CPB (C1), one hour after the termination of CPB (C2) and after the chest closure (C3). Catecholamines were used in order of dopamine, norepinephrine and dobutamine. These doses were modulated to maintain the cardiac index > 3.0 l.min-1.m-2 by each anesthesiologist. Hemodynamic parameters (at C0, C1, C2 and C3) and the doses of cathecholamine (at C1, C2 and C3) were compared among the 3 drugs. The systolic blood pressure in group M was significantly higher than that of group A and group O after chest closure. In group M and A, the systolic blood pressure showed a significant increase after CPB. On the other hand, the systolic blood pressure showed no significant change in group O after CPB. Three drugs showed no significant difference in the dosages of catecholamines used.

Aged↗
PubMed2000

[Two cases of ischemic changes indicated in the amplitude of motor evoked potentials during thoracoabdominal aortic aneurysm repair].

Monitoring of motor-evoked potentials (MEPs) is employed to examine functional integrity of descending motor pathway during thoracic aortic surgery. We experienced two cases of intraoperative changes in MEPs during thoracic aortic replacement. In one case, MEPs recovered after the intercostal artery reattachment, and in another case after the release of aortic clamping. No postoperative paraplegia was found in both cases. We conclude that monitoring of MEPs is useful not only because we can detect symptoms of the spinal cord injury from ischemia immediately but also because they give us a clue to decide operative procedures.

Aged↗
PubMed1999

[Effect of deliberate mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization in neurosurgical patients].

We investigated the effect of mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization, retrospectively. We randomly assigned 173 patients undergoing intracranial operation to mild hypothermic group (group H) of 122 patients or normothermic group (group N) of 51 patients. A water blanket and a convective device blanket were used for thermal control in the both groups. The temperature at the tympanic membrane was adjusted to 34.5 degrees C in group H and 36.0 degrees C in group N. Surgical-wound infection was found in 4 of 122 patients (3.3%) of group H but in none of 51 patients (0%) of group N. The duration of hospitalization was 36.0 +/- 25.5 days in group H and 40.2 +/- 36.9 days in group N. There were no statistical differences of the incidence of surgical-wound infection and duration of hospitalization between the two groups. However, the duration to suture removal was significantly longer in group H than in group N (8.3 +/- 1.6 vs 7.8 +/- 0.8 days). Although the effects of deliberate mild hypothermia for neurosurgery on the incidence of surgical-wound infection and duration of hospitalization were little, it may affect the recovery process of such patients.

Adult↗
PubMed1999

[The effect of intraoperative mild hypothermia on the development of perioperative cardiac ischemia].

We evaluated the risk of perioperative cardiac ischemia associated with mild hypothermia as adjunct management for neurosurgical procedures. Forty-seven elective neurosurgical patients were randomly assigned to either hypothermic group (H, n = 24) or normothermic one (N, n = 23). Patients in group H were cooled to and maintained at 34.5 degrees C (tympanic membrane temperature) and rewarmed after main neurosurgical manipulation, while those in group N were kept in normothermic state. Cardiac ischemia was diagnosed with Holter electrocardiogram monitored for 24 hours after admission to the operating room. No differences were observed in demographic data including age, gender, weight, height, rate of having cardiac disease, anesthesia methods, and contents of surgery. Temperature was significantly lower in group H than N both at the lowest point (34.6 +/- 0.5 vs 35.9 +/- 0.6, mean +/- SD) and at the conclusion of anesthesia (35.9 +/- 0.9 vs 36.5 +/- 0.5). Electrocardiographic ST segmental depression was observed in 3 (group H) and 5 cases (group N), and postoperative shivering occurred in 3 (group H) and 2 cases (group N), respectively. Those incidences were not statistically significant (chi-square test, P was set at 0.05). We concluded that intraoperative mild hypothermia might not increase the risk of perioperative cardiac ischemia in patients for neurosurgical procedures.

Adult↗
PubMed1998

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

UNLABELLED: 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 degrees 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 microm) and large (100-200 microm) 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 degrees 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.

Animals↗
PubMed1998

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.

Brain↗
PubMed1998

The effect of sevoflurane on myogenic motor-evoked potentials induced by single and paired transcranial electrical stimulation of the motor cortex during nitrous oxide/ketamine/fentanyl anesthesia.

To overcome anesthetic-induced depression of myogenic motor-evoked potentials (MEPs), several techniques of stimulation using paired pulses or trains of pulses are used. This study investigated the effect of sevoflurane on myogenic MEPs induced by single and paired transcranial electrical stimulation of the motor cortex. Nine patients undergoing elective spinal surgery were anesthetized with fentanyl-N2O-ketamine. Partial neuromuscular blockade (single-twitch height 15% of baseline) was maintained with vecuronium. Single and paired (interstimulus interval 2 milliseconds) electrical stimuli were delivered to the scalp, and compound muscle action potentials were recorded from the left and right tibialis anterior muscles. In all patients, baseline MEPs were recorded from both the left and right anterior tibialis muscles (in a total of 18 legs). During the administration of 0.25 MAC and 0.5 MAC sevoflurane, MEPs induced by stimulation with a single pulse could be recorded in 12 of 18 and 4 of 18 legs, respectively, and MEP amplitude was significantly reduced to 48% and 4% of the control value, respectively. During the administration of 0.75 MAC sevoflurane, MEPs following single-pulse stimulation could not be recorded in any legs. The success rate of MEP recording during the administration of sevoflurane was greater after paired stimulation than after single stimulation, and percentage MEP amplitude (percentage of the control value after single stimulation but before sevoflurane) after paired stimulation was significantly higher than after single stimulation before and during the administration of 0.25 MAC and 0.5 MAC sevoflurane. The success rate of MEP recording and MEP amplitude after paired stimulation decreased in a dose-dependent manner during the administration of sevoflurane. These results suggest that although facilitation by the second stimulus was considerable, paired stimuli are still not sufficient to overcome the depressant effects of sevoflurane in clinically used concentrations.

Action Potentials↗
PubMed1998

[Analysis of postoperative shivering following the deliberate mild hypothermia during neurosurgery].

We induced deliberate mild hypothermia in 96 patients who underwent intracranial operations using a water blanket and a convective device blanket. The lowest temperature measured at the tympanic membrane during mild hypothermia was adjusted to 34.5 degrees C. The patients were divided into two groups in respect to the occurrence of postoperative shivering, and the relationship between the perioperative parameters and the occurrence of postoperative shivering was evaluated. Shivering was observed postoperatively in 29 to 96 patients (30.2%). In the group with shivering (SV), age was significantly lower and body weight and body surface area were significantly larger than the group without shivering (NSV). Urinary output was significantly larger in SV than in NSV. Tympanic membrane, nasopharyngeal, and rectal temperatures at the end of surgery and nasopharyngeal, rectal, and peripheral temperatures just after the extubation were significantly lower in SV than in NSV. These results suggest that sufficient rewarming of both the core and peripheral temperatures is important to prevent the postoperative shivering following the mild hypothermic therapy in neurosurgical patients, especially in young patients.

Adult↗
PubMed1997

Risk factors for neurologic deterioration after revascularization surgery in patients with moyamoya disease.

UNLABELLED: To investigate the risk factors for postoperative neurological deterioration in patients with moyamoya disease, we retrospectively reviewed the perioperative course of 368 cases of revascularization surgery in 216 patients with this disease. Risk factors anecdotally associated with postoperative ischemic events were analyzed by comparing groups with or without a history of such events on the operative day. Ischemic events were noted in 14 cases (3.8%), 4 of which were defined as strokes and the others as transient ischemic attack (TIA). Postoperative neurological deterioration more often developed in patients who suffered from frequent TIAs, had precipitating factors for TIA, and underwent indirect nonanastomotic revascularization. The authors conclude that the incidence of postoperative ischemic events were related more to the severity of moyamoya disease and the type of surgical procedure than to other factors, including anesthetic management. IMPLICATIONS: Although preventing stroke is the major concern for patients with moyamoya disease, risk factors for perioperative cerebral ischemia have not been clarified. We retrospectively analyzed the perioperative course in 368 cases with this disease and found that the severity of the disease and type of surgical procedure were major determinants of postoperative cerebral ischemia.

Adolescent↗