Biomedical subjects

K Kitaguchi

Publications and source records attributed to K Kitaguchi.

At least 55 records · Page 3Linked to original sources

PubMed1997

[Effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass in patient undergoing coronary bypass surgery].

We evaluated the effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass (CPB) in patient undergoing coronary bypass surgery comparing with the patients not receiving amrinone. In amrinone treated patients bolus dose of amrinone 1.5 mg.kg-1 was administrated into the reservoir of CPB and followed by continuous infusion at a rate of 5 micrograms.kg-1.min-1. Hemodynamics and blood gas (arterial and mixed venous) measurements were carried out immediately after CPB, 1 hour after CPB and after the chest closure. After the chest closure, cardiac index and oxygen supply in amrinone treated group were significantly higher and systemic vascular resistance was significantly lower than in non-treated group. Left ventricular stroke work index, rate pressure product and oxygen consumption showed no significant difference between the two groups. These data indicate that the amrinone treated patients preserved better oxygen demand-supply relationship after CPB compared with the non-treated patients undergoing coronary bypass surgery.

Amrinone↗

PubMed1996

Nitric oxide involvement in hypoxic dilation of pial arteries in the cat.

BACKGROUND: The reactivity of cerebral arteries to different stimuli varies according to vessel size. Whether nitric oxide mediates hypoxic vasodilation is controversial. The authors considered this question by measuring the diameter of pial arteries and arterioles with or without exposure to the nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME). METHODS: The cranial window technique, combined with microscopic video recording, was used in an experiment involving 20 cats anesthetized with fentanyl and midazolam. The diameters of pial arteries and arterioles were measured under the following conditions: (1) normoxia (PaO2 > 100 mmHg); (2) hypoxia (PaO2 < 45 mmHg); (3) normoxia with L-NAME infusion; and (4) hypoxia with L-NAME infusion. Changes in vessel diameter were analyzed with respect to artery size. RESULTS: Under hypoxic conditions, arteries and arterioles smaller than 200 microns were dilated significantly (P < 0.05). In arterioles smaller than 200 microns, L-NAME attenuated this hypoxic vasodilation (P < 0.05). In contrast, under normoxic conditions, L-NAME caused significant vasoconstriction in arteries larger than 100 microns but not in arteries smaller than 100 microns. CONCLUSIONS: Arteries and arterioles smaller than 200 microns are dilated by hypoxia, and nitric oxide contributes to this process. Nitric oxide synthesis may also be related to the regulation of resting vascular tone in arteries larger than 100 microns.

Animals↗

PubMed1996

[Effects of prostacyclin (PGI2) on pial vessel diameter and carbon-dioxide reactivity in cats].

We studied the effects of prostacyclin (PGI2) on the pial vessel diameter (D) and CO2 reactivity in cats. Nineteen cats, weighing 1.6-4.0 kg, were divided into two groups; PGI2 administration group (n = 10) and the control group (n = 9). The animals were anesthetized with midazolam, fentanyl, pancuronium and nitrous oxide/oxygen and ventilated mechanically. The pial vessels diameter (D) was classified into 4 groups (D < 50 microns, 50 < or = D < 100 microns, 100 < or = D < 200 microns, D > 200 microns). The vascular dynamics was examined through the closed cranial window with intravital epifluorescence microscopy on which a video camera was mounted. The measurements were carried out under the steady state of hypo-, normo-, and hypercarbia, respectively and the CO2 reactivity (delta %D/delta CO) was calculated. Under the induced hypotension with PGI2 (30% reduction in mean arterial pressure), pial vessels were significantly dilated, but there was no change in CO2 reactivity in terms of vessels diameter. The vessels with diameters of less than 50 microns were more dilated compared with those with larger diameters. We concluded that pial arterioles were dilated with PGI2 but it had no effects on CO2 reactivity.

Animals↗

PubMed1996

[Anesthetic management for a patient with pheochromocytoma using magnesium sulfate and epidural block].

A 54-year-old woman with pheochromocytoma was anesthetized using magnesium sulfate infusion. Anesthesia was induced with thiopental and fentanyl, and maintained with 0.5% sevoflurane in nitrous oxide/oxygen and 60 mg.hr-1 of epidurally infused lidocaine. Muscle relaxation was achieved with intermittent administration of vecuronium under neuromuscular monitoring. Magnesium 2 g was infused prior to the tracheal intubation and followed by continuous infusion of 2 g.hr-1. These anesthetic techniques made hemodynamic state stable, and no additional vasoactive agents were needed. However, the infusion rate of magnesium was reduced to a half because of PQ interval prolongation. Magnesium is believed to be useful for anesthetic management for patients with pheochromocytoma, but the proper dose and the way of administration should be further investigated for their safe clinical use.

Adrenal Gland Neoplasms↗

PubMed1994

Internal jugular bulb blood velocity as a continuous indicator of cerebral blood flow during open heart surgery.

BACKGROUND: Most techniques for measuring cerebral blood flow (CBF) can not be performed rapidly enough to detect sudden changes in CBF. However, measurement of internal jugular bulb (IJB) blood velocity may offer real-time information on changes in CBF. In the current study, we measured IJB blood velocity and CBF in anesthetized humans. METHODS: In protocol 1, IJB blood velocity was continuously measured using an intravascular Doppler catheter during cardiac surgery under hypothermic cardiopulmonary bypass (CPB). CBF values obtained with a Kety-Schmidt method using inhalation of 30% argon in oxygen gas were compared with concurrent IJB blood velocity values in ten patients. A 3-French intravascular Doppler catheter was placed in the right IJB, and CBF measurements were made before CPB, in a stable hypothermic period during CPB, at rewarming during CPB, and after CPB. In protocol 2, dimensions of right IJB were observed before and during CPB using an intravascular rotating A scan ultrasonic catheter (5-French) in three patients. RESULTS: IJB blood velocity responded quickly to changes in arterial pressure or body temperature during CPB. The percent change in IJB blood velocity relative to pre-CPB value showed a good linear correlation with the percent change in CBF (%CBF = 0.87 x %IJB velocity + 17, r = 0.87). The mean difference between percent changes in CBF and IJB blood velocity was -5.6% and the standard deviation was 16%. Despite a large reduction in arterial pressure or IJB pressure, there were no significant changes in the IJB dimension. CONCLUSIONS: The results suggest that IJB blood velocity may represent a clinically useful monitor of changes in CBF in anesthetized humans.

Aged↗

PubMed1994

[Anesthetic management and neurological outcomes of patient for open heart surgery with infective endocarditis and neurological complications].

No reports have focused on neurological outcomes after open heart surgery of patients with infective endocarditis (IE) and neurological complications. We evaluated parameters related to anesthetic management and neurological outcomes. The subjects analyzed were 24 patients who had undergone valvular surgeries under hypothermic cardiopulmonary bypass from April 1978 to December 1990. The patients were divided into two groups according to the interval between onset of neurological complication and the time of operation: 1) acute group (within one month before the surgery: n = 11, 9.4 +/- 9 days; means +/- SD) and 2) chronic group (more than one month before the surgery: n = 13, 120 +/- 80 days). After heart surgery, 5 patients in the acute group showed newly developed neurological abnormality including death from hemorrhagic transformation, hemiplegia or aphasia. No patients in the chronic group had newly developed neurological abnormality related to the surgery. In the neurologically deteriorated patients of the acute group, interval from the onset of neurological complication to surgery was 3.5 +/- 4.5 days, whereas that of the remainders of the acute group was significantly longer (14.4 +/- 9.0 days). Intraoperative events and anesthetic management of these patients were also analyzed. However, there were no significant differences in the parameters such as cerebral perfusion pressure, arterial PaCO2, doses of anesthetics and use of vasopressors. Our results suggest that the most important factor which may influence neurological outcome was the interval between the onset of neurological abnormality and the time of operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Effects of sevoflurane on cerebral circulation and metabolism in patients with ischemic cerebrovascular disease.

BACKGROUND: Sevoflurane is a newly developed volatile anesthetic that has a low blood-gas partition coefficient. The effects of sevoflurane on the cerebral circulation or metabolism in humans have not been studied. The authors examined the cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) during sevoflurane anesthesia. The carbon dioxide response and autoregulation of cerebral circulation were also examined. METHODS: Ten patients with ischemic cerebrovascular disease undergoing extra-intracranial artery anastomosis were studied. Cerebral blood flow and CMRO2 were determined by the Kety-Schmidt method using argon. These procedures were performed during the inhalation of 33% N2O, 33% argon, and oxygen with 1.5% sevoflurane (0.88 minimum alveolar concentration). To examine the relationship of CBF to a change in PaCO2, CBF was measured repeatedly at steady state PaCO2, of 40, 35, and 45 mmHg. Furthermore, CBF was measured before and after an increase in mean arterial pressure (MAP) caused by intravenous infusion of methoxamine to determine the relationship between CBF and MAP. RESULTS: Cerebral blood flow and CMRO2 were 28 +/- 4 ml x 100 g-1 x min-1 and 1.34 +/- 0.23 ml x 100 g-1 x min-1, respectively. Cerebral blood flow was found to vary directly with PaCO2 alteration. The slope of the regression line between PaCO2 and CBF was 1.29 ml x 100 g-1 x min-1 x mmHg-1. On the other hand, CBF was constant throughout the elevation of MAP with vasopressor. CONCLUSIONS: Both carbon dioxide response and cerebral autoregulation were well maintained under 0.88 MAC sevoflurane anesthesia in patients with ischemic cerebrovascular disease.

Adult↗

PubMed1993

[Maintenance doses of vecuronium and pancuronium during hypothermic cardiopulmonary bypass].

In 31 patients undergoing coronary artery bypass grafting, we investigated the maintenance doses of pancuronium and vecuronium during hypothermic cardiopulmonary bypass. For all patients, the height of the first twitch of the train-of-four (T1) was measured with evoked electromyogram. During operation, T1 was kept from 5 to 15 per cent of control. Infusion doses of both muscle relaxants were controlled with a personal computer. During hypothermic cardiopulmonary bypass (body temperature 28 degrees C), requirement of both muscle relaxants decreased for about 90 per cent compared with pre bypass values. We consider that the prolongation of neuromuscular blockade is attributable to hypothermia rather than to other factors of cardiopulmonary bypass. After rewarming, maintenance dose of vecuronium remained about a half of the dose required in pre-bypass period. It suggests that elimination of vecuronium from liver and kidney is hindered not only during hypothermia but also after rewarming.

Cardiopulmonary Bypass↗

PubMed1993

[Does rate of urine flow influence the difference between bladder temperature and nasopharyngeal temperature during cardiac surgery with cardiopulmonary bypass?].

Recently, bladder temperature (BT) monitoring is employed instead of rectal temperature because it is possible to keep the probe clean. The relationship between BT and core temperature is different in patients with steady state compared with those with rapid changes in temperatures. This study evaluated BT compared with nasopharyngeal temperature (NPT) reflecting brain temperature during cardiac surgery with induced hypothermia using cardiopulmonary bypass. During the steady state, after induction of anesthesia and immediately before cooling or rewarming, BT was equivalent to NPT independent of urine flow rate. In rapid cooling or rewarming phase of cardiopulmonary bypass, BT was not equivalent to NPT. BT preceded NPT in case of a very high urine flow rate, and with a lower urine flow rate delayed BT lagged behind NPT. During rapid changes in core temperature during cardiopulmonary bypass, the difference of BT to NPT depends on urine flow rate.

Adult↗

PubMed1993

[Monitoring of peripheral tissue oxygenation with near infrared spectrophotometry during abdominal or iliac aortic cross-clamping surgery].

Peripheral tissue oxygenation was monitored with near infrared spectrophotometry during abdominal or common iliac aortic cross-clamping surgery. Six patients who had abdominal aortic aneurysm (AAA) and eight patients who had aortic sclerotic occlusive disease (ASO) were studied. At the beginning of cross-clamping, oxyhemoglobin was decreasing and deoxyhemoglobin was increasing in all AAA patients. Average of 37 minutes following cross-clamping of abdominal aorta, both hemoglobin values were stabilized. On the other hand, changes in both hemoglobin values were delayed or missing in ASO patients. The results suggest that the duration from cross-clamping to stabilization is related to co-lateral blood flow. During operation, monitoring of peripheral blood flow with near infrared spectrophotometry is useful for detection of peripheral ischemia and for the estimation of postoperative local blood flow.

Aorta, Abdominal↗

PubMed1993

Anesthetic management of patients undergoing bilateral unifocalization.

We report on the anesthetic management of eight patients undergoing unifocalization for pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries. Unifocalization was performed separately on the right and left lungs in the lateral decubitus position. During unifocalization, pulmonary blood flow to the nondependent lung is interrupted and arterial oxygenation is dependent solely on the blood flow to the dependent lung. Thus, PaO2 and SaO2 decreased significantly and PaCO2 increased significantly during unifocalization, as compared with before and after unifocalization. When these values are compared between first and second stage of unifocalization, SaO2 during second stage was lower than during first stage. Although PaO2, PaCO2, and pH during second stage tended to be worse than during first stage, the differences did not reach statistical significance. During unifocalization, especially in second stage, to prevent deterioration of these arterial gas variables, pulmonary blood flow had to be increased by frequent administration of catecholamine. In addition, bicarbonate infusion was also used to prevent progressive metabolic acidosis due to hypoxia during unifocalization. Because anticoagulant therapy was required during unifocalization, airway bleeding was a common complication.

Adolescent↗

PubMed1992

Clinical evaluation of cerebral oxygen balance during cardiopulmonary bypass: on-line continuous monitoring of jugular venous oxyhemoglobin saturation.

To prevent brain damage during cardiopulmonary bypass (CPB), adequate cerebral perfusion for cerebral oxygen demand should be maintained. We monitored jugular venous oxyhemoglobin saturation (SjO2), which reflects the overall balance of cerebral oxygen supply and demand, continuously in 12 patients undergoing cardiac surgery. We examined whether this balance is disrupted during CPB, and if so, analyzed critical factors that affect this phenomenon. At the initiation of CPB, in spite of a significant decrease in mean arterial pressure, SjO2 did not change, and it was stable during the hypothermic period of CPB. On the other hand, a significant reduction in SjO2 was observed during the rewarming period, and SjO2 had an inverse linear correlation with nasopharyngeal temperature. Furthermore, the percent decrease of SjO2 was significantly related to "rewarming speed" (an average increase in temperature per minute). Our results indicate that temperature change during the rewarming period is a critical factor affecting the balance of cerebral oxygen supply and demand during CPB.

Adult↗

PubMed1992

Transient increase in wall thickness of the left ventricular apex after stunned myocardium: a case report.

A case of transiently increased wall thickness in the left ventricular apex after stunned myocardium due to severe attack of vasospastic angina is described. "Ace of spades" configuration, documented by left ventriculogram and increased apical wall thickness of the left ventricle, as revealed by two-dimensional echocardiograms returned to normal in 2 months. This transiently increased left ventricular mass may have been due to myocardial edema, which is occasionally seen in the recovery course of active myocarditis.

Angina Pectoris↗

PubMed1992

[Effects of hypothermia with cardiopulmonary bypass on posterior tibial nerve somatosensory evoked potentials in man].

Somatosensory evoked potential after posterior tibial nerve stimulation (PTN-SEP), as well as nasopharyngeal, bladder and plantar temperature were recorded in ten patients during cardiac surgery with hypothermic cardiopulmonary bypass. There was a best negative correlation between latencies (P27, P40 and the interpeak latency between P40 and P27 (P40-P27)) and nasopharyngeal temperature, but no correlation was found between latencies and plantar temperature during cooling and rewarming (27-37 degrees C) with cardiopulmonary bypass. No correlation was found between changes in amplitude and temperature. The slope of linear regression line of latencies versus nasopharyngeal temperature was -1.05 msec.degrees C-1 for P27 (r = -0.93), -1.47 msec.degrees C-1 for P40 (r = -0.95) and -0.43 msec.degrees C-1 for P40-P27 (r = -0.78). This study suggests that nasopharyngeal temperature measurement is required to aid the interpretation of PTN-SEP changes during hypothermia.

Adult↗

PubMed1992

[The change in cerebral blood flow during hypotensive anesthesia induced by prostaglandin E1].

We investigated the effect of prostaglandin E1 (PGE1)--induced hypotension during sevoflurane anesthesia on the cerebral blood flow (CBF), autoregulation and internal jugular venous O2 tension (PjO2) in 8 patients undergoing neurosurgery. Although the mean arterial pressure decreased from 95.3 +/- 3.8 mmHg (mean +/- SD) to 63.6 +/- 8.0 mmHg by continuous intravenous infusion of PGE1, CBF did not change significantly (97.2 +/- 10.6% of control value). During hypotensive anesthesia, autoregulation was well maintained in all patients, and the values of PjO2 did not suggest brain hypoxia at all. The results indicate that hypotensive anesthesia induced by PGE1 and sevoflurane is a safe and a reliable method for neuroanesthesia.

Adult↗

PubMed1991

Transient segmental asynergy of the left ventricle of patients with various clinical manifestations possibly unrelated to the coronary artery disease.

Eight cases of transient reversible segmental asynergy of the left ventricle thought not to be related to coronary artery lesions are reported. Three cases were associated with inflammatory reactions of unknown origin, and one each with lactic acidosis, abdominal surgery, hypoglycemia, tetanus and pneumonia. None of the patients had symptoms suggestive of ischemic heart disease before or after these episodes. Electrocardiograms before these episodes were all normal. Two-dimensional echocardiography was performed to evaluate abnormal electrocardiograms. Coronary angiography was performed in 4 of 8 cases and was normal in all 4 cases; 2 done as emergencies and 2 non-emergencies. Two ergonovine tests were negative. Left ventricular wall motion abnormalities, present mainly at the apex of the left ventricle, returned to normal in 1 to 4 weeks. Giant negative T waves in the chest leads during this recovery period were characteristic electrocardiographic features and normalized in 6 weeks on average. We believe that these episodes were not related to ischemia due to coronary artery disease, but to some metabolic humoral factors. An excellent prognosis can be expected if these abnormal metabolic circumstances can be resolved.

Aged↗

PubMed1991

[Leukocyte removability of a newly developed filter, RC-100, in rapid transfusion].

Leukocyte-depleted blood products are currently a burning issue in transfusion medicine. As methods for depleting leukocytes, the bedside filters are shown to have a high removal rate and several kinds of them are in use. We investigated the leukocytes removal rate of a new filter RC-100 (Pall Co., Glen Cove, NY) under the condition of rapid rate of transfusion during operations. In flow rates of 30, 60, 100 ml.min-1, the removal rate of leukocytes for CRC were 99.9 +/- 0.06, 100.0 +/- 0.00 and 99.4 +/- 0.20% respectively, and for WB 100.0 +/- 0.00, 99.9 +/- 0.10 and 99.1 +/- 0.70%, respectively. The recovery rates of erythrocytes were not significantly decreased for CRC and for WB in all flow rates. These results suggest that RC-100 could be useful either for CRC and for WB even with the rapid flow rate under 100 ml.min-1.

Blood Transfusion↗

PubMed1991

[Anesthetic management of revascularization for moyamoya disease].

Anesthetic management during 85 STA-MCA anastomoses with or without encephalo-myosynangiosis for 64 patients with Moyamoya disease was evaluated retrospectively. Anesthetic agents included nitrous oxide-NLA (GONLA), nitrous oxide-halothane (GOF), nitrous oxide-enflurane (GOE), and their combinations. Slight hypercarbia (40 mmHg less than PaCO2 less than 50 mmHg) was essential to avoid cerebral ischemia. Several procedures to control heart rate by beta blockade or to control hypertension by nitroglycerin were required, because tachycardia and hypertension interfered with fine surgical procedure. During microsurgery HR of GONLA anesthetized patients was significantly lower. Postoperatively the patients anesthetized by GOE showed significantly lower PaCO2 compared with the GONLA anesthetized patients. So we recommend GONLA for anastomosis in patients with Moyamoya disease.

Adolescent↗