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Biomedical subjects

O Kemmotsu

Publications and source records attributed to O Kemmotsu.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Subdural catheterization uncovered by severe hypotension during epidural plus general anesthesia].

We experienced three cases of accidental subdural catheterization during epidural combined with general anesthesia. In each case, epidural catheterization was performed before induction of general anesthesia. Aspiration through the catheter and a response to a test dose were negative. Then anesthesia was induced with thiamylal IV and the trachea was intubated with vecuronium IV. Hypotension, which was not easily treated by vasopressors and volume load, occurred after administration of 3 to 8 ml mepivacaine with 1: 200,000 epinephrine through the catheter. We examined position of the catheter by injecting iohexol 240 and confirmed subdural catheterization after surgery. It is often difficult to identify subdural placement of an epidural catheter under general anesthesia since signs of massive sensory blockade are masked by general anesthesia. In each case, we suspected malpositioning of the catheter by severe hypotension due to sympatholysis which was difficult to treat. Subdural catheterization is a complication of epidural anesthesia that probably occurs more frequently than previously recognized and is usually unpredictable during general anesthesia.

Anesthesia, Epidural↗
PubMed1994

Effect of lactic and CO2 acidosis on neuronal function following glucose-oxygen deprivation in rat hippocampal slices.

The present study was designed to determine whether lactate changes the critical pH point at which the recovery of rat population spike is inhibited following glucose-oxygen deprivation and second, which degree of lactic acidosis is similar to the effect of CO2 acidosis. The population spike was recorded from the hippocampal CA1 region after stimulation of the Schaffer collaterals. Slices were randomly perfused with various acidotic solutions for 30 min. During the last 15 min, glucose-oxygen deprivation was combined with the acidotic perfusion. Then the hippocampal slices were perfused with a standard solution of pH 7.4 for 60 min and recovery was compared to the control population spike and expressed as a percentage of the control value. In the control acidotic solution, the critical pH point was 5.0. When 15 mM or 30 mM lactate were added to the control solution, the critical pH point changed to 5.5 or 6.0, suggesting that the inhibition of the population spike was enhanced by lactate in a dose-dependent fashion. The recovery of the population spike was inhibited by exposing the slices to CO2 of 25% or above (pH was 5.76 or below) and this inhibition of recovery associated with CO2 acidosis was the same degree as occurred with 30 mM, namely severe lactic acidosis.

Acidosis, Lactic↗
PubMed1994

Noninvasive, continuous blood pressure measurement by arterial tonometry during anesthesia in children.

BACKGROUND: The authors' previous study of arterial tonometry in children demonstrated poor agreement of tonometric blood pressure (TBP) measurements with intraarterial blood pressure (IBP) measurements. The aim of the current study is to evaluate the feasibility of TBP measurements in children aged 1-6 yr using a newly designed pediatric sensor housing, by comparing TBP values with values obtained by IBP measurements. METHODS: Thirty-four children (aged 1-6 yr, ASA physical status 1-2) were studied undergoing elective abdominal or urologic surgery under general anesthesia. A 22- or 24-G cannula was inserted into the right radial artery. A TBP sensor housing was positioned over the left radial artery. TBP and IBP were continuously monitored and data were periodically sampled during and after intubation, during surgery, and during the recovery period. RESULTS: TBP waveforms were similar to those of IBP. Limits of agreement (bias +/- 2 SD) were 12 and -13.3 mmHg for systolic, 11.6 and -10.4 mmHg for mean, and 13.2 and -10.8 mmHg for diastolic pressures for 3,400 paired points. Measurements could not be made in ten children because of insufficient pulse contour. CONCLUSIONS: When pulse contour is sufficient for analysis, TBP monitoring provides an apparently safe and accurate method for the continuous measurement of arterial blood pressure during anesthesia in children aged 1-6 yr.

Anesthesia↗
PubMed1994

The effect of fentanyl and morphine on neurons in the dorsal raphe nucleus in the rat: an in vitro study.

The dorsal raphe (DR) nucleus is a system of nuclei lying in the midline of the lower brainstem constituting the largest collection of serotonin-containing neurons in the brain. The DR nucleus, which is under the influence of various synaptic inputs containing the excitatory amino acids (EAAs), serotonin and noradrenaline (NA), has been reported to be involved in the process of nociception. We studied the effects of fentanyl and morphine on the firing activity of neurons within the DR nucleus in the rat brain slice preparation in vitro using extracellular recording techniques. The decreased activity of DR neurons induced by these opioids was reversed upon application of naloxone. Since almost all neurons were silent, N-methyl-D-aspartate (NMDA) and noradrenaline were used to excite the DR neurons. Serotonin contained in the DR nucleus acts as a neuromodulator to enhance the excitatory effects of NMDA. All DR neurons were excited by NMDA, whereas 72% of the neurons were excited by NA. NA has a long-lasting effect on the firing activity of the neurons, although the firing pattern was less regular than that induced by NMDA. Of the total number of the DR neurons excited by NMDA and/or NA, 71% were inhibited by fentanyl and 73% by morphine. The results support our hypothesis that these opioids inhibit the firing activity of DR neurons and, in turn, might alter nociception directly and/or indirectly by modifying the central serotonergic system.

Animals↗
PubMed1994

The effect of clonidine on the activity of neurons in the rat dorsal raphe nucleus in vitro.

The dorsal raphe (DR) nucleus is a system of nuclei in the midline of the lower brainstem, which is considered one of the most important nuclei in the modulation of pain in the central nervous system. Central noradrenergic systems play an important role in the control of cardiovascular regulation and pain transmission. Clonidine, an alpha 2-adrenergic agonist is used extensively in anesthesia research. In this study, we evaluated the involvement of clonidine in the activity of DR nucleus and its possible role in pain modulation. Seventy-four neurons within the DR nucleus in the rat brainstem slice preparation were tested using extracellular recording techniques. Application of noradrenaline (NA), 50 mumol/L, induced firing activity in 68 neurons tested (92%). NA produced a regular long-lasting firing activity on the DR neurons. Fifty-six neurons (88%) previously excited by NA were inhibited by clonidine, 20 mumol/L. Clonidine suppressed the firing activity of neurons. The results indicate that the firing of DR neurons was under noradrenergic influence and was inhibited by clonidine, which in turn alters nociception by modifying the central serotonergic system.

Animals↗
PubMed1994

[Fiberscopic intubation under general anesthesia for children with Goldenhar syndrome].

Goldenhar syndrome is characterised by an eye abnormality such as epibulbar dermoid and lipoma, associated with ear, mandibular, and/or vertebral anomalies. It is well documented that difficult intubation in patient with this syndrome may be expected because of mandibular hypoplasia and limitation of neck movement resulting from vertebral anomalies. We report anesthetic management of two children with Goldenhar syndrome, 9 and 14-year-old. By preoperative examination, two children were expected to be difficult in intubating trachea. We used our newly developed mask adapter which enabled us to perform fiberoptic bronchoscopy-aided tracheal intubation under general anesthesia under controlled ventilation. By using this adapter, under sevoflurane/nitrous oxide anesthesia with vecuronium, we could successfully intubate with a 6 mm spiral tube through the nostril without any major problems. Anesthesia and surgery went uneventfully, and no postoperative complications were noted. We confirmed that our newly developed mask adapter for fiberoptic bronchoscopy is as useful for children with difficult intubation as for adults.

Adolescent↗
PubMed1994

[Anesthetic management for urological surgery of patients with chronic spinal cord injury].

We evaluated retrospectively the anesthetic management and perioperative complications of 47 patients with chronic spinal cord injury for genitourinary procedures. Of the 69 cases, 38 were performed under general anesthesia, 21 cases under spinal anesthesia, one case under epidural anesthesia, four cases under axillary block, and five cases under either sedation or standby. In preoperative laboratory findings, anemia was observed in 41%, hypoproteinemia in 38%, renal insufficiency in 23%, and restrictive pulmonary dysfunction in 69%. Hypotension and bradycardia were seen in 25% and 16% of patients, respectively. Autonomic hyperreflexia was seen in four cases with cervical cord injury: two under spinal anesthesia and two under either sedation or standby. Patients with chronic spinal cord injury have disorders of various organ systems. Careful preoperative evaluation and anesthetic management are required for prevention and prompt treatment of perioperative complications related to the disorders. Autonomic hyperreflexia can be successfully prevented by either general anesthesia or spinal anesthesia. The increased anesthesia safety can be obtained by the successful management of the cardiovascular instability during surgery.

Adolescent↗
PubMed1994

[Hyperbaric oxygen therapy in the Hokkaido University Hospital].

We surveyed the hyperbaric oxygen therapy during the past seven years in the Hokkaido University Hospital. The mean number of patients was 27 per year. The average number of the therapy was 328 per year. There were neither complications nor accidents attributable to the hyperbaric oxygen therapy. Three representative diseased states hypoxic brain damage, sudden deafness and occlusion of retinal arteries, showed remarkable recovery by this therapeutic modality. A safety standard has been revised in 1991. We have been operating the hyperbaric oxygen therapy according to the revised standard. The inter-departmental approach in this therapeutic modality is mandatory in order to achieve effective outcome.

Female↗
PubMed1994

Valve injury: a new complication of internal jugular vein cannulation.

The anatomic appearance and competency of internal jugular valves were investigated in both cadavers and surgical patients. In 20 cadavers, the internal jugular vein (IJV) was dissected and the appearance of the valves observed. In two adult patients, the movements of the valves were observed by endoscopic visualization using an intravascular fiberscope, ultrasound techniques, and invasive venography. Transvalvular pressure gradients were measured in 10 adult surgical patients to examine the competence of the jugular venous valve. Nineteen internal jugular valves obtained from the 20 cadavers were situated directly above the termination of the IJV in the inferior bulb and were usually bilateral. The remaining 21 valves could not be examined since they had been already dissected out for another anatomical studies. The valves in 16 of the subjects were bicuspid and semiluminar. Two valves had a single cusp. The opening and closing of the valve was visualized easily with both a fiberscope and real-time ultrasound technique. Eight patients with normal central pressure had competent valves during cough-induced transvalvular pressure gradients of 45.3 +/- 10.1 (mean +/- SD) mmHg. Four valves from two cadavers remained competent at 75.4 +/- 18.2 mmHg, but became incompetent at 5.6 +/- 4.8 mmHg after a hole was made with a 14-gauge needle. Our results indicate that the IJV valve is located 0.5-2.0 cm above the union of the subclavian vein and IJV, and plays an important role in preventing retrograde blood flow to the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hypertensive crisis during the resection of an adrenal tumor in primary aldosteronism.

Primary aldosteronism is one of the few causes of hypertension which is subject to total surgical treatment, but a hypertensive crisis can occur during the resection of the adrenal tumor. We undertook this study to evaluate the relationship between hormonal factors and a hypertensive crisis during surgery. Sixteen patients with primary aldosteronism who were scheduled for the resection of an adrenal tumor were participated in this investigation. Hormonal factors and hemodynamic variables were evaluated before induction of anesthesia, after induction of anesthesia, 30 minutes after the incision, during tumor manipulation, during resection, and immediately after surgery. During tumor manipulation, a hypertensive crisis occurred in six patients (hypertensive group; HG) but not in any others (non-hypertensive group; NHG). There were no differences in hormonal levels, except epinephrine, during tumor manipulation between HG and NHG. Hemodynamic evaluations revealed an increase of systemic vascular resistance during the hypertensive crisis. We conclude that the hypertensive crisis during the manipulation of an adrenal tumor is caused by the rapid release of epinephrine from the manipulated adrenal gland.

Journal Article↗
PubMed1993

Does a lidocaine patch reduce the pain at venous cannulation in adults?

In this study we evaluated whether a lidocaine patch reduces the pain relating to a venous cannulation in adults. The patch is consisted of the base containing 50% lidocaine on a thin polyester membrane. Its surface area is 15 cm2. Twenty-six adult patients scheduled for elective surgery (11 males and 15 females) were randomly divided into two groups according to application periods: Group A for 15 min and Group B for 30 min. Either the dorsal part of the hand or the radial side of the wrist was chosen and covered with the patch. Pain assessment was made by patients using a 0-100 point visual analog scale (VAS). In 7 patients of Group A, plasma lidocaine levels were measured 15 min after application by homogeneous enzyme immunoassay. The levels were further measured 30 and 60 min after application in 3 of those patients. The mean VAS score was 28.4 +/- 13.1 (mean +/- SD) for Group A and 51.8 +/- 15.9 for Group B, and the difference was statistically significant (P < 0.05). Plasma lidocaine levels were always below 0.2 microg.ml(-1). The results indicate that the skin was partially anesthetized by the lidocaine patch. A lidocaine patch may be useful and safely applicable for venous cannulation in adult patients.

Clinical Trial↗
PubMed1993

Does preoperative oral clonidine inhibit salivary secretion during general anesthesia?

Clonidine is known to inhibit salivary secretions and cause dryness of the mouth. We evaluated the effect of preoperative oral clonidine on salivary secretions before and during general anesthesia. Twenty-eight adult patients, equally divided into four groups, received the following premedication 2 hr prior to induction of anesthesia. Group 1 patients received oral ranitidine 5 mg.kg(-1) alone. Groups 2 and 3 patients received oral clonidine 1 microg.kg(-1) and 3 microg.kg(-1) respectively with oral ranitidine 5 mg.kg(-1). Group 4 patients received no premedication and served as control. The volume of salivary secretions was determined by calculating the change in weight of four cotton wool cylinders placed in the oral space 10 min before and 30, 60 and 120 min after induction of anesthesia. Salivary volume was significantly less in the clonidine treatment groups before induction of anesthesia. After induction of anesthesia, there were no significant differences in salivary secretions among the four groups. No severe hypotension or bradycardia was seen in any patient of four groups. Preoperative oral ranitidine 5 mg.kg(-1) had no effect on salivary secretion. In conclusion, clonidine did not decrease salivary secretions further over the already decreased level during general anesthesia.

Journal Article↗
PubMed1993

Neuromuscular effects of pipecuronium during sevoflurane anesthesia compared with isoflurane and enflurane anesthesia.

We evaluated the neuromuscular effects of pipecuronium during anesthesia with equipotent concentrations of either sevoflurane, isoflurane or enflurane. Twenty-seven patients scheduled for minor elective otolaryngeal or plastic surgery were studied and randomly assigned to 3 groups, one group per anesthetic agent. Anesthesia was induced with thiamylal 5 mg.kg(-1) and the trachea was intubated with succinylcholine 1 mg.kg(-1), then anesthesia was maintained with 60% nitrous oxide in oxygen and sevolfurane, isoflurane or enflurane, depending on the group. Neuromuscular blocking effects were monitored by recording the electromyographic activity of the adductor pollicis muscle from supramaximal stimulation of the ulnar nerve at 10-s intervals. Pipecuronium 40 microg.kg(-1) was administered when electromyographic activity had reached a stable state, 30 min after succinylcholine administration. The maximum effect (% block of control) and clinical duration (time to 25% recovery) of pipecuronium were 99.1 +/- 1.4% and 63.7 +/- 14.7 min (mean +/- S.D.) for sevoflurane, 99.0 +/- 2.0% and 60.9 +/- 20.5 min for isoflurane, and 98.0 +/- 2.5% and 62.8 +/- 28.7 min for enflurane, respectively. There were no significant differences in these values between the anesthetics. Cardiovascular stimulant effects were not observed in any of the groups. We conclude that the effect of pipecuronium under seveflurane anesthesia is similar to that under isoflurane and enflurane anesthesia.

Clinical Trial↗
PubMed1993

Acute brain swelling after out-of-hospital cardiac arrest: pathogenesis and outcome.

OBJECTIVES: First, to examine factors that may be related to brain swelling, which was identified by the absence or compression of the lateral and third ventricles and perimesencephalic cisterns on brain computed tomography (CT) scans in the early postresuscitation period in patients who suffered an out-of-hospital cardiac arrest. Second, to characterize the neurologic outcome in those patients in whom cardiac arrest was followed by brain swelling. DESIGN: Prospective and retrospective analyses. SETTINGS: General ICU, tertiary care hospital. PATIENTS: Fifty-three patients (35 male, 18 female) who had an out-of-hospital cardiac arrest and who also had a brain CT examination on the third day after resuscitation. The 53 patients were divided into two groups: group A (25 patients) experienced brain swelling on postresuscitation day 3; group B (28 patients) did not experience noticeable brain swelling. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There was a significant difference between the two groups in the etiology of the cardiac arrest. Twenty-three of 25 patients in group A had cardiac arrest due to respiratory distress, whereas this finding was true in only five patients in group B. In laboratory data, arterial pH was significantly lower in group A than in group B (6.93 vs. 7.09), as was base deficit (-21.0 mmol/L in group A vs. -13.7 mmol/L in group B). Neurologic outcome was evaluated 1 wk after resuscitation. There were significantly more patients in group A who were not awake and who were diagnosed as brain dead. CONCLUSIONS: The cause of brain swelling may be related to the development of the metabolic acidosis (possibly lactic acidosis) due to hypoxia before the resuscitation period. Brain swelling may be one of the indicators that predicts a poor neurologic outcome in the patients who suffer an out-of-hospital cardiac arrest.

Acidosis↗
PubMed1993

Influence of hypoxic and hypercapnic acidosis on brain water content after forebrain ischemia in the rat.

OBJECTIVE: To determine whether hypoxia or hypercapnia superimposed on ischemia affects brain water content after ischemia. DESIGN: Prospective, randomized, controlled trial. SUBJECTS: Thirty-one male Wistar rats. INTERVENTIONS: The rats were assigned randomly into one of six groups: a) control; b) ischemia; c) ischemia combined with hypoxia; d) ischemia combined with hypercapnia; e) hypoxia; f) hypercapnia. Forebrain ischemia was induced for 5 mins by clamping both carotid arteries and inducing exsanguination. Either hypoxia or hypercapnia was induced until the arterial pH decreased to 7.0. The rats were decapitated after the protocol. MEASUREMENTS AND MAIN RESULTS: After the decapitation, the specific gravities of the neocortex, caudatoputamen, hippocampus, cerebellum, and midbrain were measured using a variable-density bromobenzene-kerosene column technique as an index of brain swelling. The specific gravities of the hippocampus and the neocortex were significantly lower in the ischemic group than in the control group. Specific gravities of the caudatoputamen and neocortex in the ischemia plus hypercapnia group, and specific gravities of the caudatoputamen, neocortex, and hippocampus in the ischemia plus hypercapnia group, were significantly lower than in the ischemia group. CONCLUSIONS: Cerebral water content increases more when ischemia is accompanied by hypoxia or hypercapnia than after ischemia alone. Hypoxic and/or hypercapnic acidosis during the periresuscitation period may be one of the causes of brain swelling after the resuscitation of patients after an anoxic-ischemic insult.

Acidosis, Respiratory↗
PubMed1993

End-tidal CO2 changes under constant cardiac output during cardiopulmonary resuscitation.

OBJECTIVES: To evaluate a) whether end-tidal CO2 values change under constant cardiac output during cardiopulmonary resuscitation (CPR), and b) what factors are responsible for the change. DESIGN: A cohort study. SETTING: University research laboratory. SUBJECTS: Nine mongrel dogs. INTERVENTIONS: Ventricular fibrillation was electrically induced. After 2 mins, open-chest cardiac massage was initiated to maintain cardiac output at 0.2 L/min (23% of baseline cardiac output) by the measurement of blood flow with an electromagnetic flow probe on the ascending aorta. The cardiac massage was kept constant until 50 mins after the induction of ventricular fibrillation. MEASUREMENTS AND MAIN RESULTS: Before and during ventricular fibrillation, end-tidal CO2, minute volume of alveolar ventilation, and CO2 excretion were continuously monitored. Blood gases and oxygen saturation values were also measured in arterial and the mixed venous blood samples. CO2 content was calculated. After induction of ventricular fibrillation, end-tidal CO2 decreased and thereafter continued to increase until the end of the experiment. Two mechanisms may have contributed to the early reduction in end-tidal CO2. One mechanism is a further decrease in CO2 excretion compared with the reduction in alveolar ventilation and the other is an increase in alveolar deadspace (estimated from the increase in the difference between PaCO2 and end-tidal CO2). The subsequent increase in end-tidal CO2 was mainly due to a change in CO2 excretion. There are two hypotheses concerning the subsequent increase in CO2 excretion: the increase in pulmonary capillary blood flow (estimated from the change in the arteriovenous CO2 content gradient) and the increase in CO2 production itself. CONCLUSIONS: End-tidal CO2 changes under constant cardiac output during CPR. When end-tidal CO2 is used to estimate the effectiveness of the cardiac massage, this type of change must be recognized.

Animals↗
PubMed1993

Inotropic and electrophysiologic effects of propofol and thiamylal in isolated papillary muscles of the guinea pig and the rat.

We compared the inotropic and electrophysiologic effects of propofol and thiamylal in isolated papillary muscles of the guinea pig and rat. Propofol applied in clinical 10% intralipid emulsion showed concentration-dependent negative inotropic effects, accompanied by decreased action potential duration, in the guinea pig. Intralipid alone had no effect. Although thiamylal showed a concentration-dependent depression similar to propofol in the guinea pig, depolarization of resting membrane potential was seen at 0.1 and 0.3 mM, and a slight prolongation of action potential duration at 90% repolarization at 0.1 mM, and then a decrease of action potential duration at 0.3 mM. In rat papillary muscles, propofol did not produce any depression of contractile force, whereas thiamylal produced a concentration-dependent negative inotropic effect. The important findings observed in the action potential in rat papillary muscles were the modest shortening of action potential duration after propofol application, and the significant decrease of resting membrane potential and the significant prolongation of action potential duration caused by thiamylal. Both propofol and thiamylal depressed slow action potentials and contractile force in guinea pig papillary muscles depolarized by 25 mM K+ solution. In conclusion, the negative inotropic effects of propofol and thiamylal might be caused by inhibition of trans-sarcolemmal Ca2+ influx accompanied by shortening of action potential duration in guinea pig papillary muscles. The action potential of thiamylal might be affected by the suppression of K+ current in guinea pig and rat papillary muscles that was never observed in the propofol-treated tissue.

Action Potentials↗