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Biomedical subjects

T Mizuguchi

Publications and source records attributed to T Mizuguchi.

At least 109 records · Page 6Linked to original sources
PubMed1990

[Premedication in children--a clinical trial of bromazepam and chloral hydrate suppositories].

We performed a study on 141 pediatric patients between 6 months and 7 years of age who underwent scheduled radical operation for inguinal hernia, to evaluate bromazepam suppository and chloral hydrate suppository as anesthetic premedication for short pediatric operations. The study was also focused on the difference of the effects of the two drugs between two age groups: younger than 5 years, and 5 years and older. The younger age group required a larger bromazepam dose compared with the older age group, and in the younger group even the larger bromazepam dose did not produce a high sedative effect as chloral hydrate. In the older group, bromazepam and chloral hydrate were equally effective. In respect to emergence from anesthesia, bromazepam delayed emergence compared with chloral hydrate after which children awoke from anesthesia very clearly. Thus, chloral hydrate suppository seemed more useful as premedicants in short pediatric operations for its high sedative effect without affecting emergence.

Anti-Anxiety Agents↗
PubMed1990

[Influence of hypercapnia on circulatory response to endotracheal intubation].

Effects of CO2 on circulatory responses to laryngoscopy and endotracheal intubation were investigated in 16 patients under constant depth of enflurane anesthesia (1.2MAC) at different levels of CO2 (normocapnia, PETCO2: 40mmHg or hypercapnia, PETCO2: 60mmHg). Patients were randomly divided into two groups; normocapnia group (n = 8) and hypercapnia group (n = 8). Although there was no significant difference in blood pressure response to laryngoscopy and endotracheal intubation between normocapnic and hypercapnic groups, heart rate response was significantly attenuated in hypercapnic group and the latent period between the start of laryngoscopy and the onset of increase in heart rate was significantly longer in hypercapnic group. Our results suggest that hypercapnia exerts inhibitory influence on heart rate responses to laryngoscopy and endotracheal intubation.

Adult↗
PubMed1990

[Ventilatory effects of halothane and enflurane in dogs].

The ventilatory effects of halothane and enflurane were studied in permanently tracheostomized dogs at the same anesthetic depth of 1 MAC. Inspiratory and expiratory durations were longer and tidal volume greater during enflurane than during halothane anesthesia. Mean inspiratory flow rate and minute ventilation during enflurane anesthesia were less than those during halothane anesthesia. As a result, end-expiratory carbon-dioxide concentration was higher during enflurane than during halothane anesthesia. When end-expiratory carbon-dioxide concentration was held at 7.5%, tidal volume was not different between the two anesthetics, while the difference of other parameters still remained. In addition, the magnitude of Hering-Breuer reflex determined by end-expiratory airway occlusion was essentially identical between halothane and enflurane anesthesia. The present results indicate that 1) depressant effect of enflurane on respiratory drive is greater than that of halothane and 2) the two anesthetics act on the respiratory timing mechanism differently.

Animals↗
PubMed1990

[The effects of epinephrine added to epidural morphine].

The authors studied the influence of epinephrine added to epidural morphine on morphine pharmacokinetics. Epidural morphine 3mg in 10ml of saline solution was administered from the Th11-12 interspace to 14 patients undergoing right thoracotomy. In addition, epinephrine 50micrograms was added to the epidural solution in 8 patients selected randomly. Morphine concentrations in the azygos vein and radial artery samples were measured. Compared with the plain morphine group, addition of epinephrine significantly decreased morphine concentrations in the azygos vein only at 5 and 10min after administration. At 15 and 30min after administration, the azygos vein morphine concentrations in the epinephrine group were at the same level as in the plain morphine group. The admixture of epinephrine with epidural morphine increased the individual variation in the half life of morphine concentrations in the azygos vein. All these results suggest that addition of epinephrine does not play a particularly important role in causing prolonged and profound analgesia after epidural morphine.

Aged↗
PubMed1989

Effect of high thoracic extradural anaesthesia on ventilatory response to hypercapnia in normal volunteers.

We have investigated, in six healthy male volunteers, the effect of high thoracic extradural anaesthesia on the ventilatory pattern and hypercapnic ventilatory response. Ventilatory variables were determined using a respiratory inductive plethysmograph. Duration of inspiration, rib cage excursion and its contribution to tidal volume decreased significantly following extradural anaesthesia, while mean inspiratory flow rate and minute ventilation increased. End-tidal PCO2 and the tidal excursion of the abdomen were unchanged. Hypercapnic ventilatory response decreased significantly following extradural anaesthesia, principally because of the rib cage component. The slope of the abdominal component did not change significantly. The results indicate that mechanical impairment of rib cage movement can produce decreased ventilatory response to carbon dioxide. The ventilatory impairment and the changes in breathing pattern induced by the high thoracic extradural anaesthesia probably reflect blockade of the efferent or afferent pathway (or both) of the intercostal nerve roots.

Adolescent↗
PubMed1989

Effect of repeated irradiation of low-power He-Ne laser in pain relief from postherpetic neuralgia.

In order to investigate the efficacy of repeated irradiation of low-power helium-neon laser in pain relief, we irradiated 36 outpatients suffering from postherpetic neuralgia. Each patient underwent 20 trials of irradiation on several points around the painful area at a frequency of 2 or 3 times a week. The efficacy of the laser at the end of 20 trials was noticed on 88.9%, and the degree of pain relief was 55.3%, which correlated with the number of trials. These results suggest that the irradiation of He-Ne laser is an effective and safe treatment for postherpetic neuralgia.

Adult↗
PubMed1989

Quantitative analysis of the effect of colony-stimulating factors on human marrow progenitor growth in liquid-suspension cultures: application of limiting dilution assay.

Proliferation of human marrow progenitors in liquid cultures can be quantitated by limiting dilution clonal analysis (LDA) of progenitors in microwells. In this study, we have used LDA to study the effect of purified native or recombinant granulocyte colony-stimulating factors (G-CSFs) and recombinant granulocyte-macrophage CSF (GM-CSF) on progenitor growth. These results were compared to those of simultaneous cultures in methylcellulose. In LDA, single-hit kinetics were obtained with up to 500 U/ml of the recombinant preparation. In LDA with recombinant GM-CSF, progenitor growth conformed to single-hit kinetics from 100 to 2000 U/ml with maximum progenitor frequency at 500 U/ml. In simultaneous methylcellulose cultures with recombinant GM-CSF, colony formation reached a plateau at 100 U/ml. In LDA, purified native G-CSF was shown to support progenitor growth with single-hit kinetics at 100 U/ml, but at greater concentrations (greater than 150 U/ml), it suppressed progenitor growth with almost complete inhibition at a concentration of 200 U/ml. However, this dose-response effect was not observed in either simultaneous methylcellulose culture with G-CSF or in LDA with a purified recombinant preparation of the corresponding G-CSF. In methylcellulose cultures, colony formation reached a maximum at 100 U/ml and maintained a plateau up to 1000 U/ml. Hence, liquid culture allowed detection of contaminating suppressive activity in the G-CSF preparation that was not detected by methylcellulose assay. LDA may be more sensitive than methylcellulose culture for screening factors regulating human hematopoietic cell growth.

Bone Marrow↗
PubMed1989

Effects of enflurane on contractile response of canine trachealis muscle.

The effect of enflurane anesthesia on bronchomotor tone was studied in 15 dogs, using isolated tracheal segments in situ. In six animals, the changes of tracheal tension in response to changing enflurane concentration were continuously measured while keeping tidal volume, respiratory frequency, and end-tidal PCO2 constant. In nine other dogs, the contractile response to a brief period of apnea was assessed in three planes of anesthesia, namely 0% (baseline anesthesia with pentobarbital), 1%, and 2% of inspired enflurane concentration. In addition, effects of hypercapnia, hypoxia, and changing tidal volume were also examined in three of these nine animals. Furthermore, the magnitude of contraction elicited by electrical stimulation of the recurrent laryngeal nerve (RLN) was determined at each depth of anesthesia in six animals. Increasing enflurane concentrations invariably decreased resting tracheal tension as well as the magnitude of contraction in response to apnea and RLN stimulation in a dose-dependent manner. These data suggest that enflurane not only decreases unstimulated canine bronchomotor tone but also inhibits contraction produced by various stimuli used in the present experiments.

Animals↗
PubMed1989

[Anesthesia for a patient with pheochromocytoma associated with chronic renal failure].

A case of a 54-years-old female with pheochromocytoma associated with chronic renal failure is described. The patient was having hemodialysis preoperatively. For preoperative preparation, prazosin 12 mg.day-1 was used to control arterial pressure, and we increased the patient's dry weight by 0.5 kg. Anesthesia was maintained with 67% nitrous oxide, 33% oxygen and 1.0-2.0% enflurane. For intraoperative fluid management, we administered crystalloid solution 1 ml.kg-1.hr-1 and fresh frozen plasma 1600 ml. We simultaneously used phentolamine. The anesthesia was uneventful and the patient did well postoperatively.

Anesthesia↗
PubMed1989

[Heart failure due to rapid right ventricular volume overload in patients with pulmonary hypertension].

We have described three cases of pulmonary artery hypertension (PAH). Two of them developed severe systemic hypotension and cardiac arrest following cardiopulmonary bypass (CPB). Imminent pre-operative right ventricular (RV) failure and subsequent myocardial injury during CPB may have contributed to the insult following CPB. In these cases, RV failure is presumably due to rapid volume overloading, since left atrial pressure (LAP) was essentially unchanged while right atrial pressure (RAP) was markedly elevated during the period of severe hypotension. Furthermore, these events may be attributed to protamine, since the circulatory derangement coincides with its administration. Thus, in these patients with severe PAH, blood transfusion should be carefully titrated under the strict evaluation of both LAP and RAP. Additionally, protamine should be infused at a rate slow enough to avoid concomitant hemodynamic changes. We have also reported a case of over-systemic PAH who was successfully managed intraoperatively by careful monitoring and discreet administration of protamine.

Adult↗
PubMed1988

Comparison between fluctuating PEEP and conventional PEEP in dogs with lung injury induced by blood aspiration.

It has been documented that in some patients with acute hypoxic respiratory failure the application of positive end-expiratory pressure (PEEP) may produce no improvement or even a deterioration of pulmonary oxygenation due to an increase in ventilation-perfusion mismatching. Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with localized lung injury induced by the aspiration of non-heparinized blood (2 ml.kg body weight-1), F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at frequencies of 10 min, and conventional PEEP with 3 different fixed EEPs, 0.5, 1.0 and 1.5 kPa (C-PEEP0.5, C-PEEP1.0 and C-PEEP1.5) were each applied for 60 min. F-PEEP produced a periodical change in PaO2 and hemodynamic variables including cardiac output, and in comparison with C-PEEP0.5, C-PEEP1.0 and C-PEEP1.5, a significantly greater improvement of A-aDO2 and dynamic compliance with relatively large cardiac output in the low EEP phase. These results suggest that F-PEEP is a useful mode of artificial ventilation for treating some kinds of acute hypoxic respiratory failure due to increased ventilation-perfusion mismatching.

Animals↗
PubMed1988

Fluctuating PEEP (F-PEEP) versus conventional PEEP in dogs with asymmetrical lung injury.

Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury.

Animals↗
PubMed1988

Fluctuating PEEP versus conventional PEEP in diffuse and unilateral lung injury induced by oleic acid.

Effects of fluctuating positive end-expiratory pressure (F-PEEP), in which end-expiratory pressure (EEP) was periodically changed from 0.5 to 1.5 kPa with a periodic time of 6 min, and conventional PEEP (C-PEEP) with a fixed EEP of 1.0 kPa, were comparatively studied in diffuse (Group I) and unilaterally dominant lung injury (Group II). Although F-PEEP produced cyclic alterations of PaO2 in both groups, PaO2 changed in proportion to EEP in Group I and in reciprocal proportion to EEP in Group II. There was no significant difference between PaO2 and QS/QT during F-PEEP and those during C-PEEP in Group I, whereas in Group II, F-PEEP produced a significantly greater improvement of pulmonary oxygenation at the low EEP phase than C-PEEP. In both groups, the degree of hemodynamic depression was proportional to EEP. These results suggest that F-PEEP should be indicated for acute hypoxic respiratory failure with uneven distribution of lung injury.

Animals↗