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T Kawazoe

Publications and source records attributed to T Kawazoe.

At least 37 records · Page 2Linked to original sources
PubMed1997

[The effects of premedication on induction doses of propofol and hemodynamic responses during induction].

We chose five sedatives for premedication and investigated the effect of these drugs on the induction doses of propofol. One hundred patients were allocated into one of five groups of 20. These groups consisted of control group (C) given only atropine 0.5 mg i.m.; CL group (plus clonidine 0.15 mg orally); H group (plus hydroxyzine 25 mg i.m.); M group (plus midazolam 3 mg i.m.) and D group (plus diazepam 10 mg orally). The induction dose was measured using loss of count technique. Arterial pressure and heart rate were measured, before and after propofol induction as well as after intubation. We also calculated rate pressure products (RPP) at each point. The induction doses were significantly lower in M-group than those in C-group. On the other hand, in hemodynamic responses, RPP was unchanged in any groups after propofol induction and after the intubation. Both propofol and midazolam have been known to have a depressive effect on the central nervous system via GABA-A receptor-mediated inhibition, although the exact receptor for propofol is unknown. We thought, therefore, that when the interaction occurred, both midazolam and propofol had the same effect on the GABA-A receptor and increased chloride ion flux through the channels. Hydroxyzine and clonidine, however, do not share a common receptor or exert effect on the GABA-A receptor. We consider that this was one of the reasons why induction doses of both H and CL group could not decrease significantly. We concluded that midazolam 3 mg decreased propofol induction dose significantly. Both midazolam 3 mg and clonidine 0.15 mg decreased RPP before induction and hemodynamic responses to induction and intubation were stable.

Adult↗
PubMed1996

Reduction of progressive burn injury by a stable prostaglandin I2 analogue, beraprost sodium (Procylin): an experimental study in rats.

Beraprost sodium is a chemically stable prostaglandin I2 analogue with antiplatelet and vasodilator actions. Burn injury causes thrombosis and vessel occlusion by increasing the blood viscosity and by thermal damage to the vascular network in the dermis. A vascular response also occurs in the uninjured dermis surrounding the site of injury. Diminished blood flow and spreading tissue oedema lead to progressive ischaemia and necrosis around the burn site (zone of stasis), with the final necrotic tissue area being larger than the initial one. If blood flow could be restored in the zone of stasis, secondary tissue damage would be minimized. In this study, we examined the effects of a prostaglandin I2 analogue, beraprost sodium (Procylin, Kaken Pharmaceutical Company, Tokyo, Japan) on burn injury in rats. Twenty male Sprague-Dawley rats weighing an average of 450 g were burned with a comb-shaped brass probe that produced a row of three burns measuring 10 x 30 mm each and two intervening unburned areas measuring 5 x 30 mm each. The rats were divided into two groups of 10 animals. One group received 0.015 mg of beraprost sodium intraperitoneally immediately after burn injury, while the control group received the same volume of saline. Skin blood flow was measured with a laser Doppler flowmeter, and the development of oedema as well as the area of necrotic tissue were also determined. The extent of skin necrosis and oedema were significantly reduced in the beraprost sodium-treated rats, and blood flow in the zone of stasis was increased. These findings demonstrate that prostaglandin I2 plays an important role in burn injury and that beraprost sodium can reduce secondary necrosis in the zone of stasis.

Animals↗
PubMed1996

[Changing compatibility by temperature of local anesthetics with sodium bicarbonate].

We investigated the amount of 7% sodium bicarbonate which could be added to local anesthetics (bupivacaine, mepivacaine and lidocaine) without any precipitation when temperature was altered (5 degrees C, 25 degrees C, 40 degrees C). Precipitations occurred at any temperatures and with any dose of bupivacaine. Interestingly, the higher the temperature, the more frequently precipitation with mepivacaine and lidocaine occurred. This was probably because the solubility of the precipitate produced by the interaction of the base of local anesthetics with bicarbonate was reduced when the temperature increased.

Anesthetics, Local↗
PubMed1996

[Distribution of irrigating fluid to intracellular and extracellular fluid space during transurethral prostatectomy I--Estimation of irrigating fluid absorbed by measuring serum osmolality].

Twenty-three patients undergoing transurethral resection of the prostate (TURP) under spinal anesthesia were studied. The irrigating fluid widely used in Japan is a hypo-osmolar solution with 3% sorbitol (Uromatic S, 170 mOsm.kgH2O-1, Baxter). The blood loss and the distribution of the irrigating fluid absorbed were computed from serum osmolality, blood urea nitrogen, and hematocrit using the equation we had formulated. The blood loss, the total fluid absorbed (ABS), and the volumes distributed to intracellular space (delta ICF) and extracellular space (delta ECF) were 419 +/- 677 ml, 1,582 +/- 1,446 ml, 384 +/- 348 ml and 778 +/- 1,279 ml (mean+/-SD), respectively. The correlation coefficient of delta OSM (difference between pre- and post-surgical serum osmolality) vs ABS and that of delta OSM vs delta ICF were high (0.98, 0.98) but that of delta Na (difference between pre- and postsurgical serum sodium) vs ABS was low (0.56). The linear regression equations of ABS vs delta OSM and delta ICF vs delta OSM were ABS (L) = 0.362 x delta OSM and delta ICF (L) = 0.088 x delta OSM, respectively. These equations means that one mOsm.kgH2O-1 reduction of the serum osmolality is the result of 362 ml of irrigating fluid absorbed, 88 ml of which shifting into the intracellular space.

Aged↗
PubMed1996

[Distribution of irrigating fluid in intracellular and extracellular spaces during transurethral prostatectomy II--TUR syndrome and hyponatremia].

Thirty four patients undergoing transurethral resection of the prostate (TURP) under spinal anesthesia were assigned to a TUR syndrome (TURS) group (n = 7) or an asymptomatic (ASP) group (n = 27) depending on the clinical manifestations of the TUR syndrome. Blood loss and distribution of absorbed irrigating fluid (3% sorbitol-Uromatic S, 170 mOsm.kgH2O-1, Baxter) were computed together with serum osmolality, blood urea nitrogen and hematocrit. Postoperative serum sodium concentration and hematocrit were significantly lower in the TURS group than in the ASP group (124 +/- 8.7 vs. 133.9 +/- 5.9 mOsm.l-1 and 26. 8 +/- 4.2 vs. 35.0 +/- 4.6%, respectively). Postoperative serum osmotic pressure did not differ between the groups despite the difference in sodium concentration because 3% sorbitol could contribute to osmoles in the serum. The volume of irrigating fluid absorbed and its distribution into the intracellular space (delta ICF) did not differ between the groups. However, blood loss was significantly greater in the TURS group than in the ASP group (1457 +/- 434 ml vs. 173 +/- 450 ml, P < 0.01), and consequently extracellular fluid (ECF) volume was significantly reduced in the TURS group (-354 +/- 1201 ml vs. 802 +/- 1302 ml, P < 0.05). Thus, massive blood loss and reduced ECFs rather than dilutional hyponatremia, are thought to contribute to clinical manifestation of the TUR syndrome.

Aged↗
PubMed1996

Development and validation of TMJ viscoelasticity analyzer.

We developed a TMJ viscoelasticity analyzer for non-invasive evaluation of the soft tissues of the TMJ region. We used this device to measure the viscoelastic parameters, viscosity (c), elasticity (k) and mass (m), of the TMJ region for two volunteers. Experiments were performed to determine the optimum measurement conditions for the preload magnitude, head posture and clenching level. We determined measurement variability and carried out statistical analysis by analysis of variance (ANOVA). We found that the values for c and k varied significantly depending on preload magnitudes (p < 0.001). In addition, all parameters varied significantly depending on head posture. However, clenching level did not significantly affect any of the parameters. Measurement variability was below 10% for all parameters. Examination of viscoelasticity of the TMJ region provides valuable information about functional and pathological changes in the soft tissues of this area. In this study, we were able to determine the fundamental characteristics of the TMJ viscoelasticity analyzer and develop methods for examining patients with temporomandibular disorders.

Analysis of Variance↗
PubMed1995

[The recent trend in preoperative fasting].

It has been generally practiced that patients are restrained from any foods and water 4-6 hr prior to anesthesia. Recent trends of anesthesiologist, however, are to permit the patients to take fluid until 2-3 hr before inducing anesthesia, as described in the guidelines from Canadian Anaesthetists' Society in 1990, and in the authoritative textbooks of anesthesia. We compared effects of the preoperative fasting between age-matched groups of patients constrained to: 1) 6 hr absolute preoperative fasting, and 2) 6 hr fasting but free for taking clear fluid until 2 hr before operation. Residual gastric volume and pH immediately after inducing anesthesia were monitored. In the respective age groups from infant to the aged, no significant changes were observed between 1) and 2). Considering that light meal leaves the stomach in 1.5-3 hr and clear fluid almost immediately, these results accurately explain and support relevance of the current concept concerning the preoperative fasting. Furthermore, since actual incidence of aspiration pneumonia during anesthesia is sufficiently low, strict preoperative fasting may be unreasonable. We consider that reducing the fasting time may not increase the risk of pulmonary aspiration and recommend our practical method consisting of preoperative 6 hr withholding solid foods while allowing clear fluid ingestion until 2-3 hr before inducing anesthesia.

Fasting↗
PubMed1995

[Precipitation of pH-adjusted local anesthetics with sodium bicarbonate].

Sodium bicarbonate has been added to various local anesthetics for shortening the onset time. We often noticed the precipitate in the pH-adjusted local anesthetics several minutes after adding the bicarbonate. We confirmed that this drug interaction was caused by large changes in pH. We have analyzed the precipitates by mass spectrometry and infrared absorption spectrum and have revealed it as unionized base forms of local anesthetics. Since these forms tend to be insoluble, we must limit the amount of 7% sodium bicarbonate. This study proposes a guideline for adding 7% sodium bicarbonate to the various local anesthetics. The amount of 7% sodium bicarbonate which can be added to bupivacaine without precipitation is below 0.02 ml. In cases of mepivacaine and lidocaine, allowable amount of 7% sodium bicarbonate is 0.5 ml. It is not known whether this lower dose of 7% sodium bicarbonate compared with the recent reports is effective or not. Further clinical investigation may be necessary.

Anesthetics, Local↗
PubMed1995

Visualization and quantitative analysis using normalized electromyographic linear envelopes of muscle contraction patterns during gum chewing.

Surface electromyography (EMG) has been widely used in clinical dentistry, although interpretation of the raw data is difficult owing to its low reproducibility. Linear EMG envelopes, also known as EMG profiles, which are normalized with respect to raw EMG amplitudes and stride, have been developed to analyze the time course of gait stride. Normalized EMG contraction patterns can be used for comparing individuals or recording sessions on the same individual made at different times. We made EMG profiles during unilateral gum chewing for the masticatory muscles of five asymptomatic volunteers. EMG signals were recorded from the anterior temporal (Ta), masseter (M) and anterior belly of the digastric (Da) muscles on the subject's preferred chewing side. The mandibular kinesiograph was used for tracking incisal point movement during chewing. EMGs and kinesiometric data were simultaneously recorded for 90 seconds. Ensemble averages of EMG profiles were made from 10 stable strokes after 60 seconds of initiation of chewing. Phasic characteristics of the EMG profiles were evaluated by product-moment correlation and intraclass correlation coefficients. Although the EMG profiles for Ta and M were very similar, those for Da were different from the elevator muscles.

Adult↗
PubMed1995

Effect of amplitude normalization on surface EMG linear envelopes of masticatory muscles during gum chewing.

Various amplitude normalization procedures for surface electromyographic (EMG) signals have been utilized to reduce the inter- and intrasubject variability of data collected on gait analysis. We examined two normalization methods (normalization to mean of ensemble average: NME, and normalization to peak of ensemble average: NPE) for intersubject variability and reproducibility surface EMG profiles for the masticatory muscles during unilateral gum chewing. The EMG profiles for the anterior temporal (Ta), posterior temporal (Tp), masseter (M) and anterior belly of the digastric (Da) muscles on the chewing side from five normal subjects were made at three different sessions. Coefficients of variation and intraclass correlation coefficients were used to assess variability and reproducibility. Each normalization procedure the intersubject variability of unnormalized EMG profiles for Ta, Tp and M. The NME procedure provided lower intersubject variability for Da. The reproducibility of unnormalized profiles for Ta, Tp and M was significantly improved by both procedures (p < 0.05). NME on Da was more effective in its reproducibility (p < 0.05). We found that the phasic characteristics of muscular activity influenced the outcome of amplitude normalization.

Adult↗
PubMed1995

Ultrasonographic images of tongue movement during mastication.

We observed vertical motion of the tongue during mastication in ultrasonographic images of 6 males with an average age of 28.7 years. All subjects had complete dentition and no evidence of neurological disorders. We used a 7 MHz mechanical convex scanning transducer to obtain a continuous, real-time ultrasonic image of the tongue, and carried out real-time B-mode ultrasonic observation at the median sagittal plane of the mandible. We recorded vertical motion of the tongue in the M-mode on a line connecting the mandibular first molars. The transducer produced good quality images of the dorsal surface during mastication of peanuts, rice, crackers, boiled fish paste, pickled radishes, pudding and bananas. The transducer, which was small and light, permitted capture of the images on videotape without manual placement of the scanner. Continuous images showed that the tongue turned the food, mixed it with saliva, sorted out unsuitable particles and aided in bolus formation. Vertical motion of the tongue had two phases, sorting and bolus formation.

Adult↗
PubMed1994

Effects of sevoflurane, isoflurane, enflurane, and halothane on left ventricular diastolic performance in dogs.

The effects of volatile anesthetics on active (ventricular relaxation) and passive (chamber stiffness) indices of diastolic function and on left ventricular filling rates in dogs were studied to determine how these agents affect left ventricular diastolic performance. Thirty-five mongrel dogs were randomly assigned to receive sevoflurane, isoflurane, enflurane, or halothane. Left ventricular pressure waveforms, phonocardiograms, and echocardiograms were recorded after administering the anesthetics at concentrations of 0% (control), 1%, 2%, and 3%. Ventricular relaxation was defined as the time constant of the decline in left ventricular pressure. Chamber stiffness was derived from the ventricular pressure-volume relationship during passive filling. Rapid filling rate, slow filling rate, and atrial filling rate were obtained from echocardiograms and phonocardiograms. No change in the time constant or in chamber stiffness was observed at any concentration of sevoflurane or isoflurane. However, the highest studied concentration of enflurane and halothane produced a significant increase in the time constant and in chamber stiffness. Rapid filling rate as well as atrial filling rate decreased significantly with the volatile anesthetics, especially with enflurane and halothane. Sevoflurane and isoflurane did not alter ventricular relaxation or chamber stiffness, but did affect diastolic function as manifested by their alteration of filling rates. In contrast, enflurane and halothane each prolonged ventricular relaxation and increased chamber stiffness. With the administration of the volatile anesthetics, the rapid filling rate decreased with the deterioration of diastolic function; in addition, atrial filling rates decreased and did not compensate for the reduction in early ventricular filling.

Anesthetics, Inhalation↗
PubMed1994

Effects of nicardipine, nitroglycerin, and nitroprusside on left ventricular diastolic function during enflurane anesthesia.

The purpose of this study was to evaluate the effects of nicardipine (NCR), nitroglycerin (NTG), or nitroprusside (SNP) on left ventricular diastolic function during enflurane anesthesia in acutely instrumented dogs. Using echocardiography, time constants for the decline in isovolumic left ventricular pressure (T), stiffness constant (K), diastolic time intervals, and left ventricular filling rates were measured in 21 mongrel dogs during the following conditions: (1) 0% enflurane (control), (2) 3.3% enflurane, (3) intravenous infusion of NCR, 1 microgram/kg/min, NTG, 2 micrograms/kg/min, or SNP, 2 micrograms/kg/min, during 3.3% enflurane, and (4) intravenous infusion of NCR, 2 micrograms/kg/min, NTG, 4 micrograms/kg/min, or SNP, 4 micrograms/kg/min, during 3.3% enflurane. During 3.3% enflurane anesthesia, T and K increased significantly, and left ventricular filling rates decreased. The administration of NCR, NTG, or SNP returned T and K to control levels. Left ventricular rapid filling rate returned toward the control level only with NCR (P < 0.05, NCR v NTG, SNP). It is concluded that the depression of diastolic function during enflurane anesthesia was improved by NCR or other vasodilators. The extent and mechanism of action of these vasodilators might differ, however.

Anesthesia, Inhalation↗
PubMed1994

[Anesthetic management of a patient with mild hypothyroidism].

A patient with mild hypothyroidism underwent a repair of abdominal aortic aneurysm. Although the serum TSH level of this patient was very high and T4, free T4 levels were low, T3 level remained within normal ranges. Inhalation anesthesia with continuous epidural block was selected and there was no complication such as hypotension or hypothermia during perioperative period. Recently, several reports demonstrate that the preoperative supplemental therapy of the thyroid hormone should not be necessary in the case of mild hypothyroidism. Moreover, the biological potency of T3 is higher than that of T4. Thus, in patients whose T3 level is kept within normal ranges even if serum T4 level is low and serum TSH level is high, we may say that they are in euthyroid state. We think these patients can be anesthetized safely.

Anesthesia, Epidural↗