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Biomedical subjects

O Kemmotsu

Publications and source records attributed to O Kemmotsu.

At least 127 records · Page 7Linked to original sources
PubMed1992

[A case report of a 63-year-old patient with malignant hyperthermia].

We have experienced a case of fulminant malignant hyperthermia who was a 63-year-old female weighing 44 kg. There was no particular past history nor family history. She underwent right mastoidectomy because of chronic otitis media. Her preoperative physical status was ASA I. She was premedicated with diazepam 10 mg and loxatigine 75 mg P.O. The induction was done with thiamylal 200 mg IV and fentanyl 0.1 mg IV followed by vecuronium 6 mg IV for endotracheal intubation. Intubation was easy and uneventful. Anesthesia was maintained with nitrous oxide 3 l.min-1, oxygen 3 l.min-1 and enflurane 2.0%. Seventy min after the induction of anesthesia, arterial blood gas analysis showed severe respiratory acidosis (PCO2: 63.2 mmHg, pH: 7.27) and it was improved with manual hyperventilation at that time. Pulse rate increased from 80 to 115 b.p.m. 20 minutes later. Then, the patient was ventilated with 100% oxygen, and anesthetic circuits and machine were exchanged for new units. Surgery was postponed. Muscle stiffness of upper extremities was observed and her temperature increased to a maximum of 38.9 degrees C. Surface cooling was started and dantrolene sodium 60 mg and furosemide 20 mg were given intravenously. The patient was transferred to the intensive care unit, and clinical signs improved gradually within one hour. Serum enzymes; CPK, LDH, GOT and GPT increased on the first postoperative day. On the 11 th postoperative day skeletal muscle biopsy was done under local anesthesia with 1% procaine and Ca-induced Ca-release rate test revealed positive for enflurane. This is the oldest patient of malignant hyperthermia reported in Japan.

Anesthesia, Inhalation↗
PubMed1991

Combined negative inotropic effects of calcium entry blockers and isoflurane on canine isolated heart muscles.

The combined negative inotropic effects of isoflurane and calcium entry blockers (verapamil, diltiazem, nifedipine, nicardipine) were studied utilizing isolated heart preparations of ventricular muscles from dogs. All of these calcium entry blockers exerted dose-dependent decreases in maximal velocity of shortening (Vmax), maximal developed isometric force (Fm), and the maximal first derivative of Fm (maximal dF/dt). Dose-dependent decreases of these variables of muscle mechanics were augmented in isoflurane-depressed myocardium. At equimolar concentrations, direct myocardial depression was demonstrated in the following order of severity: nifedipine > diltiazem = verapamil > nicardipine. Percent depressions of Vmax, Fm and maximal dF/dt were significantly greater in muscles when calcium entry blockers were combined with 1MAC isoflurane than in muscles of calcium entry blockers alone. These data suggest that the negative inotropic effects of verapamil, diltiazem, nifedipine, and nicardipine were potentiated by isoflurane.

Journal Article↗
PubMed1991

Arterial tonometry for noninvasive, continuous blood pressure monitoring during anesthesia.

Arterial tonometry is a technique used to measure arterial blood pressure noninvasively. The authors developed a new tonometer system containing an array of 15 piezoresistive pressure transducers, a mechanical positioning system, signal conditioning and multiplexing electronics, and a display and control console. The authors evaluated the accuracy, reliability, and clinical acceptability of this system by comparing tonometric blood pressure measurements with intraarterial blood pressure measurements in 60 anesthetized patients. Blood pressure was measured intraarterially in either the right or left radial artery by a Gould P23XL calibrated transducer, whereas blood pressure was measured by tonometer at the radial artery of the other arm. The tonometric waveform was similar to the intraarterial waveform. Simultaneous tonometer and intraarterial systolic blood pressures of the 60 patients (3,036 data sets) had an overall regression coefficient, r = 0.97, and an equation, regression equation = 0.95X + 5.8. Similar values were obtained for mean and diastolic pressures. Regression analyses of the paired tonometric and intraarterial blood pressure values showed good correlations in both sexes and in ages ranging from 8 to 82 yr (r = 0.94-0.97). Mean absolute values of error (precision) for the systolic, mean, and diastolic measurements did not differ significantly among the five systolic, five mean, and four diastolic pressure groups and ranged from 3.6 to 6.6 mmHg, with negligible bias, with intraarterial pressure used as the reference. Bias for the various pressure groups was small: -0.9-3.6 mmHg for systolic; -3.0-0.7 mmHg for mean; and -2.1-4.5 mmHg for diastolic. The "limits of agreement" (mean difference +/- two standard deviations) were within an acceptable range for clinical anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Blood pressure measurement by arterial tonometry in controlled hypotension.

A newly developed arterial tonometer enabled us to measure the blood pressure waveforms in addition to determining systolic and diastolic pressures noninvasively and continuously. Twenty-eight adult patients undergoing orthopedic surgery under controlled hypotension were studied. Systolic blood pressure was reduced to two-thirds of baseline values with an infusion of nitroglycerin during nitrous oxide/enflurane anesthesia. Intraarterial blood pressures were simultaneously measured in either the right or the left radial artery with a cannula and a Gould P23XL calibrated transducer; tonometric monitoring was performed on the contralateral radial artery using a Colin CBM-3000 instrument. The outputs of the two blood pressure measurement instruments were recorded for later data analysis. The shape of the tonometric pressure waveform was nearly identical to the waveform recorded intraarterially even during controlled hypotension. Regression analyses of 2039 paired tonometric and intraarterial blood pressure values during the hypotensive period showed good correlations (r = 0.78 for systolic, r = 0.81 for mean, and r = 0.70 for diastolic pressures). The accuracy of systolic, mean, and diastolic readings was from 4 to 7 mm Hg with negligible bias and did not differ significantly among six systolic, four mean, and four diastolic pressure groups. Our results indicate that arterial tonometry can provide accurate, reliable, and real-time monitoring of blood pressure even during controlled hypotension.

Adult↗
PubMed1991

[Enhanced myocardial depression from bupivacaine in diabetic rats].

We examined the direct effects of bupivacaine on the diabetic rat myocardium using an isolated perfused (Langendorff) heart preparation. Rats were made diabetic by injection of streptozotocin (55 mg.kg-1, i. v.). 12 weeks after the administration of streptozotocin, hearts were excised and perfused using Langendorff technique. Following 60 min for equilibration, diabetic hearts from the 12-week animals exhibited significant bradycardia. Bupivacaine 3 mcg.ml-1 did not decrease myocardial contractility in control animals. However, 3 mcg.ml-1 bupivacaine decreased contractility significantly in diabetic animals at nearly all periods. Bupivacaine decreased heart rate and coronary flow significantly and similarly in control and diabetic rats hearts. After pacing at 4 Hz, bupivacaine decreased contractility more in diabetic group than in control group. These results indicate that the presence of a diabetic state appears to enhance the sensitivity of the heart to the myocardial depressant effect of bupivacaine.

Animals↗
PubMed1991

[The effect of dopamine or dobutamine on plasma concentration of magnesium in dogs].

Plasma magnesium (Mg) concentration of dogs was determined with atomic absorption spectrophotometry during the infusion of dopamine (DOA) or dobutamine (DOB). Other electrolytes were also measured with same samples. Normoventilation was maintained during this experiment in order to avoid the respiratory interference. DOA 15-20 micrograms.kg-1.min-1 decreased Mg concentration significantly. DOB 5-20 micrograms.kg-1.min-1 did not change Mg concentration. Potassium (K) values were almost constant during infusion of both drugs, but DOB reduced K concentration at the dose of 20 micrograms.kg-1.min-1. Ionized calcium ion tended to decrease in DOA and to increase in DOB while the dose of the catecholamines was increased. These were not significant changes. These changes of concentration returned to control values 1 hour after stopping drug administrations. We speculate that beta-receptor, especially beta 2-receptor stimulation by DOA is responsible for the decrease of Mg in the mechanism of Mg uptake into cells of such tissues as liver or muscle.

Animals↗
PubMed1991

[Analysis of the clinical effect of Adelavin infusion during enflurane anesthesia on post-operative hepatic function].

The protective effect of Adelavin, which is made of liver essence, for maintaining postoperative hepatic function was analysed in 85 patients who had enflurane anesthesia. The patients who showed hepatic dysfunction preoperatively were excluded from this trial. Adelavin was infused at a speed of 0.1 mg.kg-1.hr-1 during anesthesia. The group who had upper abdominal surgery in the Adelavin group showed significantly lower incidence of postoperative hepatic dysfunction. The group who had only enflurane anesthesia in the Adelavin group showed significantly lower incidence of postoperative hepatic dysfunction. These results suggest that the Adelavin infusion has a significant protective effect on hepatic function after enflurane anesthesia.

Anesthesia, Inhalation↗
PubMed1990

Thoracic epidural anaesthesia combined with enflurane anaesthesia reduces atrioventricular conduction in dogs.

Cardiac electrophysiological variables during thoracic epidural lidocaine (TEL) were compared with those during continuous intravenous lidocaine (IVL) infusion in 14 mongrel dogs anaesthetized with enflurane in order to investigate the combined effects of thoracic epidural anaesthesia (TEA) and enflurane anaesthesia on intracardiac conduction. Thoracic epidural lidocaine suppressed intracardiac conduction. Sinus cycle length (SCL) and Atrium-His (AH) interval increased by 9 and 11 per cent respectively (P less than 0.05), 30 min after TEL. Intravenous lidocaine did not increase either SCL or AH. The functional refractory period of the atrioventricular node increased five per cent above the control value 15 min after TEL (P less than 0.05), while it was unchanged in the IVL group. The mean plasma concentrations of lidocaine ranged from 0.48 +/- 0.07 to 1.00 +/- 0.14 micrograms.ml-1 in the TEL group and from 0.98 +/- 0.13) to 1.21 +/- 0.15 micrograms.ml-1 in the IVL group. There were no significant differences in plasma concentrations of lidocaine in both groups during the observation period. Therefore, it is concluded that the depressant effects of TEA on intracardiac conduction were caused by blocking of the sympathetic efferent activity. Caution may be advised in administering TEA when cardiac conduction is already compromised.

Analysis of Variance↗
PubMed1990

Comparative inotropic effects of local anesthetics in isolated cat papillary muscles.

The direct inotropic action of seven local anesthetics: procaine, mapivacaine, lidocaine, tetracaine, chloroprocaine, bupivacaine and etidocaine were compared in isolated cat papillary muscles. All of the local anesthetics produced a dose-related depression of maximal velocity of shortening (Vmax), maximal developed force (Fm) and maximal dF/dt. The more potent local anesthetics such as bupivacaine and etidocaine depressed myocardial contractility at significantly lower concentrations than the less potent local anesthetics such as lidocaine and mepivacaine. Depression of Vmax by bupivacaine or etidocaine was three times greater than that by lidocaine and ten times greater than that by procaine. At the same concentration (10(-4) M), direct myocardial depression was demonstrated in the following order of severity: etidocaine >/= bupivacaine >> tetracaine >> chloroprocaine >/= lidocaine >> mepivacaine >> procaine.

Journal Article↗
PubMed1990

Noninvasive assessment of cardiac performance of intravenous benzodiazepines by systolic time intervals.

The effects of anesthetic induction by diazepam, flunitrazepam and midazolam on cardiac performance were evaluated in 33 ASA class I surgical patients (average age was 36 years). The patients were divided according to the 3 drug groups, and the effects of each drug assessed utilizing measurements of systolic time intervals. An increase in heart rate and decrease in blood pressure was observed following flunitrazepam and midazolam induction. There was no changes in PEPI (pre-ejection period index) and LVETI (left ventricular ejection time index) by benzodiazepines induction. The PEP/LVET ratio was increased by diazepam while the DPTI (diastolic pressure time index)/TTI (tension time index) was reduced by flunitrazepam and midazolam. However, these changes in PEP/LVET and DPTI/TTI were within normal limits. These data indicate that in healthy humans the induction dose of either diazepam, flunitrazepam or midazolam does not extremely influence either PEP/LVET for cardiac performance or DPTI/TTI for cardiac oxygen balance. The results also suggest that the simultaneous use of PEP/LVET and DPTI/TTI is more informative than any single variable for the evaluation of cardiac effects of anesthetics.

Journal Article↗
PubMed1990

Is the site of action of ketamine anesthesia the N-methyl-D-aspartate receptor?

Synaptic mechanisms underlying ketamine anesthesia were studied using in vitro preparations of the lamprey CNS. Although lampreys are one of the most primitive vertebrates, the synaptic physiology and pharmacology are similar to those in the higher vertebrates. Axonal conduction, transmitter release from the presynaptic terminal, postsynaptic response to the putative neurotransmitters, and resting and activated membrane properties were studied in the absence and the presence of various concentrations of ketamine. Ketamine markedly reduced N-methyl-D-aspartate (NMDA)-activated responses, such as depolarizations to bath-applied NMDA and bursting rhythm during "fictive locomotion." The 50% block of the responses took place in the presence of 10-20 microM ketamine, whereas those induced by kainate and quisqualate (the other two subclasses of L-glutamate/L-aspartate agonists) were spared at concentrations higher than 600-800 microM. None of the other neuronal events tested were suppressed in the presence of still higher concentrations of ketamine. The results support the hypothesis that ketamine might exert its anesthetic effect by a pharmacologically specific interaction with the NMDA receptor.

Action Potentials↗
PubMed1990

Effects of isoflurane on conduction velocity and maximum rate of rise of action potential upstroke in guinea pig papillary muscles.

This study was undertaken to determine whether isoflurane, a volatile anesthetic that is reported to possess a wide margin of cardiovascular safety, exerts electrophysiological effects on cardiac tissue. By use of standard microelectrode techniques, effects of isoflurane on the maximum rate of rise of action potential upstroke (Vmax) and conduction velocity were examined in guinea pig papillary muscles. Isoflurane decreased action potential amplitude and action potential duration in a concentration-dependent fashion. Isoflurane at 1.5 and 2.0 MAC decreased conduction velocity with as little influence on the maximum rate of rise of action potential upstroke as that exerted by halothane and enflurane. However, the effect of isoflurane in slowing intraventricular conduction was less than that of halothane and enflurane when compared at equi-MAC concentrations. Thus, isoflurane may be a safer anesthetic for the patients with intraventricular conduction abnormalities.

Action Potentials↗
PubMed1990

[Synaptic mechanisms of excitatory amino acids and NMDA receptor mediated brain excitability].

L-Glutamate and related excitatory amino acids (EAA) are firmly established as major excitatory synaptic transmitter substances in the vertebrate central nervous system. Questions which have been addressed include: How many receptors are there for the EAAs?; What ion channels and/or 'second-messenger' systems are regulated by these receptors?; What are the roles of EAAs in higher neural functions?; Are they involved in neurological disorders? EAA receptors appear not only to mediate normal synaptic transmission along excitatory pathways but also to participate in the modification of synaptic connections during development. However, overaction of receptors can also mediate neuronal degeneration and even cell death. NMDA receptor antagonists markedly attenuate neuronal necrosis. Therefore, it appears that ischemia- and hypoglycemia-associated brain damage results not from a lack of energy substrates but rather via the mediation of NMDA receptors and 'excitotoxic' mechanisms. The action of ketamine anesthesia is closely associated with a block of the NMDA receptor. Ketamine binds to a site within the lumen of the NMDA-activated channel and can become trapped there when the channel closes. Current evidence indicated that NMDA receptor antagonists will be of value for the treatment of delayed neuronal death. NMDA receptor will lead to understanding the mechanisms underlying learning and memory, the control of neuronal excitability and neuronal death.

Amino Acids↗
PubMed1990

[The effects of ulinastatin on the release of granulocyte elastase during pancreas surgery].

During a major abdominal surgery, intraoperative manipulation may cause circulatory changes, which lead to release of granulocyte elastase. Twenty one patients were studied to elucidate the release of granulocyte elastase and the inhibitory effect of a protease inhibitor (ulinastatin) on lysosomal enzyme release during pancreas surgery. Patients were divided into 3 groups. Patients in group A served as control. Patients in group B were given ulinastatin 10,000 units.kg-1 intravenously prior to surgery. Patients in group C were given ulinastatin 5,000 units.kg-1 intravenously twice prior to surgery and 3 hours after the start of surgery. The granulocyte elastase was measured by commercially available kits, at 7 points: prior to induction of anesthesia, immediately after tracheal intubation, 30, 60, 120, 180 min after the start of surgery and 30 min after surgery. The plasma level of elastase increased markedly during the operation in group A, it did not increase in groups B and C during the operation. Thirty min after the operation, the plasma level of elastase increased markedly in group A (354 +/- 63 micrograms.l-1), and in group B (396 +/- 167 micrograms.l-1). The plasma level of elastase was restored to normal levels 30 min after the operation in group C. These results indicate that granulocyte elastase values were maintained at significantly higher levels during and after pancreas surgery, and suggest that ulinastatin inhibits the release of granulocyte elastase during pancreas surgery.

Aged↗
PubMed1989

Clinical evaluation of esophageal doppler cardiac output measurement during general anesthesia.

We evaluate the accuracy of cardiac output measurement with esophageal Doppler ultrasonography (ECO). A total of 71 simultaneous measurement of esophageal Doppler and thermodilution cardiac output were compared in 16 patients undergoing general anesthesia in the supine position. ECO was determined easily with minimal experience, and significantly correlated with thermodilution cardiac output (TDCO) measurement ( P < 0.001). The regression equation obtained was Y = 0.983X + 0.019, and the correlation coefficient was 0.935. Furthermore, ECO was more reproducible than TDCO. However, ECO is not able to assess CO accurately in either lateral or prone position and after cardiopulmonary bypass in open heart surgery. Our results suggest that the esophageal Doppler technique allows a noninvasive and continuous cardiac output monitoring in patients during general anesthesia, and that it is more useful in patients for whom invasive monitoring is considered inappropriate. However, further improvement in this technique will be necessary for its routine use in clinical anesthesia.

Journal Article↗
PubMed1989

Continuous mixed venous oxygen saturation monitoring during general anesthesia.

Clinical evaluation of continuous SvO2 monitoring during general anesthesia was made in 21 surgical patients utilizing a fiberoptic reflectometry system combined with a pulmonary artery flow-directed balloon catheter. On-line in vivo values for SvO2 by the system were closely related to those obtained in vitro from a Radiometer ABL-300. There was a good correlation between changes of in vivo SvO2 and corresponding changes in cardiac index. We also observed that there were significant correlations between SvO2 and oxygen extraction ratio, and SvO2 and oxygen delivery. These data indicate that continuous monitoring of SvO2 during general anesthesia can provide on-line information not only about hemodynamic state but also on oxygen transport, which will be especially helpful in managing hemodynamically unstable patients during anesthesia.

Journal Article↗