Masui. The Japanese journal of anesthesiology
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Comparative Study
[Differential effects of muscle relaxants on the evoked electromyogram of the thenar and hypothenar muscles].
This study compares the neuromuscular blocking effect of nondepolarizing relaxants on the thenar and hypothenar muscles in 14 anesthetized patients with nitrous oxide-halothane. Vecuronium (60 micrograms.kg-1 iv) or pancuronium (60 micrograms.kg-1 iv) was given and supramaximal stimulation was applied to ulnar nerve at the wrist. The evoked compound action potentials were measured over the thenar and hypothenar muscles of the right hand simultaneously. ⋯ There was significant higher T1/Tc and T1/T4 ratio for the hypothenar muscle than for the thenar muscle within 60 minutes from pancuronium administration. These data suggest that relative potency of muscle relaxant on these two muscles seems to be drug specific. This phenomenon brings certain practical difficulties on monitoring of neuromuscular function with evoked electromyogram during anesthesia.
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We investigated the effects of arterial carbon dioxide tension on myocardial blood flow, tissue oxygen tension and metabolism in the anesthetized dogs. Eighteen adult mongrel dogs weighing 13.4 +/- 3.6 kg were anesthetized with 0.5% isoflurane, intubated and ventilated mechanically with 50% oxygen to maintain normocapnia. Endtidal CO2 fraction (FECO2) was monitored continuously by capnograph. ⋯ After normocapnic ventilation, hypocapnia was induced by increasing the respiratory rate, and hypercapnia was induced by adding 10% carbon dioxide to the inspired gas. The coronary blood flow and myocardial tissue oxygen tension increased during hypercapnia and the myocardial lactate extraction decreased, while excess lactate and cardiac venous L/P ratio increased during hypercapnia. These results indicate that hypercapnia increase coronary flow and myocardial tissue oxygen tension but myocardial aerobic metabolism is impaired during hypercapnia.
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Randomized Controlled Trial Clinical Trial
[Prolongation and recovery under sevoflurane anesthesia of neuromuscular blocking action of vecuronium].
Thirty-seven patients (ASA I or II) undergoing elective abdominal surgery were randomly allocated to four groups, which were anesthetized with nitrous oxide 67%, oxygen 33% and sevoflurane 0%, 1%, 2% and 3% respectively. We administered clinically used doses of vecuronium for abdominal surgery and studied the duration (the time from 100% block after injection to 20% recovery) and the recovery time (time from the last injection of vecuronium to 20% recovery). No prolongation of neuromuscular blocking effect was demonstrated with the initial dose of vecuronium. Significant prolongations of the duration and the recovery time were demonstrated with the maintenance dose of vecuronium only with sevoflurane over 2% and the effect was concentration-dependent.
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Total intravenous anesthesia with droperidol, fentanyl and ketamine (DFK) was given to over three thousand patients during four years from April 1989 through March 1993. The patients ranged in age from three months to eighty seven years. They underwent surgical, orthopedic, gynecological, thoracic, plastic and otolaryngeal surgeries, but patients who underwent craniotomy and obstetric operations were excluded. ⋯ Calcium channel blockers are very effective for antagonizing high blood pressure, and rapid recovery from anesthesia can be easily obtained by reducing ketamine dose given and also by application of epidural block. Intraoperative dreams may be avoided by concomitant use of benzodiazepines. Thus we are convinced that DFK can be a good as well as convenient anesthetic method for clinical anesthesia.
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Comparative Study
[Effects of sevoflurane on hemodynamics during the induction of anesthesia compared with those of isoflurane, enflurane and halothane].
The effects of sevoflurane (S), isoflurane (I), enflurane (E) and halothane (H) on hemodynamics were studied in 50 patients during the inhalation of 1.5 MAC of each anesthetic before the surgery. Mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI) and stroke volume index (SVI) were measured noninvasively using the automatic blood pressure manometer and the ultrasonic Doppler method (Accucom). ⋯ The values of CI, SVRI, SVI with S, as well as with I, were between those of E and H. These results indicate that sevoflurane causes the depression of blood pressure mostly by decreasing afterload during the induction of anesthesia, although the decrement with sevoflurane, as well as that with isoflurane, is less than that with enflurane.