Masui. The Japanese journal of anesthesiology
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This study was undertaken to examine the thermal pain thresholds over a wide area of the lower body surface following the intrathecal administration of capsaicin in rats. Thermal nociceptive thresholds measured under light halothane anesthesia were determined as skin twitch or escape response latencies to the heat stimulation (52.0 degrees C) by a thermal probe. Capsaicin (50 micrograms in 10 microliters) was injected through a chronically implanted catheter whose tip was near the lumbar enlargement of the spinal cord. ⋯ Intensities of thermal analgesia at the sole of hind paws measured by hot-plate test correlated well with those by thermal probe test. In conclusion, intrathecal capsaicin definitely produced thermal analgesia, but its intensity was considerably variable in the hind paws. These results are in keeping with our previous finding that there was much variability in the effect of capsaicin assessed by the hot-plate test, indicating a possibility that capsaicin does not spread uniformly in the CSF because of its water insolubility or difficulty in penetrating to the large nerve roots innervating the hind paws.
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In order to determine the optimal level of epidural anesthesia, the author examined respiratory function of 138 full-term pregnant women in sitting and supine positions without anesthesia, and in supine position under epidural anesthesia prior to the cesarean section. Vital capacity (VC) increased in the sitting position in comparison with supine position because expiratory reserve volume (ERV) and tidal volume (TV) increased. In contrast, %FFV1.0, peak expiratory flow (PEF) and V75 decreased as uterus shifted anteriorly in the sitting position. ⋯ This change depended on the paralysis of respiratory muscles and the dyspneic feeling of patient. Generally %FFV1.0 and the data related to flow volume curve decreased under epidural anesthesia. In conclusion, epidural anesthesia with T4-T6 levels accompanied a sufficient analgesic efficacy and respiratory function comparable with that in the sitting position without anesthesia, therefore this was considered to be a method of choice for cesarean section.
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In 105 adult patients under halothane anesthesia, the neuromuscular blocking effects of vecuronium and pancuronium were determined with prior succinylcholine 1 mg.kg-1 administration and without. Force of the evoked twitch increased 123.7% of control after recovery from succinylcholine-induced block. ⋯ Onset of the force reduction from initial dose (0.08 mg.kg-1) was faster and recovery from initial and maintenance doses (0.02 mg.kg-1) were slower. This potentiating effect persisted at least 2 hours.
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For checking the reliability of pulse oximetry in the operating rooms, we compared values of arterial O2 saturation measured by a blood gas analyzer (SAT) with values monitored by pulse oximetry (SaO2). SaO2's were found to be significantly different from SAT's. The regression equation was SAT = 0.31 X SaO2 + 68.4 and the correlation coefficient was 0.66. ⋯ P value of paired comparison was 0.3244. The reliability of pulse oximetry differs from one anesthesiologist to another and depends upon the accuracy of each pulse oximeter. In clinical experiment, using the data by pulse oximetry in operating room is misleading.