Journal of anesthesia
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Journal of anesthesia · Sep 1994
Tolerance to the mydriatic effect of buprenorphine, butorphanol, nalbuphine, and cyclorphan, and cross-tolerance to morphine in mice.
An increase in the use of opioid derivatives in the treatment of pain syndrome in clinical practice, and especially in the treatment of cancer, has added impetus to the search for an agent which does not induce tolerance and cross-tolerance to other opiodis. The mydriatic effect of opioids in mice, the correlation between analgesia and mydriasis, and tolerance to the analgesic effect of morphine in mice were evaluated previously. ⋯ Tolerance and cross-tolerance to morphine were developed following a chronic use of buprenorphine, nalbuphine, and cyclorphan. After chronic injection of butorphanol, no tolerance or cross-tolerance to morphine was observed.
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Journal of anesthesia · Sep 1994
RETRACTED ARTICLE: Airway occlusion pressure is an indicator of respiratory depression with isoflurane.
The purpose of this study was to elucidate the respiratory depressant effects of isoflurane (0%-1.0%) using airway occlusion pressure (P0.1), a known index of the output of the respiratory centers, in ten anesthetized patients. P0.1 was measured as the pressure change obtained after the first 0.1 sec of spontaneous inspiration against the occluded airway. A significant decrease in minute volume ([Formula: see text]) and a significant increase in PaCO 2 were not observed during the periods of isoflurane 1.0% at the end-tidal concentration compared with those of control period (0% isoflurane) (P<0.05), whereas a significant decrease in P0.1 was observed during the period of isoflurane 0.5%. Our results suggested that P0.1 was a more sensitive indicator of respiratory depression than PaCO 2 or[Formula: see text], and the respiratory center was depressed with a considerably lower concentration (0.5%) of isoflurane.
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Journal of anesthesia · Sep 1994
Lumbar epidural block reduces cough strength in healthy young subjects.
Effects of lumbar epidural block on maximum expiratory strength were studied in 12 healthy volunteers. Subjects performed maximum expiratory effort against occluded airway at functional residual capacity (FRC) and total lung capacity (TLC) while measuring airway pressure and electromyogram of the abdominal muscles (EMGab). Cough strength was assessed by maximum expiratory pressure (PEmax) and peak EMGab (peak-EMGab). ⋯ Compared with severe reduction in peak-EMGab, PEmax was well maintained at TLC, but changes in PEmax were identical to those in peak-EMGab at FRC. When analgesia spread to higher than T6, PEmax at TLC decreased considerably. We conclude that lumbar epidural block producing analgesia above T6 paralyzes the abdominal muscles and severely impairs the ability of effective cough in healthy young men.