Anesthesiology
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Comparative Study
Hemodynamic effects of doxacurium chloride in patients receiving oxygen sufentanil anesthesia for coronary artery bypass grafting or valve replacement.
Doxacurium chloride is an investigational long-acting neuromuscular blocking drug, which has been shown to be devoid of cardiovascular side effects when administered in modest doses to healthy patients. This is the first hemodynamic study of doxacurium in adult patients with cardiac disease. Forty-one patients scheduled to undergo cardiac surgery were studied. ⋯ At no time was there any significant change in mean arterial pressure, right atrial pressure, or cardiac output. Likewise derived hemodynamic variables including cardiac index, stroke volume, and pulmonary vascular resistance were unchanged. In addition to the decrease in heart rate, the hemodynamic changes, which reached statistical significance, were clinically insignificant and occurred predominantly in the group of patients receiving doxacurium 0.08 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
The thermoregulatory threshold in humans during nitrous oxide-fentanyl anesthesia.
Narcotics and nitrous oxide (N2O) inhibit thermoregulatory responses in animals. The extent to which N2O/fentanyl anesthesia lowers the thermoregulatory threshold in humans was tested by measuring peripheral cutaneous vasoconstriction using skin-surface temperature gradients (forearm temperature-fingertip temperature) and the laser Doppler perfusion index. Fifteen unpremedicated patients were anesthetized with N2O (70%) and fentanyl (10 micrograms/kg iv bolus followed by 4 micrograms.kg-1.h-1 infusion) during elective, donor nephrectomy. ⋯ Four hypothermic patients developed a passive thermal steady state without becoming sufficiently cold to trigger vasoconstriction. Thus, active thermoregulation occurs during N2O/fentanyl anesthesia but does not occur until core temperatures are approximately 2.5 degrees C lower than normal. The thermoregulatory threshold during N2O/fentanyl anesthesia is similar to that previously determined during halothane (34.4 +/- 0.2 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Fentanyl suppression of nociceptive neurons in the superficial dorsal horn of the cat.
This study was designed to examine the influence of spinally administered fentanyl on the spontaneous and noxiously evoked activity of high threshold (HT) and wide dynamic range (WDR) neurons in the superficial layers (lamina I and II) of the dorsal horn of cats made decerebrate and in which the spinal cord had been transected. Single unit activity was recorded using extracellular microelectrode recording techniques. Neuronal activity was evoked by the presentation of noxious radiant heat (51 degrees C) to the cells' receptive fields on the hind paws. ⋯ Within 30 minutes 10 and 25 micrograms of fentanyl reduced the mean evoked activity of WDR neurons to 61% and 19% of control values, respectively, and 25 and 50 micrograms of fentanyl reduced the mean evoked activity of HT neurons to 70% and 47% of control values, respectively. Naloxone reversed the suppression seen in all cells studied. The results of the present study demonstrate that HT neurons are significantly less suppressed by the spinal administration of fentanyl than WDR neurons located in the same superficial layers of the dorsal horn.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Isoflurane anesthesia causes a transient alteration in nocturnal sleep.
Nocturnal sleep was studied in eight healthy young volunteers before and after isoflurane anesthesia. All night polysomnographic recordings were obtained for seven consecutive nights from approximately 2300 to 0700 h. On the morning after the third night each subject was anesthetized with isoflurane 1.1 MAC for approximately 3 h. ⋯ Anesthesia was followed by daytime napping in six of the eight volunteers. Nocturnal sleep was similar in the subjects who napped and those who did not. It is concluded that anesthesia with isoflurane leads to a modest and a transient change in the architecture of nocturnal sleep.