Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1996
The effects of intrathecally administered FK480, a cholecystokinin-A receptor antagonist, and YM022, a cholecystokinin-B receptor antagonist, on the formalin test in the rat.
Cholecystokinin (CCK) is located in the brain and the spinal cord, and CCK antagonist is reported to enhance the analgesic effect of morphine. It has been suggested that, during inflammation, the level of endogenous opioid peptides increases in the spinal cord. Intrathecally administered CCK antagonist may have some analgesic effect during inflammation via the activated spinal opioid system. ⋯ Pretreatment, but not posttreatment, with YM022 depressed the Phase 1 and Phase 2 flinching behavior in a dose-dependent manner, and this YM022 effect was stereospecific and was not antagonized by naloxone. These data indicate that a CCK-B receptor antagonist, but not a CCK-A receptor antagonist, produces an antinociceptive effect in the rat formalin test. This effect of a CCK-B receptor antagonist was not mediated by the spinal opioid receptor activation.
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Anesthesia and analgesia · Jul 1996
Propofol and ethanol produce additive hypnotic and anesthetic effects in the mouse.
The sedative and anesthetic effects of ethanol and propofol when these drugs are coadministered are not known. Accordingly, we investigated the nature of the pharmacological interaction between ethanol and propofol during hypnosis and anesthesia in the mouse. Propofol, ethanol, and mixtures of the two were administered through the tail vein in male CD-1 mice (n = 162). ⋯ For the drugs in combination, the ED50 values for hypnosis with 0.95 confidence intervals were 6.98 (6.50, 7.49) mg/kg propofol with 0.61 (0.57, 0.66) g/kg ethanol, and for anesthesia were 10.55 (9.76, 11.42) mg/kg propofol with 0.93 (0.86, 1.05) g/kg ethanol, respectively. When plotted isobolographically, we found these combinations to be behaviorally additive both for hypnosis and anesthesia. Although a finding of synergism would have excluded the possibility of an identical mechanism of action for the drugs, elucidation of the molecular basis of the additivity must await further studies.
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Arterial blood pressure and heart rate changes after afferent somatic sensory nerve stimulation are termed the "somatosympathetic reflex" (SSR). Inhibition of the SSR may partially represent an antinociceptive action. This investigation examined the actions of the volatile anesthetic, desflurane, on the SSR evoked by peripheral nerve stimulation. ⋯ Sciatic nerve stimulation also elicited increases in heart rate which were significantly attenuated by desflurane (control; 37 +/- 6 bpm versus 1.5 MAC desflurane; 0 +/- 2 bpm). These findings demonstrate that desflurane produces dose-dependent cardiovascular depression in rats and, despite previous reports of sympathoexcitation, desflurane significantly attenuated both excitatory and inhibitory types of SSR. The results of this study also support a potential antinociceptive action for this anesthetic.
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Anesthesia and analgesia · Jul 1996
Preoperative fasting time: is the traditional policy changing? Results of a national survey.
Several papers in the 1980s questioned the wisdom of withholding clear liquids for more than 3 h before elective surgery. Furthermore, recent papers have suggested relaxing the current NPO after midnight (Latin: Nulla per os; or "nothing by mouth") practice in children and adults. To see whether the policy and practice regarding NPO status before elective surgery have changed in the United States, we performed a national survey. ⋯ In conclusion, our survey revealed that 69% of anesthesiologists in the United States have either changed their NPO policy or are flexible in their practice in allowing clear liquids before elective operation in children and 41% have done so for adult patients. The most frequently allowed clear liquids in the adult and pediatric population were water and apple juice. None of the respondents reported any medical adverse event associated with the institution of a flexible NPO policy.
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Anesthesia and analgesia · Jul 1996
Large-dose propofol alone in adult epileptic patients: electrocorticographic results.
The primary objective of this study was to evaluate the electrophysiologic effects of large-dose propofol, used as the sole anesthetic in patients with epilepsy. Nine patients with medically intractable complex partial epilepsy undergoing a three-stage approach to the surgical management of epilepsy were recruited. State I involved placement of the intracranial electrode array, while Stage II consisted of extraoperative localization of the seizure focus. ⋯ No ECoG evidence of seizure activity was detected in the seven patients completing the study. Burst suppression was attained in six patients using a mean dose of 5.7 mg/kg +/- 2.6. We conclude that large dose propofol alone does not trigger electrical epileptiform activity on the ECoG of seizure patients.