Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1996
Twenty-four of twenty-seven studies show a greater incidence of emesis associated with nitrous oxide than with alternative anesthetics.
All obtainable investigations that have compared the incidence of vomiting in groups of patients who received nitrous oxide (N2O) and in patients who received anesthetics or analgesics without N2O were examined for a single, dichotomous variable: whether patients who received N2O experienced an absolutely higher incidence, as distinct from a statistically significantly higher incidence, of vomiting. The null hypothesis is that N2O has no effect on emesis, such that an increased incidence of vomiting should occur in about half of the studies examined. ⋯ The two-tailed probability that this result occurred by chance is < 0.00005. It follows that N2O increases the incidence of emesis compared to alternative anesthetics.
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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
Randomized Controlled Trial Clinical TrialHemodynamic responses to an epinephrine test dose in adults during epidural or combined epidural-general anesthesia.
The efficacy of an epinephrine test dose during epidural and combined epidural-general anesthesia is unknown. Thirty-two patients were randomized to receive 2% lidocaine at either a high (25 mL) or low (12 mL) thoracic level of epidural anesthesia followed by general anesthesia with 1 minimum alveolar anesthetic concentration nitrous oxide and isoflurane. ⋯ Incidences of identification of intravascular injection from hemodynamic responses were similarly reduced for systolic blood pressure (100% vs 44%) and heart rate (100% vs 38%). The standard 15-micrograms epinephrine test dose is unaffected by low thoracic levels of epidural anesthesia, but may have decreased sensitivity for detection of intravascular injection during high thoracic levels of epidural anesthesia, especially during general anesthesia.
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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.