Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2006
A new method for estimating arterial occlusion pressure in optimizing pneumatic tourniquet inflation pressure.
To reduce pressure-related injuries resulting from pneumatic tourniquet use, the lowest possible inflation pressure is recommended. Arterial occlusion pressure (AOP) is a measure of the cuff pressure required to maintain a bloodless surgical field. However, its determination method is time consuming, requires operator skill, and is therefore seldom used in current practice. ⋯ Our results revealed tissue padding coefficients for extremities 20 to 75 cm in circumferences. An estimation method of AOP was developed [AOP = (systolic blood pressure + 10)/Tissue padding coefficient]. The new AOP estimation method may be a simple, rapid, and clinically practical alternative to the AOP determination method.
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Anesthesia and analgesia · Jun 2006
The neurotoxic effects of amitriptyline are mediated by apoptosis and are effectively blocked by inhibition of caspase activity.
Oral tricyclic antidepressants, widely used as adjuncts in the treatment of chronic pain, block sodium channels in vitro and nerve conduction in vivo. However, toxicity of amitriptyline has been observed after neural application. We therefore investigated the mechanism and possible prevention of amitriptyline neurotoxicity. ⋯ Co-incubation with z-vad-fmk substantially improved neuronal survival in culture. In conclusion, amitriptyline-induced neurotoxicity is mediated by apoptosis and is attenuated by inhibition of caspase activity, suggesting that inhibition of apoptotic pathways may be efficient at alleviating local anesthetic-induced neurotoxicity. In vivo studies will have to corroborate whether the co-injection of anti-apoptotic drugs with local anesthetics decreases neurotoxic side effects.
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Anesthesia and analgesia · Jun 2006
Comparative StudyThe effects of xenon on myogenic motor evoked potentials in rabbits: a comparison with propofol and isoflurane.
We compared the effects of xenon on myogenic motor evoked potentials (MEPs) with those of propofol and isoflurane in rabbits under ketamine/fentanyl anesthesia. Thirty animals were randomly allocated to one of 3 groups (n = 10 in each group). In the propofol group, propofol was administered at a rate of 0.4 mg x kg(-1) x min(-1) (small) and 0.8 mg x kg(-1) x min(-1) (large). ⋯ With single-pulse stimulation, MEPs were recorded in 90% and 50% of animals at small and large doses of xenon, respectively, and MEP amplitudes in the xenon and isoflurane groups were significantly lower compared with those in the propofol group. With train pulse stimulation, MEPs were recorded in 100% and 90% of animals at small and large doses of xenon, respectively, and a reduction in MEP amplitudes by xenon was more prominent than by propofol but less than isoflurane at large doses. These results suggest that MEP recording may be feasible under xenon anesthesia if multipulse stimulation is used, although xenon has suppressive effects on myogenic MEPs.
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Anesthesia and analgesia · Jun 2006
Comment Letter Comparative StudyRocuronium versus succinylcholine for rapid tracheal intubation.
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Anesthesia and analgesia · Jun 2006
The differential effects of halothane and isoflurane on electroencephalographic responses to electrical microstimulation of the reticular formation.
Isoflurane and halothane cause electroencephalographic (EEG) depression and neuronal depression in the reticular formation, a site critical to consciousness. We hypothesized that isoflurane, more than halothane, would depress EEG activation elicited by electrical microstimulation of the reticular formation. Rats were anesthetized with either halothane or isoflurane and stimulating electrodes were positioned in the reticular formation. ⋯ At 1.2 MAC isoflurane, burst suppression occurred and microstimulation decreased the period of isoelectricity (24% +/- 19% to 8% +/- 7%; P < 0.05), whereas the spectral edge and median edge frequencies were unchanged. At anesthetic concentrations required to produce immobility, the cortex remains responsive to electrical microstimulation of the reticular formation, although the EEG response is depressed in the transition from 0.8 to 1.2 MAC. These data indicate that cortical neurons remain responsive to synaptic input during isoflurane and halothane anesthesia.