Journal of anesthesia
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Journal of anesthesia · Jan 2006
Randomized Controlled TrialEffect-compartment equilibrium rate constant (keo) for propofol during induction of anesthesia with a target-controlled infusion device.
The effect-compartment concentration (C(e)) of a drug at a specific pharmacodynamic endpoint should be independent of the rate of drug injection. We used this assumption to derive an effect-compartment equilibrium rate constant (k(eo)) for propofol during induction of anesthesia, using a target controlled infusion device (Diprifusor). Eighteen unpremedicated patients were induced with a target blood propofol concentration of 5 microg x ml(-1) (group 1), while another 18 were induced with a target concentration of 6 microg x ml(-1) (group 2). ⋯ Using this population technique, we found the k(eo) to be 0.57 min(-1). The mean (SD) effect compartment concentration at loss of the eyelash reflex was 2.39 (0.70) microg x ml(-1). This means that to achieve a desired C(e) within 3 min of induction, the initial target blood concentration should be set at 1.67 times that of the desired C(e) for 1 min, after which it should revert to the desired concentration.
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Journal of anesthesia · Jan 2006
Randomized Controlled TrialEffect of peak inspiratory flow on gas exchange, pulmonary mechanics, and lung histology in rabbits with injured lungs.
The aim of this study was to evaluate, using a rabbit model, the little-known effect of different levels of peak inspiratory flow on acutely injured lungs. ⋯ In rabbits with injured lungs, high peak inspiratory flow with high tidal volume (V(T)) reduces the Pa(O(2))/FI(O(2)) ratio and increases the lung wet-to-dry ratio.
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Journal of anesthesia · Jan 2006
Randomized Controlled TrialFlexible, tapered-tip tube facilitates conventional orotracheal intubation by novice intubators.
Orotracheal intubation is the standard technique for airway management, but several untoward airway complications are possible with this method. To avoid airway trauma caused by the tube tip during intubation, the Parker Flex-Tip tube (PFT), which has a flexible, tapered tip, was developed. It has been reported that the PFT facilitates fiberoptic orotracheal intubation and introducer-guided tracheal intubation. ⋯ PFT did not shorten the time required for intubation and did not reduce the incidence of sore throat and hoarseness. However, a detailed analysis revealed that the PFT decreased the time required for intubation in the anesthesia trainee group. The PFT may help novice intubators to conduct a smooth intubation.
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Journal of anesthesia · Jan 2006
Increase in intracellular Ca2+ concentration is not the only cause of lidocaine-induced cell damage in the cultured neurons of Lymnaea stagnalis.
To determine whether the increase in intracellular Ca2+ concentration induced by lidocaine produces neurotoxicity, we compared morphological changes and Ca2+ concentrations, using fura-2 imaging, in the cultured neurons of Lymnaea stagnalis. ⋯ These results indicated that the increase in intracellular Ca2+ concentration is not the only cause of lidocaine-induced cell damage.
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Journal of anesthesia · Jan 2006
Combined effects of propofol and mild hypothermia on cerebral metabolism and blood flow in rhesus monkey: a positron emission tomography study.
Propofol reduces the cerebral metabolic rate for oxygen (CMRO2), regional CMRO2 (rCMRO2), cerebral blood flow (CBF), and regional CBF (rCBF), but maintains the coupling of cerebral metabolism and blood flow. Under mild to moderate hypothermia, the coupling is maintained, while rCBF is reduced, but no direct measurement of rCMRO2 has yet been reported. This study aimed to evaluate the effects of propofol under normothermic and mild hypothermic temperatures upon rCMRO2, rCBF, and their regional coupling, through direct measurement by positron emission tomography. ⋯ During propofol anesthesia, it is possible to reduce cerebral metabolism throughout the entire brain as well as in any brain region by increasing the propofol dose or inducing hypothermia. The concurrent use of these two interventions has an additive effect on metabolism, and can be considered as safe, as their combination does not impair the coupling of cerebral metabolism and blood flow.