Anesthesiology
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In the last 4 y, several authors have reported largely satisfactory results using the new steroid intravenous anesthetic eltanolone (pregnanolone) to induce anesthesia. Until now, however, no investigations have addressed the infusion pharmacokinetics of eltanolone or used electroencephalographic effect data for full pharmacodynamic modeling. Thus the authors conducted a study to evaluate the pharmacokinetic and pharmacodynamic properties of eltanolone after infusion in healthy volunteers. ⋯ Eltanolone is a new potent steroid-type hypnotic agent with rapid elimination characteristics. Although it is short-acting, the remarkable hysteresis limits the control and might complicate administration of eltanolone if it is used as a component of a complete intravenous anesthesia regimen. Furthermore, it involves the potential disadvantage of drug accumulation and it prolongs recovery if larger-than-necessary doses are used to induce anesthesia rapidly.
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Although evidence suggests that secretions lining the inner wall of the endotracheal tube (ETT) often reduce its cross-sectional area, no data are available on the work of breathing as affected by the ETT. A noninvasive method is proposed for estimating the additional work of breathing necessitated by the ETT in patients whose lungs are mechanically ventilated. This method (the acoustic-Blasius method) involves (1) determining the inner geometry of the ETT using the acoustic reflection method and (2) using these geometric data to solve the Blasius equation that characterizes the ETT pressure drop-flow relation. ⋯ The data show that the acoustic-Blasius method allows noninvasive quantification of the ETT-related work of breathing in situ.
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Cardiopulmonary bypass (CPB) and hypothermic circulatory arrest (HCA) are associated with neurological injury. Altered immediate-early gene expression occurs rapidly in the brain in response to ischemia, hypoxia, and severe metabolic stress, which results in long-term changes in the molecular phenotype of neurons. This study determined the effects of CPB and HCA on the expression of the immediate-early gene c-fos. ⋯ Cardiopulmonary bypass and HCA alter immediate-early gene expression in the brain. Translational processes are impaired after 120 min of HCA and correlate with neuron death in the hippocampus.
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Letter Case Reports
Spinal meningitis masquerading as postdural puncture headache.