Anesthesiology
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Randomized Controlled Trial Clinical Trial
Extent and localization of changes in upper airway caliber with varying concentrations of sevoflurane in children.
Previous studies in humans suggest that inhibition of upper airway muscle activity is independent of the dose of inhalational anesthesia. Whether a dose-independent relation applies to changes in airway caliber is unknown. The authors sought to evaluate the configurational changes that lead to upper airway narrowing during inhalational anesthesia with sevoflurane and to determine whether these changes are dose dependent within a clinically relevant dose range. ⋯ Increasing the depth of sevoflurane anesthesia resulted in a relatively uniform reduction in pharyngeal caliber at each anatomical level studied. The effect of sevoflurane on upper airway caliber is dose dependent.
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Randomized Controlled Trial
Pharmacokinetics and pharmacodynamics of midazolam and metabolites in nonventilated infants after craniofacial surgery.
Because information on the optimal dose of midazolam for sedation of nonventilated infants after major surgery is scant, a population pharmacokinetic and pharmacodynamic model is developed for this specific group. ⋯ In nonventilated infants after major surgery, midazolam clearance is two to five times higher than in ventilated children. From the model presented, the recommended initial dosage is a loading dose of 1 mg followed by a continuous infusion of 0.5 mg/h during the night for a COMFORT-Behavior of 12-14 in infants aged 1 yr. Large interindividual variability warrants individual titration of midazolam in these children.
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Preoperative clinics have been shown to decrease operating room delays and cancellations. One mechanism for this positive economic impact is that medical issues are appropriately identified and necessary information is obtained, so that knowledge of the patients' status is complete before the day of surgery. In this study, the authors describe the identification and management of medical issues in the preoperative clinic. ⋯ The preoperative evaluation can identify and resolve a number of medical issues that can impact efficient operating room resource use.
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L-Arginine transport mediated by type 2 cationic amino acid transporter (CAT-2) is one crucial mechanism that regulates nitric oxide production mediated by inducible nitric oxide synthase. Heme oxygenase (HO)-1 induction has been reported to significantly attenuate inducible nitric oxide synthase expression and nitric oxide production. The authors sought to explore the effects of HO-1 induction on CAT-2 expression and L-arginine transport. The effects of HO-1 induction on nuclear factor E2-related factor 2 (Nrf2) and nuclear factor kappaB (NF-kappaB) were also investigated. ⋯ HO-1 induction significantly inhibited CAT-2 expression and L-arginine transport in lipopolysaccharide-stimulated macrophages, possibly through mechanisms involved activation of Nrf2 and inhibition of NF-kappaB. In addition, carbon monoxide mediated, at least in part, the effects of HO-1 induction on CAT-2 expression and L-arginine transport.
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Intravenous anesthetics cause amnesia, but the underlying molecular mechanisms are poorly understood. Recent studies reveal a significant role of extracellular signal-regulated protein kinases (ERKs) in controlling synaptic plasticity and memory formation. As a major synapse-to-nucleus superhighway, ERK transmits N-methyl-D-aspartate (NMDA) receptor signals to inducible transcriptional events essential for NMDA receptor-dependent forms of synaptic plasticity and memory. This study investigated the role of the widely used intravenous anesthetic propofol in regulating NMDA receptor-dependent ERK phosphorylation. ⋯ These results suggest that propofol possesses the ability to inhibit NMDA receptor activation of the ERK pathway and subsequent transcriptional activities in hippocampal neurons. These findings indicate a new avenue to explore a transcription-dependent mechanism that may underlie anesthetic interference with synaptic plasticity related to amnesic properties of intravenous anesthetics.