Anesthesiology
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Comparative Study
Effects of isoflurane versus fentanyl-nitrous oxide anesthesia on long-term outcome from severe forebrain ischemia in the rat.
This study examined long-term outcome from severe forebrain ischemia in the rat, as a function of anesthetic given during the ischemic injury. ⋯ This study found no change in the percent alive CA1 hippocampal neurons as a function of duration of recovery from severe forebrain ischemia in isoflurane anesthetized rats. In contrast, the percent alive CA1 neurons in fentanyl-nitrous oxide-anesthetized rats tripled over 3 months of recovery. The natural history of long-term responses to forebrain ischemia requires further study before conclusions can be drawn with respect to the permanence of isoflurane neuroprotection.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of a circulating-water garment and forced-air warming on body heat content and core temperature.
Forced-air warming is sometimes unable to maintain perioperative normothermia. Therefore, the authors compared heat transfer, regional heat distribution, and core rewarming of forced-air warming with a novel circulating-water garment. ⋯ The circulating-water system transferred more heat than forced air, with the difference resulting largely from posterior heating. Circulating water rewarmed patients 0.4 degrees C/h faster than forced air. A substantial peripheral-to-core tissue temperature gradient with each device indicated that peripheral tissues insulated the core, thus slowing heat transfer.
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Comparative Study
Smoking behavior and perceived stress in cigarette smokers undergoing elective surgery.
The forced abstinence from cigarettes accompanying surgery in smoke-free facilities may increase psychological stress by removing a coping mechanism and by nicotine withdrawal. The authors tested the hypothesis that abstinence from cigarette smoking contributes to psychological stress in the perioperative period. ⋯ Although smokers report increased baseline stress, smoking status does not affect changes in perceived stress over the perioperative period. Nicotine withdrawal symptoms do not seem to be a clinically significant problem in the perioperative period for most smokers.
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Comparative Study
Propofol modulates gamma-aminobutyric acid-mediated inhibitory neurotransmission to cardiac vagal neurons in the nucleus ambiguus.
Although it is well recognized that anesthetics modulate the central control of cardiorespiratory homeostasis, the cellular mechanisms by which anesthetics alter cardiac parasympathetic activity are poorly understood. One common site of action of anesthetics is inhibitory neurotransmission. This study investigates the effect of propofol on gamma-aminobutyric acid-mediated (GABAergic) and glycinergic neurotransmission to cardiac parasympathetic neurons. ⋯ Propofol may vary heart rate by modulating GABAergic neurotransmission to cardiac parasympathetic neurons. At clinically relevant concentrations (> or =1.0 microm), propofol facilitated GABAergic responses in cardiac vagal neurons by increasing decay time, which would increase inhibition of cardioinhibitory cardiac vagal neurons and evoke an increase in heart rate. At higher supraclinical concentrations (> or =50 microm), propofol inhibits GABAergic neurotransmission to cardiac vagal neurons, which would evoke a decrease in heart rate.
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Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility. ⋯ Ultrasound guidance seems to be a promising new technique with clinical relevance and the potential to increase practicability while avoiding radiation in lumbar facet nerve block.