Anesthesiology
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Comparative Study
Intracranial self-stimulation of the paraventricular nucleus of the hypothalamus: increased faciliation by morphine compared to cocaine.
Neuropathic pain attenuates opioid facilitation of rewarding electrical stimulation of limbic dopaminergic pathways originating from the ventral tegmental area. Whether neuropathic pain alters opioid effects of other brain-reward systems is unknown. ⋯ PVN ICSS is facilitated to a greater extent by morphine than cocaine, and the effects of each drug on this behavior are unaltered after spinal nerve ligation. These effects contrast those observed with direct stimulation of limbic dopamine pathways, suggesting that the PVN may have a greater role in the reinforcing effects of opioids than classic limbic regions, particularly in the presence of chronic pain.
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The evaluation of pain intensity during the immediate postoperative period is a key factor for pain management. However, this evaluation may be difficult in some circumstances. The pupillary dilatation reflex (PDR) has been successfully used to assess the analgesic component of a balanced anesthetic regimen. We hypothesized that PDR could be a reliable index of pain intensity and could guide morphine administration in the immediate postoperative period. ⋯ In the immediate postoperative period, the PDR is significantly correlated with the VRS. The pupillometer could be a valuable tool to guide morphine administration in the immediate postoperative period.
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High tidal volumes in patients with acute respiratory distress syndrome and acute lung injury lead to ventilator-induced lung injury and increased mortality. We evaluated the impact of tidal volumes on cardiac surgery outcomes. ⋯ Tidal volumes of more than 10 ml/kg are risk factors for organ failure and prolonged intensive care unit stay after cardiac surgery. Women and obese patients are particularly at risk of being ventilated with injurious tidal volumes.
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Methoxycarbonyl etomidate is an ultrarapidly metabolized etomidate analog. It is metabolized to methoxycarbonyl etomidate carboxylic acid (MOC-ECA), which has a hypnotic potency that is 350-fold less than that of methoxycarbonyl etomidate. The authors explored the relationships between methoxycarbonyl etomidate infusion duration, recovery time, metabolite concentrations in blood and cerebrospinal fluid (CSF), and methoxycarbonyl etomidate metabolism in brain tissue and CSF to test the hypothesis that rapid metabolism of methoxycarbonyl etomidate may lead to sufficient accumulation of MOC-ECA in the brain to produce a pharmacologic effect. ⋯ In rats, methoxycarbonyl etomidate metabolism is sufficiently fast to produce pharmacologically active MOC-ECA concentrations in the brain with prolonged methoxycarbonyl etomidate infusion.