Anesthesiology
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Case Reports
Does the A118G polymorphism at the mu-opioid receptor gene protect against morphine-6-glucuronide toxicity?
Some, but not all, patients with renal dysfunction suffer from side effects after morphine administration because of accumulation of the active metabolite morphine-6-glucuronide (M6G). The current study aims to identify genetic causes that put patients at risk for, or protect them from, opioid side effects related to high plasma M6G. Candidate genetic causes are the single nucleotide polymorphism (SNP) A118G of the mu-opioid-receptor gene (OPRM1), which has recently been identified to result in decreased potency of M6G, and mutations in the MDR1-gene coding P-glycoprotein, of which morphine and M6G might be a substrate. ⋯ The authors hypothesize that the A118G single nucleotide polymorphism of the mu-opioid-receptor is among the protective factors against M6G-related opioid toxicity. The observation encourages the search for pharmacogenetic reasons that cause interindividual variability of the clinical effects of morphine.
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The unprotected upper airway tends to obstruct during general anesthesia, yet its mechanical properties have not been studied in detail during this condition. ⋯ Isoflurane anesthesia is associated with decreased muscle activity and increased collapsibility of the upper airway. In this state it adopts the behavior of a Starling resistor. The decreased collapsibility observed with decreasing anesthetic depth was not a consequence of neuromuscular activity, which was unchanged. Rather, it may be related to increased lung volume and its effect on airway wall longitudinal tension. The predominant site of collapse is the soft palate.
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Randomized Controlled Trial Clinical Trial
Hemostatic activation and inflammatory response during cardiopulmonary bypass: impact of heparin management.
Cardiac surgery involving cardiopulmonary bypass (CPB) leads to fulminant activation of the hemostatic-inflammatory system. The authors hypothesized that heparin concentration-based anticoagulation management compared with activated clotting time-based heparin management during CPB leads to more effective attenuation of hemostatic activation and inflammatory response. In a randomized prospective study, the authors compared the influence of anticoagulation with a heparin concentration-based system (Hepcon HMS; Medtronic, Minneapolis, MN) to that of activated clotting time-based management on the activation of the hemostatic-inflammatory system during CPB. ⋯ Compared with heparin management with the activated clotting time, heparin concentration-based anticoagulation management during CPB leads to a significant reduction of thrombin generation, fibrinolysis, and neutrophil activation, whereas there is no difference in the effect on platelet activation. The generation of fibrin even in the presence of high heparin concentrations most likely has to be attributed to the reduced antithrombin III concentrations or reduced inhibition of clot-bound thrombin. Therefore, in addition to maintenance of higher heparin concentrations, monitoring and substitution of antithrombin III should be considered to ensure more efficient antithrombin activity during CPB.
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Randomized Controlled Trial Clinical Trial
Dose response of intrathecal adenosine in experimental pain and allodynia.
Intrathecal adenosine reduces areas of mechanical hypersensitivity and provides analgesia in patients with neuropathic pain. Adenosine also causes side effects, yet its dose response for either efficacy or side effects has not been examined in double blind studies. We studied two doses of intrathecal adenosine in humans with experimental hypersensitivity and the ability of the adenosine receptor antagonist, aminophylline, to reverse adenosine's effects. ⋯ There is no difference in efficacy to experimental hypersensitivity between the largest approved dose of intrathecal adenosine and a dose 25% this size, but side effects are more common with the larger dose. Failure of aminophylline to reverse adenosine's effects could reflect inadequate concentrations at receptors in the spinal cord after intravenous injection.