Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Postoperative wound oxygen tension with epidural or intravenous analgesia: a prospective, randomized, single-blind clinical trial.
Adequate tissue oxygen tension is an essential requirement for surgical-wound healing. The authors tested the hypothesis that epidural anesthesia and analgesia increases wound tissue oxygen tension compared with intravenous morphine analgesia. ⋯ Epidural anesthesia and postoperative analgesia for major abdominal surgery increases wound tissue oxygen tension compared with general anesthesia and intravenous morphine analgesia.
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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.
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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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Sleep and anesthesia differ physiologically but produce a similar loss of responsiveness to environmental stimuli. Recent data suggest that neuronal networks active in naturally occurring sleep also play a role in the anesthetized state. Changes in the propensity to sleep may then modify the response to anesthetic agents. The authors tested the hypothesis that sleep-deprived rats would require less anesthetic than rested rats to achieve a similar loss of responsiveness. ⋯ Sleep deprivation significantly potentiated the ability of inhaled and intravenous anesthetic agents to induce a loss of righting reflex. These results support the hypothesis that neuronal networks active in sleep are also involved in the anesthetized state and suggest that sleep deprivation may partly explain the variability in patient response to anesthesia.