Anesthesiology
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Randomized Controlled Trial
A practical tranexamic acid dosing scheme based on population pharmacokinetics in children undergoing cardiac surgery.
Pediatric cardiac surgery patients are at high risk for bleeding, and the antifibrinolytic drug tranexamic acid (TA) is often used to reduce blood loss. However, dosing schemes remain empirical as a consequence of the absence of pharmacokinetic study in this population. The authors' objectives were thus to investigate the population pharmacokinetics of TA in pediatric cardiac surgery patients during cardiopulmonary bypass (CPB). ⋯ The authors report for the first time the pharmacokinetics of TA in children undergoing cardiac surgery with CPB, and propose a dosing scheme for optimized TA administration in those children.
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Use of high-dose inhalational anesthesia during open fetal surgery may induce maternal-fetal hemodynamic instability and fetal myocardial depression. The authors' preliminary human retrospective study demonstrated less fetal bradycardia and left ventricular systolic dysfunction with lower dose desflurane supplemented with propofol and remifentanil IV anesthesia (SIVA). In this animal study, the authors compare maternal-fetal effects of high-dose desflurane anesthesia (HD-DES) and SIVA. ⋯ In sheep, SIVA affects maternal hemodynamics less and provides better fetal acid/base status than high-dose desflurane. Fetal echocardiography did not reflect myocardial dysfunction in this model.
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Ultrasound guidance during peripheral nerve blocks has allowed for reduction in dose and volume of local anesthetic required to accomplish successful blockade using multiple injections through a needle. The authors undertook this study to determine the minimal effective volume required to accomplish successful interscalene brachial plexus block (ISB) through the catheter. ⋯ An injection of a minimum of 7 ml of ropivacaine 0.75% through the catheter is required for success rate and timely onset of surgical anesthesia with ISB.
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Ketamine is a commonly used anesthetic, but the mechanistic basis for its clinically relevant actions remains to be determined. The authors previously showed that HCN1 channels are inhibited by ketamine and demonstrated that global HCN1 knockout mice are twofold less sensitive to hypnotic actions of ketamine. Although that work identified HCN1 channels as a viable molecular target for ketamine, it did not determine the relevant neural substrate. ⋯ These data indicate that forebrain principal cells represent a relevant neural substrate for HCN1-mediated hypnotic actions of ketamine. The authors suggest that ketamine inhibition of HCN1 shifts cortical neuron electroresponsive properties to contribute to ketamine-induced hypnosis.
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Many children experience significant distress before and after surgery. Previous studies indicate that healthcare providers' and parents' behaviors may influence children's outcomes. This study examines the influence of adults' behaviors on children's distress and coping in the postanesthesia care unit. ⋯ Adults can influence children's distress and coping in the postanesthesia care unit. Empathy, distraction, and assurance talk may be helpful in keeping a child from becoming distressed, and nonprocedural talk and distraction may cue children to cope. Reassurance should be avoided when a child is already distressed.