Anesthesiology
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Randomized Controlled Trial
Anesthetic-induced improvement of the inflammatory response to one-lung ventilation.
Although one-lung ventilation (OLV) has become an established procedure during thoracic surgery, sparse data exist about inflammatory alterations in the deflated, reventilated lung. The aim of this study was to prospectively investigate the effect of OLV on the pulmonary inflammatory response and to assess possible immunomodulatory effects of the anesthetics propofol and sevoflurane. ⋯ This prospective, randomized clinical study suggests an immunomodulatory role for the volatile anesthetic sevoflurane in patients undergoing OLV for thoracic surgery with significant reduction of inflammatory mediators and a significantly better clinical outcome (defined by postoperative adverse events) during sevoflurane anesthesia.
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Comment Review Historical Article
Massive blood transfusions: the impact of Vietnam military data on modern civilian transfusion medicine.
To determine the coagulation defects associated with massive blood transfusions, coagulation studies were performed on 21 battle casualties admitted to the US Naval Support Activity Hospital, Da Nang, Vietnam. All but one patient who received less than 20 units of Acid-Citrate-Dextrose blood (7 patients) did not develop a coagulopathy. All patients who received more than 20 units (14 patients) developed a clinically significant coagulation defect. ⋯ The authors conclude that clinically important coagulopathies predictably occur after administration of 20-25 units of stored Acid-Citrate-Dextrose blood in acutely wounded, previously healthy soldiers. Fresh frozen plasma should not be a major therapeutic choice for coagulopathies in massive blood transfusions. Treatment of dilutional thrombocytopenia (50,000/mm(3)) is a primary component of treating coagulopathies associated with massive blood transfusions.
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When switching from two-lung to one-lung ventilation (OLV), shunt fraction increases, oxygenation is impaired, and hypoxemia may occur. Hypoxemia during OLV may be predicted from measurements of lung function, distribution of perfusion between the lungs, whether the right or the left lung is ventilated, and whether the operation will be performed in the supine or in the lateral decubitus position. ⋯ Hypoxemia during OLV may be treated symptomatically by increasing inspired fraction of oxygen, by ventilating, or by using continuous positive airway pressure in the nonventilated lung. Hypoxemia during OLV may be treated causally by correcting the position of the double-lumen tube, clearing the main bronchi of the ventilated lung from secretions, and improving the ventilation strategy.
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Nondepolarizing neuromuscular blocking agents (NMBAs) are classic competitive-inhibitors at the muscle nicotinic acetylcholine receptor (nAChR). Although the fetal subtype muscle nAChR has been extensively studied at a molecular level, less is known about the interaction between nondepolarizing NMBAs and the human adult muscle nAChR. The aim of this study was to investigate the effect of clinically used nondepolarizing NMBAs at human adult muscle nAChRs and the mechanisms behind the inhibition. ⋯ This study demonstrates that nondepolarizing NMBAs inhibit human adult muscle nAChRs expressed in Xenopus oocytes by mixed mechanisms. When using the nondesensitizing agonist dimethylphenylpiperazinium, inhibition by the NMBA is competitive, whereas activation with high concentrations of acetylcholine in combination with NMBA induces a noncompetitive inhibition, which the authors speculate can involve receptor desensitization similar to that observed in the neuromuscular junction.
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Residual neuromuscular blockade increases the risk to develop postoperative complications. The authors hypothesized that minimal neuromuscular blockade (train-of-four [TOF] ratio 0.5-1) increases upper airway collapsibility and impairs upper airway dilator muscle compensatory responses to negative pharyngeal pressure challenges. ⋯ Minimal neuromuscular blockade markedly increases upper airway closing pressure, partly by impairing the genioglossus muscle compensatory response. Increased airway collapsibility despite unaffected values for resting ventilation may predispose patients to postoperative respiratory complications, particularly during airway challenges.