Anesthesiology
-
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.
-
Randomized Controlled Trial Comparative Study
Is the performance of acceleromyography improved with preload and normalization? A comparison with mechanomyography.
Many studies have indicated that acceleromyography and mechanomyography cannot be used interchangeably. To improve the agreement between the two methods, it has been suggested to use a preload and to refer all train-of-four (TOF) ratios to the control TOF (normalization) when using acceleromyography. The first purpose of this study was to test whether a preload applied to acceleromyography would increase the precision and the agreement with mechanomyography. The second purpose was to evaluate whether normalization would improve the agreement with mechanomyography. ⋯ Preload increases the precision of acceleromyography, and normalization of the TOF ratios decreases bias in relation to mechanomyography. When both acceleromyography and mechanomyography are normalized, there is no significant bias between the two methods.
-
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.
-
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.