Anesthesiology
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Multicenter Study
Early exposure to anesthesia and learning disabilities in a population-based birth cohort.
Anesthetic drugs administered to immature animals may cause neurohistopathologic changes and alterations in behavior. The authors studied association between anesthetic exposure before age 4 yr and the development of reading, written language, and math learning disabilities (LD). ⋯ Exposure to anesthesia was a significant risk factor for the later development of LD in children receiving multiple, but not single anesthetics. These data cannot reveal whether anesthesia itself may contribute to LD or whether the need for anesthesia is a marker for other unidentified factors that contribute to LD.
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Randomized Controlled Trial Comparative Study
Continuous positive airway pressure via the Boussignac system immediately after extubation improves lung function in morbidly obese patients with obstructive sleep apnea undergoing laparoscopic bariatric surgery.
Morbidly obese patients are at elevated risk of perioperative pulmonary complications, including airway obstruction and atelectasis. Continuous positive airway pressure may improve postoperative lung mechanics and reduce postoperative complications in patients undergoing abdominal surgery. ⋯ Administration of continuous positive airway pressure immediately after extubation maintains spirometric lung function at 24 h after laparoscopic bariatric surgery better than continuous positive airway pressure started in the postanesthesia care unit.
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Review
Obstructive sleep apnea of obese adults: pathophysiology and perioperative airway management.
Collapsible pharyngeal airway size is determined by interaction between structural properties of the pharyngeal airway and neural regulation of the pharyngeal dilating muscles. Obesity seems to have two distinct mechanical influences on the pharyngeal airway collapsibility. First, obesity increases soft tissue surrounding the pharyngeal airway within limited maxillomandible enclosure occupying and narrowing its space (pharyngeal anatomical imbalance). ⋯ Neural compensation for functioning structural abnormalities operating during wakefulness is lost during sleep, leading to pharyngeal obstruction. Instability of the negative feedback of the respiratory system may accelerate cycling of pharyngeal closure and opening. Improvement of the pharyngeal anatomical imbalance and maintenance of lung volume are the keys for safe perioperative airway managements of obese patients with obstructive sleep apnea.
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Emerging evidence indicates that an endogenous autocrine/paracrine system involving gamma-aminobutyric acid (GABA) is present in airways. GABAA channels, GABAB receptors, and the enzyme that synthesizes GABA have been identified in airway epithelium and smooth muscle. However, the endogenous ligand itself, GABA, has not been measured in airway tissues. The authors sought to demonstrate that GABA is released in response to contractile agonists and tonically contributes a prorelaxant component to contracted airway smooth muscle. ⋯ These studies demonstrate that GABA is endogenously present and increases after contractile stimuli in guinea pig upper airways and that endogenous GABA contributes a tonic prorelaxant component in the maintenance of airway smooth muscle tone.
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The Drosophila Shaker mutant fruit-fly, with its malfunctioning voltage-gated potassium channel, exhibits anesthetic requirements that are more than twice normal. Shaker mutants with an abnormal Kv1.2 channel also demonstrate significantly reduced sleep. Given the important role the thalamus plays in both sleep and arousal, the authors investigated whether localized central medial thalamic (CMT) microinfusion of an antibody designed to block the pore of the Kv1.2 channel might awaken anesthetized rats. ⋯ These findings support the idea that the CMT plays a role in modulating levels of arousal during anesthesia and further suggest that voltage-gated potassium channels in the CMT may contribute to regulating arousal or may even be relevant targets of anesthetic action.