Anesthesiology
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Comparative Study
Comparison of static end-expiratory and effective lung volumes for gas exchange in healthy and surfactant-depleted lungs.
Effective lung volume (ELV) for gas exchange is a new measure that could be used as a real-time guide during controlled mechanical ventilation. The authors established the relationships of ELV to static end-expiratory lung volume (EELV) with varying levels of positive end-expiratory pressure (PEEP) in healthy and surfactant-depleted rabbit lungs. ⋯ The parallel changes in ELV and EELV with PEEP in healthy and surfactant-depleted lungs support the clinical value of ELV measurement as a bedside tool to estimate dynamic changes in EELV in children and infants.
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The exact neurophysiological mechanisms of anesthetic-induced unconsciousness are not yet fully elucidated. The cortical information integration theory hypothesizes that loss of consciousness during general anesthesia is associated with breakdown of long-distance cortical connectivity across multiple brain regions. However, what is the effect of anesthetics on neural activities at a smaller spatial scale? ⋯ The results suggest that it is feasible to use the SI to measure cortical synchrony, and over a local spatial scale of 2-14 mm, synchrony increased during general anesthesia.