Heliox improves pulmonary mechanics in a pediatric porcine model of induced severe bronchospasm and independent lung mechanical ventilation

摘要

Background:A helium-oxygen gas mixture (heliox) has low gas density and lowturbulence and resistance through narrowed airways. The effects of heliox onpulmonary mechanics following severe methacholine-induced bronchospasm wereinvestigated and compared to those of a nitrogen-oxygen gas mixture (nitrox) inan innovative pediatric porcine, independent lung, mechanical ventilationmodel.Results:All of the lungs showed evidence of severe bronchospasm aftermethacholine challenge. Prospective definition of 'heliox response'was a 15% or greater improvement in lung function in the lung receiving helioxcompared with the matched lung receiving nitrox. Seven out of 10 pigs respondedto heliox therapy with respect to resistance and eight out of 10 pigs respondedto heliox therapy with respect to compliance and tidal volume (P< 0.03). After crossover from nitrox to heliox, eight out of eight lungssignificantly improved with respect to tidal volume, resistance and compliance(P < 0.001). After crossover from heliox to nitrox all eight lungsshowed a significant increase in resistance and a significant decrease in tidalvolume (P < 0.001).Conclusions:In a pediatric porcine model of acute, severe methacholine-inducedbronchospasm and independent lung mechanical ventilation, administration ofheliox improves pulmonary mechanics, gas flow, and ventilation. Administrationof heliox should be considered for support of pediatric patients with acute,severe bronchospasm requiring mechanical ventilation through small artificialairways.