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Airway Closure (airway + closure)
Selected AbstractsAirway closure in anesthetized infants and children: influence of inspiratory pressures and volumesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2002A. Thorsteinsson Background: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. Methods: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF6) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6,13 years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH2O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to ,20 cmH2O. (CC/EEV >1 indicates that airway closure might occur during tidal breathing). Furthermore, a measure of uneven ventilation, multiple breath alveolar mixing efficiency (MBAME), was obtained. Results: Airway closure within the tidal volume (CC/EEV >1) was observed in four and eight children (not significant, NS) after 20 and 30 cmH2O inflation, respectively. However, CC30/EEV was >CC20/EEV in all children (P,0.001). The MBAME was 75±7% (normal) and did not correlate with CC/EEV. Conclusion: Airway closure within tidal volumes may occur in artificially ventilated healthy children during ventilation with low inspiratory pressure. However, the risk of airway closure and thus opening within the tidal volume increases when the inspiratory pressures are increased. [source] The role of small airways in monitoring the response to asthma treatment: what is beyond FEV1?ALLERGY, Issue 11 2009N. Scichilone The definition of asthma has evolved from that of an episodic disease characterized by reversible airways constriction to a chronic inflammatory disease of the airways, with at least partially reversible airway constriction. Increasing evidence supports the notion that small and large airways play a central role in asthma pathophysiology with regard to inflammation, remodeling and symptoms. The contribution of the distal airways to the asthma phenotype carries implications for the delivery of inhaled medications to the appropriate areas of the lung and for the monitoring of the response to asthma treatment. Asthma control is evaluated on the basis of symptoms, lung function and exacerbations. However, evidence suggests that dissociation between lung function and respiratory symptoms, quality of life and airway inflammation exists. In this study, common spirometric parameters offer limited information with regard to the peripheral airways, and it is therefore necessary to move beyond FEV1. Several functional parameters and inflammatory markers, which are discussed in the present study, can be employed to evaluate distal lung function. In this study, extrafine formulations deliver inhaled drugs throughout the bronchial tree (both large and small airways) and are effective on parameters that directly or indirectly measure air trapping/airway closure. [source] | ||||||||||