Effectiveness of a heat and moisture exchanger in preventing hyperpnoea induced bronchoconstriction in subjects with asthma.
AUTOR(ES)
Gravelyn, T R
RESUMO
The effect of a heat and moisture exchanger, a device with hygroscopic material for conditioning inspired air, on hyperpnoea induced bronchoconstriction was studied in nine non-smoking volunteers with asthma, aged 19-32 years. Each had previously shown an increase of at least 100% in specific airways resistance (sRaw) to isocapnic hyperpnoea with dry air. On two separate days the subject performed isocapnic hyperpnoea with dry air at 60-70 l min-1 for five minutes. Before, immediately after, and five minutes after completion of a test sRaw measurements were made. Heat and moisture exchangers were placed in the breathing circuit on one of the two days. All subjects had an increase in sRaw of 100% or more without the heat and moisture exchangers (average increase 300%) but were protected from bronchoconstriction with the devices in place (average increase 7%) (p less than 0.005). The exchanger's resistance to airflow was less than 1 cm H2O for flow rates of 100 l min-1. A heat and moisture exchanger designed as a facemask or mouthpiece may allow a person with asthma to exercise without the need for prophylactic drugs.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=461013Documentos Relacionados
- Inhaled frusemide and exercise-induced bronchoconstriction in children with asthma.
- Plasma catecholamines during exercise-induced bronchoconstriction in bronchial asthma.
- Decrease of histamine induced bronchoconstriction by caffeine in mild asthma.
- Effect of verapamil and sodium cromoglycate on leukotriene D4 induced bronchoconstriction in patients with asthma.
- Effect of acetazolamide and amiloride against sodium metabisulphite-induced bronchoconstriction in mild asthma.