Studies have shown that with a greater number of inflammatory cells in the airways, there is a higher degree of airway responsiveness. Airway Response to Allergen Challenge Researcher-induced models of human asthma to evaluate inflammation. Decreased PaO2 and narrowing of airways results in increased minute ventilation with excessive elimination of CO2 and respiratory alkalemia. Increased PCO2 usually not seen until airway obstruction is severe.
Respiratory alkalosis is most common.
Subgroup of asthmatics have persistent abnormalities in spirometry, lung volumes, etc., indicating a possible irreversible component. Diagnostic criteria for asthma Nocturnal episodes of coughing, dyspnea, wheezing, and chest tightness Waxing and waning symptoms History of heightened airway reactivity after exposure to exercise, aeroallergens, cold air, etc. Onset of bronchodilation relatively slow- maximum bronchodilation approx. Some studies show additive benefit of nebulized Ipratropium to B2-agonists in asthma.