Monitoring of asthma patients for bronchoconstriction has often relied on the use of pulmonary function tests such as the PEFR. Noninvasive attempts to measure respiratory obstruction have included the use of ear oximetry. Although oximetry is a useful method, it is insensitive except when severe abnormalities are present. It is therefore of limited value in moderate asthma. In the present study, no patient had significant desaturation while asleep.
Double-blind Crossover Study of Five Bronchodilator Medications and Two Delivery Methods in Stable Asthma: Is There a Best Combination for Use in the Pulmonary Laboratory?
There have been many investigations examining the physiologic responses of subjects to single bron-chodilator drugs, the physiologic responses to one drug in comparison to another, and the method of inhalation. The majority of these studies have looked at the safety and relative efficacies of the medications in relation to the speed of onset of bronchodilation in the treatment of asthmatic subjects, the time of peak response, the duration of the response, and the degree of side effects. There is still debate as to whether there is a best drug or method of delivery for circumstances such as laboratory testing. In our USAF Reference Cardiopulmonary Laboratory, nearly one third of our studies of pulmonary function involved bronchodilator agents in patients with reversible bronchospastic disease. It is obviously important to use the best medication and method of delivery to derive optimal changes on the tests of pulmonary function—within the twin restraints of cost and time available. In our laboratory, we had access to two different methods of delivery (compressed air-driven nebulizer and metered-dose inhalers) and medications from three major classes of autonomic active bronchodilator medications: (1) catecholamines (isoproterenol and isoetharine); (2) resorcinols (meta-proterenol and terbutaline); arid (3) saligenin (albuterol [salbutamol]). We therefore designed this double-blind crossover study to determine whether any one medication, method of delivery, or combination of medication and method of delivery would be statistically superior in a busy laboratory for the demonstration of short-term reversibility in a group of subjects with stable asthma.