Pulmonary Disease, Chronic ObstructiveForced Expiratory VolumeBronchodilator AgentsLung Diseases, ObstructiveDyspneaSpirometryRespiratory Function TestsPhosphodiesterase 4 InhibitorsVital CapacitySeverity of Illness IndexExercise ToleranceCyclopropanesOxygen Inhalation TherapyScopolamine DerivativesAminopyridinesAdministration, InhalationAlbuterolInspiratory CapacityMetered Dose InhalersGlycopyrrolateRespiratory MusclesIpratropiumTropanesPregnadienediolsTreatment OutcomeAdrenergic beta-2 Receptor AgonistsEthanolaminesSmokingLungLung Volume MeasurementsCholinergic AntagonistsExercise TestAdrenal Cortex HormonesEmphysemaQuality of LifeMuscarinic AntagonistsExercise TherapySputumResidual VolumeTotal Lung CapacityCross-Over StudiesPulmonary EmphysemaDouble-Blind MethodDiaphragmOxygenBreathing ExercisesQuadriceps MuscleStatistics, NonparametricAndrostadienesQuestionnairesNebulizers and VaporizersWalkingDrug CombinationsCarbon DioxideCase-Control StudiesHypercapniaDrug Therapy, CombinationExerciseDisease ProgressionAdrenergic beta-AgonistsCohort StudiesTime FactorsProspective StudiesHospitalizationCross-Sectional StudiesGlucocorticoidsBenzamidesActivities of Daily LivingRisk FactorsSingle-Blind MethodDrug Administration ScheduleRespirationFollow-Up StudiesCost-Benefit AnalysisHealth StatusRandomized Controlled Trials as TopicRespiratory MechanicsPrognosisPulmonary MedicineAsthmaRespiratory System AgentsBronchitis, ChronicPrevalenceExhalationReproducibility of ResultsRespiratory TherapyExpectorantsBronchiRetrospective StudiesBiological MarkersRespiratory InsufficiencyIndansComorbiditySmokeBronchitisalpha 1-Antitrypsin DeficiencyPredictive Value of TestsAnalysis of VarianceAirway ObstructionBreath Tests