Here is the design of a clinical trial:

Official Title: Investigating the Role of Gas Flow in Transnasal Pulmonary Aerosol Delivery Via Nasal Cannula: A Double-blinded, Randomized Controlled Trial

Included conditions:
- COPD Asthma

Study Armgroups:
- {'label': 'Gas flow 50 L/min', 'type': 'ACTIVE_COMPARATOR', 'description': 'In this group, nasal cannula gas flow will be set at 50 L/min.', 'interventionNames': ['Other: nasal cannula gas flow']}
- {'label': 'GF:IF=1', 'type': 'EXPERIMENTAL', 'description': "In this group, nasal cannula gas flow will be set at each individual patient's own inspiratory flow (GF:IF=1)", 'interventionNames': ['Other: nasal cannula gas flow']}
- {'label': 'GF:IF=0.5', 'type': 'EXPERIMENTAL', 'description': "In this group, nasal cannula gas flow will be set at 50% of each individual patient's own inspiratory flow (GF:IF=0.5)", 'interventionNames': ['Other: nasal cannula gas flow']}

Interventions:
- {'type': 'OTHER', 'name': 'nasal cannula gas flow', 'description': 'High flow nasal cannula (HFNC) is a relatively new oxygen device, which provides warmed and humidified oxygen for patients. When patients need to inhale aerosolized medication during HFNC, the nebulizer will be placed in-line in order to provide both treatments. This study will investigate the influence of three flow settings (50 L/min, GF:IF=1, GF:IF=0.5) on the clinical effects of nebulization.', 'armGroupLabels': ['GF:IF=0.5', 'GF:IF=1', 'Gas flow 50 L/min']}

Primary Outcomes:
- {'measure': 'The number of patients who meet the positive criteria of responding to albuterol at the dose of 0.5mg', 'description': 'The number of patients in HFNC nebulization who respond to albuterol at the dose of 0.5mg', 'timeFrame': '30 minutes'}
- {'measure': 'The number of patients who meet the positive criteria of responding to albuterol at the dose of 1.5 mg', 'description': 'The number of patients in HFNC nebulization who respond to albuterol at the dose of 1.5mg', 'timeFrame': '60 minutes'}
- {'measure': 'The number of patients who meet the positive criteria of responding to albuterol at the dose of 3.5 mg', 'description': 'The number of patients in HFNC nebulization who respond to albuterol at the dose of 3.5mg', 'timeFrame': '90 minutes'}
- {'measure': 'The number of patients who meet the positive criteria of responding to albuterol at the dose of 7.5mg', 'description': 'The number of patients in HFNC nebulization who respond to albuterol at the dose of 7.5mg', 'timeFrame': '120 minutes'}

Please estimate the sample size based on the assumption: 
Confidence level (α) of 95%, power (1−β) of 80%, and margin (Δ) of 0.2.
Sample size calculation
        This study is a superiority study. Since all the recruited subjects are responders to 400 Î¼g of bronchodilator via MDI+VHCâand the inhaled dose of MDI+VHC is reported to be approximately 20% of emitted dose (80 Î¼g).21 From our in vitro study, inhaled dose of bronchodilator via nasal cannula at GF:IF=0.5 was found to be approximately 20% of dose,16 compared with 3.5% with gas flow rate at 50âL/min.14 15 We hypothesise that a 20% inhaled dose of 0.5âmg in the group of GF:IF=0.5âwould be 100 Î¼g, which is >80 Î¼g administered with MDI+VHC. In contrast, at 50âL/min with 3.5% lung dose an accumulative inhaled dose of 2.5âmg would provide an inhaled dose of 87.5 Î¼g. We hypothesise that almost all subjects in the GF:IF=0.5âgroup would respond to albuterol at the accumulative inhaled dose of 1.5âmg. To calculate the sample size, with confidence level (Î±) of 95%, power (1âÎ²) of 80% and margin (Î) of 0.2, we assumed 80% of GF: IF=0.5âgroup will respond to cumulative dose of 1.5âmg albuterol, compared with 40% 50âL/min group. The number of subjects in each group will be 25 and the total number of subjects will be 75.