Here is the design of a clinical trial:

Official Title: A Randomized Controlled Trial of the Effect of Hydrocortisone on Survival Without Bronchopulmonary Dysplasia and on Neurodevelopmental Outcomes at 22 - 26 Months of Age in Intubated Infants < 30 Weeks Gestation Age

Included conditions:
- Infant, Newborn
- Infant, Small for Gestational Age
- Infant, Very Low Birth Weight
- Infant, Premature
- Bronchopulmonary Dysplasia

Study Armgroups:
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'Saline placebo', 'interventionNames': ['Drug: Placebo']}
- {'label': 'Hydrocortisone', 'type': 'EXPERIMENTAL', 'description': 'hydrocortisone sodium succinate for intravenous administration (unpreserved, Solu-Cortef plain, Pfizer®, reconstituted with unpreserved normal saline to avoid exposure to the benzyl alcohol contained in preserved diluents)', 'interventionNames': ['Drug: Hydrocortisone']}

Interventions:
- {'type': 'DRUG', 'name': 'Hydrocortisone', 'description': 'Hydrocortisone sodium succinate for intravenous administration (unpreserved, Solu-Cortef plain, Pfizer®, reconstituted with unpreserved normal saline to avoid exposure to the benzyl alcohol contained in preserved diluents), to be administered either intravenously or orally if no intravenous line is available at the same dose, and tapered as follows:\n\n4mg/kg/day ¸ q 6 hours x 2 days, then 2mg/kg/day ¸ q 6 hours x 3 days; then\n\n1mg/kg/day ¸ q 12 hours x 3 days; then 0.5mg/kg/d as a single dose x 2 days', 'armGroupLabels': ['Hydrocortisone']}
- {'type': 'DRUG', 'name': 'Placebo', 'description': 'Saline placebo to be administered either intravenously or orally if no intravenous line is available, at the same dose, and tapered as follows:\n\n4mg/kg/day ¸ q 6 hours x 2 days, then 2mg/kg/day ¸ q 6 hours x 3 days; then\n\n1mg/kg/day ¸ q 12 hours x 3 days; then 0.5mg/kg/d as a single dose x 2 days', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Survival Without Moderate/Severe Physiologic Bronchopulmonary Dysplasia (BPD)', 'description': 'Survival without moderate or severe physiologic BPD at 36 weeks postmenstrual age. Moderate or severe physiologic BPD is defined as a requirement for supplemental oxygen and/or positive airway pressure to maintain oxygen saturation greater than 90 percent. A room air challenge was performed for infants estimated to be receiving less than 0.30 FiO2 by nasal cannula.', 'timeFrame': 'From day of randomization to 36 weeks post menstrual age'}
- {'measure': 'Survival Without Moderate/Severe Neurodevelopmental Impairment (NDI)', 'description': 'Survival without moderate or severe neurodevelopmental impairment (NDI) at 22-26 months corrected age. NDI is defined as defined as any of: Bayley Scales of Infant and Toddler Development-III (Bayley-III) cognitive composite score less than 85 (standardized mean 100, SD 15, range 55-145) or motor composite score less than 85 (standardized mean 100, range 45-155) (lower scores indicating greater impairment), Gross Motor Function Classification System (GMFCS) level greater than or equal to II (on a scale from level I to V; I=normal and progressively higher levels indicate greater impairment), severe vision impairment in both eyes (consistent with refraction from less than 20 to 200), or bilateral hearing impairment with or without amplification (by report).', 'timeFrame': 'From day of randomization to 22-26 months corrected age'}

Please estimate the sample size based on the assumption: 
The study assumes a two-tailed test with a Type I error set at 5% and aims for ≥80% power. It also accounts for potential difficulty in recruitment and changes in the NRN composition. For functional respiratory outcomes, the study assumes a small-sized effect f (standard deviation of the means) of 0.12 or higher, with 10 covariates accounting for 20% of the variation in the outcome. For impulse oscillometry, the study assumes a medium-sized effect f of 0.26 or higher.
Sample size and power estimates
          The sample size for the HYBRiD Outcomes Study is dictated by the number of participants who were enrolled in the primary trial (nâ=â800) and survived until early school age (approximate nâ=â720). Based on prior NRN follow-up studies, we anticipate that about 80% of surviving children enrolled in the parent trial will be evaluated for this proposed follow-up study (nâ=â575). To account for potential difficulty in recruitment of older children who are not currently being actively tracked at all sites and potential losses with changes to the composition of the NRN, we conservatively present power projections using 500 children or 250 on each arm.
          Projected power for the HYBRiD Outcomes Study composite primary outcome of functional impairment is based on estimated event rates from the neonatal literature, because no study has assessed the same composite outcome and the current study population is expected to have higher morbidity than many existing trial or population-based cohorts [8, 56]. The Victorian Infant Collaborative Study reported âclinically important neurobehavioral impairmentâ (mild to major neurosensory, intellectual, educational, or behavioral impairment) in 55% of extremely low birth weight infants at 8 years [57]. Based on these data, we conservatively hypothesized that at least one component of the composite (functional motor, cognitive, academic, or respiratory impairment) will be present in about 50% of the placebo group. Note that this assumption provides the most conservative estimate of power for this study.
          Assuming a two-tailed test with Type I error set at 5%, a sample size of 500 participants will provideââ¥â80% power to detect a difference of â¥â13% in the risk of functional developmental impairments between the two treatment groups. This is a clinically meaningful difference in outcome rates, with 8 being the number needed to treat to prevent one child from having functional disability. This magnitude of difference is similar to the effect size noted for trials of high-risk populations in the meta-regression of the relationship between of dexamethasone exposure and death or cerebral palsy by Doyle, et al. [18]
          In addition to the outcome of functional developmental impairment, we examined power for comparisons of functional respiratory outcomes (e.g., distance from 6-minute walk test). With Nâ=â500, we would have >â80% power to detect differences in mean scores between the two treatment groups with a small-sized effect f expressed as the standard deviation of the means [58]. Specifically, we have >â80% power to detect fâ=â0.12 or higher, assuming the inclusion of 10 covariates accounting for 20% of the variation in the outcome. For the subgroup receiving impulse oscillometry (Nâ=â100), we would have >â80% power to detect differences in mean values for impulse oscillometry between the two groups for medium-sized and larger effects (fâ=â0.26 or higher).