Here is the design of a clinical trial:

Official Title: A Phase II Trial on the Safety and Efficacy of C1 Inhibitor for the Acute Management of Severe Traumatic Brain Injury

Included conditions:
- Traumatic Brain Injury
- Trauma, Head

Study Armgroups:
- {'label': 'C1-inhibitor', 'type': 'EXPERIMENTAL', 'description': 'One dose 6000 IU C1-inhibitor intravenously', 'interventionNames': ['Drug: C1 Inhibitor, Human']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': '0.9% saline', 'interventionNames': ['Drug: Placebo']}

Interventions:
- {'type': 'DRUG', 'name': 'C1 Inhibitor, Human', 'description': '6000 IU C1-INH', 'armGroupLabels': ['C1-inhibitor'], 'otherNames': ['Cinryze']}
- {'type': 'DRUG', 'name': 'Placebo', 'description': '0.9% saline', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Therapy Intensity Level (TIL) Scale', 'description': 'TIL differentiated for various treatment modalities aimed at prevention or control of raised Intracranial Pressure (ICP) and/or for CPP management (0 to 38 points)', 'timeFrame': 'First four ICU days'}
- {'measure': 'Glasgow Outcome Scale Extended (GOSE)', 'description': 'Functional outcome (minimum score = 1, maximum score = 8)', 'timeFrame': 'At 6 months after trauma'}
- {'measure': 'Complication rate', 'description': 'Adverse and serious adverse events related possibly related to study medication', 'timeFrame': 'Up to 1 year'}

Please estimate the sample size based on the assumption: 
90% power, 0.05 (two-sided) significance level, and approximately 10% withdrawal and loss to follow-up rate.
Sample size
        To detect a between-group difference in the TIL Scale of 2.2, with 90% power and 0.05 (two-sided) significance level, a total of 106 patients are required. Calculations were based on the anticipated mean of 8.2 and standard deviation 3.2 of the novel TIL in TBI patients admitted to the ICU [38]. The patient group treated with C1-INH is estimated to have an average TIL of 6 [39, 51]. Both treatment groups will include 53 patients to power the trial and to account for withdrawal and loss to follow-up (approximately 10%). With this sample size, a difference of 2.2 on the TIL scale can be detected, which is clinically relevant as it corresponds to one medium level of intervention (such as CSF drainage or mannitol treatment) less to control ICP indicating a significant treatment effect. As no minimal clinically important difference (MCID) for the TIL scale is defined in the literature, we will adhere to this shift of 2.2 points on the right-skewed scale.