Here is the design of a clinical trial:

Official Title: Intrapleural Fibrinolysis and DNase Versus VATS for the Treatment of Pleural Empyema: a Randomized, Controlled Trial

Included conditions:
- Pleural Empyema

Study Armgroups:
- {'label': 'VATS / surgical group', 'type': 'EXPERIMENTAL', 'description': 'The VATS procedure must be completed as soon as possible and no later than 48 hours after randomisation. The surgery is performed with the patient in a 90 degree sideways position, using general anesthesia. Access is obtained through one to three ports, followed by purification and possibly decortication, and insertion of one pleural drain (sizes 24 - 32F) at the end of surgery. 20 ml Marcain is used as local analgetic and applied at the incision sites or as a nerve block. In the VATS group, suction on drain (- 15 cm H20) is applied in the first day after the procedure. Operator must have relevant training and competencies corresponding to the specialist level within the relevant specialty and be registered and approved by the steering committee.', 'interventionNames': ['Procedure: VATS group']}
- {'label': 'Drain and intrapleural therapy group', 'type': 'ACTIVE_COMPARATOR', 'description': 'Pigtail is applied as soon as possible and within 48 hours after randomisation. Drain placement is carried out using ULS. Operators (conductors of the procedure) must have relevant training and competencies corresponding to the specialist level within the relevant specialty and be approved by the steering committee to conduct the procedure. A pigtail catheter (minimum 10F) is inserted. Operator determines the size of drain and whether drain placement is done with one-step or Seldinger technic.\n\nThe intrapleural therapy consists of treatment with the following two drugs:\n\n* intrapleural Actilyse® (alteplase) 10 mg twice daily for three days\n* intrapleural Pulmozyme® (DNase) 5 mg twice daily for three days', 'interventionNames': ['Procedure: Drain and intrapleural therapy group']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'VATS group', 'description': 'VATS procedure with drainage, including rinse with NaCl', 'armGroupLabels': ['VATS / surgical group']}
- {'type': 'PROCEDURE', 'name': 'Drain and intrapleural therapy group', 'description': 'Drainage with pigtail and Intrapleural therapy', 'armGroupLabels': ['Drain and intrapleural therapy group']}

Primary Outcomes:
- {'measure': 'Length of hospital stay', 'description': 'Admission time is defined as the time from first admission in the course of the hospitalization and to the completion of treatment defined as time of discharge from hospital without need of any additional invasive treatment.', 'timeFrame': 'Through study completion, an average of 1 year'}

Please estimate the sample size based on the assumption: 
The distribution of hospitalisation time is expected to be skewed, requiring a logarithmic transformation. The study assumes 80% power, a coefficient of variation (CV) of 40%, and a significance level of 0.05. A 20% exclusion rate is also considered.
Sample size and power calculation
        The study is based on assumptions and knowledge about LOS, both from national and international publications. We calculated the sample size based on the following assumptions: the main effect target is the difference between the total time (primary endpoint) between the two groups of patients (VATS vs drainage). The distribution of the hospitalisation time is expected to be skewed to the right, so that a logarithmic transformation is needed to achieve normality.
        We assume a median hospitalisation period in the drainage group of 12 days, a minimum clinically relevant difference in hospitalisation of 2âdays, 80% power and coefficient of variation (CV) of 40%.
        Significance level is set to 0.05. Thus, 77 patients in each group must be included. To account for excluded patients (set at 20%), we expect to include 92 patients in each group. A total of 184 patients is to be included.
        In terms of showing clinically relevant non-inferiority with a difference in hospitalisation of 1âday with an 80% power, and CV of 40%, 70âpatients is needed in each group. This is based on a true improvement of 1 hospitalisation day. Based on the annual number of patients diagnosed with pleura empyema in Denmark, we find it feasible to include the needed number of patients in the trial during the inclusion period.