Here is the design of a clinical trial:

Official Title: Integrated Strategies to Prevent Intradialytic Hypotension: a Prospective Randomized Cross-over Trial in Hypotension-prone Hemodialysis Patients (The DialHypot Study)

Included conditions:
- Hypotension During Dialysis
- Dialysis Hypotension

Study Armgroups:
- {'label': 'Linear descending UF profile', 'type': 'EXPERIMENTAL', 'description': '2-step descending Na profile, linear descending UF profile 3 weeks (9 sessions)', 'interventionNames': ['Other: UF and Na profiling']}
- {'label': 'Run-in & washout phases', 'type': 'EXPERIMENTAL', 'description': 'constant Na concentration, constant UF rate 3 weeks (6+3 sessions)', 'interventionNames': ['Other: UF and Na profiling']}
- {'label': 'Ascending/descending UF profile', 'type': 'EXPERIMENTAL', 'description': '2-step descending Na profile, ascending/descending UF profile 3 weeks (9 sessions)', 'interventionNames': ['Other: UF and Na profiling']}

Interventions:
- {'type': 'OTHER', 'name': 'UF and Na profiling', 'description': 'Modulation of UF and dialysate sodium', 'armGroupLabels': ['Ascending/descending UF profile', 'Linear descending UF profile', 'Run-in & washout phases']}

Primary Outcomes:
- {'measure': 'Occurrence of intradialytic hypotensive episodes (number of episodes within every HD session and time interval from HD start)', 'description': 'Hypotensive events and symptoms (headache, cramps, nausea and vomiting) will be recorded and analyzed as both number of occurrences and time of occurrence from the beginning of the HD session.\n\nIDH will be defined as follows:\n\n* "symptomatic IDH": decrease in SBP ≥ 20 mmHg or in MAP ≥ 10 mmHg associated with symptoms (KDIGO definition)\n* "asymptomatic IDH": drop in BP (SBP ≥ 20 mmHg or MAP ≥ 10 mmHg) within a 20 minutes interval, regardless of symptoms\n* for patients whose SBP is \\< 100 mmHg at the beginning of treatment, the investigators will consider as IDH any decrease of SBP ≥ 10%', 'timeFrame': 'Within each dialysis session from the time of enrolment to the end of each study phase (9-11 weeks)'}

Please estimate the sample size based on the assumption: 
85% power, alpha level of 0.05, two-tailed test, correlation between paired observations ranges between 0.1 and 0.5, dropout rate of 20%.
Sample size and assumptions
          Based on our preliminary data, assuming an incidence of hypotensive events of 4/9 of HD sessions with a classic (linear) UF profile, and a reduction in the incidence of IDH by 2/9 sessions with new (ascending/descending) UF profile, we estimated that at least 50 patients in a three-period three-treatment crossover trial would be needed to achieve 85% power to detect such difference between individualised ascending/descending UF profile and linear UF profile, with an alpha level of 0.05, using a two-tailed test if the correlation between paired observations ranges between 0.1 and 0.5. Therefore, we established a target sample of 60 patients, accounting for an approximate dropout rate of 20%.