Here is the design of a clinical trial:

Official Title: Evaluation of the Effect of Cooled Haemodialysis on Cognitive Function in Patients Suffering With End-stage Kidney Disease: Feasibility Study

Included conditions:
- Cognitive Impairment

Study Armgroups:
- {'label': 'Control Group', 'type': 'NO_INTERVENTION', 'description': 'The control group will be at the standard dialysate temperature of 36.5 °C (which is the standard of care in the sites), 3 times a week for 12 months'}
- {'label': 'Lower Temperature Group', 'type': 'EXPERIMENTAL', 'description': 'These patients will receive haemodialysis with a dialysate temperature of 35 degree centigrade. The intervention group will start off using a dialysate temperature that is 36 °C. Thereafter the dialysate temperature will be reduced every two week by 0.5 °C until 35 °C or the lowest tolerated temperature reached. Patients who would fail to tolerate the temperature of 35 °C, the lowest tolerated temperature will be carried over to the end of the study.', 'interventionNames': ['Procedure: Lower Temperature Group']}
- {'label': 'Caregivers', 'type': 'NO_INTERVENTION', 'description': "Patients, who consent for the study, will be asked to identify the most suitable carer to participate in the study who could be approach in person, over the phone or by post as deemed suitable by the research team and convenient by the carer. Patient's permission to contact their identified carer will be recorded. Carers of consenting patients will be approached in the same manner as above after obtaining patients consent to contact their carers. Patients will still be able to take part in the study even if their carer declines consent."}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Lower Temperature Group', 'description': 'Dialysate temperature of 35 degree centigrade. The intervention group will start off using a dialysate temperature that is 36 °C. Thereafter the dialysate temperature will be reduced every two week by 0.5 °C until 35 °C or the lowest tolerated temperature reached.', 'armGroupLabels': ['Lower Temperature Group']}

Primary Outcomes:
- {'measure': 'Investigation of lower temperatures of dialysis and cognitive decline', 'description': 'To assess whether lower temperatures of dialysis fluid prevents the decline in cognitive function via utilisation of the Montreal Cognitive Assessment (MOCA) v7.2. The MOCA includes activities relating to Visuospatial / Executive (score out of 5); Naming (score out of 3); Memory (score of of 10); Attention (score out of 6); Naming (score out of 3) Abstraction (score out of 2); Delayed Recall (score out of 5) and Orientation (score out of 6). 1 point is given for each correct answer, and a higher score represents normal cognitive function, whilst lower scores represent possible cognitive decline. A total of 30 points can be achieved.', 'timeFrame': '1.5 years'}

Please estimate the sample size based on the assumption: 
The study aims for a 95% confidence interval. An expected attrition rate of 20% is considered.
Sample size
        The outcome data from this feasibility study will be used to inform the sample size calculation for the definitive trial, by providing estimates of the primary outcome and its variability and the expected attrition. The study aims to recruit a total of 90 patients from four sites. Lancaster and co-workers outlined the key aspects of feasibility studies and indicated at least 30 patients per each arm are required to identify the sample variability (standard deviation) in key variables to enable the calculation of power for testing hypotheses in subsequent definitive studies [46]. The primary outcome in the definitive study is likely to be a value from the MoCA. With 45 patients in each arm, and if the mean (SD) value of the MoCA is 27 (2) in the control and intervention arms at the study start, we could expect a 95% confidence interval to range from 26.4 to 27.6 in each arm. This will give adequate precision for the estimate required in the study. With 45 patients in the control arm, and assuming a mean (SD) value of MoCA of 22 (3) after 12âmonths, we could expect a 95% confidence interval to range from 21.1 to 22.9. In the intervention arm, assuming a mean (SD) MoCA value of 25 (3) after 12âmonths, we could expect a 95% confidence interval to range from 24.1 to 25.9. Furthermore, with a total sample size of 90 patients, with an expected loss of 20% of the patients, a 95% confidence interval could be produced, ranging from 70.2 to 87.7%.