Here is the design of a clinical trial:

Official Title: PANDORA: Scheduled Prophylactic 6-hourly Intravenous Acetaminophen to Prevent Postoperative Delirium in Older Cardiac Surgical Patients

Included conditions:
- Delirium in Old Age
- Delirium
- Coronary Artery Disease

Study Armgroups:
- {'label': 'IV Acetaminophen', 'type': 'EXPERIMENTAL', 'description': '1 g IV acetaminophen every 6 hours for 48 hours during the first 2 days postoperatively', 'interventionNames': ['Drug: IV acetaminophen']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'Volume of the placebo (saline) will match that of IV acetaminophen at 100ml 0.9% NaCl', 'interventionNames': ['Other: Placebo']}

Interventions:
- {'type': 'DRUG', 'name': 'IV acetaminophen', 'description': 'use of IV tylenol for pain', 'armGroupLabels': ['IV Acetaminophen'], 'otherNames': ['ofirmev']}
- {'type': 'OTHER', 'name': 'Placebo', 'description': 'Volume of the placebo (saline) will match that of IV acetaminophen at 100ml 0.9% NaCl', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Incidence of postoperative delirium', 'description': 'Occurrence of delirium on any postoperative day, as assessed using the CAM, 3D CAM, CAM Only, or CAM-ICU daily until hospital discharge.', 'timeFrame': 'Participants will be followed for the duration of the hospital stay, an average of 5 days'}

Please estimate the sample size based on the assumption: 
Two-sided significance level at alpha=0.05, power=0.9, and allowance for 10% potential dropouts.
Sample size calculation
        The sample size calculation for the proposed trial is based on the primary outcome, in-hospital delirium up to day 30, adjusting for one planned interim analysis, which allows early stopping for efficacy. An effect size of 66% with a baseline incidence of 30% was seen in a pilot study conducted at BIDMC.27 In this trial, with the inclusion of a much broader group of patients including those with pre-existing cognitive dysfunction, it was determined that the effect size could be reduced to as low as 33%. Using OâBrien Flemingâs boundary to maintain the overall two-sided significance level at alpha=0.05âand power=0.9, 402 patients per arm will be needed to show a 33% reduction in in-hospital delirium, assuming the baseline postoperative delirium incidence is 30%. To allow for roughly 10% potential dropouts (attrition will accommodate both prerandomisation withdrawalsâie, cancelled surgeryâas well as postrandomisation withdrawalsâie, intraoperative change in surgery type), the trial will enrol up to 900 patients.