Here is the design of a clinical trial:

Official Title: Diaphragmatic Paralysis After Interscalene Brachial Plexus Block: A Randomized, Double-blinded, Unicenter and Controlled Clinical Trial to Reduce the Dose of Levobupivacaine 0,25% 20 ml to 10 ml Undergoing Arthroscopic Shoulder Surgery

Included conditions:
- Diaphragmatic Paralysis
- Brachial Plexus Block

Study Armgroups:
- {'label': 'Standard Volume Dose', 'type': 'ACTIVE_COMPARATOR', 'description': '24 patients will be included in the Standard Volume Dose arm. 20 ml Levobupivacaine Hydrochloride 2.5 MG/ML will be administered in the Interscalene brachial plexus block before the arthroscopic shoulder surgery.', 'interventionNames': ['Procedure: Interscalene brachial plexus block', 'Drug: Levobupivacaine Hydrochloride 2.5 MG/ML']}
- {'label': 'Low Volume Dose', 'type': 'EXPERIMENTAL', 'description': '24 patients will be included in the Low Volume Dose arm. 10 ml Levobupivacaine Hydrochloride 2.5 MG/ML will be administered in the Interscalene brachial plexus block before the arthroscopic shoulder surgery.', 'interventionNames': ['Procedure: Interscalene brachial plexus block', 'Drug: Levobupivacaine Hydrochloride 2.5 MG/ML']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Interscalene brachial plexus block', 'description': 'Interscalene brachial plexus block is a locorregional anaesthesia technique which is indicated in shoulder and upper arm surgery. The goal of this block is to place the needle in the tissue space between the anterior and middle scalene muscles and inject local anesthetic until the spread around the brachial plexus is documented by ultrasound.', 'armGroupLabels': ['Low Volume Dose', 'Standard Volume Dose'], 'otherNames': ['MeSH Unique ID: D065527', 'CIE-10 code 3E0T3CZ', 'Interscalene block']}
- {'type': 'DRUG', 'name': 'Levobupivacaine Hydrochloride 2.5 MG/ML', 'description': "Levobupivacaine Hydrochloride 2.5 MG/ML is an anesthestic product intended for epidural, intradural and perineural administration. Levobupivacaine is chemically described as (S)-l-butyl-2-piperidylformo-2',6'-xylidide hydrochloride. It is a white crystalline powder with a molecular formula of C18H28N2O. HCl, with a molecular weight 324.9.\n\nFDA approval: NDA-20997 (1999).", 'armGroupLabels': ['Low Volume Dose', 'Standard Volume Dose'], 'otherNames': ['Chirocaine® 2.5 MG/ML']}

Primary Outcomes:
- {'measure': 'Change from Baseline Diaphragmatic Thickness Ratio at 4 hours', 'description': 'The primary outcome is the difference in the proportion of patients with Hemidiaphragmatic paralysis acute (HDPA) according to diaphragmatic thickness ratio (DTR) in ultrasounds between the Treatment and Control groups. DTR will be the result of Inspiratory Diaphragmatic Thickness and Expiratory Diaphragmatic Thickness. The ratio will be defined by DTR=IDT/EDT. HDPA after IBPB at 4 hours will be diagnosed with a DTR\\<1.2.', 'timeFrame': 'Before (Baseline) and 4-hour after interscalene brachial plexus block'}

Please estimate the sample size based on the assumption: 
The trial is powered to identify a mean difference of 90-33% with a two-sided significance level of 1% and a power of 90%, assuming a 10% dropout rate.
Sample size {14}
        Drawing on previous studies, this trial will assume an IBPB-induced HDP rate of 90% for the control group and of 33% for the treatment group [6, 15, 26]. These findings suggest that decreasing the IBPB LA dose (10âml, 0.25%, or 25âmg) should result in less IBPB-induced HDP.
        Therefore, powering this trial to identify a mean difference of 90â33% with a two-sided significance level of 1% and a power of 90% with the same allocation to the two arms will require 21 patients in each arm. Assuming a 10% dropout rate, 24 patients will be enrolled per arm, i.e., 48 participants will be the total sample size, as calculated using EpidatÂ® software [27, 28].