- Effective calculation. We evaluated two strategies for sedation during a preliminary study of 45 patients (Gaillard, SRLF 2010 summary 003940). Cough of more than 10 seconds occurred in 76% of patients sedated with propofol and 32% of patients sedated with Remifentanil. From these data, A number of N = 71 patients will have a power of 80% to demonstrate a difference by Fisher exact probability test between two groups of 35% of percentage of cough of more than 10 secondes.