Sample size calculations
The COOL trial is overall powered to detect a significant difference in the primary outcome, 90-day survival. Although imperfect, the preceding Intra-Peritoneal Vacuum Trial study revealed an Intention-to-treat 90-day mortality of 21.7% in the ABThera group versus 50.0% in the Barker’s vacuum pack group [HR, 0.32; 95% confidence interval (CI), 0.11– 0.93; P = 0.04] [