A power calculation also suggested that this would provide an adequate sample size to demonstrate mortality differences. A recent paper showed 30 day mortality for emergency laparotomy to be 14.9% (Saunders DI, Murray D, Pichel AC, Varley S, Peden CJ. Variations in mortality after emergency laparotomy: the first report of the UK Emergency Laparotomy Network. Br J Anaesth. 2012 Sep 1;109(3):368-75.)