A

Large-volume resuscitation requires the widest-bore peripheral access available; flow rises steeply as gauge decreases, and guidelines for trauma resuscitation favor two 14–16 G catheters. Among the colours listed, the grey cannula is 16 G and thus provides the greatest flow for rapid blood and fluid transfusion, making it the preferred choice in massive haemorrhage [Rottman 1990, 10148916; Reddick 2011, 20581377].