Both ginger ale and apple juice are relatively easy on the stomach, so if there is any residual stomach upset or nausea they would be less likely to aggravate it. Some hospitals offer additional options, such as popsicles or 7up (or some other variety of clear lemon-lime carbonated drink).
Yet today's hospitals are veritable sugar shacks. This doesn't make sense. Our bodies weren't designed to process copious amounts of sugar. Excess sugar causes our pancreases to produce excess insulin, which disrupts our metabolisms and causes our bodies to store its extra energy as body fat.