[例1]男,37天,因呕吐半月余入院。患儿为第一胎(双胎)第二产,足月顺产,出生体重3.1kg,生后19天开始呕吐,并逐渐加重,几乎每次奶后即吐,吐物为胃内容物,不含胆汁,入院前7天未排便。体检:体重3kg,营养欠佳,皮肤弹性稍差,眼窝及前囱稍凹陷,心肺未见异常, [Example 1] Male, 37 days, due to vomiting more than half a month after admission. Children with the first child (twins) second production, full-term birth, birth weight 3.1kg, 19 days after birth began to vomit, and gradually increased, almost every time after milk vomit, spit into the stomach contents, excluding Bile, 7 days before admission without defecation. Physical examination: body weight 3kg, poor nutrition, skin elasticity is slightly worse, slightly reduced orbital and front chimney, no abnormal heart and lung,