In premature babies, gastric residuals are checked when infants have a feeding tube such as an NG tube or a G-tube. The nurse or doctor checking the residual amount will attach a syringe to the end of the feeding tube and gently pull back on the plunger. Any air or food left in the stomach will flow into the syringe. If the residual looks healthy, it will usually be returned to the stomach after discarding the air. Green or bloody residuals may be a sign of infection such as NEC, and will be reported to the physician.