To check gastric residual in a gastrostomy tube, connect the syringe to the tube, pull back on the plunger, read the syringe, and push down on the tube to put the residual back into the stomach, states the Shepard Center. Flush out the tube with 30 cubic centimeters of water.
The Shepard Center also says that when you are finished flushing the tube, it is important to wash the syringe and container with warm water, then let them air dry. It is also possible to wash them on the top rack of a dishwasher. If the residual is more than 200 cubic centimeters, do not feed the person, and wait 30 to 60 minutes.
After at least 30 minutes, measure the residual again. If it is still more than 200 cubic centimeters, then contact a health care provider for further instructions. If the person receives feedings continuously, check his residuals every four hours. If the residual is more than 200 cubic centimeters for continuous feedings, check the residual again in one hour. Checking stomach residual is necessary because it tells you if the person you are treating is able to tolerate any formula or medication that goes into his feeding tube.