Explainer

How Do Feeding Tubes Work?

The ins and outs of percutaneous endoscopic gastrostomy.

A federal appeals court rejected a request to reinsert Terri Schiavo’s feeding tube today. The tube has now been removed by court order on three occasions: on April 24, 2001; on Oct. 15, 2003; and finally last Friday. The multiple removals and reinsertions have led many Slate readers to wonder: How hard is it to get a tube into someone’s stomach?

Not hard at all, thanks to a couple of doctors in Cleveland. In 1979, Jeffrey Ponsky and Michael Gauderer performed the first percutaneous endoscopic gastrostomy; they were able to insert a feeding tube without invasive surgery. Up to that point, feeding tubes were put in on the operating table, and surgeons had to cut holes first in a patient’s abdomen and then in the wall of his stomach. Ponsky and Gauderer were able to insert the feeding tube during an office visit, using only local anesthetic.

The endoscope was their secret weapon. First they would slide it into a patient’s mouth and down into his stomach, so they could observe the procedure on a video monitor. Then they would inflate the stomach with air, pushing its walls flush up against the inside of the abdomen. This allowed them to poke a needle directly through the abdominal wall and into the stomach and pass a string in through the tiny hole. Using the endoscope as a guide, they would then pull the string up and out of the mouth of the patient.

In the “pull method” of performing a PEG, doctors attach a feeding tube to the string coming out of the patient’s mouth and then gently pull it down into the stomach and out through the needle-hole. The hole stretches open, and doctors pull the tube until the end—which has a rubber ridge or a small balloon attached to it—lodges against the inside of the stomach. In the “introducer method,” doctors use needles of increasingly large sizes to stretch the hole in the abdomen to the requisite 6 or 8 millimeters and then insert the tube directly through that hole.

These procedures take no more than half an hour. They can be performed on a conscious patient without much pain. Removing the tube is a simple matter of yanking it out with a firm tug—doctors sometimes rub a little bit of topical anesthetic to dull the burning sensation.

What if you have to put the tube back? After a patient spends about a month with a feeding tube, the holes in her abdomen and her stomach begin to fuse together. In this case, a “track” is formed where a feeding tube might be easily reinserted. But the hole can close up pretty quickly: If the federal judge had ordered the reinsertion of Schiavo’s tube, doctors might have been able to slide it right back in, or they might have been forced to perform a new PEG.

Tubes wear out every year or so: They become distended, or they spring leaks. Schiavo’s tube was probably pulled out and replaced multiple times over the years for reasons that had nothing to do with the legal battles over her care.

When it was time to feed her, caretakers would have attached a syringe to the end of her tube, and pulled out the plunger to see how much fluid came out of her stomach. If there wasn’t too much in there already, they’d fill up the syringe with a commercial liquid diet product like Ensure. (A single meal consists of 2 or 3 cans, or you can use regular food that’s been liquefied in a blender.) It’s also possible that Schiavo received continuous feeding using a 24-hour pumping mechanism, which is used for patients at higher risk for regurgitation and aspiration pneumonia.

Next question?

Explainer thanks Dr. Jeffrey Ponsky of Case Western Reserve University, Dr. Mark Delegge of the Medical University of South Carolina, and Dr. Alan L. Levin.