Intravenous feeding, also called parenteral nutrition, delivers food to the body through the veins. This puts nutrition directly into the bloodstream, avoiding the digestion processes. Patients may require intravenous feeding if their digestive system is unable to pass or absorb food. This is can be the result of trauma, surgery, damage to the gastrointestinal (GI) tract, disorders that render the bowels non-functioning, a coma, or short gut syndrome.
The gastrointestinal tract is the system of organs that ingests, digests, and excretes food. This begins with the mouth, which takes in food and begins breaking it down with chemicals in the saliva and chewing. The food, now called the bolus, is then moved through the pharynx in the throat into the esophagus, which extends from the throat to the stomach. The stomach continues to break down the bolus, turning into chyme. The chyme is then taken into the intestines, or bowels, which are responsible for absorbing nutrients into the bloodstream and preparing the waste materials for excretion.
When this system is not functioning properly, the patient must receive food through enteral feeding or parenteral nutrition (PN). During enteral feeding, a tube is inserted into the patient’s gastrointestinal tract, usually through the nose, stomach, or small intestine. The nose and stomach feeding tubes bypass the mouth and throat, but still make use of the stomach. A jejunostomy, in which the feeding tube is surgically placed in the small intestine, bypasses the mouth, throat, and stomach, but still makes use of the bowels. Because it presents less risk, enteral feeding is often preferred to parenteral feeding.
Certain patients are ineligible for enteral feeding and require total parenteral nutrition (TPN), which relies solely on intravenous feeding. This procedure is most commonly performed on patients whose GI tract is paralyzed due to surgery. Intravenous feeding may also be needed if the patient has chronic vomiting or diarrhea, or if a severely undernourished patient requires surgery. Lack of development in the GI tract of a baby, birth defects in the digestive system, bowel obstructions, and inflammation of the bowels, such as from Crohn’s disease, can also necessitate TPN.
Patients needing intravenous feeding will usually receive a local anesthetic before the doctor inserts a feeding tube, or catheter, into the vein. Doctors usually use the subclavian vein, located below the collarbone, the jugular vein, located in the neck, or a large vein in the arm. The tube delivers a small amount of liquid nutrition continuously to keep the vein open. Larger amounts of nutrition are infused roughly every few hours, depending on the patient’s feeding schedule. A device called an infusion pump is used to control the timing and amount of nutrition administered.
When the patient regains strength, she can often to return to normal eating. Some patients, however, require long term intravenous feeding. These chronic PN patients may be able to self-administer nutrition at home. Side effects, though uncommon, include blood clots, cholecystitis, or gall bladder inflammation, bacterial and fungal infections, and liver failure due to excessive glucose in the nutritious solution.