Living on Liquids: How an IV-Only Diet Works

Total parenteral nutrition needed for some patients
silhouette IV drip

For most of us, the smell of our favorite meal cooking on the stove might inspire a little taste test. But for some people, taking any kind of forkful isn’t an option.

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Approximately 40,000 people in the U.S. rely solely on intravenous fluids (IV) to meet their caloric and nutritional needs. This therapy is known as total parenteral nutrition (TPN). Any number of conditions can make it necessary, such as Crohn’s Disease, bowel obstructions, shortened intestines, or vascular disease that causes gangrene intestines.

If you require TPN, your digestive tract is to blame because it can’t absorb nutrients properly. Depending on your diagnosis, eating small amounts might be possible.

“It’s a completely different lifestyle. Some patients can eat and absorb some nutrients,” says Ezra Steiger, MD. “But others, because of their circumstances, are encouraged to limit oral intake and think about nutrition in a different way.”

These patients are often discouraged from drinking fluids because they’ll actually expend more fluid trying to process the liquids than what they take in — leading to dehydration.

What’s in TPN and what will you feel?

TPN is comprised of proteins, carbohydrates, fats and various water- and fat-soluble vitamins, as well as electrolytes, essential fatty acids and trace elements, such as zinc and copper. Your body needs them all to work properly.

There’s still a chance you’ll feel hungry, though, Dr. Steiger says, at least initially.

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“We usually hear hunger complaints when someone first starts TPN because they’re not getting that feeling of satiety from a full stomach,” he says. “But other patients might experience more nausea than hunger if an obstruction is preventing them from eating.”

There are other side effects to watch for: mouth sores, skin changes and poor night vision. These are not side effects of TPN but are possible signs of malnutrition or vitamin deficiency that may result from it. If you have fever, stomach pain, swelling, muscle weakness, vomiting or seizures, call your doctor.

Most patients maintain their normal daily activities, says dietitian and home nutrition support clinician Denise Konrad.

“As long as TPN provides enough calories, patients have the energy and endurance to do the things they want,” she says. “They’re usually tired right after surgery or hospitalization, but they rebound and do a lot better.”

How does it work?

TPN infusions must stay refrigerated, and they’re delivered through a special IV catheter placed either in your chest or arm. Typically, the fluid bag hangs from an IV pole next to your bed. Backpacks are also provided (to hold the infusion pump and TPN bag) so that patients can be mobile while infusing, especially if they infuse during the day.

Your small intestine’s absorption ability determines the fluid amount you’ll need. Some patients need two liters of fluid nightly while others need only a liter three to four nights a week.

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TPN therapy length also varies, Dr. Steiger says.

“Much depends on a patient’s underlying condition. A lot of patients with malabsorption due to short bowels or a temporary blockage come off TPN,” he says. “For many, it’s a three-to-12-month therapy. Maximum adaptation occurs after about two years, and people are usually able to reduce their dependency.”

Getting TPN supplies

Infusion pharmacies typically deliver seven nights’ worth of TPN supplies weekly, Ms. Konrad says, including the tubing that connects to the infusion pump and the IV pole. Some pharmacies also provide separate refrigerators to store infusion additives, such as multi-vitamins or insulin. Backpacks with battery pumps are available for patients who prefer daytime infusions.

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