MSD Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Intravenous Feeding

(Parenteral Nutrition)

By

David R. Thomas

, MD, St. Louis University School of Medicine

Last full review/revision Jul 2020| Content last modified Jul 2020
Click here for the Professional Version
Topic Resources

Food given intravenously can provide part of a person's nutritional requirements (partial parenteral nutrition), supplementing the food eaten by mouth. Or it may provide all of a person's nutritional requirements (total parenteral nutrition).

Parenteral nutrition requires a large intravenous tube. The tube (called a central venous catheter) must be inserted into a large vein, such as the subclavian vein, which is located under the collarbone. Parenteral nutrition may be used at home or in the hospital.

Total parenteral nutrition may be required in people with the following:

Compared with tube feeding Tube Feeding Tube feeding may be used to feed people whose digestive tract is functioning normally but who cannot eat enough to meet their nutritional needs. Such people include those with the following... read more Tube Feeding , intravenous feeding causes more complications, does not preserve the structure and function of the digestive tract as well, and is more expensive. Intravenous feeding is usually not the first choice for nutritional support when the digestive tract is functioning.

Procedure for Intravenous Feeding

Because the central venous catheter must remain in place for a long time, infections are a risk. To reduce the risk, health care practitioners use strict sterile techniques when inserting and maintaining the catheter. For example, they do the following:

  • Clean the skin at the insertion point before inserting the catheter

  • Change the tubing connecting the catheter to the bag of formula every day

  • Change the dressings that hold the catheter in place every other day

Using the catheter only for intravenous feeding also helps reduce the risk of infection.

To place the catheter, doctors insert a needle through the skin into the vein, then thread a guide wire through the needle. The needle is removed, and the catheter is passed over the guide wire, which is then removed. A small ultrasound device may be used to guide the placement of the catheter, and an x-ray may be taken afterward to confirm that the placement is correct. Often, the catheter is placed in the subclavian vein, under the collarbone. The catheter may be inserted into a vein in the neck if it is to be used only during a hospital stay.

An interdisciplinary nutrition team (including a doctor, dietitian, pharmacist, and nurse), if available, should monitor the person's progress. They regularly measure body weight, the number of blood cells in blood (complete blood count Complete blood count Doctors select tests to help diagnose blood disorders based on the person's symptoms and the results of the physical examination. Sometimes a blood disorder causes no symptoms but is discovered... read more ), and levels of electrolytes Overview of Electrolytes Well over half of the body's weight is made up of water. Doctors think about the body's water as being restricted to various spaces, called fluid compartments. The three main compartments are... read more and other minerals, blood sugar, and urea (a waste product normally removed by the kidneys). They also do blood tests to evaluate protein levels and liver function (liver tests Liver Blood Tests Liver tests are blood tests that represent a noninvasive way to screen for the presence of liver disease (for example, hepatitis in donated blood) and to measure the severity and progress of... read more ) and keep track of how much fluid the person is getting and how much urine is excreted. A complete nutritional assessment, including calculating body mass index (BMI) and analyzing body composition, is done every 2 weeks.

If total parenteral nutrition is given outside the hospital, the person is taught to recognize the symptoms of infection, and home nurses visit regularly to check for problems.

Formulas

In the standard formula for intravenous feeding, carbohydrates provide most of the calories. Formulas may also contain water, protein Proteins Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more , fats Fats Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more , vitamins Vitamins and Minerals The human body needs various vitamins and minerals in order to thrive. Many of these nutrients can be found in whole, non-processed foods such as fruits and vegetables. However, most modern... read more , and minerals Vitamins and Minerals The human body needs various vitamins and minerals in order to thrive. Many of these nutrients can be found in whole, non-processed foods such as fruits and vegetables. However, most modern... read more . Essential amino acids Proteins Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more (components of protein) and essential fatty acids Fatty acids Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more (components of fat) are also included. These nutrients are called essential because the body cannot make them from other nutrients. Thus, they must be consumed in the diet.

However, different formulas can be used based on test results, other disorders present, the person's age, and other factors, as for the following:

  • For people with kidney failure when dialysis is not being used or for people with liver failure: A formula with less protein but a high percentage of essential amino acids

  • For people with heart or kidney failure: A formula with less fluid

  • For people with respiratory failure: A formula with less carbohydrate and more fat, which is added to provide the needed amount of calories (processing fat is less work for the lungs than processing carbohydrates)

  • For newborns: A formula with less sugar

  • For obese people: A formula with less fat

Complications of Intravenous Feeding

Intravenous feeding can cause problems related to the central venous catheter or to the formula, as well as other problems. Why some problems occur is unknown.

Injury during insertion of the catheter may occur. For example, a blood vessel, nerve, or lung may be injured.

Infections are more likely when an incision is made in the skin, as is needed to insert a catheter, especially when it is left in place a long time. (Normally, the skin helps prevent organisms that cause infection from entering the body.) Infections may spread to the bloodstream, and bloodstream infections can lead to a serious condition called sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more . Using sterile techniques can help prevent infections.

A blood clot sometimes forms in the vein that the catheter is in.

Nutritional imbalances and deficiencies can occur during intravenous feeding. Blood sugar (glucose) levels that are too high (hyperglycemia) or too low (hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by drugs taken to control diabetes. Much less common causes of hypoglycemia include other... read more ) are relatively common. Rarely, deficiencies of certain vitamins and minerals occur. To identify these problems, doctors do blood tests to measure levels of sugar and minerals (electrolytes Overview of Electrolytes Well over half of the body's weight is made up of water. Doctors think about the body's water as being restricted to various spaces, called fluid compartments. The three main compartments are... read more ). They adjust the formula as needed and periodically recheck sugar and electrolyte levels.

Too much water (volume overload) or too little water may be given. Too much water (overhydration Overhydration Overhydration is an excess of water in the body. People can develop overhydration if they have a disorder that decreases the body’s ability to excrete water or increases the body's tendency... read more ) can cause fluid to collect in the lungs, making breathing difficult. Too little water results in dehydration Dehydration Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more . Thus, doctors regularly monitor the person's weight and the amount of urine excreted. Blood tests to measure urea can help doctors identify dehydration. Disproportionately high levels may indicate dehydration. To the reduce the risk of water imbalances, doctors may try to calculate the amount of water required before feedings are started.

Problems due to formulas that contain more fat and fewer carbohydrates (called lipid emulsions) occasionally occur. These problems include difficulty breathing, allergic reactions, nausea, headache, back pain, sweating, and dizziness. Fat (lipid) levels in the blood may increase temporarily, especially in people with kidney or liver failure. Later, the liver and/or spleen may enlarge, and people may tend to bleed and bruise more easily or develop infections more often. Premature infants Premature Newborn A premature newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, premature newborns have underdeveloped organs, which may not be ready to function outside... read more with respiratory distress syndrome Respiratory Distress Syndrome in Newborns Respiratory distress syndrome is a lung disorder in premature newborns in which the air sacs in their lungs do not remain open because a substance that coats the air sacs called surfactant is... read more or other lung disorders are particularly at risk of these problems. To try to prevent or minimize these problems, doctors may temporarily or permanently slow or stop the formula.

Liver problems can develop in people of any age but are most common among infants, particularly premature ones (whose liver is immature). Doctors do blood tests to measure levels of liver enzymes and thus evaluate how well the liver is functioning. Reducing the amount of protein in the formula may help. If the liver is enlarged and painful, the amount of carbohydrate is reduced. If liver problems develop in infants, ammonia may accumulate in the blood. If ammonia accumulates, symptoms may include sluggishness, seizures, and twitches in muscles. Giving the infant an amino acid (arginine) supplement can correct this problem.

Gallbladder problems may develop or worsen when the gallbladder is inactive, as may occur during intravenous feeding. Substances (such as cholesterol) that are normally processed and moved through the gallbladder may accumulate, forming gallstones Gallstones Gallstones are collections of solid material (predominantly crystals of cholesterol) in the gallbladder. The liver can secrete too much cholesterol, which is carried with bile to the gallbladder... read more Gallstones or sludge. Stones may block a duct, causing inflammation (cholecystitis Cholecystitis Cholecystitis is inflammation of the gallbladder, usually resulting from a gallstone blocking the cystic duct. Typically, people have abdominal pain, fever, and nausea. Ultrasonography can usually... read more ). Increasing the amount of fat in the formula and not giving sugar for several hours a day can stimulate contractions in the gallbladder and thus help move accumulated substances on their way. Giving food by mouth or through a tube inserted in the nose may also help. Drugs, such metronidazole, ursodeoxycholic acid, phenobarbital, or cholecystokinin, may be used to stimulate gallbladder activity.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Test your knowledge
Chromium
Chromium is a mineral required in small quantities by the body, and it enables insulin to function. People with which of the following disorders should avoid taking chromium? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP