Total parenteral nutrition



Total parenteral nutrition



Learning objectives



1. Discuss conditions in which total parenteral nutrition would be appropriate and list five goals of parenteral nutrition.


2. List the basic design of a total parenteral nutrition solution and purpose of each component.


3. Perform necessary techniques required to prepare total parenteral nutrition solutions.




Terms & definitions


Additives 


Drugs commonly added to an intravenous solution


Anorexia 


Extreme loss of appetitive


Hypermetabolic states 


Condition in which an abnormal rate of metabolism occurs, such as in trauma, fever, or severe burns


Hypoglycemia 


Abnormally low level of glucose in the blood


Kilocalorie (kcal) 


A unit of measurement in nutrition


Macronutrients 


A source of carbohydrates, protein, and fat


Malnutrition 


Any disease-promoting condition that results from either inadequate or excessive exposure to nutrients


Micronutrients 


Additives in a total parenteral nutrition (TPN), such as vitamins, electrolytes, and trace elements


Pancreatitis 


Inflammation of the pancreas


Peritonitis 


Inflammation of the lining of the abdominal cavity


Specific gravity 


Weight of a substance measured in grams per milliliters as compared to an equal volume of water


Total parenteral nutrition (TPN) 


Nutritional support in an intravenous preparation for patients who cannot take in sufficient calories due to trauma or certain diseases



Introduction


In this chapter we will discuss total parenteral nutrition (TPN) as well as the various components, preparation techniques, and calculation and storage information. There are many employment opportunities for technicians in the area of nutritional support. It is essential to understand the proper techniques as well as the goals of TPN therapy in order to prevent patient harm and provide the proper amount of calories required for a specific patient.



Patient considerations and rationale for using parenteral nutrition solutions


Nutritional imbalance occurs in patients who are not able to take in adequate amounts of nutrients through the gastrointestinal (GI) tract due to diseases or conditions, surgery, or trauma. Nutritional requirements for a patient can vary but commonly range from 2500 to 3000 calories per day while on TPN therapy, which is supplied in 2 to 3 liters of fluid daily. TPN solutions are intravenous admixtures that can be individually designed to meet a patient’s nutritional requirements based on their disease or condition. These must be prepared using the highest quality of aseptic technique to prevent the spread of any bacteria that may be passed to the already critically ill or susceptible patient. They also can be very complex and require many calculations and manipulations.


The basic goals of parenteral nutrition are as follows:



TPN should be administered to patients who are malnourished or have the potential of becoming malnourished. Often, a good candidate has multiple problems, and TPN often follows a surgery or procedure where food intake is inhibited. Conditions can include:



Hypermetabolic states, like some of those listed above, require additional energy for the body to heal. A balance of nitrogen in the blood is essential to keep a balance of protein. A negative nitrogen balance is an indicator that lean body mass is being broken down faster than it is being replaced. When this occurs in malnourished patients, the body converts the protein to glucose (sugar) for energy. Conditions such as, fever, surgery, starvation, burns, and critical illness can cause metabolism to increase in an effort to speed up the healing process.



imageTECH NOTE!


For each gram of nitrogen loss over the amount the body requires for intake, 6.25 g of protein or 25 g of muscle tissue is lost.




Solution components and special considerations when preparing admixtures


Components


The components of TPN consist of an energy source, such as carbohydrate, a protein, and a fat. These three components are known as the base, or macronutrients. Sterile water for injection is also used to adjust the volume of the final solution.



Carbohydrates


The major function of carbohydrates is to provide energy. The most common intravenous source for carbohydrates is glucose. When glucose in the form of dextrose is provided in a parenteral solution, it is completely bioavailable for the body without any effects of malabsorption. The highest concentration that should be given through a peripheral vein is 10% dextrose in water (D10W), and it should not be given for more than 7 to 10 days. This is considered peripheral parenteral nutrition (PPN) and is only used for short-term therapy in those whose normal GI functions will resume in 3 to 4 weeks. For TPN, a 20% to 70% solution of dextrose may be used. These solutions are administered through the central vein that leads directly to the heart due to their hypertonic qualities.



imageTECH NOTE!


Hypertonic fluids cause the water from the cell to move outward which causes the cell to shrink. Hypotonic fluids cause water to move into the cell and, therefore, swell and possibly burst. Isotonic fluids are similar in solute concentration to the body fluids and have no effect on the volume of fluid inside the cell. See Chapter 5 for additional information.



This provides calories that are essential to the patient for long-term therapy. If 20% to 70% solution of dextrose is stopped abruptly, hypoglycemia may occur due to an imbalance of glucose and insulin in the body due to the high concentration utilized in the solution. For this reason, TPN is started gradually and tapered off. A 10% dextrose solution may be required in some patients to allow for the dextrose load to level out.



imageDID YOU KNOW?






Fats or lipids


Intravenous fats are primarily made up of safflower or soybean oil, egg yolks, and some glycerol to provide tonicity. Fat emulsions are available in 1.1 kcal/mL, which is a 10% solution and a 2.0 kcal/mL in a 20% solution. These solutions are known as the trade name, Liposyn, and they are a milky, white solutions.


Fat is a primary source of energy and heat. It provides twice as much energy calories per gram as either carbohydrates or proteins. It is essential for all structural cell membrane integrity. A condition known as essential fatty acid deficiency (EFAD) can occur, which causes complications such as impaired wound healing and an increased susceptibility to infections.



imageDID YOU KNOW?





It is very important to carefully, visually inspect the fat emulsions for separation of the emulsion, and to not use them if there is a visible yellowish streaking.



Proteins


Proteins are body-building nutrients that promote the replacement of cells as well as tissue growth and repair. Protein can be found in scar tissue, antibodies, and even clots. Amino acids are the basic units of proteins and are used in the TPN solution. Some typical manufacturers’ names are Aminosyn, Travasol, FreAmine, and Clinimix. These come in 3% to 15% solutions, and they are available with or without electrolytes.



imageDID YOU KNOW?



Related posts:

  1. Administration of intravenous products
  2. Chemotherapy nutrition
  3. Quality assurance and medication error prevention
  4. Techniques for preparing intravenous admixtures

Stay updated, free articles. Join our Telegram channel
Tags:
Aug 9, 2016 | Posted by in PHARMACY | Comments Off on Total parenteral nutrition

Full access? Get Clinical Tree
Get Clinical Tree app for offline access