Administration of Injectable Medications (Pharmacology and Administration of Medications) (Nursing) Part 5

Total Parenteral Nutrition

Total parenteral nutrition (TPN), formerly known as hyperalimentation, is also called central parenteral nutrition (CPN). This is a method by which fluids and nutrients are administered to a client. The volume administered is approximately equal to that of a routine maintenance IV. A commonly used TPN solution contains amino acids, dextrose (10%-70%), and electrolytes, making it much thicker than traditional IV solution. Other components sometimes include vitamins and trace elements, such as zinc, copper, manganese, or chromium. Lipids (fats) can also be given by a special method. TPN can help maintain adequate levels of carbohydrates, proteins, fats, vitamins, minerals, water, and electrolytes for clients who are unable to receive adequate nourishment by mouth.

Infusion of TPN requires insertion of an IV line in a large blood vessel, such as the subclavian vein, the internal jugular vein in the neck (an IJ line), or the superior vena cava (SVC line). Rationale: The nutritive solution is concentrated and could cause irritation, clots, or swelling if administered into a smaller vessel. The larger vessel provides sufficient blood to dilute the TPN solution adequately.

Insertion of a central line should be performed only by physicians working under aseptic conditions. Rationale: For example, the subclavian vein is very close to the lung. Certain precautions are necessary in caring for clients who are receiving TPN. In Practice: Nursing Care Guidelines 64-3 identifies some of the nursing considerations in caring for the client who is receiving TPN.

ADMINISTRATION OF INTRAVENOUS MEDICATIONS

Many drugs, including antibiotics, electrolytes, and vitamins, are commonly added to IV infusions. Many of these solutions are premixed and supplied by the manufacturer. If other medications must be added, the pharmacy does this, working in a special laminar flow hood to decrease the risk of contamination. In other cases, the primary provider orders a smaller amount of a drug to be administered by the nurse. Medications for IV administration are supplied in a number of ways, including ampules, vials, and prefilled syringes. Take care to ensure that the label of the medication to be infused states that it is safe for IV administration. The following section of this topic outlines methods for administration of medications via the intravenous method. This method of administration is an important and potentially dangerous nursing responsibility. In some states and provinces, an LPN/LVN is not permitted to administer IV medications. It is the individual nurse’s responsibility to determine the parameters of legal nursing practice in the local area.

IN PRACTICE: NURSING CARE GUIDELINES 64-3

MANAGING PARENTERAL NUTRITION

•    The new nurse will require in service education before working with central lines. This section presents an overview. Most facilities require two nurses to check before any total parenteral nutrition (TPN) bag is hung. Be sure to check every element of the orders—dextrose, electrolytes, protein, vitamins, and so forth— with the pharmacy label. The bag should be at room temperature for at least 30 to 60 minutes before being hung. Rationale: Doublechecking helps prevent errors, which could be fatal. Administration of cold fluid is uncomfortable and could cause shock.

•    Be sure the appropriate inline filter is being used. Filters of different sizes are used for specific purposes. TPN solutions usually require a 1.2 micron filter If a new filter is added or the tubing is changed, be sure to saturate the filter with IV fluid and remove all air bubbles. Rationale: The filter prevents the passage of particles too large to be safely infused, as well as undesirable materials, such as bacteria or fungi. The introduction of air bubbles into the IV could be life threatening for the client.

One type of inline IV filter is shown here. A filter is used with parenteral nutrition and with certain other infusions. The filter tube may be color-coded to denote the size of particles to be filtered. A special filter is also used for transfusion of blood and blood products and in some other situations.

• The TPN solution should be checked for discoloration or precipitates. Rationale: Any deviation in the fluid may cause problems and should be discarded.

•    After a central line is inserted, a sterile dressing is applied to the site. The site must be monitored carefully Some central catheters are held in place with sutures. Make sure the sutures are intact. Rationale: It is important to monitor for signs of infection and for the tubing’s patency. The short catheter will advance or come out if the sutures are not in place.

•    Nurses who have received inservice instruction concerning care of central lines perform sterile dressing changes. Sterile technique is also very important when changing bags, tubing, or filters. Dressings at the insertion site are kept clean. Infection is always a concern. Rationale: The high concentration of dextrose (D-glucose, a simple sugar) contained in TPN provides an excellent medium for bacterial growth. Bacteremia (bacteria in the blood) can be rapidly fatal. Because the catheter is in a major blood vessel, any infection would spread rapidly throughout the body.

•    The client’s vital signs are checked at least every 4 hours. Rationale: It is important to discover any evidence of developing infection as soon as possible.

•    Many of the same precautions are used forTPN as when managing any other IV (see In Practice: Nursing Care Guidelines 64-2).

•    The TPN line is usually one line, without any connections between the bag and the insertion site. The catheter insertion site is covered with a transparent dressing, which is changed every 4 to 7 days or more often, as needed. Follow the facility’s protocol. Rationale: The continuous line prevents loose connections. A transparent dressing allows visualization of the site without removal of the dressing. Tubing changes are necessary, to prevent fluid build-up and infections.

•    The facility often uses "click-lock” or Luer-Lok connections at the insertion site (see Nursing Procedure 64-8.) Rationale: This helps ensure that the connections are secure and air cannot enter the system. An air embolus in the general circulation is life threatening.

•    The client’s blood glucose level is measured several times a day. Higher concentrations of dextrose are used when the client’s fluids must be restricted; lower concentrations help control hyperglycemia. The client is also on intake and output (I&O) and is weighed daily. Rationale: Metabolic and fluid balance changes can occur very quickly. It is important not to raise the blood sugar to a dangerous level, to make sure the client is not retaining too much fluid, and is voiding in appropriate amounts. In addition, these clients are often in very poor physical condition.

•    The rate of infusion for TPN must be constant. An infusion pump is used. Rationale: This helps prevent episodes of hypoglycemia or hyperglycemia.

•    Lipids (fats) can be administered through a separate peripheral line, through a central line via a Yconnector or as an admixture in the TPN solution. This provides supplemental kilocalories, and prevents fatty acid deficiencies and deficiencies of fat-soluble vitamins (A, D, E, and K). When lipids are added, this is called a 3:1, 3-in-one, or a total nutrition admixture (TNA). The addition of lipids can cause complications, which are beyond the scope of this topic. Rationale: The addition of lipids to TPN allows the lipids to be infused slowly, decreasing carbon dioxide (CO2) production and accumulation of fats in the liver.

Nursing Alert A medication given IV, even though it may be the correct medication and in an IV form, must be also given in the correct dosage. For example, an oral dosage given IV will most likely be too large and can rapidly be fatal.

In some cases, the order is for the nurse to administer medications via a continuous IV, or to administer these medications directly into the IV line. This section of the topic describes common methods used to administer IV medications. In most facilities, specific inservice education and performance testing is required before any nurse, RN or LPN/LVN, is allowed to work with IVs or administer IV medications. In Practice: Nursing Care Guidelines 64-4 details special considerations for administration of IV medications.

Nursing Alert Never administer IV medications into tubing that is infusing blood or blood products or TPN solutions.

Converting the Continuous IV Infusion to a Saline Lock

In some cases, the client no longer needs a continuous IV infusion, but will need intermittent IV administration of medications or fluids. The IV line can be capped, leaving a venous access (saline lock) available. Facilities use a number of procedures and devices for this; it is important to determine the policies in your facility. In Practice: Nursing Procedure 64-7 presents an overview of one procedure used to cap an IV line and convert it into a saline lock.

IN PRACTICE: NURSING CARE GUIDELINES 64-4

ADMINISTERING INTRAVENOUS (IV) MEDICATIONS

•    Prepare IV medications for only one client at a time. Rationale: It is vital to ensure that IV medications are prepared and given accurately. Confusion must be avoided.

•    Extra care is required when administering IV medications. Rationale: Because IV medications are entering the general circulation immediately, it is nearly impossible to reverse their effect after being administered. An error can be rapidly fatal.

•    Absolute sterile technique is required. Rationale: Introduction of any microorganisms will immediately enter the client’s blood stream.

•    The nurse must protect himself or herself. Rationale: Because the IV exposes the nurse to the client’s blood, it is particularly important to observe Universal Precautions.

•    Several methods are used to administer IV medications. They include:

•    IV push: injection of a single small dose of medication through a venous access device

•    Bolus infusion: A special solution, such as a colloid, is rapidly infused for volume replacement. The specified quantity is run in as fast as possible unless ordered otherwise.

•    Continuous infusion: IV fluids are administered without stopping, until ordered otherwise. Sometimes, this is to keep open (TKO) or keep vein open (KVO) and is run very slowly

•    Intermittent infusion: A medication dose or specific volume of fluid is infused over a designated period of time, usually between 15 minutes and 2 to 3 hours, stopped, and repeated at specified intervals.

•    Piggyback (superimposed) infusion: A secondary bag of fluid is infused as an intermittent infusion, usually while the primary infusion is stopped.

•    Volume-controlled infusion: Use of a device such as the Buretrol allows medication to be added to a specific volume of fluid. Usually this is infused as a piggyback.

•    An infusion pump is required in certain situations, such as infusion of TPN and lipids, any use of a central catheter, when it is vital to control the exact amount of fluid infused, and when administering drugs that have been identified as particularly dangerous (e.g., KCl). Rationale: The infusion pump helps prevent errors in speed of administration.

•    Usually drugs that have been identified as high risk require doublechecking by two nurses; some facilities require double-checking for all IV medications. Rationale: It is vital to prevent errors.

•    Some medications require special tubing or the use of a filter Rationale: These facilitate the safe administration of the medication (or of blood) and help prevent difficulties.

•    If an inline filter is not present, a filter needle is recommended for drawing up IV medications, particularly if the medication is drawn up from a glass ampule. Rationale: Minute particles of glass or other contaminants may be present. The filter needle catches particles from 1 to 5 microns in diameter and prevents them from being introduced into the IV.

•    Be sure that the tubing used is appropriate for the pump or controller used. Rationale: Use of the wrong tubing could be dangerous. The correct tubing facilitates the safety features of the pump used. These include free-flow prevention, accurate rate control, and the antisiphon device.

•    Most facilities require an independent double-check by another nurse before any IV infusion is started. The second nurse verifies the "7 Rights” of medication administration, and traces the tubing from the bag through the pump to the client to make sure everything is correct. A double-check of the pump’s programming is also required (see Nursing Procedure 64-5). In some cases, the client’s laboratory results and/or weight must also be considered. Both nurses sign off in the medical record. Rationale: These procedures provide additional safety for the client.

The Saline Lock

A saline lock (formerly called a heparin lock), is sometimes referred to as a hep lock, intravenous infusion port, peripheral saline lock, or intermittent infusion device. This is an IV catheter inserted in a vein and left in place, either for intermittent administration of medication or to provide an open line in case of an emergency (Fig. 64-14). The peripheral saline lock provides continuous peripheral IV access without continuous infusion. A seal or cap is attached to the hub (end) of the IV catheter, making it a “saline lock.” To reduce the possibility of clotting, the lock may be flushed with 2 to 3 mL of saline every 8 hours or as ordered. A needleless system is used to flush the lock (Fig. 64-15). Some locks are not flushed. In the past, heparin was used to flush these locks; however, today, saline is the solution of choice but you may still hear this device referred to as a heparin lock. On the other hand, central lines, such as PICC lines, are often flushed with heparin.

The main advantage of the saline lock is the freedom it allows the client because he or she is no longer “attached” to an IV line and controller or pump. Many times, clients are sent home with a lock in place. A provider’s order is necessary to convert a continuous IV to a lock, or to discontinue a lock. The provider prescribes which type of lock to use. Some facilities have “lock kits” that contain syringes prefilled with normal saline. In Practice: Nursing Procedure 64-8 describes how to flush the saline lock and how to give medications by saline lock. (See also Nursing Care Guidelines 64-4.)

Discontinuation of an Infusion or Saline Lock

When the nurse receives an order to discontinue an infusion or a saline lock, the tubing will be clamped and the catheter removed from the vein. In Practice: Nursing Procedure 64-9 describes the process of discontinuing an IV or lock.

FIGURE 64-14 · An intermittent infusion device (saline lock, intravenous [IV] port). This lock allows an IV to be restarted or small amounts of medication to be given with a syringe, without an additional venipuncture. The arrow points to the IV port on the extension tubing. This port is used to connect an IV tubing for continuous administration or to administer medications with a syringe. Note the blue slide clamp positioned above the client’s hand; this is used to shut off flow in the lock. The notations on the tape indicate the date the lock was placed and the initials of the nurse.

FIGURE 64-15 · Some type of needleless system is usually used to prevent needlestick injuries when administering intravenous (IV) medications, flushing saline locks, or drawing blood. Some needleless systems require the use of a vial adapter, shown here, to draw up medications or saline from a vial.