Administration of Injectable Medications (Pharmacology and Administration of Medications) (Nursing) Part 4

Patient-Controlled Analgesia and Portable Pumps

Sometimes, the client with chronic or intractable pain controls his or her own patient (client)-controlled analgesia (PCA). Medications commonly administered in this manner include morphine, fentanyl, and hydromorphone, as well as a combination of drugs called BAD (Benadryl, Ativan, and Decadron). These drugs are often used in oncology. The pump, such as the CADD-Solis Intravenous Pump, is preprogrammed to deliver a set dose of medication. The medication may be delivered by continuous infusion or in the PCA mode (the client activates the pump). Limits are preset, as well as time intervals between PCA doses (“PCA lockout”). A number of regulations apply to the use of PCA pumps and many of the safety procedures are the same as those for administering any controlled substance.

In other situations, clients are also allowed to manage their own medication pumps. This includes the insulin pump for diabetics and a pump containing an antiemetic, such as metoclopramide (Reglan) or odansetron (Zofran), for the client undergoing cancer chemotherapy or who has hyper-emesis of pregnancy.

Microdrip Setup

A nurse may encounter an IV in a long-term care setting or in the client’s home that uses the microdrip setup. This setup allows IV solution to be administered in very small “mini” drops that allow better regulation of fluid flow when no pump is available (Fig. 64-12). The microdrip usually delivers approximately 60 drops per milliliter of fluid. (The more commonly used system, the macrodrip, delivers 10 to 15 drops per milliliter, depending on the tubing’s manufacturer.) The microdrip setup is often used without a pump or controller, but has many advantages over the conventional macrodrip setup, using only gravity. Because the microdrip delivers fluid in very small drops, it can be used in situations in which careful flow rate regulation is necessary to prevent overload, when a pump or controller is not feasible or available (e.g., in children and confused adults, or for clients in long-term care settings or at home).

FIGURE 64-12 · (Left) a macrodrip intravenous (IV) drip chamber. This device delivers approximately 10 to 15 drops per milliliter of fluid. (Right) the microdrip setup delivers approximately 60 drops per milliliter.

Regulating the Infusion Rate

If an infusion pump or controller is not used, the size of the catheter, the height of the solution bag or bottle, and the position of the insertion site influence the infusion rate. A catheter with a larger inner diameter (bore) allows solution to flow faster. The higher the IV bag, the faster the infusion will flow. Calculation of drip rates is usually the function of the registered nurse (RN) or pharmacist. The new nurse will require assistance in setting up the infusion and determining the rate of flow (Box 64-2). If no pump is used, tape is applied to the bag, indicating the times the fluid should reach each level. Do not write directly on the bag. In the healthcare facility, a pump or controller is nearly always used and the primary provider will specify the volume of fluid to be infused per hour. The electronic device will be programmed to deliver that volume.

If the insertion site allows a great deal of movement (e.g., the arm), and the IV is inserted into the antecubital area (inner aspect of the elbow), the solution can flow freely if the client extends the arm. However, should the client bend the arm at the elbow, the IV fluid flow will be obstructed. In some instances, immobilization of the insertion site is desirable, to allow a regulated flow. An armboard can be attached to the arm that will keep the insertion site stable, but will not restrict arm movement completely.

A slower rate of infusion is usually necessary for older adults, small children, clients with kidney or heart disease, or clients with a head injury. A rapid infusion rate may cause circulatory overload or increased intracranial pressure in these clients.However, a faster infusion rate is often desirable for persons who have lost large amounts of body fluids and are severely dehydrated.

BOX 64-2.

Calculating the Rate of Infusion

In most cases, the licensed practical nurse or licensed vocational nurse (LPN/LVN) is not expected to calculate the rate of an intravenous (IV) infusion. However, in the long-term care facility or home care, when a pump is not used, this may be necessary. Follow the policies of the agency. General Guidelines are:

♦    Check the tubing wrapper to determine the drip rate factor of the tubing being used.

♦    For example, if the microdrip tubing set delivers 60 drops per milliliter (mL) of fluid, an example of calculations would be as follows:

Drops per minute =

So, if the order is to give 1,000 mL in 10 hours, the formula would be written thus:

Drops per minute =

Therefore,

The answer would be 100 drops per minute. Another method is to find milliliters per hour by dividing 1,000 mL by 10 hours This would be 100 mL per hour Therefore,

The formula would set up as:

The answer would be 100 drops per minute.

If a macrodrip setup is used, the drip rate factor would be much different, but would still yield 100 mL per hour: However; to attain 100 mL per hour; it would require many fewer drops per minute.

Nursing Considerations

In Practice: Nursing Care Guidelines 64-2 highlights the major aspects of caring for any client receiving IV therapy. Be sure to monitor this client, to determine adverse infusion reactions. In addition, monitor the rate of flow and the appearance of the administration site. Check the site for signs of infiltration or irritation caused by the infusion. Document all findings on an IV flow sheet or in the computer. Report any untoward findings immediately.

Changing the IV Bag

When the IV bag is nearing empty, the bag must be discontinued and a new bag added. It is important to prevent the bag from becoming completely empty, because this can introduce air into the line and/or cause blood clotting. The nurse may also be requested to change the IV tubing or the dressings over the IV site. These procedures are outlined in In Practice: Nursing Procedure 64-6.

Long-Term Infusions, Central Lines, and Infusion Ports

There are several types of IVs called central lines, central venous access devices (CVAD), or central venous catheters (CVC), because they deliver fluid into a large central vein or directly into the heart. The type depends on the fluids to be delivered, the client’s condition, and the length of time the CVC will be in place. A short percutaneous (through the skin) CVC may be surgically threaded from its entrance site (usually the subclavian vein) into a large central vein, such as the vena cava. This CVC may consist of one, two, or three lumens (tubes) and is used for several purposes. For example, if incompatible fluids are being infused, they may be delivered into different areas. The short CVC is sutured to the skin at the insertion site. The long CVC peripherally inserted central catheter (PICC) has a single lumen and is threaded through veins from an entrance site, often in the antecubital area of the arm, into the superior vena cava or the right atrium of the heart. The short CVC is most suitable for short-term use. The PICC can be left in place for a longer time and can be used to administer blood transfusions or medications and to measure central venous pressure. The PICC line is frequently used in home care. Central lines lower the risk of IV infiltration and infection because of their deep placement into the superior vena cava.

An LPN/LVN often is not allowed to work with central lines in the acute-care facility, but should be aware of the basics. In any case, special inservice education is required before working with these lines. Check with the state or province for guidelines. In nearly all cases, the LPN/LVN’s role is to assist the RN. An LPN/LVN may observe the insertion site and make sure the fluid is infusing properly and, in some cases, they are allowed to change site dressings. An LPN/LVN does not change the infusion rate.

The Short Central Venous Catheter

The short CVC is used for the client who requires large amounts of supplementary fluids or a total parenteral nutrition (TPN) infusion for a limited length of time (Fig. 64-13A). This CVC can also be tunneled under the subcutaneous skin into the subclavian vein for longer-term use. Tunneling allows the skin exit site to be a distance from the catheter’s placement in the vein. (TPN is discussed in the next section of this topic.)

Nursing Alert Total parenteral nutrition (TPN) can be administered only by way of a large central venous catheter because it is very concentrated. A peripheral blood vessel would not have sufficient blood flow to dilute the TPN solution.

FIGURE 64-13 · Central lines are used to administer large amounts of fluid, including total parenteral nutrition. (A) A short (nontunneled) triple-lumen percutaneous (through the skin) central venous catheter This catheter is inserted into the subclavian vein and threaded up into the superior vena cava (Lynn, 2008). (B) The peripherally inserted central catheter (PICC) line is inserted into the antecubital space and is sufficiently long to be threaded up into the superior vena cava (Lynn, 2008). (C) The implanted port allows long-term, intermittent access to the central vein, without the need for a catheter protruding from the skin. Shown here with the 90-degree noncoring needle inserted, to administer medications or transfuse blood products (Lynn, 2008). (continued)

FIGURE 64-13 · (Continued) (D) A double-lumen hickman catheter showing snap clamps and two types of ports. Dacron cuff helps hold it in place.

The PICC Line

One type of long central catheter is the peripherally intravenous central catheter (PICC). The PICC is inserted into a peripheral vein, at the antecubital space or another site, and threaded up through the vein to a large central vein (Fig. 64-13B). This catheter is not tunneled. The catheter’s length (12-16 inches or more) is determined by measuring the client’s arm to the central location. The PICC line can remain in place for weeks or months. Advantages of the PICC are similar to the advantages of the shorter CVC catheter. However, use of PICC restricts the use of the client’s arm into which it is inserted. Excessive arm use can cause the catheter’s outward migration or irritation at the insertion site. The PICC is usually not sutured to the skin.

The Midline Catheter

The midline catheter is not specifically a central venous catheter, because it does not extend into the great central veins. However, care of the midline catheter is the same as for a CVC. It is a shorter catheter (about 4-8 inches, or 8.8-17.6 cm) long. It is inserted in the antecubital area and extends only to the larger blood vessels in the proximal area of the arm. This catheter can remain in place for 2 to 4 weeks and supplies greater blood volume than the peripheral vessels, but not as great as the central veins.

Infusion Ports

Subcutaneously implanted (under the skin) CVC devices have the advantage of long-term access for frequent infusions, without any part of the catheter outside the skin. Infuse-a-Port, Mediport, and Port-a-Cath are examples (Fig. 64-13C). Catheters used in these systems are often placed in the superior vena cava via the subclavian vein. Implanted ports are often used for cancer chemotherapy  and may also be used to administer blood products.To administer medications, the port is palpated under the skin. Then a special angled needle (e.g., a Huber 90-degree noncoring needle) is inserted into the port. A 20G needle is used for most infusions; a 19-G needle may be used for blood transfusion. The port is kept patent with periodic flushing.

Nursing Alert Remember that special techniques are required for administration of chemotherapy products and disposing of the materials used. Scrupulous site care is required for any central line, to prevent infection.

Key Concept The first brand of tunneled central venous catheters was the Hickman. The term "hickman" generally refers to all standard tunneled central catheters (Fig. 64-13D). The Hickman may have one, two, or three lumens. It is large enough to draw blood, as well as to infuse fluids. Another brand, the Broviac, is smaller and can only be used for intravenous infusions. Another type, the double-lumen catheter, may be used to deliver nutrients, such as TPN, through a smaller lumen. A larger lumen allows blood to be drawn and medications to be administered. There are many other brand names and types of central venous catheters.

Nursing Alert It is vital to close the clamp on the CVC whenever the end will be opened for any reason. This helps to prevent air embolism.