Lab - Injections

A filter needle is used to trap any rubber or glass fragments that may be drawn up with the medication in a vial or ampule. The nurse must replace the filter needle with a regular needle before injecting the medication into the patient.

• Vials are plastic or glass containers that hold one or more doses of medication. The vial is opened by removing a plastic cap that covers a rubber diaphragm at the top of the container. A needle is used to pierce the center of the diaphragm, and the correct amount of medication is withdrawn into a syringe. Vials can also be fitted with adaptors that permit access through a valve system without a needle (Fig. 20-14). Blunt tip needles are also used to access vials while avoiding the risk of needlesticks.
• Medications that are not stable for long periods may be supplied in a vial in powdered form. A diluent (sterile liquid specified by the drug manufacturer—usually sterile water or saline) is mixed with the powder to reconstitute it. Most hospitals with on-site pharmacies prepare medications from vials in the pharmacy and then dispense the labeled syringe into the automated dispensing machine. Nurses working in extended care facilities or in home care may need to prepare medications from vials.

Ampules are thin-walled glass containers that hold a single dose of a liquid medication. An ampule is shaped like a bowling pin; it has a wide base, narrow neck, and pointed top. Using a gauze pad, the neck of the ampule is snapped off and the medication is withdrawn with a filter needle and syringe.

• Drawing up medications is the process of moving medications from a vial or ampule into a syringe (Procedures 20-3 and 20-4). When withdrawing medication from a vial, first withdraw and inject an equal amount of air into the vial; then, turn the vial over and withdraw the proper dose of medication. When withdrawing medication from an ampule, first open the ampule and then remove the needle cap from the syringe. Place the filter needle directly into the open ampule, and pull the syringe plunger back until all medication enters the syringe.
• When drawing up medication from a vial or ampule, air may also be drawn into the syringe along with the liquid medication. To dispel the air, take the syringe out and hold the syringe with the needle pointed upward. If any medication has adhered to the top of the syringe in the air bubble, tap the barrel of the syringe until the liquid moves down the barrel to the rest of the medication. Expel the air and any volume of unneeded medication slowly.

Medications are reconstituted by adding the proper amount and type of diluent to a powdered medication. Vials of powdered medications may be packaged along with vials of the proper type and volume of diluent. The manufacturer’s directions printed on the medication box or vial indicate the amount and type of diluent to add. To reconstitute the medication, remove the caps from both the medication and diluent vials, and clean the tops of both vials with an alcohol wipe. Draw up the diluent into the syringe, and inject it into the medication vial. Hold the medication vial and mix the medication and diluent until the medication has dissolved. Draw the reconstituted medication into a syringe, and remove air and unneeded medication from the syringe. Administer the medication as directed.

Mixing medications, such as two types of insulin, in the same syringe may allow a patient to receive fewer injections at a lower cost. Medications may be mixed only if they are compatible. Pharmaceutical companies study the compatibility of medications (the ability to mix medications without affecting their constituents or actions). Medication references usually present compatibility information. Medications are mixed in a syringe by first injecting appropriate amounts of air into each vial, then drawing up one medication into the syringe, and expelling any air and unneeded volume of medication. The ordered volume of the second medication is then slowly added to the syringe containing the first medication. If the medication is added rapidly, too much of the second medication may be drawn up. If this occurs, the syringe and medications must be discarded. Refer to Procedure 20-5 for more information.

Discarding equipment carefully decreases the risk of needlestick injuries and exposure to a patient’s blood. Needlestick injuries expose healthcare providers and ancillary workers to dangerous bloodborne pathogens, including HIV and hepatitis B and C viruses. After administering an injection, activate an active design safety needle, if used, and then immediately place the syringe and needle in a needle disposal box or sharps container (see Chapter 19). A sharps container is the only acceptable receptacle for used needles.

• The TST, also referred to as the purified protein derivative (PPD) test or the Mantoux test, is the most commonly administered ID injection. The TST is the standard screening method for identifying persons infected with Mycobacterium tuberculosis. The inner forearm is the site for the test. The test is administered with a tuberculin syringe—a 1-mL syringe with a short, half-inch, small-gauge (26- to 28-gauge) needle. After the skin is cleansed with an alcohol wipe, allow the site to dry. While holding the syringe with the bevel of the needle up, almost parallel to the skin, insert the needle until the entire bevel lies under the skin. Slowly inject a small volume of medication (usually 0.1 mL). A wheal (or bleb) will rise under the epidermis.
• Do not apply pressure or massage the injection site; the dermal tissue will quickly absorb the medication. Because the medication is administered into dermal tissue and the injection site is not touched after the injection, the use of gloves is considered optional. Document the location of the injection and time of the test. Forty-eight to seventy-two hours after the injection is given, the test area is inspected and palpated for evidence of induration (palpable swelling). When reading a test, palpate the site and measure the induration. Measure the diameter of the indurated area in millimeters across the width of the forearm. Do not measure erythema (redness). Interpretation of the TST results (positive or negative) is based on the millimeters of induration and the risk category of the person being tested. An induration of more than 5 mm is classified as positive in high-risk people (e.g., those who have had recent close contact with persons with active tuberculosis, those infected with HIV). An induration of more than 10 mm is considered a positive reaction in people with moderate risk (e.g., injection drug users, immunocompromised people, healthcare workers employed in high-risk settings). An induration of more than 15 mm is considered a positive reaction in people in low-risk groups.

Subcutaneous injections are given into the subcutaneous tissue, the layer of fat located below the dermis and above the muscle tissue (Fig. 20-15). When a medication is injected into subcutaneous tissue, absorption is usually slow, sustained, and complete. Small amounts (0.5 to 1 mL) of medication may be injected subcutaneously using a syringe with a short (½- to ⅝-inch), small-gauge (26- to 30-gauge) needle. Subcutaneous injections may be given in the upper arm, upper back, abdomen, upper buttocks, or thigh (Fig. 20-16).

• Insulin is administered subcutaneously using an insulin syringe (1-mL syringe with 26- to 30-gauge nondetachable needle) to regulate a patient’s blood glucose levels. The syringe is calibrated in units. Insulin vials typically contain 100 U/mL and should be given using syringes designed for that concentration (referred to as U-100 syringes). Although U-500 insulin (500 U/mL) is also available, it is used with extreme caution because miscalculations could result in a patient receiving five times the prescribed dose. When insulin is administered, the number of units, rather than the number of milliliters, is prescribed and measured in the syringe. Low-dose insulin syringes (0.3 mL, 30 U or 0.5 mL, 50 U) permit better visualization when small insulin doses (e.g., less than 30 U) are given.
• Insulin pens are also available for the administration of insulin. Pens are advantageous for patients who wish to self-administer insulin but who are visually impaired or lack the manual dexterity required for a regular syringe (e.g., someone with arthritis). Twisting the barrel of the pen sets the dose; an audible click assists with dose identification. Nurses educate patients in the proper use of insulin pens. Insulin is available in rapid-, short-, intermediate-, long-acting, and around-the-clock formulations (see Table 20-4).
• The complexity of insulin therapy has risen sharply in the past decade. Insulin is considered a high-alert medication. The patient is most likely to experience hypoglycemia when the insulin administered is at its peak action. Nurses are advised to review onset, peak, and duration of insulin and to check insulin types and doses carefully with an RN before administration. To avoid dosing errors, always spell out the word units rather than abbreviate using “U” (e.g., “4U” can be misread as “40 units”). Be alert to which insulin can and cannot be combined in a syringe with another type of insulin.
• Insulin may be administered subcutaneously in the upper arm, anterior or lateral aspects of the thigh, buttocks, or abdomen (avoiding a 2-inch radius around the umbilicus). Rotate the site for each injection systematically about 1 inch from the previous injection site. Rotation within one area is preferred to rotation to a new body area with each injection in order to minimize daily variability in absorption associated with different sites (ADA, 2011). Plan and document site rotation well to prevent repeated use of the same site. Insulin need not be refrigerated for short-term use. A 10-mL vial of insulin will maintain its potency for 1 month without refrigeration if the vial is kept cool and away from heat and sunlight. For teaching, observe patients injecting their insulin because technique problems can affect dose administration and absorption.
• In addition to being classified by time of onset, peak, and duration of action, insulin is also identified by its purpose. Those types of insulin that mimic the natural action of the pancreas (long-acting insulin) are called basal insulin. Intermediate-acting insulins are sometimes used as a basal insulin. Insulin given routinely with meals to manage the carbohydrates in the food is called nutritional insulin. This is most commonly a rapid- or short-acting insulin. Insulin given on an as-needed basis to manage elevations in blood glucose level is called correctional insulin. The goal is to manage the insulin needs of diabetic patients with basal and nutritional doses of insulin; ideally, this would mean correctional insulin is not needed. However, hospitalization usually changes the diet and activity of patients, and the illness itself changes the body’s glucose management, so correctional insulin is often needed in hospitalized patients. Some nondiabetic patients may also need insulin, for example, those receiving glucocorticoid medications such as prednisone. Typically, those patients will not need insulin after being discharged, but some may continue on insulin after returning home.

Subcutaneous heparin or enoxaparin (low-molecular-weight heparin) is used to help prevent deep vein thrombosis (blood clots in the legs) and subsequent pulmonary embolism (blood clots in the lungs). Because subcutaneous injections of heparin frequently cause bruising, precautions are necessary. Heparin is considered a high-alert drug, and student nurses are advised to check the dose with an RN before administering it to the patient. Recommendations for administering heparin are included in the modifications for heparin administration in Procedure 20-7.

• Intramuscular injections are given into the muscle layer beneath the dermis and subcutaneous tissue (Fig. 20-17). According to the CDC (2011) and Crawford & Johnson (2012), needle aspiration is not required for IM injections since no large blood vessels exist at the recommended injection sites. Medications administered by IM injection are usually absorbed more slowly than IV administration but more rapidly than subcutaneous injections. A larger volume of medication per injection and a wider variety of medications may be administered into IM sites than into subcutaneous sites. Refer to Table 20-5 for appropriate sites and volumes of medication to inject for patients of different ages.
• Medications in solution or suspension (including antibiotics, antiemetics, opiates, and vaccines) may be injected into IM sites. IM injections are administered with a 3-mL syringe and a 20- to 25-gauge, 1- to 3-inch needle. The larger-gauge needles are used when the medication solution is very thick. Longer needles are used for larger adults. A 23-gauge, 1.25-inch needle is commonly used for IM injections for average-sized adult patients. Procedure 20-8 discusses administration of IM injections.
• Most medications that are appropriate for IM injection can be given using the technique described in Procedure 20-8. Depot IM preparations (i.e., Depo-Provera) allow for very slow absorption from the muscle, providing prolonged action over days or weeks. Medications that irritate SC tissue (e.g., hydrOXYzine) or that discolor subcutaneous tissue (e.g., iron) should be given by the Z-track method (Fig. 20-18), which also is described in Procedure 20-8. Although the Z-track technique is generally used with medications that are irritating to the tissues, it can be used routinely for all IM injections, provided that the overlying tissue at the chosen site can be displaced by at least 1 inch (Encyclopedia of Nursing Practice, 2011). The Z-track technique allows medication to be administered into the muscle tissue with no tracking of medication in the subcutaneous tissues as the needle is removed. If these techniques are not followed or if site selection is not accurate, complications can occur (see Table 20-6).
• IM injections may be administered into sites in the upper arm (deltoid muscle), hip (ventrogluteal), or thigh (vastus lateralis or rectus femoris). Factors that influence the site choice include the age of the patient, the medication to be injected, the amount of medication, and the patient’s general condition. The CDC recommends deltoid and vastus lateralis sites for vaccines (CDC, 2011). Injections are not given into abnormal muscle tissue, such as tissue underneath burns or scars.

• The deltoid site has a small amount of muscle mass with little overlying subcutaneous fat. Medication injected into this site is absorbed rapidly. Because the muscle is small and lies close to the radial nerve and the brachial artery, the deltoid site is usually only used for vaccines that are small in volume.
• The deltoid site is located by drawing an imaginary line two to three fingerbreadths (2.5 to 5 cm) below the lower edge of the acromion (shoulder) process. The injection is given into the thickest area of muscle that lies in the center of an imaginary triangle whose base is the central half of this horizontal line and whose apex is formed inverted on the midpoint of the lateral aspect of the arm in line with the axilla (Fig. 20-19). To give the injection, slightly angle the needle toward the acromion process or insert it at a 90-degree angle. This site may be higher than you have had with previous injections but is evidence based.

• Injection sites in the thigh, the vastus lateralis and rectus femoris sites, offer rapid rates of medication absorption. Because these muscles contain no large blood vessels or nerves, they are safe to use for IM injections for most patients.
• The rectus femoris is located midway between the patella and the superior iliac crest, in the center of the anterior thigh (Fig. 20-20). An injection is administered into this site by lifting the muscle away from the bone and inserting the needle at a right angle to the muscle. This site is convenient for patients who self-inject medication.
• The vastus lateralis site is used for IM injections for infants, children, and adults. In adults, the vastus lateralis site is the area between one handbreadth above the knee and one handbreadth below the greater trochanter on the medial outer portion of the thigh. An injection is administered into this site by lifting the muscle away from the bone and inserting the needle at a right angle to the muscle.
• In infants and children, the vastus lateralis site is located in the middle third of the area between the greater trochanter and the knee on the medial outer aspect of the thigh (Fig. 20-21). Use short needles (not exceeding 1 inch) to administer injections into the vastus lateralis site in children.

The ventrogluteal site on the lateral hip is free of major blood vessels, nerves, and fat. It is considered the safest and least painful site for delivering IM injections. To locate the ventrogluteal site, place the heel of the opposite hand (for right hip, use left hand; for left hip, use right hand) over the greater trochanter, with the index finger pointing toward the anterior superior iliac spine and the middle finger stretched dorsally toward but below the iliac crest. Give the injection in the center of the triangular area thus formed, with the needle directed at a 90-degree angle to the skin or angled slightly toward the iliac crest (Fig. 20-22).

The dorsogluteal site of the buttocks has been used commonly for IM injections in the past. However, because of its proximity to the sciatic nerve and superior gluteal artery and the possibility of administering the injection subcutaneously into the thick layer of fat over the dorsal gluteal muscle, the routine use of this site for IM injections is not recommended (Malkin, 2008). Patients may describe numbness, tingling, or weakness if the sciatic nerve has been injected.