Fundamental Nursing Chapter 34 Parenteral Medications Inst.: Dr. Ashraf El - Jedi

Needles The needle gauge (diameter) refers to its width. For most injections, 18- to 27-gauge needles are used; the smaller the number, the larger the diameter. For example, an 18-gauge needle is wider than a 27-gauge needle. A wider diameter provides a larger lumen, or opening, through which drugs are administered into the tissue.

Injection Routes There are four injection routes for parenteral administration: intradermal injections (between the layers of the skin), subcutaneous injections (beneath the skin but above the muscle), intramuscular injections (in muscle tissue), and intravenous injections (instilled into veins; Fig. 34-8).

Injection routes: intradermal (A), subcutaneous (B), intramuscular and subcutaneous in other than thin persons (C), and intravenous (D).

Intradermal Injections Intradermal injections are commonly used for diagnostic purposes. Examples include tuberculin tests and allergy testing. Small volumes, usually 0.01 to 0.05 mL, are injected because of the small tissue space.

Injection Sites A common site for an intradermal injection is the inner aspect of the forearm. Other areas that may be used are the back and upper chest.

Injection Equipment A tuberculin syringe holds 1 mL of fluid and is calibrated in 0.01-mL increments (Fig. 34-9). It is used to administer intradermal injections. A 25- to 27-gauge needle measuring a half-inch in length commonly is used when administering an intradermal injection.

Figure 34-9 • A tuberculin syringe.

Injection Technique When giving an intradermal injection, the nurse instills the medication shallowly at a 10- to 15-degree angle of entry

Subcutaneous Injections A subcutaneous injection is administered more deeply than an intradermal injection. Medication is instilled between the skin and muscle and absorbed fairly rapidly: the medication usually begins acting within 15 to 30 minutes of administration. The volume of a subcutaneous injection is usually up to 1 mL. The subcutaneous route commonly is used to administer insulin and heparin.

Injection Sites The preferred site for giving a subcutaneous injection of insulin and heparin is the abdomen. Additional or alternative injection sites for insulin are the outer back area of the upper arm, where it is fleshier, and outer areas of the thigh and upper buttocks

Injection Sites Rotating within one injection site, preferably the abdomen, is recommended rather than rotating to a different area with each injection The rate of drug absorption at various subcutaneous sites from fastest to slowest is abdomen, arms, thighs, and buttocks.

Injection Equipment Insulin is prepared in an insulin syringe A 25-gauge needle is used most often

Injection Technique To reach subcutaneous tissue in a normal-sized or obese person who has a 2-inch tissue fold when it is bunched, the nurse inserts the needle at a 90-degree angle. The tissue usually is bunched between the thumb and fingers before administering the injection to avoid instilling insulin within the muscle.

Figure 34-11 • Angles and needle lengths for subcutaneous injections.

Intramuscular Injections An intramuscular injection is the administration of up to 3 mL of medication into one muscle or muscle group. Because deep muscles have few nerve endings, irritating medications commonly are given intramuscularly.

Injection Sites The five common intramuscular injection sites are named for the muscles into which the medications are injected: dorsogluteal, ventrogluteal, vastus lateralis, rectus femoris, and deltoid.

Dorsogluteal Site The dorsogluteal site is the upper outer quadrant of the buttocks and is a common location for intramuscular injections. The primary muscle in this site is the gluteus maximus, which is large and therefore can hold a fair amount of injected medication with minimal postinjection discomfort. This site is avoided in clients younger than 3 years because their muscle is not sufficiently developed.

If the dorsogluteal site is not identified correctly, damage to the sciatic nerve with subsequent paralysis of the leg can result. To locate the appropriate landmarks

Divide the buttock into four imaginary quadrants. Palpate the posterior iliac spine and the greater trochanter. Draw an imaginary diagonal line between the two landmarks. nsert the needle superiorly and laterally to the midpoint of the diagonal line.

Ventrogluteal Site The ventrogluteal site uses the gluteus medius and gluteus minimus muscles in the hip for injection. This site has several advantages over the dorsogluteal site: it has no large nerves or blood vessels, and it is usually less fatty and cleaner because fecal contamination is rare at this site. The ventrogluteal site is also safe for use in children.

To locate the ventrogluteal site: Place the palm of the hand on the greater trochanter and the index finger on the anterior-superior iliac spine (Fig. 34-15). Move the middle finger away from the index finger as far as possible along the iliac crest. Inject into the center of the triangle formed by the index finger, middle finger, and iliac crest.

Figure 34-14 • Dorsogluteal site.

Figure 34-15 • Ventrogluteal site.

Vastus Lateralis Site The vastus lateralis site uses the vastus lateralis muscle, one of the muscles in the quadriceps group of the outer thigh. Large nerves and blood vessels usually are absent in this area,

The nurse locates the vastus lateralis site by placing one hand above the knee and one hand just below the greater trochanter at the top of the thigh (Fig. 34-16). He or she then inserts the needle into the lateral area of the thigh (Fig. 34-17).

Figure 34-16 • Locating the vastus lateralis muscle.

Figure 34-17 • Spreading the skin at the vastus lateralis site and darting the tissue

Rectus Femoris Site The rectus femoris site is in the anterior aspect of the thigh. This site may be used for infants. The nurse places an injection in this site in the middle third of the thigh, with the client sitting or supine (Fig. 34-18).

Figure 34-18 • Location of rectus femoris injection site.

Deltoid Site The deltoid site in the lateral aspect of the upper arm (Fig. 34-19) is the least-used intramuscular injection site because it is a smaller muscle than the others. It is used only for adults because the muscle is not sufficiently developed in infants and children. Because of its small capacity, intramuscular injections into this site are limited to 1 mL of solution.

Figure 34-19 • Deltoid site.

There is a risk for damaging the radial nerve and artery if the deltoid site is not well identified. To use this site safely: Have the client lie down, sit, or stand with the shoulder well exposed. Palpate the lower edge of the acromion process. Draw an imaginary line at the axilla. Inject in the area between these two landmarks.

Injection Technique When administering intramuscular injections, nurses use a 90-degree angle for piercing the skin (Skill 34-3).

Reducing Injection Discomfort Use the smallest-gauge needle that is appropriate. Change the needle before administering a drug that is irritating to tissue. Select a site that is free of irritation. Rotate injection sites. Numb the skin with an ice pack before the injection. Insert and withdraw the needle without hesitation. Instill the medication slowly and steadily. Use the Z-track method for intramuscular injections. Apply pressure to the site during needle withdrawal. Massage the site afterward, if appropriate.

Nursing Implications Acute Pain Anxiety Fear Risk for Trauma Deficient Knowledge Ineffective Therapeutic Regimen Management