1. Parenteral Medications
Chapter 34:
Parenteral Medications

2. Parenteral Administration Equipment
Syringes: all syringes contain a barrel, a plunger, and a tip or hub
Calibrated in milliliters (mL), cubic centimeters (cc), units (U), and in some cases minims (m)

3. Parts of a Syringe

4. Parenteral Administration Equipment (cont’d)
Needles are supplied in various lengths and gauges
Shaft: length of the needle
Gauge: diameter of the needle
Lengths vary from approximately 0.5 to 2.5 inches
Filter needles are used when withdrawing medication from a glass ampule

5. Needles

6. Parenteral Administration Equipment (cont’d)
Needle gauge refers to width
For most injections, 18- to 27-gauge needles are used; the smaller the number, the larger the diameter

7. Parenteral Medication Equipment cont.
Factors in selection of syringe and needle
Type of medication
Depth of tissue
Volume of prescribed drug
Viscosity of the drug
Size of the client

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

9. Parenteral Administration Equipment (cont’d)
Modified safety injection equipment:
Avoids needlestick injuries to reduce the risk for acquiring a blood-borne viral disease such as hepatitis or AIDS
Plastic shields that cover the needle after use, needles that retract into the syringe, and gas-pressured devices that inject medications without needles

10. Parenteral Administration Equipment (cont’d)
Two techniques with standard equipment to prevent needlestick injuries:
Before administering an injection, the protective cap covering a needle is replaced by using the scoop method
After administering an injection, the needle is left uncapped and deposited in the nearest biohazard container

11. Safety Injection Devices

12. Ampule, Vial, and Prefilled Cartridge

13. Drug Preparation Ampule: sealed glass drug container
Vial: glass or plastic container of parenteral medication with a self-sealing rubber stopper
Reconstitution: process of adding liquid, known as diluent, to a powdered substance

14. Drug Preparation (cont’d)
Prefilled cartridges: sealed glass cylinder of parenteral medication
Cartridge comes with an attached needle and the cylinder is made so that it fits in a specially designed syringe
Combining medications in one syringe: exact amounts must be withdrawn from each drug container; once the drugs are in the barrel of the syringe there is no way to expel one without expelling some of the other

16. Injection Routes
Intradermal injections: between the layers of the skin
Diagnostic purposes
Examples: tuberculin tests and allergy testing
Injection sites: inner aspect of the forearm

18. Injection Routes (cont’d)
Injection equipment: tuberculin syringe
25- to 27-gauge needle measuring one- half inch in length is commonly used
Injection technique: nurse instills the medication shallowly at a 10° to 15° angle of entry

19. Injection Routes (cont’d)
Subcutaneous injections: beneath the skin but above the muscle
Medication is instilled between the skin and muscle and absorbed fairly rapidly
Commonly used to administer insulin and heparin
Injection sites: insulin and heparin are administered in the abdomen

21. Injection Routes (cont’d)
Injection equipment used for a subcutaneous injection depends on the type of medication prescribed
Example: insulin is prepared in an insulin syringe and heparin is prepared in a tuberculin syringe

22. Injection Routes (cont’d)
Injection technique (subcutaneous)
For obese clients, the nurse inserts the needle at a 90° angle
For thin clients, the nurse inserts the needle at a 45° angle

23. Injection Routes (cont’d)
Administering insulin: hormone required by some clients with diabetes
Common route for administration: subcutaneous or intravenous injection
Inhaled form of insulin: Exubera
Insulin syringe: calibrated in units

24. Injection Routes (cont’d)
Administering insulin (cont’d): injection site for insulin is rotated each time the injection is administered to avoid
Lipoatrophy: breakdown of subcutaneous fat at the site of repeated insulin injections
Lipohypertrophy: buildup of subcutaneous fat at the site of repeated insulin injections

26. Low-Dose and Standard Insulin Syringes

27. Injection Routes (cont’d)
Preparing insulin: when preparing other than rapid-acting and short-acting insulin or the long-acting insulin, glargine (Lantus), the nurse rotates the vial between the palms to redistribute the additive and insulin before filling the syringe
Mixing insulins: insulins tend to bind and become equilibrated
Should be injected within 15 minutes of being combined

29. Injection Routes (cont’d)
Administering heparin: an anticoagulant drug administered subcutaneously as well as intravenously, heparin prolongs the time it takes for blood to clot
Nurse removes needle after withdrawal of the drug from a multidose vial and replaces it with another before administration

30. Injection Routes (cont’d)
Administering heparin (cont’d):
To prevent bruising in the area of the injection, the nurse changes the needle before injecting the client
The nurse rotates the sites with each injection to avoid a previous area where there has been local bleeding
The nurse does not aspirate the plunger once the needle is in place

31. Injection Routes (cont’d)
Intramuscular injections: in muscle tissue
Absorption from an intramuscular injection occurs more rapidly than from the other parenteral routes
Injection sites
Dorsogluteal site: upper outer quadrant of the buttocks

33. Injection Routes (cont’d)
Ventrogluteal site: gluteus medius and gluteus minimus muscles in the hip for injection
Vastus lateralis site: vastus lateralis muscle, one of the muscles in the quadriceps group of the outer thigh

35. Figure 34-18
(A) Locating the vastus lateralis muscle. (B) Spreading the skin at the vastus lateralis site and darting the tissue.

36. Injection Routes (cont’d)
Rectus femoris site: anterior aspect of the thigh
Deltoid site: lateral aspect of the upper arm
Injection equipment: 3- to 5-mL syringes are used to administer medications by the intramuscular route

37. Figure 34-19
The rectus femoris injection site is on the lateral aspect of the anterior thigh.

39. Injection Routes (cont’d)
Injection technique: nurses use a 90° angle for piercing the skin
Z-track technique: technique for manipulating the tissue to seal medication, especially an irritant, in the muscle

41. Reducing Injection Discomfort
Nurses use these alternative techniques to reduce discomfort associated with injections:
Use the Z-track method for intramuscular injections
Apply pressure to the site during needle withdrawal
Massage the site afterward, if appropriate

43. Question What is the function of a syringe barrel?
a. Holds the medication
b. Withdraws the medication
c. Instills the medication
d. Attaches the needle

44. Answer a. Holds the medication
The barrel is the part of the syringe that holds the medication. The plunger is a part of the syringe within the barrel that moves back and forth to withdraw and instill the medication. The tip or hub is the part of the syringe to which the needle is attached.

45. Question
Which angle is used by the nurse to administer a subcutaneous injection to a thin client?
a. 90°
b. 15°
c. 10°
d. 45°

46. Answer
d. 45°
The nurse inserts the needle at a 45° angle for thin clients. For obese clients, and when administering intramuscular injections, the nurse inserts the needle at a 90° angle. When giving an intradermal injection, the nurse instills the medication shallowly at a 10° to 15° angle of entry.

47. Question
Which intramuscular injection site is used for clients with debilitated and poorly developed gluteal muscles?
a. Deltoid
b. Vastus lateralis
c. Rectus femoris
d. Ventrogluteal

48. Answer b. Vastus lateralis
The vastus lateralis site is used for clients with debilitated and poorly developed gluteal muscles. The deltoid site is used for adults. The rectus femoris site is used for infants. The ventrogluteal site is used for children.