Intramuscular Injection in Pediatrics

Intramuscular Injections in Children

• Paediatric intramuscular injections must be administered into muscles large enough to accommodate the medication and avoid major nerves or blood vessels.

Complications of Intramuscular Injections

• Muscle contractures occur most commonly after injections in the anterior and lateral thigh.
• Sciatic nerve injury is the most frequently reported serious complication of the gluteal area.

Factors Affecting Absorption of Injected Drugs

• Variability in their chemical characteristics
• Differences in absorption by site of injection
• Variability in muscle mass among children (reduced muscle mass)
• Illness (e.g., compromised circulatory status)
• Immature vasculature resulting in erratic blood flow to and from the muscle, leading to slow absorption rate
• Variability in depth of injection (too deep or too shallow)

Choosing the Right Muscle for Injection

• The IM route allows for rapid absorption of specific medications.
• Selection of the injection site is based on the patient's age, muscle mass, medication volume, and medication viscosity.

Site Selection and Landmarking

Vastus Lateralis

• Preferred IM site for neonates and infants.
• Up to 1ml can be injected into this site in neonates, up to 3mls in children, and up to 5mls in adults.
• Landmarking: palpate the muscle below the greater trochanter and above the lateral femoral condyle (knee joint).
• Administer the injection into the middle third of the muscle, in the outer anterolateral aspect, lateral to the midpoint of the thigh.

Deltoid

• Preferred injection site in children aged 3-18 years when muscle mass is more developed.
• Suitable for small volume injections (up to 2mls).
• Landmarking: palpate the acromion (outer edge of the scapula) and trace an imaginary inverted triangle below the shoulder.
• Administer the injection 3-5cms below the acromion, in the middle of the triangle.

Dorsogluteal

• Not the preferred site due to its proximity to the sciatic nerve and major blood vessels.
• Up to 4mls can be injected into this site.
• Landmarking: locate the muscle in the upper outer quadrant of the buttock, approximately 5-8cm below the iliac crest.
• Confirmation: draw an imaginary line between the posterior superior iliac spine and the greater trochanter of the femur.