Parenteral drug administration refers to the delivery of medications through routes other than the alimentary canal, bypassing the gastrointestinal tract entirely. In midwifery and obstetric care across Nigeria, you will frequently rely on parenteral routes when rapid therapeutic action is required, when a drug would otherwise be destroyed by digestive enzymes, or when a mother is vomiting, unconscious, or unable to swallow.
Selecting the correct equipment is vital for safe and effective medication administration in midwifery. Syringes consist of a barrel, a plunger, and a tip, and they come in various sizes measured in milliliters. For precise doses, especially in neonates or potent drugs, you will use tuberculin or insulin syringes marked in units or hundredths of a milliliter.
Needle selection depends on the route of administration, the viscosity of the medication, and the patient's body build. Needle size is described by length and gauge. The gauge refers to the width of the needle lumen; paradoxically, a higher gauge number indicates a smaller needle diameter. For instance, a 25-gauge needle is much thinner than an 18-gauge needle. Thicker, more viscous oily solutions require a wider needle with a lower gauge number, whereas routine aqueous injections can easily pass through finer, higher-gauge needles.
Because parenteral routes puncture the body's primary protective barrier—the skin—maintaining strict asepsis is non-negotiable. Microorganisms introduced during an injection can easily cause localized abscesses or severe systemic infections like septicaemia.
Always perform thorough hand hygiene before preparing any medication. Never touch critical parts of the equipment, including the needle hub, the shaft, the syringe tip, or the inner plunger. When opening ampoules or vials, inspect them carefully for cracks, discoloration, or particulate matter. Clean the injection site on the patient's skin using an alcohol swab in a firm, circular motion starting from the center and moving outward, allowing the antiseptic to dry completely before piercing the skin. A common mistake is blowing on the alcohol to dry it, which recontaminates the area with airborne droplets.
Mastering injection techniques ensures comfort and proper drug absorption. For subcutaneous injections, pinch a fold of skin and insert the needle at a 45 to 90-degree angle depending on needle length and subcutaneous fat thickness. Common sites include the outer aspect of the upper arm, the abdomen, and the anterior thigh.
For intramuscular injections, you must accurately identify anatomical landmarks to avoid hitting major nerves or blood vessels.
For deep intramuscular injections, use the Z-track technique: pull the skin laterally before insertion, inject the medication slowly, wait ten seconds, withdraw the needle, and then release the skin. This traps the medication inside the muscle tissue and prevents tracking into subcutaneous layers.
Intravenous therapy involves cannulating a peripheral vein to deliver fluids, electrolytes, and medications directly into circulation. Because this route bypasses all body defense mechanisms, vigilance is required to prevent complications such as air embolism, fluid overload, and localized infiltration.
When setting up an infusion, purge all air bubbles completely from the infusion tubing before connecting it to the cannula. Calculate and monitor the drop factor carefully—measured in drops per milliliter (gtt/mL)—to ensure the prescribed fluid volume infuses at the correct rate over time. Regularly inspect the insertion site for signs of infiltration (where fluid leaks into surrounding tissue, causing swelling, coolness, and pallor) or phlebitis (inflammation of the vein wall marked by pain, redness, and warmth along the vein). If either occurs, stop the infusion immediately, remove the cannula, and apply appropriate localized care.
Despite careful preparation, parenteral administration carries risks ranging from mild localized discomfort to life-threatening systemic reactions. Midwives must remain alert and prepared to manage emergencies swiftly.