Final answer:
For venipuncture in a 3-year-old, the first choice veins are typically the median cubital, cephalic, and basilic veins due to their accessibility and size in pediatric patients.
Step-by-step explanation:
Venipuncture in Pediatric Patients
When performing a venipuncture on a 3-year-old, the first choice veins are typically those that are easiest to locate and access due to the smaller size and less cooperativeness of pediatric patients. The median cubital vein, which is located in the antecubital fossa (the front of the elbow), is often preferred due to its usually prominent size and accessibility. Other veins that can be considered include the cephalic vein on the lateral aspect of the forearm and the basilic vein on the medial aspect. It is important for a phlebotomist or healthcare provider to be gentle and use a suitable sized needle to ensure the comfort and safety of the child during the procedure.