Final answer:
The priority assessment before beginning the infusion of oxytocin (Pitocin) to the pregnant patient is the respiratory excursion.
Step-by-step explanation:
Before beginning the infusion of oxytocin (Pitocin) to the pregnant patient, the nurse should prioritize assessing the respiratory excursion. This involves evaluating the breathing patterns and lung function of the patient. This assessment is important because oxytocin can cause uterine contractions, which may affect the respiratory system. By assessing the respiratory excursion, the nurse can ensure the proper oxygenation of both the mother and the fetus during the administration of oxytocin.