Final answer:
The nurse's priority action for a client experiencing postpartum hemorrhage due to uterine atony is to massage the client's fundus.
Step-by-step explanation:
The nurse's priority action for a client experiencing postpartum hemorrhage due to uterine atony is to massage the client's fundus.
Uterine atony is the failure of the uterus to contract after delivery, which can lead to excessive bleeding. Massaging the client's fundus helps to stimulate uterine contractions and promote hemostasis.
Checking the client's capillary refill, inserting an indwelling urinary catheter, and preparing the client for a blood transfusion may be important actions in the overall management of the client, but they are not the priority in this situation.