Final answer:
The nurse's next action when caring for a client experiencing hypovolemic shock should be to initiate fluid resuscitation with intravenous fluids.
Step-by-step explanation:
When a nurse on a postpartum unit is caring for a client experiencing hypovolemic shock, the nurse's next action after notifying the provider should be to initiate fluid resuscitation with intravenous fluids (option b). Hypovolemic shock is caused by a loss of blood volume, so providing intravenous fluids is crucial to restore the patient to normal function. Administering a diuretic to reduce fluid overload (option a) or encouraging increased oral intake of fluids (option c) would not be appropriate in this situation. Placing the client in a supine position (option d) would not address the underlying issue of fluid loss.