Final answer:
A nurse's most important concern when caring for a client with a ruptured tubal pregnancy is infection.
Step-by-step explanation:
When caring for a client with a ruptured tubal pregnancy, a nurse's most important concern is infection. According to the clinical focus, the client's condition increases the risk for infections and makes her more vulnerable to them. The immune system is downregulated during pregnancy, making the client susceptible to pathogens. In the case mentioned, there is a suspicion of infection by Listeria monocytogenes based on the signs and symptoms exhibited by the patient. Therefore, preventing and treating infections would be the nurse's top priority.