Final answer:
The nurse should ask the client to empty her bladder, as the deviated fundus suggests a full bladder could be at play, potentially leading to complications if not addressed.
Step-by-step explanation:
In the case of the client who is 14 hours postpartum with a finding of breasts soft; fundus firm, slightly deviated to the right; moderate lochia rubra; temperature 37.7° C (100° F), pulse rate 88/min, and respiratory rate 18/min, the most appropriate action for the nurse to perform is to ask the client to empty her bladder. The fundus being deviated to the right suggests a full bladder, which might cause complications such as uterine atony or infection. Encouraging the client to nurse more frequently is unnecessary at this time since soft breasts are expected, and the slight temperature elevation is not unusual, as it may be a result of dehydration and not necessarily indicative of infection.