Final answer:
The nurse should suspect evisceration due to moderate serosanguineous drainage and puffy tissue protruding through the non-approximated wound edges, which indicates a severe complication postoperatively.
Step-by-step explanation:
Based on the description provided that the nurse observes moderate amounts of serosanguineous drainage, wound edges not approximated, and puffy tissue protruding through the wound, the condition the nurse should suspect is evisceration. Evisceration is a surgical emergency where the abdominal wound has dehisced (came apart) to the extent that internal tissues or organs protrude through the incision. This finding necessitates immediate medical attention to prevent further complications and to likely require surgical intervention.