Final answer:
The nursing intervention of assisting Mrs. Plank in splinting her incision for a strong cough relates to the nursing diagnosis of Risk for Ineffective Airway Clearance, aimed at preventing respiratory complications after surgery.
Step-by-step explanation:
The nursing intervention where the nurse assists Mrs. Plank in splinting her incision to produce a strong cough is most likely addressing the nursing diagnosis of Risk for Ineffective Airway Clearance. This diagnosis is pertinent because postoperative patients are at risk for respiratory complications, such as pneumonia, which can result from the inability to clear secretions due to pain or discomfort from the surgery. By splinting the incision and encouraging coughing, the nurse is taking measures to prevent respiratory secretions from accumulating, which thereby supports respiratory health and prevents complications related to ineffective airway clearance.