Final answer:
A nurse should monitor for adverse effects such as bone marrow suppression, reduced saliva production, and gastrointestinal symptoms like nausea in a client receiving radiation therapy.
Step-by-step explanation:
The nurse should monitor for a variety of potential adverse effects in a client who is receiving radiation therapy post-radical head and neck resection to treat cancer. These side effects can include changes in blood cell production, leading to bone marrow suppression, which can result in anemia and weakened immunity. Another potential effect is changes in saliva production, which could lead to dry mouth and tooth decay. Gastrointestinal symptoms like nausea may also occur due to radiation-induced damage to rapidly reproducing cells in the lining of the digestive system.