Final answer:
True, insulin is a substance that can affect a patient in surgery by managing blood glucose levels, which is important for optimal recovery and avoiding complications.
Step-by-step explanation:
Substances that can affect the client in surgery include insulin. This statement is true. Insulin is a hormone that has significant effects on metabolism and other body systems, especially regarding blood glucose levels. During and after surgery, maintaining proper blood glucose levels is critical for optimal recovery and to avoid complications. Insulin injections are typically administered to decrease blood glucose levels after consuming a high-glucose meal. In medical contexts, such as surgery, insulin must be managed carefully to prevent both hyperglycemia and hypoglycemia, which can both be dangerous to the patient.