Final answer:
Informed consent protects the principle of autonomy in healthcare ethics, which allows patients to make informed decisions about their own healthcare.
Step-by-step explanation:
A patient undergoing surgery signs an informed consent for the procedure. The principle of health care ethics that informed consent protects is autonomy. The principle of autonomy states that in clinical settings, patients have the right to exercise agency or self-determination when making decisions about their own health care. Informed consent ensures that an individual is provided with all relevant information necessary to make an informed decision about their participation in a trial or medical procedure, thus protecting them from exploitation and preserving their autonomy.