Final answer:
Respiratory depression indicates that the patient is experiencing a cholinergic crisis.
Step-by-step explanation:
When a nurse administers endrophonium chloride (Tensilon) to a patient with myasthenia gravis, they are trying to determine the appropriate treatment for the patient. If the patient is experiencing a cholinergic crisis, it is indicated by respiratory depression (option B), which can be a serious and life-threatening condition. In a cholinergic crisis, there is an excessive stimulation of the cholinergic system, leading to overactivity of acetylcholine, the neurotransmitter responsible for muscle contraction. This can result in a variety of symptoms, including respiratory depression.