Final answer:
In this situation, consent should be obtained directly from the patient. Obtaining a signed consent from a previous procedure or waiting for the mother to return to complete the consent are not appropriate options.
Step-by-step explanation:
In this situation, consent should be obtained directly from the patient. It is important to ensure that the patient fully understands the procedure, its potential risks, and implications before giving consent. Obtaining a signed consent from a previous procedure or waiting for the mother to return to complete the consent are not appropriate options as they do not involve obtaining consent from the patient in the present situation.