Euthanasia is an intentional action or omission of an action that causes the death of the person for reasons of "mercy." That action or omission of an action is also the intentional cause of the death.
The concern with deep sedation is only minimally related to the sedation itself, but primarily related to the withdrawal of fluids and food with the intention of causing death. People need to demand that fluids and food not be withheld during sedation, unless that person is very near to death.
When someone is very near to death, and their body is shutting down, fluids and food can be ethically withdrawn because they do not benefit the person and their withdrawal will not intentionally cause death.