Respiratory insufficiency is a state in which the lungs are unable to sufficiently oxygenate the body.
The internist is the specialist in comprehensive care focused on diseases that affect internal organs and systems.
The pulmonologist is a medical specialist in respiratory diseases.
A doctor or family doctor is responsible for diagnosing and prescribing medical treatments to patients. The family doctor refers to patients where a specialist when a specific treatment is required.
Remember that for the proper selection of health professional that treats respiratory insufficiency you must consider the nature, severity and symptoms you are presenting.