A respiratory care practitioner, also known as a pulmonologist, is a physician who specializes in the treatment of patients with breathing issues and other respiratory conditions. As a respiratory care practitioner, your duties are to assess your patient using a variety of tests, such as having your patient blow into a specialized device that measures their lung capacity, and to suggest different types of therapy or treatment options, such as oxygen, based on your assessment. Other responsibilities include supervising respiratory therapists and educating patients about their condition.