Respiratory therapists or “respiratory care practitioners” evaluate, treat, and care for patients with asthma, emphysema, and other breathing disorders. As part of the evaluation process, therapists measure the lung capacity of patients and analyze the oxygen and carbon dioxide concentrations in the blood. Sometimes, therapists may also take electrocardiograms and administer stress tests. Treating patients may involve chest physiotherapy and other “airway clearance techniques” to remove mucus and other blockages. It may also involve inserting a tube into a patient’s windpipe and connecting it to a ventilator or other equipment designed to force oxygen into the lungs. The formal training needed to enter this field is available from hospitals, medical schools, colleges, trade and technical schools, and from the Armed Forces. Most programs last for two years and lead to an associate degree. In most states, you’ll also need a license before you can begin caring for patients.