text: what do a respiratory therapist do?   respiratory therapists and respiratory therapy technicians—also known as respiratory care practitioners—evaluate, treat, and care for patients with breathing or other cardiopulmonary disorders. practicing under the direction of a physician, respiratory therapists assume primary responsibility for all respiratory care therapeutic treatments and diagnostic procedures, including the supervision of respiratory therapy technicians. respiratory therapy technicians follow specific, well-defined respiratory care procedures under the direction of respiratory therapists and physicians. in clinical practice, many of the daily duties of therapists and technicians overlap; furthermore, the two have the same education and training requirements. however, therapists generally have greater responsibility than technicians. for example, respiratory therapists will consult with physicians and other health care staff to help develop and modify individual patient care plans. respiratory therapists also are more likely to provide complex therapy requiring considerable independent judgment, such as caring for patients on life support in intensive-care units of hospitals. in this handbook statement, the term respiratory therapists includes both respiratory therapists and respiratory therapy technicians.  respiratory therapists evaluate and treat all types of patients, ranging from premature infants whose lungs are not fully developed to elderly people whose lungs are diseased. respiratory therapists provide temporary relief to patients with chronic asthma or emphysema, as well as emergency care to patients who are victims of a heart attack, stroke, drowning, or shock.  to evaluate patients, respiratory therapists interview them, perform limited physical examinations, and conduct diagnostic tests. for example, respiratory therapists test patients’ breathing capacity and determine the concentration of oxygen and other gases in patients’ blood. they also measure patients’ ph, which indicates the acidity or alkalinity of the blood. to evaluate a patient’s lung capacity, respiratory therapists have the patient breathe into an instrument that measures the volume and flow of oxygen during inhalation and exhalation. by comparing the reading with the norm for the patient’s age, height, weight, and sex, respiratory therapists can provide information that helps determine whether the patient has any lung deficiencies. to analyze oxygen, carbon dioxide, and ph levels, therapists draw an arterial blood sample, place it in a blood gas analyzer, and relay the results to a physician, who then may make treatment decisions.  to treat patients, respiratory therapists use oxygen or oxygen mixtures, chest physiotherapy, and aerosol medications. when a patient has difficulty getting enough oxygen into his or her blood, therapists increase the patient’s concentration of oxygen by placing an oxygen mask or nasal cannula on the patient and set the oxygen flow at the level prescribed by a physician. therapists also connect patients who cannot breathe on their own to ventilators that deliver pressurized oxygen into the lungs. the therapists insert a tube into the patient’s trachea, or windpipe; connect the tube to the ventilator; and set the rate, volume, and oxygen concentration of the oxygen mixture entering the patient’s lungs.  therapists perform regular assessments of patients and equipment. if the patient appears to be having difficulty breathing or if the oxygen, carbon dioxide, or ph level of the blood is abnormal, therapists change the ventilator setting according to the doctor’s orders or check the equipment for mechanical problems. in home care, therapists teach patients and their families to use ventilators and other life-support systems. in addition, therapists visit patients several times a month to inspect and clean equipment and to ensure its proper use. therapists also make emergency visits if equipment problems arise.  respirator