Respiratory care refers both to the delivery of pul-monary therapy and diagnostic tests and to the allied health profession that has become an integral part of cardiopulmonary diagnostics and critical care. Respiratory therapistsâ€™ scope of practice encom-passes medical gas therapy, delivery of aerosolized medications, airway management, mechanical ven-tilation, positive airway pressure therapy, critical care monitoring, cardiopulmonary rehabilitation, and the application of various techniques collec-tively termed chest physiotherapy. The latter includes administering aerosols, clearing pulmonary secre-tions, reexpansion of atelectatic lung, and preserv-ing normal lung function postoperatively or during illness. Diagnostic services may include pulmonary function testing, arterial blood gas analysis, elec-trocardiography testing, and evaluation of sleep-disordered breathing. The majority of respiratory care procedures are based on clinical practice guide-lines developed by the American Association for Respiratory Care using best practice/evidence-based medicine criteria.