Respiratory therapy apparatus refers to a group of different inhalation devices and equipment used to treat a variety of respiratory ailments. Patients may have mechanical difficulties within the lungs and trachea that make it difficult to get enough oxygen. Often these instances are life threatening and must be treated immediately. Obstructions and injury are common situations in which breathing assistance is necessary. In these cases, intubation is necessary to open the airway so that oxygen can be administered. Ventilators regulate the amount of oxygen that the patient receives and even how often the patient breathes. Disease and atrophy of the lungs may require the use of a ventilator to help a patient breathe. Nebulizers and inhalers provide medications in a fine mist that the patient breathes. Inhalers provide metered doses of medication and come prepackaged. They are portable and can be tucked into a pocket or handbag. So-called 'rescue' inhalers are often carried by people with asthma and used when they have an episode. Special dry powder inhalers provide medications that do not work well in liquid form. These inhalers deliver the medication in fine, dry particles that are inhaled. Metered-dose inhalers dispense specific medications and can be grouped according to type of medication. They are usually bronchodilators, inhaled steroids, cromolyn, nedrocromil, and ipratropium bromide.Nebulizers are hand-held machines with an airflow meter that measures oxygen flow. T