What is the medical term for "difficulty breathing"?

Throughout the whole process of respiration, the brainstem constantly senses the level of ____________________ in the arterial blood supply.

This respiratory disease is caused by inflammation and swelling of the pharynx, larynx, and trachea. It is most commonly seen in children between the ages of 6 months and 3 years. It is characterized by fever, barking cough and stridor.

This respiratory disease is a life-threatening inflammatory disease of the epiglottis. It is most often seen in preschool and school-aged children. It is characterized by dyspnea, high fever, stridor, drooling, difficulty swallowing and severe sore throat.

This lung disease includes both emphysema and chronic bronchitis.

This condition is defined as a collection of fluid outside the lung on one or both sides of the chest.

This condition is defined as a partial or complete accumulation of air in the pleural space.

This disease is an acute spasm of the bronchioles associated with excessive mucus production and with swelling of the mucus lining of the respiratory passage.

This condition is a severe allergic reaction characterized by airway swelling and dilation of blood vessels all over the body.