Final answer:
Breathing difficulties can arise from central sleep apnea, respiratory distress syndrome in premature infants, and chocking due to airway obstruction. Conditions affecting lung compliance and resistance, such as fibrosis, asthma, and emphysema, can also impair breathing.
Step-by-step explanation:
Three conditions that can cause breathing difficulties while a person is still responsive are central sleep apnea, respiratory distress syndrome (RDS), and chocking. Central sleep apnea occurs when the brain's respiratory centers do not respond correctly to carbon dioxide levels, resulting in irregular breathing. It may be triggered by medical conditions like stroke and congenital heart failure, or certain pharmaceuticals such as morphine. RDS is seen mostly in premature infants due to insufficient production of pulmonary surfactant which leads to difficulty in inflating the lungs and poor gas exchange resulting in dyspnea. Choking is an acute emergency where a foreign body obstructs the airway, rendering the person unable to speak or breathe properly which, if not promptly addressed, can lead to unconsciousness due to oxygen deprivation.
Physiologic changes that affect breathing include alterations in the compliance and resistance of the lung. For example, diseases like fibrosis decrease lung compliance, while conditions like asthma and emphysema increase airway resistance. Both situations lead to difficult breathing and possible V/Q mismatch affecting gas exchange.