We live in an ocean of air.*
The air in which we live is a mixture of gasses: about 21% oxygen, 78% nitrogen, and trace amounts of carbon dioxide and other gasses. Just as combustion requires a spark, fuel, and air, the human body requires oxygen in order to process nutritional substrates for energy and growth. These same processes produce carbon dioxide as a byproduct, and if allowed to accumulate it becomes toxic. The primary function of the respiratory system is the exchange of oxygen and carbon dioxide between the external environment and the bloodstream.
In this chapter, we will care for a patient with a serious respiratory problem. We will first learn about the anatomy, physiology, and pathophysiology of the respiratory system, and then highlight some of the clinical tools at our disposal to help in the diagnosis and treatment of respiratory ailments. Finally, armed with this knowledge, we will return to our patient and see what we can do to help him.