What does respiratory failure indicate?

Respiratory failure indicates a significant impairment in the ability to maintain adequate gas exchange in the lungs. This can manifest as either hypoxemia, which is low levels of oxygen in the blood, or hypercapnia, high levels of carbon dioxide. The condition can arise from various underlying issues, such as obstructive or restrictive lung diseases, central nervous system conditions affecting the respiratory drive, or other acute or chronic illnesses.

In the context of respiratory health, maintaining proper gas exchange is critical for supplying oxygen to the body's tissues and removing carbon dioxide, a waste product of metabolism. When this balance is disrupted, the body cannot function optimally. This makes understanding respiratory failure essential for diagnosing and managing patients with respiratory illnesses.

The other options relate to respiratory function but do not accurately describe respiratory failure. The ability to breathe without effort suggests normal pulmonary function, which is contrary to the definition of respiratory failure. Increased lung capacity and normal gas exchange in the lungs also indicate good respiratory health, which does not align with the concept of respiratory failure.