What Is Respiratory Failure? Understanding Types, Causes, and Symptoms

Respiratory failure is a serious medical condition that occurs when the lungs are unable to effectively perform their primary function—exchanging oxygen and carbon dioxide. This condition can be classified into two main types: acute respiratory failure, which develops rapidly and requires immediate medical attention, and chronic respiratory failure, which progresses over time and may become a long-term health issue.

How Respiratory Failure Develops

Pulmonary ventilation and gas exchange are critical processes for maintaining adequate oxygen levels in the blood and removing excess carbon dioxide. When these functions are severely impaired due to illness, injury, or underlying conditions such as COPD, pneumonia, or pulmonary embolism, the body may fail to sustain essential gas exchange—even at rest. This leads to hypoxemia, a condition characterized by abnormally low levels of oxygen in the bloodstream, with or without the buildup of carbon dioxide (hypercapnia).

Diagnosing Respiratory Failure

Doctors typically diagnose respiratory failure based on arterial blood gas (ABG) analysis. Under normal resting conditions while breathing room air—and after ruling out cardiac shunts or low cardiac output—an arterial oxygen pressure (PaO₂) below 60 mmHg, with or without an arterial carbon dioxide pressure (PaCO₂) above 50 mmHg, confirms the presence of respiratory failure.

Type I vs. Type II Respiratory Failure

Type I (hypoxemic) respiratory failure is defined by low oxygen levels without elevated CO₂. It's commonly seen in conditions like acute respiratory distress syndrome (ARDS), severe pneumonia, or pulmonary edema. On the other hand, Type II (hypercapnic) respiratory failure involves both low oxygen and high carbon dioxide levels, often resulting from neuromuscular disorders, chest wall abnormalities, or advanced chronic obstructive pulmonary disease (COPD).

Recognizing the Warning Signs

Early symptoms may include persistent shortness of breath, chest tightness, fatigue, and dizziness. As the condition worsens, individuals might experience confusion, rapid breathing, bluish skin tone (cyanosis), and extreme lethargy. In severe cases, untreated respiratory failure can lead to life-threatening complications such as shock, organ damage, or loss of consciousness.

Timely recognition and intervention are crucial. Treatment options vary depending on severity and may involve oxygen therapy, non-invasive ventilation (like CPAP or BiPAP), or mechanical ventilation in critical cases. Managing the underlying cause—whether it's infection, lung disease, or neurological impairment—is key to recovery and long-term stability.