AACN ECCO Pulmonary Practice Exam

The classification of respiratory failure into two major types—Type 1 (hypoxemic) and Type 2 (hypercapnic)—is widely recognized in clinical practice.

Type 1 respiratory failure, or hypoxemic respiratory failure, is characterized by a significant decrease in arterial oxygen levels (PaO2), typically occurring in conditions such as pneumonia, acute respiratory distress syndrome (ARDS), or pulmonary edema. In this type, the carbon dioxide level may remain normal or even be low due to adequate or increased respiratory effort.

Type 2 respiratory failure, or hypercapnic respiratory failure, occurs when there is inadequate ventilation leading to elevated levels of carbon dioxide (PaCO2) in the blood. This condition is often seen in cases of chronic obstructive pulmonary disease (COPD), respiratory muscle weakness, or central respiratory depression.

Together, these two categories encompass the primary mechanisms leading to respiratory failure in clinical scenarios, making them essential for healthcare providers to differentiate when diagnosing and managing patients with respiratory distress. Understanding these types helps guide appropriate intervention strategies based on the underlying pathophysiology.