When you breathe, you take in oxygen-rich air. This oxygen moves through the bloodstream and into the organs and tissues of your body. The respiratory (breathing) system also removes carbon dioxide from your blood. When you exhale, you release this carbon dioxide from your body. When either of these processes fails, respiratory failure can occur. Respiratory failure may be acute or chronic.
Acute respiratory failure is short term and chronic respiratory failure is long term. Acute respiratory failure happens suddenly and is treated as a medical emergency. Chronic respiratory failure develops over a longer amount of time and requires long-term treatment.
Chronic respiratory failure can also be classified as hypoxemic or hypercapnic respiratory failure. Low blood oxygen levels cause hypoxemic respiratory failure. High carbon dioxide levels cause hypercapnic respiratory failure.