Acute respiratory failure

Acute respiratory failure results from acute or chronic impairment of gas exchange between the lungs and the blood causing hypoxia with or without hypercapnia.

Patients may present with shortness of breath, anxiety, confusion, tachypnoea, cardiac dysfunction, and cardiac arrest. Central nervous system depression can occur as a result of lack of oxygenation of the blood and vital organs or excessive accumulation of carbon dioxide.

Pulse oximetry, chest x-rays, blood gas analysis, and end-tidal carbon dioxide monitoring (capnometry) are key diagnostic tests.

Management involves first ensuring that the upper airway is patent and clear of obstructions. Supplemental oxygenation and ventilatory support are likely to be required, with immediate attention to the underlying cause or causes for respiratory failure.

Endotracheal intubation and mechanical ventilation are employed when other less invasive manoeuvres have failed.

The coronavirus disease (COVID-19) pandemic introduced new challenges for recognition, treatment, and complications of acute respiratory failure.

This topic covers acute respiratory failure in patients over the age of 12 years.

Acute impairment in gas exchange between the lungs and the blood causing hypoxia with or without hypercapnia (e.g., caused by acute decompensation of chronic pulmonary disease). Hypoxic respiratory failure (type I respiratory failure) is hypoxia without hypercapnia and with an arterial partial pressure of oxygen (PaO₂) of <8 kPa (<60 mmHg) on room air at sea level. Hypercapnic respiratory failure (type II respiratory failure) is hypoxia with an arterial partial pressure of carbon dioxide (PaCO₂) of >6 kPa (>45 mmHg) on room air at sea level.[1]Mirabile VS, Shebl E, Sankari A, et al. Respiratory failure in adults. Treasure Island (FL): StatPearls Publishing; 2023 [internet publication]. https://www.ncbi.nlm.nih.gov/books/NBK526127