Acute Respiratory Failure (ARF) and Acute Respiratory Distress Syndrome (ARDS) are critical pulmonary conditions where gas exchange is insufficient to support systemic organs.

The 80/20 Core: Pathophysiology & Clinical Care

1. Classification of ARF ARF is a symptom of inadequate lung function, categorized into two types:

• Hypoxemic (Oxygenation Failure): PaO2​<60 mm Hg on room air. The core defect is inadequate O2​ exchange, caused by V/Q mismatch, shunt, diffusion impairment, or alveolar hypoventilation. Shunt is an extreme mismatch where alveoli fill with fluid, making O2​ therapy alone ineffective.
• Hypercapnic (Ventilatory Failure): PaCO2​>50 mm Hg with pH< ...