Respiratory acidosis

The inability of the lungs to adequately exhale carbon dioxide due to alveolar hypoventilation, characterized by elevated arterial PaCO2 (>6.0 kPa), a reduced HCO₃⁻/PaCO₂ ratio (range 0.5-0.7), and a resultant acidosis (pH <7.35). Possible causes lung disease (COPD, asthma, pneumonia, pulmonary fibrosis), airway obstruction (foreign objects, edema, allergic reactions), neuromuscular disorders (ALS, myasthenia gravis, Guillain-Barré syndrome), chest deformity (scoliosis, kyphosis), CNS depression (opioids, sedatives, stroke, tumor, head trauma), obesity hypoventilation syndrome, and obstructive sleep apnea.