Hypoventilation

Inadequate alveolar ventilation of the lungs causing insufficient respiratory gas exchange, leading to hypercapnia (PaCO₂ >6.0 kPa or >45 mmHg) with or without hypoxemia (PaO₂ <10.6 kPa or <80 mmHg), and resulting in respiratory acidosis. Possible causes are drugs (opioids, sedatives, anesthetics), Obesity Hypoventilation Syndrome, neuromuscular disease (muscular dystrophy, ALS, myasthenia gravis), CNS disease (head trauma, tumor, stroke, congenital disorders like Ondine's curse), pulmonary factors (COPD, obstructive sleep apnea), and chest wall/ribcage deformities such as scoliosis.