Hypercapnia

Anormally elevated CO₂ in arterial blood (normal range: 35-45 mmHg or 4.6-6.1 kPa), usually due to alveolar hypoventilation, and commonly associated with respiratory acidosis. Possible causes are lung disease (COPD, asthma, cystic fibrosis, pulmonary fibrosis), mechanical obstruction (obstructive sleep apnea, obesity hypoventilation syndrome, tracheal tumor), neurological disorders (muscular dystrophy, myasthenia gravis, Guillain-Barré syndrome, spinal cord injury, stroke, trauma, encephalitis), medication (sedatives or opioids), enviromental factors (poor air circulation, deep-sea diving), and systemic infections (sepsis, fever).