Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1107 page)

   Interpretation

Increased In

   Decreased ventilation

   Airway obstruction

   Drug overdose

   Metabolic disorders (e.g., myxedema, hypokalemia)

   Neurologic disorders (e.g., Guillain-Barré syndrome, multiple sclerosis)

   Muscle disorders (e.g., muscular dystrophy, polymyositis)

   Chest wall abnormalities (e.g., scoliosis)

   Increased dead space in the lungs (perfusion decreased more than ventilation decreased)

   Lung diseases (e.g., COPD, asthma, pulmonary fibrosis, mucoviscidosis)

   Chest wall changes affecting lung parenchyma (e.g., scoliosis)

   Increased production (e.g., sepsis, fever, seizures, excess carbohydrate loads)

Decreased In

   Hypoventilation (e.g., chronic airflow obstruction): caused by increased alveolar CO
₂
that displaces O
₂
.