HYPOXEMIA

HYPOXEMIA High AA Gradient Normal AA Gradient Hypoxemia Right-to-Left Shunt Ventilation/Perfusion Mismatch Low PO2, Low O2, Cyanosis Low Inspired PO2 Hypoventilation Increased PCO2 Central Peripheral Parenchymal Intracardiac Pulmonary Damaged Lung Structure Severe Pneumonia Atelectasis Ventricular Septal Defect Atrial Septal Defect Status Asthmaticus* Advanced COPD Chest Wall Arteriovenous Malformation Obesity Neuromuscular Kyphosis Airway Disease (Asthma, COPD) Vascular (PE*)Parenchymal Disease (+/- Diffusion Defect) Drugs* Coma Hypothyroidism Alveolar-Arterial Gradient = PAO2 - PaO2PAO2 = FiO2 (PB-PH2O)-(PaCO2/0.8)*In Calgary, PB = 660mmHg, Sea level PB = 760mmHg* Denotes acutely life-threatening causesHigh Altitude