- 5 Classic Causes of Hypoxemia
- V-Q Mismatch (elevated A-a gradient)
- Diffusion problems (elevated A-a gradient)
- Shunting (right to left shunt, PE) (Elevated A-a gradient)
- Hypoventilation (normal A-a gradient)
- Altitude, low inspired FiO2 (normal A-a gradient)
- Illness script for PCP Pneumonia: Usually HIV +, chronic non-productive cough (due to high viscosity of sputum), often normal lung exam and chest film, may see ground glass opacities in the bilateral lower lung fields, hypoxia worse with exertion
- Start steroids in addition to Bactrim for FiO2 < 70 or A-a gradient > 35, treatment of PCP fungal death causes a profound inflammatory reaction which is why steroids decrease mortality, treatment course is for 21 days
- Prophylaxis for PCP in HIV for CD4 < 200, 95% effective in preventing PCP
