3. Bluish Skin and Lips (Cyanosis)
Why it happens: Oxygen-poor blood gives the skin and lips a bluish tint. This indicates severe hypoxemia and often means the lungs are failing badly.
How it looks: Patients may have blue lips, nail beds, or fingertips. Family members often notice it first, especially in cold weather, but cyanosis indoors is a red flag.
Medical Tests:
- Pulse Oximetry: SpO₂ usually <85%.
- ABG: PaO₂ <60 mmHg confirms hypoxemia.
- Chest X-ray/CT: Helps find structural cause (pneumonia, fibrosis, etc.).