Sally is a 60-year-old retiree in northern Alberta. One bitter cold March morning (-50 °C), she decided to warm her car in the garage. Thirty minutes later, Sally's husband found her slumped in the front seat of the car, confused and breathing rapidly. She was taken to a nearby emergency department, where she was diagnosed with acute carbon monoxide poisoning and given 100% O2 to breathe. An arterial blood

Sample had an unusual cherry red color.

1. The normal percent O2 saturation of hemoglobin in arterial blood is 95%-100%. Why was Sally's O2 saturation reduced to 50%?
2. What percentage of the heme groups on her hemoglobin were bound to carbon monoxide? Describe normal O2-hemoglobin dissociation curve, and compare the O2-hemoglobin dissociation curve that would have been obtained on Sally in the emergency department.
3. What effect did CO poisoning have on her O2-binding capacity? What effect did CO poisoning have on the affinity of hemoglobin for O2?
4. What was the rationale for giving Sally 100% O2 to breathe?