Final answer:
CO2 is eliminated from the anesthesia circuit with a CO2 absorber, and administering 100% oxygen can save a patient from carbon monoxide poisoning by displacing the CO from hemoglobin, allowing oxygen to bind instead.
Step-by-step explanation:
CO2 can be eliminated from the anesthesia circuit primarily by the use of a CO2 absorber. This method involves using substances like soda lime to chemically absorb the exhaled carbon dioxide, preventing it from being re-inhaled by the patient. Additionally, increasing oxygen concentration in the breathing circuit can help flush out CO2. However, adding more anesthetic agents or decreasing fresh gas flow does not directly contribute to the elimination of CO2 from the circuit.
Regarding carbon monoxide poisoning, administration of 100 percent oxygen is effective as it significantly increases the partial pressure of oxygen in the blood. This high partial pressure encourages the release of carbon monoxide from the hemoglobin, allowing oxygen to bind instead and restoring the blood's ability to transport oxygen. Administering carbon dioxide would not be beneficial, as it would not aid in displacing the carbon monoxide bound to hemoglobin, nor would it improve the oxygen-carrying capacity of the blood.