Which of the following are true based on an elevated COHb?I….

Which of the following are true based on an elevated COHb?I. the pulse oximetry reading is reflective of the level of carbon monoxide poisoningII. mechanical ventilation should be considered on a patient who has a COHb < 10III. hyperbaric chamber should be used for a COHb of > 30IV. 100% oxygen should be used on a patient who is showing signs of respiratory distress       when CO poisoning is suspected