However, many of these devices require the user to inhale deeply and hold their breath to allow the CO in the blood to escape into the lung before the measurement can be made. As this is not possible in people who are unresponsive, these devices may not appropriate for use in on-scene emergency care detection of CO poisoning. Differential diagnosis
There are many conditions to be considered in the differential diagnosis of carbon monoxide poisoning. The earliest symptoms, especially from low level exposures, are often non-specific and readily confused with other illnesses, typically flu-like viral syndromes, depression, chronic fatigue syndrome, chest pain, and migraine or other headaches. Carbon monoxide has been called a "great mimicker" due to the presentation of poisoning being diverse and nonspecific. Other conditions included in the differential diagnosis include acute respiratory distress syndrome, altitude sickness, lactic acidosis, diabetic ketoacidosis, meningitis, methemoglobinemia, or opioid or toxic alcohol poisoning. Treatment
Initial treatment for carbon monoxide poisoning is to immediately remove the person from the exposure without endangering further people. Those who are unconscious may require CPR on site. Administering oxygen via non-rebreather mask shortens the half-life of carbon monoxide from 320 minutes, when breathing normal air, to only 80 minutes. Oxygen hastens the dissociation of carbon monoxide from carboxyhemoglobin, thus turning it back into hemoglobin. Due to the possible severe effects in the baby, pregnant women are treated with oxygen for longer periods of time than non-pregnant people.
Hemoglobin
Carbon monoxide has a higher diffusion coefficient compared to oxygen, and the main enzyme in the human body that produces carbon monoxide is heme oxygenase, which is located in nearly all cells and platelets. Most endogenously produced CO is stored bound to hemoglobin as carboxyhemoglobin. The simplistic understanding for the mechanism of carbon monoxide toxicity is based on excess carboxyhemoglobin decreasing the oxygen-delivery capacity of the blood to tissues throughout the body. In humans, the affinity between hemoglobin and carbon monoxide is approximately 240 times stronger than the affinity between hemoglobin and oxygen. However, certain mutations such as the Hb-Kirklareli mutation has a relative 80,000 times greater affinity for carbon monoxide than oxygen resulting in systemic carboxyhemoglobin reaching a sustained level of 16% COHb.Hemoglobin is a tetramer with four prosthetic heme groups to serve as oxygen binding sites. The average red blood cell contains 250 million hemoglobin molecules, therefore 1 billion heme sites capable of binding gas. The binding of carbon monoxide at any one of these sites increases the oxygen affinity of the remaining three sites, which causes the hemoglobin molecule to retain oxygen that would otherwise be delivered to the tissue; therefore carbon monoxide binding at any site may be as dangerous as carbon monoxide binding to all sites. Delivery of oxygen is largely driven by the Bohr effect and Haldane effect.