American Board of Medicolegal Death Investigators (ABMDI) Practice Exam

What substances can lead to oxygen deprivation?

1. Hydrogen sulfide, ammonia

2. Carbon monoxide, cyanide

3. Ozone, nitrogen dioxide

4. Chlorine, sulfur dioxide

The correct answer is: Carbon monoxide, cyanide

The correct answer highlights substances that can cause oxygen deprivation, which is critical for understanding how certain toxic agents affect human physiology. Carbon monoxide is a colorless, odorless gas that binds with hemoglobin in the blood much more effectively than oxygen does. This binding prevents oxygen from being transported to various tissues in the body, leading to hypoxia (a deficiency in the amount of oxygen reaching tissues) and potentially resulting in serious health consequences, including death. Cyanide, on the other hand, interferes with cellular respiration. It inhibits cytochrome c oxidase in the electron transport chain, which is essential for aerobic metabolism. Consequently, even in the presence of adequate oxygen, cells cannot utilize it effectively, leading to a state of suffocation at the cellular level, further contributing to oxygen deprivation. Other choices may include substances that are harmful or toxic but do not specifically impair the uptake or utilization of oxygen in the same direct manner as carbon monoxide and cyanide do. For example, while ozone and nitrogen dioxide are respiratory irritants, they do not bind hemoglobin or disrupt cellular respiration in the same effective way that the correct substances do.