American Board of Medicolegal Death Investigators (ABMDI) Practice Exam

Which of the following is an indication of asphyxia?

1. Rapid heart rate

2. High blood pressure

3. Excess carbon dioxide in the body

4. Decreased blood flow to the brain

The correct answer is: Excess carbon dioxide in the body

Excess carbon dioxide in the body, also known as hypercapnia, is a key indication of asphyxia. Asphyxia occurs when there is insufficient oxygen available to sustain bodily functions, leading to a range of physiological responses. When the body does not receive enough oxygen, carbon dioxide (a byproduct of respiration) begins to accumulate because it isn't being expelled effectively. This build-up can result in symptoms such as confusion, dizziness, and ultimately unconsciousness if the asphyxia is severe. Rapid heart rate could be observed in various conditions and isn't specific to asphyxia. High blood pressure may also arise from a multitude of factors and does not solely indicate asphyxia. While decreased blood flow to the brain can occur due to several medical emergencies, it is not a direct indicator of asphyxia without the context of hypoxia (low oxygen levels) specifically affecting airflow or oxygenation. Therefore, the presence of excess carbon dioxide serves as a direct confirmation of the body's inability to exchange gases effectively due to asphyxia.