Certified Transport Registered Nurse Certification Practice Exam

What type of hypoxia is experienced at 15,000 ft due to atmospheric pressure?

1. Hyperemic hypoxia

2. Hypoxic hypoxia

3. Histotoxic hypoxia

4. Stagnant hypoxia

The correct answer is: Hypoxic hypoxia

Hypoxic hypoxia occurs when there is a deficiency of oxygen in the atmosphere, particularly at higher altitudes where atmospheric pressure is significantly lower. At 15,000 feet, the partial pressure of oxygen decreases, leading to reduced available oxygen for respiratory gas exchange in the lungs. This results in decreased oxygen saturation in the blood, manifesting as hypoxic hypoxia. In this scenario, the altitude itself is a critical factor; as the elevation increases, the atmospheric pressure falls, which in turn reduces the amount of oxygen available for the body to utilize, regardless of how effectively the lungs are functioning. It's specifically tied to the decreased availability of oxygen in the external environment, distinguishing it from other types of hypoxia that may not be related directly to altitude or atmospheric conditions. Hyperemic hypoxia, on the other hand, relates to inadequate oxygen in the blood due to reduced blood volume or hemoglobin issues; histotoxic hypoxia refers to the inability of cells to utilize oxygen (often due to toxins); and stagnant hypoxia is associated with poor circulation or blood flow issues. None of these conditions are primarily influenced by atmospheric pressure in the way that hypoxic hypoxia is.