Which of the following is NOT a common early sign of hypoxia?

• A. Tachycardia
• B. Nervous, irritable behavior
• C. ALOC
• D. Bradypnea

Answer: (D)

Early hypoxia triggers the body's compensatory responses to keep tissues oxygenated. The heart rate rises to improve oxygen delivery, and brain oxygen deficit can make a person feel nervous or irritable. As hypoxia persists, mental-status changes such as confusion or an altered level of consciousness can appear. Breathing rate usually increases early on as the body works harder to take in oxygen. Slow breathing, or bradypnea, on the other hand, tends to occur only as hypoxia becomes more severe and the respiratory muscles fatigue, signaling a later, more dangerous stage. So the sign that is not an early sign is slow breathing.