Which of the following is a consequence of respiratory arrest?

Respiratory arrest results in a cessation of breathing, which leads to a lack of oxygen supply to the body, particularly affecting the brain. The brain is highly sensitive to oxygen deprivation and can start to suffer damage within just a few minutes without adequate oxygen. This condition can lead to irreversible brain damage if not promptly addressed, making it crucial to recognize and respond to respiratory arrest quickly.

The other options do not accurately reflect the physiological consequences of respiratory arrest. For instance, increased heart rate is not a direct result of respiratory arrest; rather, the heart may eventually slow down or stop due to hypoxia. Heightened muscle tone would not occur in the context of respiratory failure, as muscle relaxation typically takes place without adequate oxygen. Similarly, circulation efficiency does not improve; rather, it often worsens due to the heart struggling to maintain effective blood flow in the absence of sufficient oxygenation.