What symptom might result from local anesthetic systemic toxicity?

Local anesthetic systemic toxicity (LAST) can lead to various symptoms, and changes in breathing, particularly respiratory depression, are among the more serious consequences. When local anesthetic agents are administered, if they enter systemic circulation in significant amounts, they can affect the central nervous system and cardiovascular system. Respiratory depression occurs because the anesthetic can inhibit the normal function of the brainstem, which is responsible for initiating and regulating breathing.

The central nervous system effects can manifest as a range of symptoms, starting from initial excitement or seizures, followed by a phase of central nervous system depression, which can lead to decreased respiratory drive. This diminished respiratory effort can result in inadequate ventilation and subsequent hypoxia, making it potentially life-threatening.

In contrast, the other options do not correctly reflect the effects of systemic toxicity related to local anesthetics. Increased reaction time would suggest a slowing of responses, which may occur due to sedation but not specifically as a direct result of LAST. Improved cognitive function contradicts the expected effects of systemic toxicity, which generally leads to confusion or impaired cognitive function. Enhanced pain perception can occur with other conditions but is not typically a symptom associated with local anesthetic toxicity; rather, LAST can produce a paradoxical response in which pain thresholds are affected in