Final answer:
Among the given options, CNS signs and symptoms of LAST include numbness of lips and tongue and respiratory depression. LAST affects both the central nervous system and cardiovascular system and can have serious symptoms like seizures and loss of consciousness. Option c.
Step-by-step explanation:
The CNS signs and symptoms of LAST (Local Anesthetic Systemic Toxicity) can be quite serious and diverse. LAST can occur when local anesthetics enter the bloodstream in significant quantities, influencing central nervous system and cardiovascular system functions. CNS manifestations of LAST may include respiratory depression option c, which is a decline in the effectiveness of breathing; numbness of limbs or around the mouth, which might be experienced as numbness of lips and tongue; visual disturbances such as blurred vision; muscle twitching or fasciculations; and in severe cases, seizures and loss of consciousness. Specifically addressing the student's question: 'CNS signs and symptoms of LAST include: a) hypertension b) numbness of lips and tongue c) respiratory depression d) elevated temperature', the correct response would be 'b) numbness of lips and tongue' and 'c) respiratory depression', as hypertension and elevated temperature are more commonly associated with other conditions.