What is the most likely cause of tongue numbness and visual disturbances during thermal ablation?

Lidocaine toxicity is associated with tongue numbness and visual disturbances due to the way local anesthetics affect the nervous system. When lidocaine is administered, particularly in higher doses or in patients with varying sensitivities, it can lead to systemic absorption and toxicity. This toxicity can impact the central nervous system (CNS), resulting in neurological symptoms such as numbness or tingling in areas like the tongue and visual disturbances such as blurred vision or double vision.

The mechanism behind lidocaine toxicity includes inhibition of sodium channels, which are crucial for the propagation of nerve impulses. This can lead to symptoms that manifest in both sensory and visual areas. Monitoring dosage and the patient's response during procedures where lidocaine is used is critical to prevent these types of complications.

While the other options (hypotension, dehydration, and patient anxiety) can cause various side effects during medical procedures, they do not typically lead to the specific combination of symptoms—tongue numbness and visual disturbances—that are characteristic of lidocaine toxicity.