A highly anxious patient feels short of breath immediately after receiving a local anesthetic injection in the dental chair. The vital signs are normal. What is the most likely cause?

In a highly anxious patient with normal vital signs who feels short of breath after receiving local anesthesia, the most likely cause is anxiety-induced hyperventilation (psychogenic reaction). Hyperventilation causes a decrease in blood carbon dioxide (hypocapnia), leading to respiratory alkalosis, which can cause dizziness, tingling in the extremities, and a feeling of shortness of breath. Management includes calming the patient, having them breathe into a paper bag, or asking them to breathe slowly. Local anesthetic systemic toxicity (LAST) would present with neurological (tinnitus, metallic taste, seizures) and cardiovascular symptoms. Anaphylaxis would present with urticaria, hypotension, and bronchospasm.