General Anaesthetics

A 52-year-old man with hypertension and coronary artery disease is scheduled for elective laparoscopic cholecystectomy. Anaesthesia is induced with propofol 2 mg/kg IV. Within 30 seconds of induction, his blood pressure drops from 140/90 mmHg to 85/50 mmHg, and heart rate rises from 72 to 105 bpm. He remains unconscious and adequately oxygenated. Which of the following best explains the cardiovascular effects observed with propofol in this patient?

Which of the following general anaesthetics is a GABA_A receptor agonist and is commonly used for induction in adults due to its rapid onset and short duration of action?

A 38-year-old woman with asthma and a history of anaphylaxis to penicillin is scheduled for emergency appendectomy. During rapid sequence intubation, she is induced with thiopental 5 mg/kg IV. Within 2 minutes of induction, she develops bronchospasm, hypotension (BP 78/45 mmHg), and a diffuse erythematous rash. Oxygen saturation drops to 88% on 100% O₂. Which of the following is the MOST likely mechanism underlying this adverse reaction?