A 58-year-old man with a history of hypertension (BP 160/95 mmHg) and coronary artery disease presents for elective laparoscopic cholecystectomy. On induction, propofol 2 mg/kg IV is administered. Within 30 seconds, his blood pressure drops to 95/55 mmHg and heart rate increases to 110 bpm. He remains conscious but drowsy. Which of the following best explains the cardiovascular response observed and would be the most appropriate alternative induction agent for this patient?

Explanation

## Cardiovascular Effects of Propofol in High-Risk Patients **Key Point:** Propofol causes direct myocardial depression and peripheral vasodilation, leading to dose-dependent hypotension—a significant concern in hypertensive and coronary artery disease patients. ### Analysis of the Clinical Scenario This patient experienced: - Systolic BP drop of ~65 mmHg (160 → 95) - Reflex tachycardia (sympathetic compensation) - Preserved consciousness initially (indicating adequate drug delivery) Propofol's mechanism of hypotension involves: 1. Direct negative inotropic effect 2. Peripheral vasodilation (decreased SVR) 3. Blunted baroreceptor reflex in elderly/hypertensive patients ### Comparison of Induction Agents in Hemodynamically Unstable Patients | Agent | BP Effect | HR Effect | Airway Reflexes | Ideal For | |-------|-----------|-----------|-----------------|----------| | **Propofol** | ↓↓ (20–30%) | ↑ (reflex) | Preserved | Healthy, normotensive | | **Thiopentone** | ↓↓ (10–20%) | ↑ (reflex) | Preserved | Rarely used now | | **Etomidate** | ↓ (minimal, 5–10%) | ↔ (minimal change) | Preserved | Hemodynamically unstable | | **Ketamine** | ↑ or ↔ (sympathomimetic) | ↑ | Preserved | Shock, trauma, hypotensive | **High-Yield:** Ketamine is the agent of choice for hemodynamically compromised patients because it: - Maintains or increases BP via sympathomimetic effects (↑ NE/dopamine release) - Preserves airway reflexes and spontaneous ventilation - Maintains cerebral perfusion pressure - Has analgesic properties **Clinical Pearl:** In this hypertensive, CAD patient with a 65 mmHg systolic drop, ketamine's sympathomimetic profile makes it superior to etomidate (which, despite minimal BP drop, offers no analgesia and carries adrenal suppression risk with repeated dosing). ### Why Ketamine Is Correct 1. **Sympathomimetic mechanism:** Inhibits noradrenaline reuptake and stimulates catecholamine release, offsetting the depressant effects 2. **Preserved hemodynamics:** Maintains or increases BP and HR, critical in CAD 3. **Airway protection:** Maintains pharyngeal and laryngeal reflexes 4. **Analgesic bonus:** Provides intraoperative analgesia **Mnemonic:** **KETAMINE = Keep Everything Tight (BP, HR, airway)**