IV Induction Agents – Hypnosis

🧴 Propofol

  • Mechanism: GABA receptor agonist → Causes neuronal inhibition
  • Uses: Induction & maintenance of anesthesia
  • Best for:
    • Short procedures
    • Day surgery
    • TIVA (Total Intravenous Anesthesia)
  • Special Considerations:
    • Causes hypotension
    • Pain on injection (Lidocaine prior to pushing may help but not always)
    • Some preparations contain egg/soy, so be sure to ask about allergies!
  • Clinical Use:
    • Ideal for outpatient surgery (fast recovery)
    • Used in procedures requiring frequent neurological assessments
    • Avoid in elderly with cardiovascular compromise

🦄 Ketamine

  • Mechanism: NMDA receptor antagonist → Blocks excitatory pathways
  • Uses:
    • Dissociative anesthesia (Patient is awake but unaware)
    • Powerful analgesia
  • Best for:
    • Hemodynamically unstable patients
    • Pediatric cases
    • Patients with airway diseases (e.g., asthma)
  • Special Considerations:
    • Can cause emergence reactions (hallucinations, nightmares)
    • Maintains airway reflexes
    • Increases bronchial secretions
  • Clinical Use:
    • Perfect for trauma patients & burn victims
    • Great for asthmatics due to bronchodilation
    • Caution in psychiatric patients (may worsen symptoms)

🛡️ Etomidate

  • Mechanism: GABA receptor modulator → Enhances inhibitory signals
  • Uses:
    • Induction of anesthesia
    • Preferred in hemodynamically unstable patients
  • Best for:
    • Patients with cardiovascular instability
    • Trauma cases
    • Patients at risk for hypotension
  • Special Considerations:
    • Causes adrenal suppression (Even with ONE dose)
    • Caution in sepsis patients (They rely on catecholamine synthesis to maintain BP)
  • Clinical Use:
    • Best for patients at risk of hypotension
    • Avoid in long-term use due to adrenal suppression

📚 References

1️⃣ Miller RD. Miller’s Anesthesia. 9th ed. Philadelphia, PA: Elsevier; 2020.

2️⃣ Morgan GE, Mikhail MS, Murray MJ. Morgan & Mikhail’s Clinical Anesthesiology. 6th ed. New York, NY: McGraw Hill; 2018.

3️⃣ Steiner J. Anesthesia Made Easy: The Survival Guide to Make Your First Anesthesia Rotation a Success. 2nd ed. Independently Published; 2019.