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1# General Anesthesia

1. Which component of balanced anesthesia is primarily responsible for rapid loss of consciousness within 30 seconds?

Inhalational anesthetics
Preanesthetic medications
Intravenous anesthetics
Opioid analgesics
Explanation:
IV anesthetics are highly lipid-soluble, cross the BBB rapidly, and induce unconsciousness in <30 seconds. Inhalational agents are mainly used for maintenance.

2. Why is increased parasympathetic stimulation considered more dangerous than sympathetic stimulation during anesthesia?

It causes hypertension and tachycardia
It leads to hypotension and bradycardia that are difficult to manage
It increases anesthetic requirements
It causes bronchospasm via β₂ blockade
Explanation:
Excess parasympathetic activity causes hypotension and bradycardia, increasing the risk of arrhythmias and death, and is harder to reverse intraoperatively.

3. During stage IV anesthesia overdose, which muscle is the LAST to lose function?

Intercostal muscles
Extraocular muscles
Pharyngeal muscles
Diaphragm
Explanation:
The diaphragm is the most resistant respiratory muscle and is the last to lose function in medullary paralysis.

4. Recovery from general anesthesia occurs mainly due to:

Redistribution of anesthetic from brain to peripheral tissues
Hepatic metabolism
Renal excretion
Pulmonary metabolism
Explanation:
Early recovery is mainly due to redistribution away from the brain, not metabolism—especially important for lipid-soluble agents.

5. Which receptor is INHIBITED by most general anesthetics?

GABA-A
NMDA
Glycine
Potassium channels
Explanation:
General anesthetics inhibit excitatory receptors such as NMDA and AMPA, while enhancing inhibitory receptors like GABA-A.

6. Which IV anesthetic reduces intracranial pressure without depressing myocardial contractility?

Propofol
Ketamine
Thiopental
Midazolam
Explanation:
Propofol reduces ICP and cerebral blood flow while maintaining myocardial function, making it useful in cerebral ischemia.

7. A patient appears conscious with open eyes but cannot move or respond to pain. Which agent was most likely used?

Propofol
Etomidate
Ketamine
Midazolam
Explanation:
Ketamine produces dissociative anesthesia, where patients appear awake but are disconnected from sensory input.

8. Which IV anesthetic is contraindicated in patients with psychosis?

Propofol
Thiopental
Etomidate
Ketamine
Explanation:
Ketamine causes vivid dreams, hallucinations, and delusions, which can worsen psychosis.

9. Which barbiturate lowers seizure threshold and is used in electroconvulsive therapy?

Thiopental
Methohexital
Phenobarbital
Pentobarbital
Explanation:
Methohexital uniquely lowers seizure threshold, making it useful in ECT.

10. Which drug provides sedation and anterograde amnesia but NO analgesia?

Benzodiazepines
Ketamine
Opioids
Dexmedetomidine
Explanation:
Benzodiazepines cause sedation and anterograde amnesia but lack analgesic properties.

11. Which opioid is preferred intraoperatively due to faster onset and stronger analgesia?

Morphine
Meperidine
Fentanyl
Codeine
Explanation:
Fentanyl is more potent, faster acting, and widely used intraoperatively.

12. Which IV anesthetic inhibits 11β-hydroxylase and suppresses cortisol synthesis?

Propofol
Ketamine
Thiopental
Etomidate
Explanation:
Etomidate inhibits adrenal steroid synthesis and should not be used for prolonged infusions.

13. Which anesthetic provides sedation with minimal respiratory depression and is an α₂ agonist?

Dexmedetomidine
Midazolam
Propofol
Ketamine
Explanation:
Dexmedetomidine is an α₂ agonist causing sedation and analgesia with minimal respiratory depression.

14. Low blood-gas partition coefficient indicates:

Slow induction and recovery
Fast induction and recovery
High anesthetic potency
Increased metabolism
Explanation:
Low solubility in blood allows rapid equilibration with the brain → fast induction and recovery.

15. Which inhalational agent has the LOWEST MAC value?

Nitrous oxide
Sevoflurane
Isoflurane
Halothane
Explanation:
Halothane has the lowest MAC, making it the most potent inhalational anesthetic.

16. Which inhalational anesthetic is contraindicated in pneumothorax?

Nitrous oxide
Sevoflurane
Isoflurane
Desflurane
Explanation:
Nitrous oxide expands air-filled spaces and can worsen pneumothorax.

17. Which inhalational agent is preferred for pediatric mask induction?

Isoflurane
Desflurane
Sevoflurane
Halothane
Explanation:
Sevoflurane is non-pungent with minimal airway irritation, ideal for children.

18. Malignant hyperthermia is caused by uncontrolled release of:

Sodium
Calcium
Potassium
Chloride
Explanation:
MH results from excessive Ca²⁺ release from sarcoplasmic reticulum, causing muscle rigidity and hyperthermia.

19. Which drug is the definitive treatment for malignant hyperthermia?

Naloxone
Atropine
Epinephrine
Dantrolene
Explanation:
Dantrolene blocks Ca²⁺ release from the sarcoplasmic reticulum, reversing MH.

20. Reduced cardiac output causes which effect on IV anesthetics?

Stronger brain effect despite slower onset
Weaker anesthetic effect
Faster elimination
Reduced brain exposure
Explanation:
Low CO slows distribution but prolongs brain exposure, allowing drug concentration to reach threshold → stronger effect.