Free FMGE Anesthesia questions

Explanation

Preoxygenation increases the oxygen reservoir in the functional residual capacity by denitrogenating the lungs. This delays arterial desaturation during apnea after induction.

Explanation

Mallampati class IV means only the hard palate is visible. Higher classes are associated with a greater likelihood of difficult laryngoscopy, though no single test is perfectly predictive.

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Rapid sequence induction minimizes the interval between loss of protective airway reflexes and cuffed tracheal intubation. It is used when aspiration risk is considered high.

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Propofol is widely used for induction because of rapid onset and recovery. Vasodilation and myocardial depression can produce hypotension, and injection pain is common.

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Ketamine tends to preserve cardiovascular tone through sympathetic stimulation and also provides potent analgesia. Emergence phenomena and increased secretions are notable adverse effects.

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Etomidate produces relatively little cardiovascular depression and is useful in hemodynamically fragile patients. It can inhibit adrenal steroidogenesis, especially with repeated or prolonged exposure.

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Low blood solubility allows alveolar and brain partial pressures to rise and fall rapidly. Therefore agents with a lower blood-gas partition coefficient generally have faster onset and recovery.

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Nitrous oxide diffuses into air-filled cavities faster than nitrogen leaves them. It can therefore enlarge conditions such as pneumothorax or certain bowel and intracranial air collections.

Explanation

Succinylcholine depolarizes nicotinic receptors at the neuromuscular junction and initially causes fasciculations. It has a rapid onset and short duration but several important contraindications and adverse effects.

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After major burns, denervation-type injuries, and certain neuromuscular conditions, extrajunctional acetylcholine receptors increase. Succinylcholine can then cause a marked potassium release and life-threatening hyperkalemia.

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Dantrolene reduces calcium release from the sarcoplasmic reticulum and is the specific treatment for malignant hyperthermia. Triggering anesthetic agents must also be stopped and supportive measures started urgently.

Explanation

An unexplained rise in end-tidal CO2 is often an early clue to malignant hyperthermia. Rigidity, acidosis, hyperkalemia, tachycardia, and hyperthermia may follow.

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Spinal anesthesia blocks sympathetic efferent fibers, producing arterial and venous vasodilation. Reduced venous return and systemic vascular resistance can lead to hypotension.

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The adult spinal cord usually ends around L1-L2, so lumbar puncture is commonly performed at L3-L4 or L4-L5. The needle then enters the lumbar cistern below the cord.

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An epidural catheter can remain in the epidural space for repeated or continuous administration. Spinal anesthesia usually involves a smaller single injection into CSF.

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Local anesthetics bind voltage-gated sodium channels and prevent action-potential propagation along nerves. Their effect is use-dependent and influenced by tissue pH and drug properties.

Explanation

CNS excitation followed by cardiovascular toxicity is characteristic of systemic local anesthetic poisoning. Intravenous lipid emulsion is an important component of treatment for severe toxicity.

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Capnography displays exhaled CO2 over time and provides the end-tidal CO2 value. It is especially useful for confirming ventilation and detecting airway or breathing problems.

Explanation

Pulse oximetry noninvasively estimates peripheral arterial oxygen saturation using differential light absorption. It does not directly measure ventilation or PaCO2.

Explanation

Ondansetron blocks 5-HT3 receptors and is commonly used as an antiemetic in the perioperative period. Other antiemetic classes may be combined according to patient risk.