NCE (CRNA) Practice Questions (2026) — Free Sample Questions with Answers

Answer: A

Desflurane: Correct. Desflurane has the lowest blood:gas partition coefficient of the volatile agents (about 0.42), so little dissolves in blood, alveolar partial pressure rises fastest, and washout on emergence is fastest.

Sevoflurane: Sevoflurane (about 0.65) is less soluble than isoflurane but more soluble than desflurane, so its uptake and elimination are slightly slower.

Isoflurane: Isoflurane (about 1.4) is more blood-soluble, so FA/FI rises more slowly and emergence is slower.

Halothane: Halothane (about 2.4) is the most blood-soluble of these agents and has the slowest induction and emergence.

Lower blood:gas solubility means faster induction and emergence. Rough order: desflurane (0.42) < N2O (0.47) < sevoflurane (0.65) < isoflurane (1.4) < halothane (2.4). Potency is predicted by the oil:gas coefficient, not blood:gas.

Answer: B

About 16 minutes: This underestimates the volume left by half, as if the cylinder held only about 330 L when full.

About 33 minutes: Correct. Oxygen is a compressed gas, so volume is proportional to pressure (Boyle's law): 1,000/2,000 x 660 L = 330 L; 330 L / 10 L/min = 33 minutes.

About 66 minutes: 66 minutes would require the full 660 L. It ignores that the gauge shows the cylinder half empty.

About 100 minutes: This overestimates the supply and could lead to oxygen running out during transport.

For oxygen and air (compressed gases), remaining volume is proportional to gauge pressure. For N2O (a liquid in the cylinder) pressure stays at about 745 psig until roughly 75% is used, so weigh the cylinder instead.

Answer: D

Metabolic acidosis with respiratory compensation: Metabolic acidosis requires a low HCO3- (below 22); here HCO3- is normal and the PaCO2 is high.

Chronic respiratory acidosis with metabolic compensation: Chronic compensation would raise HCO3- by about 3.5 to 4 mEq/L per 10 mm Hg rise in PaCO2 (to about 30); HCO3- is still normal.

Mixed metabolic and respiratory alkalosis: The pH is acidemic (below 7.35), which rules out alkalosis.

Acute respiratory acidosis, uncompensated: Correct. Low pH with high PaCO2 and normal HCO3- is acute respiratory acidosis. pH falls about 0.08 per 10 mm Hg acute rise in PaCO2 (15 mm Hg rise gives about 7.28), consistent with opioid-induced hypoventilation.

ABG steps: pH (acidemia or alkalemia), then which value explains it (PaCO2 = respiratory, HCO3- = metabolic), then compensation (acute vs. chronic expected changes).

Answer: A

Perform emergency front-of-neck access (cricothyrotomy): Correct. This is a 'cannot intubate, cannot oxygenate' emergency. The ASA difficult airway guideline calls for immediate emergency invasive airway access when face mask and supraglottic ventilation have both failed.

Make a third and fourth attempt with a different laryngoscope blade: Repeated attempts cause airway trauma and edema and waste time while the patient desaturates; attempts should be limited.

Give sugammadex and wait for spontaneous breathing to return: Reversal may be considered, but waiting for spontaneous breathing during critical hypoxemia is unsafe and may not restore a patent airway.

Place a nasal cannula at 15 L/min and continue to observe: Apneic oxygenation cannot rescue an obstructed airway in a patient who cannot be ventilated.

Difficult airway sequence: limit intubation attempts, then supraglottic airway, then face mask. If oxygenation fails (cannot intubate, cannot oxygenate), go immediately to emergency invasive airway access.

Answer: A

Ask the surgeon to flood the field with saline and switch to 100% oxygen: Correct. This is venous air embolism. Stop further air entry first (flood or pack the field, wax bone edges), give 100% O2 and stop N2O, then aspirate air through a right atrial catheter and support circulation.

Increase minute ventilation to return the end-tidal CO2 toward 35 mm Hg: The ETCO2 fall is from increased dead space caused by air in the pulmonary circulation, not hyperventilation; more ventilation does not help.

Add nitrous oxide to deepen anesthesia and reduce the sympathetic response: N2O diffuses into air bubbles and enlarges them, worsening the embolism. It must be stopped.

Raise the head further to improve venous drainage from the surgical site: Raising the head increases the gradient that pulls air into open veins. Lowering the head, if feasible, reduces entrainment.

VAE: TEE is the most sensitive monitor, then precordial Doppler. Signs: sudden ETCO2 drop, ETN2 rise, hypotension. Management: flood the field, 100% O2, stop N2O, aspirate the RA catheter, jugular compression, and give hemodynamic support.

Answer: B

3.5 mm: 3.5 mm is the typical cuffed tube size for infants under about 1 year, not a 4-year-old.

4.5 mm: Correct. Cuffed tube ID (mm) = (age / 4) + 3.5 = (4 / 4) + 3.5 = 4.5 mm. Have a half-size smaller and larger ready.

5.0 mm: 5.0 mm is the uncuffed size: (age / 4) + 4 = 5.0 mm. A cuffed tube should be a half size smaller.

6.0 mm: 6.0 mm suits children of about 10 years and would be too large, risking subglottic injury.

Pediatric ETT: cuffed = age/4 + 3.5; uncuffed = age/4 + 4; oral depth (cm) about 3 x ID (or age/2 + 12). Keep the cuff pressure below about 20 to 25 cm H2O.