CEN Practice Questions (2026) — Free Sample Questions with Answers

Answer: C

"It feels like an elephant is sitting on my chest.": Heavy, crushing pressure describes ischemic pain from ACS; sharp pain after a viral illness points elsewhere.

"The pain started suddenly and tore through to my back.": Sudden tearing pain radiating to the back suggests aortic dissection.

"The pain eases when I sit up and lean forward.": Correct. Sharp chest pain after a viral illness with ST elevation across multiple leads (rather than one coronary territory) suggests acute pericarditis. Relief when sitting up and leaning forward, which lifts the heart off the inflamed pericardium, supports that diagnosis.

"The pain goes away when I rest after walking.": Pain brought on by exertion and relieved by rest describes stable angina.

Pericarditis: pleuritic chest pain relieved by leaning forward, a friction rub, and diffuse ST elevation with PR depression.

Answer: A

Palpable femoral pulse at the paced rate: Correct. Mechanical capture means each paced beat produces a pulse. The femoral pulse is checked because pacing causes chest and neck muscle contractions that can be mistaken for a carotid pulse.

A pacer spike before each QRS complex: A spike followed by a wide QRS shows electrical capture, which the monitor already shows; it does not prove the heart is pumping.

Visible skeletal muscle twitching with each spike: Muscle twitching shows current is reaching the chest wall, not that the myocardium is contracting.

Palpable carotid pulse at the paced rate: Pacing-induced muscle twitching near the neck can mimic a carotid pulse and give false reassurance.

Confirm both electrical capture (spike followed by a wide QRS) and mechanical capture (a femoral pulse that matches the paced rate).

Answer: B

"Your child can go home now, because the stridor has fully resolved.": Discharge right after nebulized epinephrine misses a rebound of airway swelling as the drug wears off.

"We should watch your child a few more hours, as stridor can return.": Correct. Nebulized epinephrine works for about 2 hours and symptoms can rebound as it wears off, so children are observed for several hours (commonly 2 to 4) before discharge.

"Your child needs to stay for a dose of antibiotics before leaving.": Antibiotics do not treat viral croup.

"Your child needs a throat culture before we can discharge you.": Croup is viral (usually parainfluenza); a throat culture does not guide care.

After nebulized epinephrine for croup, observe for several hours for rebound stridor before discharge.

Answer: C

"There is a blister on my hand from the doorknob.": A small partial-thickness hand burn needs care later; it is not the priority.

"My eyes are burning and watering.": Eye irritation from smoke needs irrigation and an exam but is not an airway threat.

"My voice sounds hoarse, and my throat feels tight.": Correct. Hoarseness and throat tightness signal upper airway edema from thermal injury. Edema can progress quickly to complete obstruction, so early intubation is anticipated.

"I keep thinking about the fire.": Distress is expected and should be addressed, but it does not threaten the airway.

After smoke exposure, hoarseness, stridor or throat tightness means airway edema: prepare for early intubation before swelling closes the airway.

Answer: D

1.: ESI 1 requires an immediate lifesaving intervention; this patient is alert with a protected airway and stable vital signs.

4.: One resource would be a gross under-triage of a possible aneurysmal bleed.

3.: This counts resources (CT, labs, IV medication) but skips the ESI 2 high-risk decision point, under-triaging the patient.

2.: Correct. A thunderclap headache with exertional onset is a high-risk presentation for subarachnoid hemorrhage; high-risk situations are ESI 2 regardless of the resources needed.

Before counting resources, ask whether the patient is high risk; a sudden worst-ever headache is ESI 2.

Answer: D

ESI level 1.: ESI 1 requires an immediate lifesaving intervention; this patient is stable and protecting the airway.

ESI level 2.: Over-triage: the patient is not high risk, confused or in severe pain or distress, and the vital signs are outside the danger zone.

ESI level 4.: Under-triage: ESI 4 is for patients expected to need only one resource, and this workup needs at least two.

ESI level 3.: Correct: the patient is not ESI 1 or 2 and will need two or more resources (laboratory studies, ultrasound, likely IV fluids or IV medication); danger-zone vital signs are absent, so ESI 3 stands.

Once ESI 1 and 2 criteria are excluded, count predicted resources (labs, imaging, IV fluids/medications); two or more is ESI 3 if danger-zone vitals are absent.

Answer: C

Transabdominal ultrasound: Ultrasound is the safe way to locate the placenta and confirm previa.

Continuous electronic fetal monitoring: Fetal monitoring is appropriate for any third-trimester bleeding.

Digital cervical examination: Correct: painless bright red bleeding with a soft uterus suggests placenta previa; a digital exam can disrupt the placenta and cause massive hemorrhage, so it is avoided until ultrasound excludes previa.

Type and crossmatch: Blood bank preparation is appropriate given the risk of sudden hemorrhage.

Painless bright red bleeding with a soft uterus points to previa (no digital exam); painful bleeding with a rigid, tender uterus points to abruption.

Answer: A

Rapid IV normal saline infusion: Correct: a very high CK with heme-positive urine but no red cells (myoglobinuria) after a long lie is rhabdomyolysis. Early, aggressive isotonic fluid restores renal perfusion and flushes myoglobin to prevent or limit acute kidney injury.

IV furosemide to promote urine flow: A diuretic before the patient is volume-repleted worsens hypovolemia and renal injury; fluids come first.

Fluid restriction to 1 L per day: Fluid restriction is for established oliguric renal failure with overload; here it would worsen myoglobin-induced kidney injury.

Preparation for emergent hemodialysis: Dialysis is reserved for refractory hyperkalemia, acidosis or fluid overload; potassium is only mildly raised and fluids have not been tried.

Rhabdomyolysis (very high CK, heme-positive urine without RBCs) is treated first with early, aggressive isotonic IV fluids to protect the kidneys, with close monitoring of urine output and potassium.

Answer: C

a low-sodium diet to reduce fluid retention.: Low sodium increases renal lithium reabsorption and worsens toxicity.

activated charcoal by mouth to bind the drug.: Activated charcoal does not bind lithium.

IV isotonic saline and a serum lithium level.: Correct. Lithium toxicity is worsened by volume depletion; isotonic fluids restore renal lithium clearance, and the level guides need for hemodialysis in severe toxicity.

an extra lithium dose for breakthrough mania.: These are toxicity signs, not breakthrough mania; more lithium would be harmful.

Dehydration and sodium loss raise lithium levels; treat toxicity with isotonic fluids, levels and hemodialysis when severe. Charcoal does not bind lithium.

Answer: A

neuroleptic malignant syndrome.: Correct. Hyperthermia, lead-pipe rigidity, altered mental status and autonomic instability after starting an antipsychotic define NMS; stop the drug, cool, hydrate and monitor CK and renal function.

serotonin syndrome.: Serotonin syndrome develops within hours after serotonergic drugs and shows clonus and hyperreflexia rather than lead-pipe rigidity.

malignant hyperthermia.: Malignant hyperthermia is triggered by volatile anesthetics or succinylcholine, not antipsychotics.

anticholinergic toxicity.: Anticholinergic toxicity causes dry, flushed skin and no rigidity; this patient is diaphoretic.

Antipsychotic plus fever, lead-pipe rigidity, altered mental status and autonomic instability is NMS; distinguish it from serotonin syndrome by rigidity versus clonus.

Answer: A

IV lorazepam.: Correct: benzodiazepines reduce central sympathetic outflow, lowering heart rate, BP, agitation and temperature in sympathomimetic toxicity.

IV metoprolol.: Beta-blockade can leave alpha stimulation unopposed, worsening hypertension and coronary vasospasm.

IV haloperidol.: Antipsychotics can lower the seizure threshold, prolong the QT interval and impair heat loss.

IV naloxone.: Naloxone reverses opioids; it has no role in cocaine-induced sympathomimetic toxicity.

For cocaine-associated chest pain and agitation, start with benzodiazepines and avoid beta-blockers in the acute phase.

Answer: A

loosen the splint and keep the leg at heart level.: Correct. Pain out of proportion and pain on passive stretch are early signs of compartment syndrome; releasing constriction and keeping the limb at heart level (not above it) protects perfusion while the provider is notified for compartment pressure measurement or fasciotomy.

apply ice packs over the anterior calf.: Ice is right for an ordinary sprain or fracture, but cold causes vasoconstriction and does not relieve the pressure causing the ischemia.

elevate the leg on two pillows above heart level.: Elevation above the heart lowers arterial inflow and worsens perfusion in a compartment that is already under pressure.

administer another prescribed dose of IV opioid for pain.: More analgesia masks the key warning sign and delays recognition; a palpable pulse does not rule out compartment syndrome.

Suspect compartment syndrome when pain is out of proportion and worsens with passive stretch; remove constriction, keep the limb at heart level and escalate. Pulses are often present until late.

Answer: B

measure intraocular pressure with tonometry.: Tonometry presses on the globe and is contraindicated with suspected rupture.

place a rigid eye shield without pressure.: Correct. A teardrop pupil and uveal prolapse indicate an open globe; a rigid shield protects the eye without pressure that could extrude intraocular contents.

apply a firm pressure patch.: A pressure patch can push intraocular contents out through the wound.

irrigate the eye with normal saline.: Irrigation is for chemical exposure; in an open globe it adds pressure and contamination.

Suspected open globe: rigid shield, no pressure, no tonometry, elevate the head, give antiemetics and analgesia, and get emergent ophthalmology.

Answer: C

a semi-private room with contact precautions.: Contact precautions do not stop airborne spread, and a shared room exposes others.

a private room with droplet precautions.: Droplet precautions suit pertussis or influenza; measles particles remain suspended in the air.

an airborne infection isolation room.: Correct: this presentation suggests measles, which spreads by the airborne route and needs a negative-pressure room and N95 respirators for staff.

the waiting room with a surgical mask on.: Measles can stay in the air for up to 2 hours; the waiting room exposes other patients.

Measles, varicella and TB need airborne precautions: a negative-pressure room and an N95 respirator.

Answer: C

IV sodium bicarbonate: Treats the number, not the cause; the acidosis comes from cyanide blocking cellular respiration.

IV methylene blue: The antidote for methemoglobinemia, a look-alike that causes cyanosis with a low SpO2.

IV hydroxocobalamin: Correct: severe lactic acidosis with hypotension in an enclosed-space fire victim, despite a high PaO2 and only modest carboxyhemoglobin, suggests cyanide poisoning; hydroxocobalamin binds cyanide.

IV naloxone: Reverses opioids; there is no evidence of opioid toxicity here.

In smoke inhalation, a lactate far out of proportion to the carboxyhemoglobin points to cyanide; give hydroxocobalamin early.

Answer: A

ESI level 2.: Correct. The patient needs many resources, but danger-zone vital signs (heart rate and respiratory rate) and abdominal pain in an older adult make this a high-risk situation, so the nurse upgrades to ESI 2.

ESI level 1.: The patient does not need an immediate lifesaving intervention such as intubation or vasopressors right now.

ESI level 3.: Settling on ESI 3 without acting on the danger-zone vital signs undertriages a patient who may have ischemic bowel, perforation or sepsis.

ESI level 4.: ESI 4 is one predicted resource; this patient needs several.

Before assigning ESI 3, check danger-zone vital signs; abnormal values in a high-risk patient, such as an older adult with abdominal pain, justify ESI 2.