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CEN — Emergency Nursing
CEN Respiratory Emergencies Review
Respiratory emergencies test the emergency nurse's ability to recognize impending failure early and intervene in the right order — because the patient who looks like they're 'just working hard' can decompensate to arrest quickly. The CEN expects you to distinguish distress from failure, manage obstructive disease, recognize the can't-miss diagnoses (PE, tension pneumothorax), and know when noninvasive ventilation buys time versus when the airway must be secured.
This guide reviews high-yield respiratory emergencies with CEN-style questions and rationales. Educational review only — settings, medications, and protocols follow your department's policies and current guidelines; verify before applying.
Obstructive disease and the failing airway
Asthma/COPD exacerbation: the management scaffold is oxygen titrated to target, bronchodilators (and ipratropium), systemic corticosteroids early, and escalation for severe cases (magnesium, NIV per protocol). The danger signs the CEN tests are subtle: a 'quiet chest' (too little air movement to wheeze) is worse than loud wheezing; a rising or normalizing CO2 in a previously hyperventilating, tiring patient signals impending failure, not improvement; and a drowsy, slumping asthmatic is pre-arrest. COPD patients retain CO2 chronically — the goal is their baseline, and oxygen is titrated (hypoxia kills, but reckless high-flow can blunt respiratory drive in select patients) — but never withhold oxygen from a hypoxemic patient.
Distress vs failure vs the failing airway: respiratory distress is increased work with adequate gas exchange; respiratory failure is inadequate gas exchange (hypoxemia and/or hypercapnia with acidosis, altered mentation, exhaustion). NIV (CPAP/BiPAP) supports the awake, cooperative patient who can protect their airway (classic wins: COPD exacerbation, cardiogenic pulmonary edema) — contraindicated in apnea, hypotension, vomiting, or inability to cooperate. When NIV fails or the patient can't protect the airway, intubation is the answer, and the exam expects you to recognize the tipping point rather than persist with NIV in a deteriorating patient.
The can't-miss diagnoses
Pulmonary embolism: dyspnea, tachycardia, pleuritic chest pain, hypoxemia, and risk factors (immobility, surgery, malignancy, hormones, prior VTE); massive PE causes obstructive shock and right-heart strain. The CEN wants recognition, risk stratification, anticoagulation per protocol, and the awareness that a hypotensive PE may need thrombolysis/embolectomy — and that the presentation can masquerade as other complaints. Pneumothorax: a simple pneumothorax presents with unilateral diminished breath sounds and pleuritic pain; a tension pneumothorax is the emergency — progressive respiratory distress, absent unilateral breath sounds, hypotension and JVD with late tracheal deviation — requiring immediate needle decompression and chest tube, not imaging delay.
Other patterns: anaphylaxis with airway involvement (epinephrine first, immediately), upper-airway emergencies (angioedema — especially ACE-inhibitor-related — and the calm, hands-off approach to the patient with stridor and a threatened airway), inhalation injury (facial burns, singed nasal hair, hoarseness, soot — the airway can close hours later, so early intervention is favored), and carbon monoxide poisoning (flu-like symptoms in groups, falsely reassuring standard pulse oximetry — give high-flow oxygen regardless of the reading). The respiratory throughline: anticipate the airway that's about to close, support oxygenation/ventilation, and don't let a reassuring number (SpO2, a quieting chest) override clinical deterioration.
Practice questions with answers & rationales
Q1. An asthmatic who was loudly wheezing now has a 'quiet chest,' is drowsy, and has a normalizing CO2. Is she improving?
Answer: No — these are ominous signs of impending respiratory failure. A quiet chest means air movement is too poor to generate wheeze; drowsiness signals rising CO2 and exhaustion; and a 'normalizing' CO2 in a previously hyperventilating, tiring asthmatic means she can no longer blow it off. This patient needs aggressive escalation — maximal bronchodilation, steroids, magnesium/NIV per protocol, and preparation for intubation. Mistaking these signs for improvement is the planted, dangerous error.
Q2. When is noninvasive ventilation appropriate, and when must you move to intubation?
Answer: NIV (CPAP/BiPAP) suits the awake, cooperative patient who can protect their airway and has a reversible process — classic wins are COPD exacerbation and cardiogenic pulmonary edema. It's contraindicated in apnea, hemodynamic instability, vomiting/airway-protection failure, or inability to cooperate. Move to intubation when NIV fails to improve the patient, when mentation declines, or when the airway is threatened — the exam tests recognizing that tipping point rather than persisting with NIV in a deteriorating patient.
Q3. A patient with sudden dyspnea, tachycardia, pleuritic chest pain, and recent surgery becomes hypotensive. What's the concern and the implication of the hypotension?
Answer: Pulmonary embolism — and hypotension signals a massive PE with obstructive shock from right-heart strain. The implications: this is high-acuity, anticoagulation alone may be insufficient, and thrombolysis or embolectomy may be needed for the unstable patient per protocol. Recognize the risk-factor-plus-presentation pattern, support oxygenation and hemodynamics, and escalate — a hypotensive PE is a different urgency than a stable one.
Q4. A trauma patient develops worsening respiratory distress, absent breath sounds on the right, hypotension, and distended neck veins. What is it and what's the action?
Answer: Tension pneumothorax — air trapped under pressure collapses the lung and compresses the mediastinum, dropping venous return (hence hypotension and JVD; tracheal deviation is a late sign). The action is immediate needle decompression followed by chest tube — you do not wait for a chest X-ray to confirm a tension pneumothorax. Recognizing it clinically and decompressing without imaging delay is the tested priority.
Q5. Why is standard pulse oximetry unreliable in suspected carbon monoxide poisoning?
Answer: Standard pulse oximetry can't distinguish carboxyhemoglobin from oxyhemoglobin, so it reads falsely normal/high even as oxygen-carrying capacity is severely impaired. The clue is the presentation — flu-like symptoms (headache, nausea, confusion) in a group sharing a space, often in winter with combustion sources. The action: high-flow oxygen regardless of the oximeter reading, and consider co-oximetry and hyperbaric criteria. Trusting the SpO2 here is a classic, dangerous error.
Q6. A patient on an ACE inhibitor presents with lip and tongue swelling and a muffled voice. What's the priority and the cautious approach?
Answer: ACE-inhibitor-induced angioedema with a threatened airway — the priority is the airway, which can deteriorate rapidly. Keep the patient calm and upright, avoid agitation and unnecessary throat manipulation, prepare for a difficult airway with the most skilled provider and surgical-airway backup available, and treat per protocol. Because it's bradykinin-mediated, it may not respond like allergic angioedema to standard allergy treatment — so airway readiness, not just medication, is the safeguard the exam emphasizes.
Q7. How do you tell respiratory distress from respiratory failure at the bedside?
Answer: Distress is increased work of breathing (tachypnea, accessory muscle use, retractions) with still-adequate gas exchange and intact mentation. Failure is inadequate gas exchange — hypoxemia and/or hypercapnia with acidosis — manifesting as altered mentation, exhaustion, a falling respiratory effort, cyanosis, or a rising/normalizing CO2 in a tiring patient. The distinction drives escalation: distress may respond to oxygen and treatment; failure demands ventilatory support (NIV or intubation). Recognizing the transition early is the core respiratory skill tested.
Common mistakes to avoid
- Mistaking a quiet chest, drowsiness, or a normalizing CO2 in a tiring asthmatic for improvement.
- Persisting with NIV in a patient who is deteriorating or can't protect their airway.
- Treating a hypotensive PE as a routine anticoagulation case rather than a potential thrombolysis/embolectomy emergency.
- Waiting for imaging to confirm a tension pneumothorax instead of decompressing clinically.
- Trusting standard pulse oximetry in carbon monoxide poisoning.
- Underestimating ACE-inhibitor angioedema — the airway can close, and it may not respond to standard allergy treatment.