Chapter 2 of 612% of exam

Respiratory

The respiratory section covers acute respiratory failure, ARDS, pulmonary edema and embolism, chronic lung disease, pleural problems, airway trauma and complications of mechanical ventilation. Expect questions on oxygen and ventilator strategy, chest drains and prevention of ventilator-associated events.

ARDS and lung-protective ventilation

ARDS is acute hypoxemic respiratory failure with bilateral opacities that are not explained by effusion, collapse or nodules. The 2024 global definition widened the criteria to include patients on high-flow oxygen and oximetry-based ratios. Ventilation limits tidal volume and plateau pressure, and prone positioning is used in moderate to severe disease.

Global definition oxygenation
PaO2/FiO2 ≤300 or SpO2/FiO2 ≤315 (SpO2 ≤97%), including patients on high-flow nasal oxygen at ≥30 L/min.
Matthay et al., Am J Respir Crit Care Med 2024
Timing and imaging
Onset within 1 week of a known insult; bilateral opacities on X-ray, CT or ultrasound not fully explained by other causes.
Matthay et al., Am J Respir Crit Care Med 2024
Low tidal volume
About 6 mL/kg of predicted body weight, with an upper plateau pressure goal of 30 cm H2O.
Surviving Sepsis Campaign 2021
Prone positioning
More than 12 hours daily in moderate to severe ARDS.
Surviving Sepsis Campaign 2021

Oxygen strategy in acute respiratory failure

Match the device and the target to the patient. In COPD, too much oxygen can raise carbon dioxide; in sepsis-related hypoxemic failure, high-flow nasal cannula is favored as the first device. Always interpret the blood gas to tell hypoxemic from hypercapnic failure.

COPD oxygen target
Titrate to an SpO2 of 88–92%; high inspired oxygen can cause hypercapnia and acidosis.
STOP-COPD protocol, Trials 2024 (guideline background)
High-flow first in sepsis
High-flow nasal cannula is favored over conventional oxygen and noninvasive ventilation for sepsis with acute hypoxemic respiratory failure.
Surviving Sepsis Campaign 2026
Respiratory acidosis
Low pH with high PaCO2; a normal bicarbonate means the process is acute and uncompensated.
MedlinePlus (NLM), Respiratory acidosis
Asthma danger signs
Drowsiness, confusion, difficulty speaking or cyanosis during an attack mean failing ventilation.
MedlinePlus (NLM), Asthma

Preventing ventilator-associated events

The 2022 SHEA/IDSA/APIC compendium separates essential practices from those no longer recommended. Several long-standing habits, such as chlorhexidine mouthwash, were downgraded.

Essential practices
Avoid intubation where safe, minimize sedation and avoid benzodiazepines, keep patients mobile, elevate the head of the bed 30–45°, and feed enterally.
SHEA/IDSA/APIC 2022 Update
Oral care
Toothbrushing without chlorhexidine; chlorhexidine oral care is generally not recommended.
SHEA/IDSA/APIC 2022 Update
Circuits
Change the ventilator circuit only when visibly soiled or malfunctioning.
SHEA/IDSA/APIC 2022 Update
Liberation
Assess readiness to extubate daily with spontaneous breathing trials.
SHEA/IDSA/APIC 2022 Update

Pleural space, embolism and pulmonary edema

A chest drain that stops swinging or bubbling is blocked or displaced until proven otherwise. Pulmonary embolism ranges from minor to life-threatening, and severity decides whether clot-dissolving therapy is used. Cardiogenic pulmonary edema is treated with positioning, oxygen and diuresis.

Blocked drain for pneumothorax
Do not clamp it; check for kinks or clots and get an urgent chest X-ray to avoid tension pneumothorax.
Cureus 2024, blocked chest drain review
Stripping chest tubes
Milking or stripping is not recommended after lung resection and is considered ineffective and potentially harmful after cardiac surgery.
J Thorac Dis 2026 chest tube review
High-risk embolism
Thrombolysis or thrombectomy is reserved for severe, life-threatening PE with hemodynamic instability.
MedlinePlus (NLM), Pulmonary embolus; ESC 2019 PE guideline
Cor pulmonale
Right heart failure from lung disease: neck vein distention, ankle swelling, liver enlargement; oxygen is central to treatment.
MedlinePlus (NLM), Cor pulmonale

Keep going: the full CCRN (Adult) — Acute/Critical Care Nursing Certification Exam guide covers every section of the exam. CCRN (Adult) Study Guide — 2026 Edition — PDF + EPUB, $24.99 · 14-day refund →

Practice this topic →← All chapters
Studying in order?

Practice stays free. The full CCRN (Adult) — Acute/Critical Care Nursing Certification Exam study guide is the material itself, taught start to finish — a downloadable PDF + EPUB you keep.

Get the book — $24.99
Report