Respiratory

12% of the CCRN · blueprint Adult CCRN Test Plan (exams on and after 2025-11-12)

Short answer

Respiratory is 12% of the adult CCRN. It covers acute pulmonary oedema and pulmonary embolus, ARDS, acute respiratory failure, pneumonia and chronic conditions such as COPD and asthma, mechanical-ventilation complications, pleural-space abnormalities including pneumothorax and effusion, pulmonary hypertension and haemorrhage, status asthmaticus, thoracic and airway trauma, and thoracic surgery.

Why it matters on this exam

Ventilator questions dominate. You need to read an ABG, decide whether the problem is oxygenation or ventilation, and pick the change that fixes it without causing harm.

Key concepts

ABG interpretation: pH, PaCO2, HCO3, then compensation; anion gap when metabolic acidosis is present.
Oxygenation vs ventilation: oxygenation is FiO2 and PEEP/mean airway pressure; ventilation is rate and tidal volume.
ARDS: acute onset, bilateral infiltrates, not explained by cardiac failure, P/F ratio thresholds; lung-protective ventilation with low tidal volume and permissive hypercapnia; prone positioning.
Mechanical-ventilation complications: auto-PEEP in obstructive disease, barotrauma, VAP prevention, high peak with normal plateau (resistance) vs high plateau (compliance).
Tension pneumothorax: sudden hypotension, tracheal deviation, absent breath sounds and rising peak pressures — immediate decompression.
PE: sudden hypoxaemia with clear lungs, low ETCO2, right-heart strain.
Status asthmaticus: silent chest is deterioration, not improvement.

Common mistakes

Increasing tidal volume for hypoxaemia when PEEP/FiO2 is the oxygenation lever.
Missing auto-PEEP in a hyperinflated asthmatic with hypotension after intubation.

Worked example

Peak pressure rises while plateau stays unchanged: an airway-resistance problem — secretions, bronchospasm, a kinked or biting tube — not a compliance problem like pulmonary oedema or ARDS.

Original practice questions

RespiratoryDifficulty 3/5

A ventilated patient's peak inspiratory pressure rises from 28 to 42 cmH2O while the plateau pressure stays at 22 cmH2O. What does this indicate?

ATension pneumothorax with mediastinal shift and cardiovascular collapse
BVentilator circuit disconnection causing loss of delivered pressure
CReduced lung compliance from developing acute respiratory distress syndrome
DIncreased airway resistance from secretions, bronchospasm or a kinked tube

Show answer and rationale

Correct: D. The difference between peak and plateau reflects airway resistance; an isolated rise in peak with an unchanged plateau points to a resistance problem. A compliance problem such as ARDS or pneumothorax raises the plateau as well.

C — Reduced compliance raises the plateau pressure.
A — Tension pneumothorax raises both peak and plateau and causes haemodynamic collapse.
B — A disconnection produces low pressures and an alarm, not high peak pressures.

RespiratoryDifficulty 3/5

Which ventilator strategy is most consistent with lung-protective ventilation in ARDS?

ATidal volume 6 mL/kg predicted body weight with plateau below 30 cmH2O
BPressure support ventilation with the highest tolerated tidal volume for comfort
CTidal volume titrated to the patient's actual body weight and normal carbon dioxide
DTidal volume 10 mL/kg predicted body weight to guarantee adequate minute ventilation

Show answer and rationale

Correct: A. Lung-protective ventilation uses low tidal volumes based on predicted body weight with plateau pressure limited, accepting permissive hypercapnia. Higher tidal volumes worsen ventilator-induced lung injury.

D — 10 mL/kg is the volume associated with ventilator-induced injury.
B — Maximising tidal volume for comfort contradicts lung protection.
C — Volumes are calculated from predicted, not actual, body weight, and normocapnia is not the goal.

RespiratoryDifficulty 2/5

An arterial blood gas shows pH 7.28, PaCO2 58 mmHg, HCO3 26 mEq/L. How is this best described?

AMixed respiratory and metabolic alkalosis from over-ventilation
BAcute respiratory acidosis, with the kidneys not yet compensating
CChronic respiratory acidosis with full renal compensation and a normal pH
DMetabolic acidosis with appropriate respiratory compensation

Show answer and rationale

Correct: B. The pH is acidic and the PaCO2 is elevated, so the primary problem is respiratory. The bicarbonate is nearly normal, indicating the kidneys have not yet compensated — an acute picture.

C — Chronic compensation would show a markedly elevated bicarbonate and a near-normal pH.
D — A metabolic acidosis would show a low bicarbonate.
A — Alkalosis would raise the pH above normal.

All 3 Respiratory questions →

3 flashcards for Respiratory

Practice this topic

Blueprint-mapped questions with full rationales for every choice.

Start practice

Primary references

CCRN Exam Handbook — Direct Care (July 2026) — AACN Certification Corporation · primary · retrieved 2026-09-22, verified 2026-09-22

Last reviewed: 2026-09-22Next review by: 2026-11-06Draft — pending editorial reviewHow we verify facts