CCRN Plan

CCRN practice question: Respiratory

RespiratoryDifficulty 2/5

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

  1. AMixed respiratory and metabolic alkalosis from over-ventilation
  2. BAcute respiratory acidosis, with the kidneys not yet compensating
  3. CChronic respiratory acidosis with full renal compensation and a normal pH
  4. 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.

Concept being tested

12% of the exam. Acute pulmonary edema and embolus, ARDS, acute respiratory failure and infection, chronic conditions, mechanical-ventilation complications, pleural-space abnormalities, pulmonary hemorrhage and hypertension, status asthmaticus, thoracic and airway trauma, and thoracic surgery. — 12% of the exam. Study guide for Respiratory.

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Primary references

  1. CCRN Exam Handbook — Direct Care (July 2026) — AACN Certification Corporation · primary · retrieved 2026-09-22, verified 2026-09-22
Last reviewed: 2026-10-07Reviewed by: Marcus Vance, MSN, RN, CCRN-CSC, Critical care nursing curriculum & clinical item reviewHow we verify facts