A 68-year-old man with COPD, known baseline PaCO2 of 58 mmHg, presents dyspneic with SpO2 of 82 percent on room air. According to standard practice for chronic CO2 retainers, the appropriate immediate intervention is:

• A High-concentration oxygen via non-rebreather mask at 15 L/min
• B Immediate elective intubation before any oxygen is administered
• C Withhold oxygen until an arterial blood gas confirms the PaCO2
• D Controlled low-flow oxygen titrated to a target SpO2 of 88 to 92 percent ✓

Explanation

Chronic retainers should receive oxygen, but delivered cautiously and titrated to a saturations target of 88 to 92 percent. Excess oxygen worsens hypercapnia by suppressing hypoxic ventilatory drive, abolishing compensatory hypoxic pulmonary vasoconstriction (worsening V/Q matching), and increasing the Haldane displacement of CO2 from hemoglobin. Withholding oxygen risks death from hypoxia, and high concentration oxygen invites progressive CO2 narcosis.

Reference: Kumar and Clark's Clinical Medicine, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.