A nurse is caring for a patient with suspected carbon monoxide poisoning. Which nursing action should be the highest priority?

The highest priority is administering 100% oxygen via non-rebreather mask to rapidly displace carbon monoxide from hemoglobin and treat tissue hypoxia. Other interventions like ABG or neurological assessment are secondary and should not delay oxygen therapy.

Clinical Judgment This question assesses prioritization and emergency nursing interventions. Carbon monoxide (CO) poisoning is a Notify HCP! life-threatening emergency. The core pathophysiology is that CO has an affinity for hemoglobin 200–250 times greater than oxygen, forming carboxyhemoglobin (COHb) and causing tissue hypoxia. The patient's symptoms (altered consciousness, headache, nausea) are typical of CO poisoning. The highest priority intervention is to remove this toxic substance and restore oxygen delivery—that is, immediate administration of 100% high-concentration oxygen. This reduces the half-life of CO from 4–6 hours in room air to 60–90 minutes with 100% oxygen, minimizing tissue damage. All other interventions should follow this life-saving measure. Memory Tip CO poisoning = Come On! (Give oxygen!)
Remember the principle: O₂ First, Ask Later. In CO poisoning, start treatment immediately without wasting time confirming the diagnosis. KR vs US The basic emergency treatment principles for CO poisoning (high-concentration oxygen administration) are the same in both Korea and the US. However, in the US NGN exam, for questions asking for the "highest priority," the "ABCs (Airway, Breathing, Circulation)" principle is applied, emphasizing that the intervention addressing breathing (oxygen administration) must come first. While rapid oxygen administration is also critical in Korean clinical practice, this prioritization logic is demanded more explicitly in the exam context.

Clinical Practice Guide The clinical guide for when you encounter a CO poisoning patient is as follows: 1. Immediate action: Administer 100% oxygen immediately via a non-rebreather mask. Pay attention to airway maintenance depending on the patient's level of consciousness. 2. Monitoring: Continuous oxygen saturation (SpO2) monitoring is performed, but because COHb can fool the SpO2 monitor (a normal SpO2 reading does not rule out danger), arterial blood gas (ABG) analysis and COHb level confirmation are essential. 3. Considerations: In severe cases (decreased consciousness, severe metabolic acidosis, COHb >25%, etc.), hyperbaric oxygen therapy may be necessary. Caution Trap point in SATA (Select All That Apply) questions: Distinguish between "First action" and "Actions to take." In cases like this question that ask about priority, "Obtain ABG" or "Assess neurological status" are important interventions, but they cannot take priority over immediate treatment (oxygen administration). If asked to select all "Actions to take," 1, 2, 3, and 4 might all be included, but there is only one "highest priority."