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.

Core Nursing Explanation Key Concept Analysis: This question tests the priority nursing intervention for carbon monoxide (CO) poisoning. CO is a colorless, odorless gas that binds to hemoglobin with an affinity over 200 times greater than oxygen, forming carboxyhemoglobin (COHb). This prevents oxygen from binding, leading to severe tissue hypoxia. The primary goal of treatment is to rapidly reduce the half-life of COHb and restore oxygen delivery to tissues.

Answer Rationale: Key Point! The immediate administration of 100% oxygen via a non-rebreather mask is the highest priority. This action directly addresses the life-threatening pathophysiology. High-flow, high-concentration oxygen competes with CO for hemoglobin binding sites and significantly shortens the half-life of COHb from about 4-6 hours on room air to about 60-90 minutes. This is a critical, time-sensitive intervention that must not be delayed by diagnostic assessments.

Distractor Analysis: Watch out for confusion! Option ① (Obtain ABG) is important for diagnosis and monitoring but is secondary to initiating life-saving treatment. An ABG on room air may show a normal PaO2 because it measures dissolved oxygen, not hemoglobin-bound oxygen, which can be misleading. The priority is to treat, not just assess.
Option ③ (Assess neurological status) is a crucial part of the ongoing nursing assessment, especially since CO poisoning can cause significant neurological sequelae. However, this assessment should occur concurrently with or immediately after initiating oxygen therapy, not before it.
Option ④ (Insert IV line) may be necessary for administering fluids or medications, but it is not the immediate priority. The primary threat is hypoxia, not hypovolemia. Fluid resuscitation is not a first-line treatment for isolated CO poisoning.

Related Concepts: The principle of ABC (Airway, Breathing, Circulation) from basic life support is directly applicable. Securing the airway and ensuring effective oxygenation (Breathing) is the paramount concern. Understanding that CO poisoning is a form of histotoxic hypoxia (impaired oxygen use at the cellular level) reinforces why providing the highest possible concentration of oxygen is the definitive treatment. Concept Summary

Concept	Key Takeaway
Pathophysiology	CO binds tightly to hemoglobin, causing tissue hypoxia despite normal PaO2.
Priority Intervention	Immediate administration of 100% oxygen via non-rebreather mask.
Goal of Treatment	Shorten COHb half-life, displace CO, restore oxygen delivery.
Nursing Process	Implementation of emergency treatment takes precedence over detailed assessment.
Safety	Remove patient from source, ensure safety of responders.

Side-by-Side Comparison!

Intervention	Priority in CO Poisoning	Rationale
Administer 100% O2	HIGHEST PRIORITY	Directly treats the cause of hypoxia; time-critical.
Obtain ABG / Assess Neuro	Secondary / Concurrent	Important for diagnosis & baseline, but does not reverse the poisoning.
Start IV / Fluids	Lower Priority	Addresses potential complications, not the primary insult.

Anatomy, Physiology & Pharmacology Points

• Hemoglobin (Hb): The oxygen-carrying protein in red blood cells. CO has a 200-250x greater affinity for Hb than O2.
• Carboxyhemoglobin (COHb): The stable compound formed. Levels > 10-15% often cause symptoms; > 25-30% can be life-threatening.
• Half-life of COHb: On room air: ~4-6 hrs. On 100% O2: ~60-90 min. In hyperbaric oxygen: ~20-30 min.
• Pulse Oximetry (SpO2) Limitation: It is unreliable in CO poisoning! Standard pulse oximeters cannot distinguish between oxyhemoglobin and carboxyhemoglobin, so SpO2 readings may appear falsely normal.

Memory Tips

• CO = "Carbon Monoxide = Can't Oxygenate": Remember the key problem is oxygen delivery failure.
• Priority: O2 Before All: In any suspected inhalation poisoning where hypoxia is the threat, think "Airway, Breathing" first. Give the O2!
• SpO2 is a LIAR in CO poisoning. Don't be fooled by a normal reading; treat based on clinical suspicion and history.

High-Frequency NCLEX Topics This is a classic NCLEX priority-setting question. The exam loves to test: 1. Recognizing "silent" hypoxia (normal PaO2, false-normal SpO2). 2. Applying the ABC framework to determine the immediate life threat. 3. Knowing the specific, definitive treatment for common poisonings (e.g., O2 for CO, Naloxone for opioids).
Watch Out for Question Variations!

• Symptom Identification: "A patient found in a closed garage with a running car presents with headache, nausea, and cherry-red skin. What does the nurse suspect?" (Answer: CO poisoning).
• Equipment Knowledge: "Which oxygen delivery device is most appropriate for initial management of CO poisoning?" (Answer: Non-rebreather mask).
• Patient Education: "The nurse is discharging a patient after CO poisoning. Which statement indicates understanding? 'I will install a carbon monoxide detector in my home.'"
• Next Step After O2: "After initiating 100% oxygen for a patient with severe CO poisoning, which action should the nurse take next?" (Answer: Often a focused neurological assessment or preparing for possible hyperbaric oxygen therapy).

Nursing Clinical Practice Guide Clinical Scenario: You are the triage nurse in the Emergency Department. Paramedics bring in an elderly couple found confused and lethargic in their home by a family member. The home uses a gas furnace for heating. The husband is drowsy but arousable, complaining of a severe headache and nausea. His skin has a faint, unusual pinkish hue.

Nursing Intervention Strategy: 1. Immediate Action (Priority): While the paramedics give report, you immediately apply a non-rebreather mask (NRB) connected to 100% oxygen to both patients. You ensure the reservoir bag is inflated and the mask is sealed properly. 2. Simultaneous Assessment: As oxygen is flowing, you perform a rapid ABC assessment. You check airway patency, respiratory rate/effort, and obtain vital signs. You ask a colleague to draw blood for a carboxyhemoglobin (COHb) level and an arterial blood gas (ABG). 3. Focused History & Neurological Exam: Once oxygen is established, you quickly assess neurological status using the Glasgow Coma Scale (GCS) and ask about duration of exposure, source, and other symptoms (dizziness, vomiting). 4. Collaboration & Preparation: You notify the physician immediately. For a patient with a very high COHb level, altered mental status, or signs of cardiac involvement, you prepare for the possibility of hyperbaric oxygen (HBO) therapy and initiate IV access.

Patient Safety and Precautions:

• Source Control: Ensure the patient is removed from the toxic environment. Notify public health or fire department if others may be at risk in the same building.
• Monitor for Complications: CO poisoning can cause delayed neurological sequelae (memory problems, personality changes) days or weeks later. Document baseline neurological function thoroughly.
• Pulse Ox Caution: Document that SpO2 readings are not reliable for monitoring efficacy in this case. Patient improvement is assessed by clinical status (mental alertness, resolution of headache) and serial COHb levels.

Nursing Procedure & Medication Flow Administering 100% Oxygen via Non-Rebreather Mask: 1. Gather: Non-rebreather mask, oxygen tubing, flowmeter set to 15 L/min (to ensure reservoir bag stays inflated). 2. Action: Place mask over patient's nose and mouth, secure elastic strap. Ensure one-way valves on the mask side ports are functioning (prevent room air entrainment). 3. Verify: Check that the reservoir bag inflates with inspiration and does not completely collapse. Listen for hiss of oxygen flow. 4. Monitor: Continuously assess patient's respiratory status, work of breathing, and level of consciousness. Stay with an unstable patient.

A Word from Your Senior Nurse "In the chaos of the ED, it's easy to get caught up in tasks like starting lines and drawing labs. But with CO poisoning, your first and most powerful nursing action is simple: give the oxygen. You are literally providing the antidote. That act of putting on the non-rebreather mask is more critical than any lab slip. Always remember your ABCs—they are the bedrock of nursing priority-setting, both on the NCLEX and at the bedside. Trust your assessment: if the story fits (closed space, fuel-burning appliance) and the patient is confused with a headache, don't wait for the lab confirmation. Treat first. You could be saving brain cells with every breath you give them."