Carbon Monoxide Poisoning
What compound is formed when carbon monoxide binds to hemoglobin, preventing oxygen from attaching?
Carboxyhemoglobin
What were the two main conditions considered in the differential diagnosis before confirming carbon monoxide poisoning?
Acute Coronary Syndrome and Hypoxic Ischemic Encephalopathy (HIE).
Lucy’s arterial pO₂ was normal, but her oxygen content (CaO₂) was low. What does this discrepancy indicate?
It shows that oxygen delivery is impaired because hemoglobin is bound by CO, not oxygen.
What is hypoxia?
A condition where tissues receive insufficient oxygen.
What is the normal carboxyhemoglobin level in non-smokers?
<2%
Why was Hypoxic Ischemic Encephalopathy ruled out as the cause of Lucy’s symptoms?
Lack of neurological signs (like seizures or coma) and normal pH, showing no brain injury or acid-base imbalance.
What does a normal arterial blood gas (ABG) value indicate about the lungs’ ability to exchange gases?
That gas exchange and acid-base balance in the lungs are normal.
Which type of hypoxia best describes Lucy’s condition?
Anemic hypoxia
Name two key treatments for severe carbon monoxide poisoning
Immediate removal from source
Administer 100% oxygen through mask
HyperBaric Oxygen Treatment, when cases are severe (over 25% CBHb) patient placed in chamber for more rapid oxygen movement
Monitor vital signs with heart & brain function
Supportive care if any complications arise like low BP or brain swelling
What are three typical symptoms of ACS?
Chest pain or discomfort (pressure, squeezing, burning)
Tachycardia (increased heart rate)
Shortness of breath
Diaphoresis (sweating)
Nausea or vomiting
Dizziness or lightheadedness
Palpitations
Why was Lucy’s venous pO₂ (22 mmHg) considered abnormally low, and what does it reveal about tissue oxygen use?
It shows tissues are extracting more oxygen than usual due to low oxygen supply
Why does carbon monoxide cause tissue hypoxia even when arterial pO₂ levels appear normal?
CO binds to hemoglobin with 200× higher affinity than oxygen, reducing oxygen-carrying capacity