A curious case of carbon monoxide poisoning

After two days of nausea, dizziness and fatigue, a 60-year old woman in North Carolina, US, called the emergency services to her home. Responding paramedics noted additional issues – lack of focus and factual recall, as well as drowsiness. Alarm bells went off – literally. While paramedics were rendering aid, an alarm rang out inside the woman’s home. She could not recall what type of alarm it was – burglar, smoke or carbon monoxide. It was that last type that seemed to correspond to her symptoms. Dizziness, headache, nausea and vomiting are all low-level carbon monoxide exposure symptoms. High carbon monoxide levels can cause disorientation, unconsciousness, coma, cardiorespiratory failure and death.

Paramedics, suspecting environmental carbon monoxide poisoning and concerned over the indoor air quality, moved their patient outside where she ‘appeared less disoriented’. En route to the hospital, paramedics used a pulse CO-oximeter to determine their patient’s carboxyhaemoglobin level. It was 25% – far above a normal value of approximately 2%. CO was displacing O₂, tying up haemoglobin and keeping this transport protein in red blood cells from its main job – getting oxygen to tissues.

Initial blood work at the emergency department indicated the patient did not have enough functioning red blood cells or haemoglobin. With emergency treatment, she seemed to improve and become more responsive. Her haemoglobin levels increased. Then, instead of continued positive progress, she took a turn for the worse. All further attempts to render aid brought no improvement and she went into cardiac arrest. For about an hour, medical professionals attempted resuscitation. But 19 hours after paramedics first reached her, she was pronounced dead.