Elevated ETCO2 (>45 mmHg) can be a sign of which condition?

Elevated ETCO2 (>45 mmHg) can be a sign of which condition?

• A. Allergic reaction
• B. Hyperventilation
• C. Hypothermia
• D. Opioid overdose / CNS depression

Answer: (D)

Elevated ETCO2 means the patient isn’t ventilating enough, so CO2 builds up in the blood. Opioid overdose causes CNS depression that slows breathing—lower rate and shallower breaths—leading to hypoventilation and CO2 retention. With ongoing CO2 production, less CO2 is expelled, so the end-tidal CO2 reading rises above 45 mmHg. Hyperventilation would blow off CO2 and lower ETCO2, while hypothermia tends to reduce CO2 production and ETCO2, not elevate it. So the pattern of increased CO2 on capnography best fits opioid-induced respiratory depression.

Elevated ETCO2 means the patient isn’t ventilating enough, so CO2 builds up in the blood. Opioid overdose causes CNS depression that slows breathing—lower rate and shallower breaths—leading to hypoventilation and CO2 retention. With ongoing CO2 production, less CO2 is expelled, so the end-tidal CO2 reading rises above 45 mmHg. Hyperventilation would blow off CO2 and lower ETCO2, while hypothermia tends to reduce CO2 production and ETCO2, not elevate it. So the pattern of increased CO2 on capnography best fits opioid-induced respiratory depression.