Which could cause an inaccurate SpO2 reading?

Which could cause an inaccurate SpO2 reading?

• A. Severe anemia.
• B. Hypovolemia.
• C. CO Poisoning.
• D. All of the above

Answer: (D)

SpO2 readings come from pulse oximetry, which estimates the percentage of hemoglobin molecules carrying oxygen by comparing light absorption through a finger or similar site. This measurement assumes normal perfusion, typical hemoglobin, and no interfering forms of hemoglobin; when any of these conditions are off, the reading can be unreliable. Severe anemia reduces the total amount of hemoglobin available to carry oxygen, so the percentage saturated may appear normal even though the overall oxygen content delivered to tissues is low. That can mislead about true oxygen delivery. Hypovolemia or poor peripheral perfusion weakens the pulsatile signal the sensor relies on, making the reading more prone to inaccuracy. Carbon monoxide poisoning creates carboxyhemoglobin, which can absorb light similarly to oxyhemoglobin at the device’s wavelengths, causing the SpO2 to read normal or high despite significant hypoxia. Because each of these conditions can distort the reading, all of the above could lead to an inaccurate SpO2.

SpO2 readings come from pulse oximetry, which estimates the percentage of hemoglobin molecules carrying oxygen by comparing light absorption through a finger or similar site. This measurement assumes normal perfusion, typical hemoglobin, and no interfering forms of hemoglobin; when any of these conditions are off, the reading can be unreliable.

Severe anemia reduces the total amount of hemoglobin available to carry oxygen, so the percentage saturated may appear normal even though the overall oxygen content delivered to tissues is low. That can mislead about true oxygen delivery. Hypovolemia or poor peripheral perfusion weakens the pulsatile signal the sensor relies on, making the reading more prone to inaccuracy. Carbon monoxide poisoning creates carboxyhemoglobin, which can absorb light similarly to oxyhemoglobin at the device’s wavelengths, causing the SpO2 to read normal or high despite significant hypoxia. Because each of these conditions can distort the reading, all of the above could lead to an inaccurate SpO2.