Which factor would elevate a client’s oxygen saturation reading?

Which factor would elevate a client’s oxygen saturation reading?

• A. Carbon monoxide
• B. Anemia
• C. Dehydration
• D. Hyperthermia

Answer: (A)

Pulse oximetry measures the percentage of hemoglobin bound with oxygen by analyzing light absorption, but it can be fooled when carbon monoxide is present. Carbon monoxide forms carboxyhemoglobin, which absorbs light in a way that mimics oxyhemoglobin to many pulse oximeters, so the device reads a higher saturation than is actually delivering oxygen to tissues. That’s why exposure to carbon monoxide can elevate the reading, even though oxygen delivery is impaired. In practice, if CO exposure is suspected, use a co-oximeter to distinguish carboxyhemoglobin from oxyhemoglobin for an accurate assessment. Other factors like anemia reduce the total amount of hemoglobin available for oxygen transport (so saturation reading can be normal even when delivery is limited), while dehydration or hyperthermia affect perfusion or metabolic demand but do not inherently raise SpO2 readings.

Pulse oximetry measures the percentage of hemoglobin bound with oxygen by analyzing light absorption, but it can be fooled when carbon monoxide is present. Carbon monoxide forms carboxyhemoglobin, which absorbs light in a way that mimics oxyhemoglobin to many pulse oximeters, so the device reads a higher saturation than is actually delivering oxygen to tissues. That’s why exposure to carbon monoxide can elevate the reading, even though oxygen delivery is impaired. In practice, if CO exposure is suspected, use a co-oximeter to distinguish carboxyhemoglobin from oxyhemoglobin for an accurate assessment. Other factors like anemia reduce the total amount of hemoglobin available for oxygen transport (so saturation reading can be normal even when delivery is limited), while dehydration or hyperthermia affect perfusion or metabolic demand but do not inherently raise SpO2 readings.