A patient who reports palpitations and syncope is admitted to a hospital for observation.The patient has a methemoglobin level of 18%.Which diagnostic data should a nurse identify as most likely to be inaccurate for this patient?
A)Arterial blood gases
B)CT scan
C)Pulse oximetry
D)Serum lactate level

Question

Quizplus · Accepted Answer

Pulse oximetry measures peripheral oxygen saturation (SpO2) which may be inaccurate in cases of methemoglobinemia. Methemoglobinemia is a condition where there is an abnormal amount of methemoglobin in the blood, which cannot carry oxygen efficiently, resulting in hypoxemia. However, pulse oximetry relies on the assumption that all hemoglobin in the blood is oxygenated, so it may overestimate SpO2 in patients with methemoglobinemia. Therefore, if a patient has methemoglobinemia, pulse oximetry is likely to be inaccurate. Arterial blood gases, CT scan, and serum lactate level are not affected by methemoglobinemia and are likely to be accurate measures for assessing oxygenation status and identifying the cause of the patient's symptoms.

A Patient Who Reports Palpitations and Syncope Is Admitted to a Hospital