What is the primary purpose of an oximeter?

• A. To determine oxygen saturation of blood
• B. To measure blood glucose
• C. To assess carbon dioxide elimination
• D. To monitor blood pressure

Answer: (A)

Oximeters determine how much of the hemoglobin in arterial blood is saturated with oxygen. They work by shining light at two wavelengths through a fingertip or earlobe and measuring how the light is absorbed as blood pulses. The device converts that information into a percentage called SpO2, which reflects oxygen delivery to tissues. This noninvasive reading helps assess whether a patient has adequate oxygenation and guides decisions about supplemental oxygen or ventilation.

The oximeter doesn’t measure blood glucose, which would require a glucose meter; it doesn’t directly assess carbon dioxide elimination (that’s monitored with capnography or arterial blood gas analysis); and it doesn’t monitor blood pressure (that requires a cuff or arterial line).