Final answer:
The sensor of a pulse oximeter should be placed on an infant's palm, foot, or big toe to accurately monitor oxygen saturation. Correct placement is vital to obtain proper readings indicating the percent saturation of oxygen in the blood.
Step-by-step explanation:
When monitoring oxygen saturation in an infant, the sensor of a pulse oximeter should be placed on a thin part of the baby's body because hemoglobin absorption varies with oxygen saturation. While it is common to apply the oximeter to a fingertip in an adult, for an infant, options include the palm, foot, or the baby's big toe. Ensuring proper placement is crucial for accurate readings, which typically range from 95-100 percent, reflecting the percent saturation of oxygen in the blood. Lower percentages could indicate hypoxemia, or low blood oxygen levels, which is a critical condition requiring immediate attention.