Where should a pulse oximetry sensor be secured on an infant to monitor oxygen saturation effectively?

A pulse oximetry sensor should be secured on the great toe of an infant for effective monitoring of oxygen saturation. The great toe is often preferred because it is a site that allows for adequate blood flow and is less likely to be affected by movement compared to other sites. This is particularly important in infants who may be more restless. Securing the sensor on the toe can also help minimize the risk of false readings due to peripheral circulation issues, which might occur if the sensor were placed on a hand or a less perfused area.

Placing the sensor on the heel is another common practice, but the great toe generally provides better perfusion and is easier to secure without compromising comfort. Additionally, using the index finger or wrist is less appropriate in infants due to the smaller size and variations in peripheral circulation, which can lead to inaccurate readings. Therefore, the great toe is the most suitable site for accurately monitoring an infant's oxygen saturation levels with a pulse oximeter.