1. A method for estimating oxygen saturation in the presence of noise, the method comprising: determining a change in estimated oxygen saturation comprising calculating a difference between a first estimated oxygen saturation value at a first time and a second estimated oxygen saturation value at a second time; determining a change in a saturation noise estimate between a first saturation noise estimate at the first time and a second saturation noise estimate at the second time, wherein the change in the saturation noise estimate attends the change in estimated oxygen saturation; selecting either the first estimated oxygen saturation value or the second estimated oxygen saturation value based at least in part on a comparison between the change in the estimated oxygen saturation and the change in the saturation noise estimate; and displaying the selected estimated oxygen saturation value.