The present invention provides compounds having a structure according to Formula I: or a salt or solvate thereof, wherein R1, R2, R3 and R4 are defined herein. The emulsions are of the type oil-in-water. The method further comprises transmitting the audio parameter to the clinician device, updating the history parameter in response to receiving a second patient parameter or a second clinician parameter, and updating the audio parameter in response to receiving a second patient parameter.