Do courts accept long pre-planned work-related trips as valid excuses for exemption from jury duty?

I work with the mentally retarded and am scheduled to take a client to Disneyland the week that I was told to report for jury duty. I'm hoping this is ample reason for an exemption, but if it isn't I'll have to think of something else I guess. I have some hearing loss and an ear disorder called tinnitus that I believe would perhaps prevent me from being able to accurately hear all the goings-on of a trial. Just wondering if anyone has experience with this and knows what is likely to be accepted for an exemption. Thanks!!