I have general power of attorney and medical power of attorney for my sister who has Alzheimer's and is confined to a skilled care nursing home in another state. It is necessary for me to make periodic trips to consult with her medical providers. Are my travel expenses tax deductible? I do not claim her as a dependent.

Sorry, but if you do NOT claim here as a dependent, then the costs are NOT deductible UNLESS you are drawing a salary or fee for acting as her agent in these matters.

Such fees would be considered self-employement income that must be claimed on Schedule C, which is where you could deduct the expenses you have cited.