can i deduct the purchase price of a whole house generator required to run medical equipment during a power outage. If so, where do i start? Do I have to itemize?

In general, a generator is not deductible as a medical expense. It is considered a property improvement that raises the cost basis of your property. It does not get reported on your tax return. It will only come into play when your property is sold to reduce the amount of any capital gain.

If you can show that its primary purpose is for medical care, you may be able to deduct it but your deduction would be reduced by the amount that this improvement to your home increases the value of your property.  You would have to itemize to take it as a medical expense. See this link for further explanation of Capital Expenses. 

There is a worksheet in this link that explains the way a capital expense would work.