Either of APC or Powercom shud b good enuff...
But how did u arrive at the figure of 2KVA ?
Hope u realize that UPS can deliver only ~60% of their VA rating in terms of actual Watts...
Ex: a 600VA Wipro UPS is rated 365W...
If the load does come out to be 2KVA,then get a UPS which allows u to add External batteries to increase the Backup time,Both APC & Powercom have that option,tho i think that only APC offers to sell the Extra Battery at the time of purchase,shud u need it....
And one more thing, consult some technician etc b4 getting a UPS...
Coz a ON-line UPS can b dangerously Unreliable when working with Medical Equipment...
U r better off with a CVT or a OFF-line UPS,which are considerably more expensive than ON-line UPS'