Track Direct
Ground Level Helipad figures for SL 30 deg C:
155B - MTOW 3800kg
155B1 - MTOW 4100kg
The Eurocopter website link I posted previously might give you enough info to work out a guestimate for an EMS machine basic weight. I don't know of any 155 EMS machines out there, but there might be some in the States. As 212 Man says, an EMS equipped machine will probably not be that light and I assume that an EMS operation will have to work to public transport performance standards so you have to go on the figures given in the Flight Manual Supplement.
The 155 is probably not the machine you need for EMS. The 145 on the other hand would be ideal I should think. Rear clam shell doors for stretcher loading, large, unobstructed cabin, skids for rough terrain landings and more grunt than the 155. That's the one I would be looking at.
Regards, 155 Man