The American Red Cross has issued an appeal for blood donations in the Louisville area.Spokesperson Loni White says a loss of electrical services means a drastic drop in donations."If the power outages remain widespread, we're looking at at least 200 units a day, a loss. And that is a very precarious situation for our community, because we were already operating with barely a two-day supply of blood," she said.White says all blood types are needed, but there's a critical shortage of negative types.The agency has scheduled three donation sessions Tuesday and Wednesday.Donors can visit the Downtown Louisville Donation Center on East Chestnut Street from 10am-6pm Tuesday, the Woodlawn Shopping Center on North Hubbards Lane from Noon-7pm Tuesday and the Clark County Chapter Red Cross Building in Jeffersonville, Indiana on Wednesday from 1-6pm.