In a multicentric ( @ ICUs ) , controlled , open-label trial ( from February @ to August @ ) , the authors randomized patients with signs of acute hypovolemia , defined by the combination of hypotension , evidence of low filling pressures or cardiac index and at least two signs of tissue hypoperfusion ( such as altered consciousness , mottled skin , oliguria , lactate levels > @ mmol/L ) , to received either a colloid - or crystalloid-based therapy .