AVP and respiratory failure: However, the average concentration of 10 g/100 ml hemoglobin associated with 23 g/l albumin (Table 2), widely tolerated combination of hypoalbuminemia/anemia frequently seen in critically ill patients [42], might have contributed to the activation of AVP (given the altered circulating blood volume), besides the well-known factors (acute respiratory failure, pneumonia, trauma, mechanical ventilation, history of COPD) [8] that are nonetheless present in the case-mix.