Organ dysfunction was defined as shock, hypotension or the need for vasopressor support despite adequate fluid resuscitation, relative hypoxemia (ratio of partial pressure of oxygen in arterial blood in mmHg to the percentage of oxygen in the inspired air expressed as a decimal (PaO2/ FiO2 ratio) < 250), oliguria despite adequate fluid resuscitation, marked reduction in blood platelet counts, and/ or elevated lactic acid concentrations.