GSTM1 and septic shock: However, the transfusion requirements in critical care and septic shock (Transfusion requirements in septic shock trial) trials did not observe significant differences in mortality rates for pRBC transfusions performed for higher versus lower thresholds of Hb levels within 72 hours after ICU admission or during their ICU stay, respectively.11,13,24 Nevertheless, none of the following clinical trials focused on the effect of early blood transfusion; they examined only the overall transfusion rate for patients with critical illnesses.