Blood transfusions in septic shock: is 7.0g/dL really the appropriate threshold?

Abstract

ObjectiveTo evaluate the immediate effects of red blood cell transfusion on central venous oxygen saturation and lactate levels in septic shock patients with different transfusion triggers.MethodsWe included patients with a diagnosis of septic shock within the last 48 hours and hemoglobin levels below 9.0g/dL Patients were randomized for immediate transfusion with hemoglobin concentrations maintained above 9.0g/dL (Group Hb9) or to withhold transfusion unless hemoglobin felt bellow 7.0g/dL (Group Hb7). Hemoglobin, lactate, central venous oxygen saturation levels were determined before and one hour after each transfusion.ResultsWe included 46 patients and 74 transfusions. Patients in Group Hb7 had a significant reduction in median lactate from 2.44 (2.00 - 3.22) mMol/L to 2.21 (1.80 - 2.79) mMol/L, p = 0.005, which was not observed in Group Hb9 [1.90 (1.80 - 2.65) mMol/L to 2.00 (1.70 - 2.41) mMol/L, p = 0.23]. Central venous oxygen saturation levels increased in Group Hb7 [68.0 (64.0 - 72.0)% to 72.0 (69.0 - 75.0)%, p < 0.0001] but not in Group Hb9 [72.0 (69.0 - 74.0)% to 72.0 (71.0 - 73.0)%, p = 0.98]. Patients with elevated lactate or central venous oxygen saturation < 70% at baseline had a significant increase in these variables, regardless of baseline hemoglobin levels. Patients with normal values did not show a decrease in either group.ConclusionRed blood cell transfusion increased central venous oxygen saturation and decreased lactate levels in patients with hypoperfusion regardless of their baseline hemoglobin levels. Transfusion did not appear to impair these variables in patients without hypoperfusion.ClinicalTrials.gov NCT01611753

Is haemoglobin below 7.0 g/dL an optimal trigger for allogenic red blood cell transfusion in patients admitted to intensive care units? A meta-analysis and systematic review

“…The eight included RCTs ranged in publication year from 1999 to 2019 and contained a total of 3415 patients 10 22 23 25–29. The patient population sizes of the included trials were very diverse, ranging from 44 to 998.…”

“…In fact, this study was the first comprehensive meta-analysis to address different transfusion thresholds among critically ill and perioperative patients, but it lacked a valid analysis of secondary outcomes which were noteworthy factors for the effects of RBC transfusions. Furthermore, Chong and colleagues also conducted an updated analysis on the effects of RBC transfusion, which included two more RCTs other than the same 10 trials included in Fominskiy’s study 18 19 23 30. These results suggested that RBC transfusion with restrictive threshold significantly reduced the risk of overall 30-day mortality (OR: 0.82, 95% CI: 0.70 to 0.97, p=0.019) when compared with that with liberal threshold, accompanied with declining risk of stroke/transient ischaemic attack (OR: 0.63, 95% CI: 0.40 to 0.99, p=0.04), transfusion reactions (OR: 0.48, 95% CI: 0.29 to 0.80, p=0.005), allogenic blood exposure (OR: 0.04, 95% CI: 0.01 to 0.14, p=0.001) and length of hospital stay (95% CI: 0.42 to 1.64, p=0.001), hinting the safety of using restrictive transfusion protocol.…”

“…The TRISS trial demonstrated the safety and economic efficiency of the restrictive blood transfusion threshold, with a well-controlled risk of bias. Mazza et al 23 performed a randomised physiological study of septic shock patients with the endpoint of abnormal lactate and ScvO 2 under distinct pretransfusion haemoglobin concentrations. However, they failed to provide valid data on mortality with a relatively small sample size provided.…”

“…We assumed that these results might be, at least in part, due to the overwhelming weight that the TRISS trial carried and the relatively low quality of the other three studies. Moreover, the study by Mazza et al 23 enrolled participants with a diagnosis of malignant tumorous, which might generate heterogeneity. Taken together, we cannot determine that blood transfusion at thresholds of 7 g/dL is the optimal transfusion threshold for patients with septic shock based on current evidences, which urges more as well as large clinical trials.…”

“…Indeed, blood transfusion is frequently administered as an efficient remedy for patients with septic shock, but the protocol for transfusion is different in patients with septic shock from patients with other critical illnesses 1 21 22. In fact, there is still a lack of conclusive data regarding the rational transfusion threshold for patients with septic shock 22 23. The transfusion requirements in septic shock (TRISS) trial did provide strong evidences that no significant difference was noted between RBC transfusion with lower and higher haemoglobin thresholds in long-term mortality and adverse reactions 22.…”