Effects of red blood cell transfusion on global oxygenation in anemic critically ill patients

Abstract

Background Consensus for transfusion in intensive care unit (ICU) patients recommends a restrictive strategy, based on a hemoglobin (Hb) concentration of 7 g/dL. Red blood cell (RBC) transfusion is used to prevent tissue hypoxia by improving oxygen transport (DO2) and therefore oxygen consumption (VO2). We studied the effects of RBC transfusion on systemic oxygenation parameters reflecting systemic oxygen extraction (EO2 = DO2/VO2): S(c)vO2, lactate level, venous‐to‐arterial carbon dioxide difference (Pv‐aCO2), and cardiac index/EO2 (CI/EO2) and evaluated their usefulness in guiding transfusion decisions in ICU patients. Study Design and Methods Prospectively, all adult patients transfused were included except those with active bleeding or without a jugular or subclavian catheter. We measured O2 parameters before and after transfusion. Patients were a priori grouped according to their initial S(c)vO2 (< or ≥70%), treatment with vasopressors, cardiac function, and septic status. Results A total of 62 patients received 105 RBC transfusions. For all, mean arterial pressure (77 [69‐88] to 81 [73‐91] mm Hg), Hb concentration (7.4 [7.0‐7.8] to 8.4 [7.7‐8.9] g/dL) and S(c)vO2 (65% [59%‐73%] to 69% [62%‐75%]) increased after transfusion (all P < .001). S(c)vO2 improved after transfusion only when initial S(c)vO2 was less than 70% (62% [56%‐65%] to 66% [61%‐71%]; P < .001). In this group, Pv‐aCO2, lactate concentrations, and CI/EO2 did not change after transfusion. Cardiac function, sepsis, or vasopressor therapy did not affect these results. Conclusions Among systemic O2 parameters, only a S(c)vO2 < 70% in anemic ICU patients improves after transfusion. As S(c)vO2 can reflect a DO2/VO2 imbalance, it could be helpful when combined with the Hb concentration to decide whether to transfuse. However, the benefit on outcome should be further studied.

The Impact of Red Blood Cell Transfusion on Blood Lactate in Non-Bleeding Critically Ill Patients—A Retrospective Cohort Study

“…In our study we analysed only RBCT with elevated (≥1.8 mmol/L) pre-transfusion lactate in order to show the effect of RBCT on its concentration. Normal (<1.8 mmol/L) lactate does not decrease further following RBCT, as was shown in the study by Themelin et al [15]. Themelin showed that even with normal pre-RBCT lactate, ScvO 2 improved significantly following RBCT, showing that lactate does not have appropriate sensitivity as a physiologic RBCT trigger.…”

Target blood pressure management during cardiopulmonary bypass improves lactate levels after cardiac surgery: a randomized controlled trial

“…Therefore, multicenter, larger-sample studies are required in the future. Based on the finding that a relatively high MAP improved tissue perfusion during CPB, our future study will monitor the peripheral circulation during CPB by ultrasound and calculate oxygen supply and consumption for more convincing evidence [ 21 , 22 ].…”

Patient Blood Management in der Intensivmedizin

“…Themelin et al deuten in einer Studie mit Intensivpatienten an, dass Transfusionen vor allem einen Effekt auf die zentralvenöse Sauerstoffsättigung hatten, wenn diese initial bei < 70 % lag [57]. Außerdem sollte die Kompensationsfähigkeit des Patienten bei der Transfusionsentscheidung mit einbezogen werden.…”