Nicolas Themelin1, Patrick Biston1, Jacqueline Massart1, Christophe Lelubre2, Michaël Piagnerelli1,3. 1. Intensive Care, CHU-Charleroi Marie-Curie, Université Libre de Bruxelles, Charleroi, Belgium. 2. Internal Medicine, CHU-Charleroi Marie-Curie, Université Libre de Bruxelles, Charleroi, Belgium. 3. Experimental Medicine Laboratory, CHU-Charleroi, A Vésale Hospital, ULB 222 Unit, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium.
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.
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 ICUpatients 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.