TY - JOUR

T1 - Effect of low vs high haemoglobin transfusion trigger on cardiac output in patients undergoing elective vascular surgery

T2 - Post-hoc analysis of a randomized trial

AU - Møller, Anders

AU - Wetterslev, Jørn

AU - Shahidi, Saeid

AU - Hellemann, Dorthe

AU - Secher, Niels H.

AU - Pedersen, Ole B.

AU - Marcussen, Klaus V.

AU - Ramsing, Benedicte G.U.

AU - Mortensen, Anette

AU - Nielsen, Henning B.

PY - 2021

Y1 - 2021

N2 - Background: During vascular surgery, restricted red-cell transfusion reduces frontal lobe oxygen (ScO2) saturation as determined by near-infrared spectroscopy. We evaluated whether inadequate increase in cardiac output (CO) following haemodilution explains reduction in ScO2. Methods: This is a post-hoc analysis of data from the Transfusion in Vascular surgery (TV) Trial where patients were randomized on haemoglobin drop below 9.7 g/dL to red-cell transfusion at haemoglobin below 8.0 (low-trigger) vs 9.7 g/dL (high-trigger). Fluid administration was guided by optimizing stroke volume. We compared mean intraoperative levels of CO, haemoglobin, oxygen delivery, and CO at nadir ScO2 with linear regression adjusted for age, operation type and baseline. Data for 46 patients randomized before end of surgery were included for analysis. Results: The low-trigger resulted in a 7.1% lower mean intraoperative haemoglobin level (mean difference, −0.74 g/dL; P <.001) and reduced volume of red-cell transfused (median [inter-quartile range], 0 [0-300] vs 450 mL [300-675]; P <.001) compared with the high-trigger group. Mean CO during surgery was numerically 7.3% higher in the low-trigger compared with the high-trigger group (mean difference, 0.36 L/min; 95% confidence interval (CI.95), −0.05 to 0.78; P =.092; n = 42). At the nadir ScO2-level, CO was 11.9% higher in the low-trigger group (mean difference, 0.58 L/min; CI.95, 0.10-1.07; P =.024). No difference in oxygen delivery was detected between trial groups (MD, 1.39 dLO2/min; CI.95, −6.16 to 8.93; P =.721). Conclusion: Vascular surgical patients exposed to restrictive RBC transfusion elicit the expected increase in CO making it unlikely that their potentially limited cardiac capacity explains the associated ScO2 decrease.

AB - Background: During vascular surgery, restricted red-cell transfusion reduces frontal lobe oxygen (ScO2) saturation as determined by near-infrared spectroscopy. We evaluated whether inadequate increase in cardiac output (CO) following haemodilution explains reduction in ScO2. Methods: This is a post-hoc analysis of data from the Transfusion in Vascular surgery (TV) Trial where patients were randomized on haemoglobin drop below 9.7 g/dL to red-cell transfusion at haemoglobin below 8.0 (low-trigger) vs 9.7 g/dL (high-trigger). Fluid administration was guided by optimizing stroke volume. We compared mean intraoperative levels of CO, haemoglobin, oxygen delivery, and CO at nadir ScO2 with linear regression adjusted for age, operation type and baseline. Data for 46 patients randomized before end of surgery were included for analysis. Results: The low-trigger resulted in a 7.1% lower mean intraoperative haemoglobin level (mean difference, −0.74 g/dL; P <.001) and reduced volume of red-cell transfused (median [inter-quartile range], 0 [0-300] vs 450 mL [300-675]; P <.001) compared with the high-trigger group. Mean CO during surgery was numerically 7.3% higher in the low-trigger compared with the high-trigger group (mean difference, 0.36 L/min; 95% confidence interval (CI.95), −0.05 to 0.78; P =.092; n = 42). At the nadir ScO2-level, CO was 11.9% higher in the low-trigger group (mean difference, 0.58 L/min; CI.95, 0.10-1.07; P =.024). No difference in oxygen delivery was detected between trial groups (MD, 1.39 dLO2/min; CI.95, −6.16 to 8.93; P =.721). Conclusion: Vascular surgical patients exposed to restrictive RBC transfusion elicit the expected increase in CO making it unlikely that their potentially limited cardiac capacity explains the associated ScO2 decrease.

KW - abdominal aortic aneurysm

KW - anaesthesia

KW - arterial occlusive disease

KW - erythrocyte transfusion

KW - tissue oxygenation

U2 - 10.1111/aas.13733

DO - 10.1111/aas.13733

M3 - Journal article

C2 - 33141936

AN - SCOPUS:85097256044

VL - 65

SP - 302

EP - 312

JO - Acta Anaesthesiologica Scandinavica

JF - Acta Anaesthesiologica Scandinavica

SN - 0001-5172

IS - 3

ER -