From the Department of Anesthesiology and Intensive Care Medicine (CCM, CVK); Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington.
ASAIO J. 2022 May 1;68(5):721-729. doi: 10.1097/MAT.0000000000001592. Epub 2021 Nov 27.
The contribution of veno-venous (VV) extracorporeal membrane oxygenation (ECMO) to systemic oxygen delivery is determined by the ratio of total extracorporeal blood flow () to cardiac output (). Thermodilution-based measurements of may be compromised by blood recirculating through the ECMO (recirculation fraction; Rf). We measured the effects of and Rf on classic thermodilution-based measurements of in six anesthetized pigs. An ultrasound flow probe measured total aortic blood flow () at the aortic root. Rf was quantified with the ultrasound dilution technique. was set to 0-125% of and was measured using a pulmonary artery catheter (PAC) in healthy and lung injured animals. PAC overestimated () at all settings compared to . The mean bias between both methods was 2.1 L/min in healthy animals and 2.7 L/min after lung injury. The difference between and increased with an of 75-125%/ compared to QEC <50%/. Overestimation of was highest when resulted in a high Rf. Thus, thermodilution-based measurements can overestimate cardiac output during VV ECMO. The degree of overestimation of depends on the EC/ ratio and the recirculation fraction.
静脉-静脉（VV）体外膜肺氧合（ECMO）对全身氧输送的贡献取决于总体外血流量（）与心输出量（）的比值。基于热稀释的可能会因 ECMO 中血液再循环（再循环分数；Rf）而受到影响。我们在六只麻醉猪中测量了和 Rf 对经典基于热稀释的测量的影响。超声流量探头在主动脉根部测量总主动脉血流量（）。使用超声稀释技术定量 Rf。在健康和肺损伤动物中，通过肺动脉导管（PAC）将设置为 0-125%的。与相比，PAC 在所有设置下均高估了（）。两种方法之间的平均偏差在健康动物中为 2.1 L/min，在肺损伤后为 2.7 L/min。与 QEC <50%/相比，当达到 75-125%/时，与之间的差异增加。当导致高 Rf 时，基于热稀释的测量对心输出量的高估最大。因此，在 VV ECMO 期间，基于热稀释的测量可能会高估心输出量。高估的程度取决于 EC/比和再循环分数。
