Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Department of Emergency Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Crit Care. 2024 Aug 17;28(1):274. doi: 10.1186/s13054-024-05055-2.
Our study aimed to investigate the effects of different extracorporeal membrane oxygenation (ECMO) blood flow rates on lung perfusion assessment using the saline bolus-based electrical impedance tomography (EIT) technique in patients on veno-venous (VV) ECMO.
In this single-centered prospective physiological study, patients on VV ECMO who met the ECMO weaning criteria were assessed for lung perfusion using saline bolus-based EIT at various ECMO blood flow rates (gradually decreased from 4.5 L/min to 3.5 L/min, 2.5 L/min, 1.5 L/min, and finally to 0 L/min). Lung perfusion distribution, dead space, shunt, ventilation/perfusion matching, and recirculation fraction at different flow rates were compared.
Fifteen patients were included. As the ECMO blood flow rate decreased from 4.5 L/min to 0 L/min, the recirculation fraction decreased significantly. The main EIT-based findings were as follows. (1) Median lung perfusion significantly increased in region-of-interest (ROI) 2 and the ventral region [38.21 (34.93-42.16)% to 41.29 (35.32-43.75)%, p = 0.003, and 48.86 (45.53-58.96)% to 54.12 (45.07-61.16)%, p = 0.037, respectively], whereas it significantly decreased in ROI 4 and the dorsal region [7.87 (5.42-9.78)% to 6.08 (5.27-9.34)%, p = 0.049, and 51.14 (41.04-54.47)% to 45.88 (38.84-54.93)%, p = 0.037, respectively]. (2) Dead space significantly decreased, and ventilation/perfusion matching significantly increased in both the ventral and global regions. (3) No significant variations were observed in regional and global shunt.
During VV ECMO, the ECMO blood flow rate, closely linked to recirculation fraction, could affect the accuracy of lung perfusion assessment using hypertonic saline bolus-based EIT.
本研究旨在探讨不同体外膜肺氧合（ECMO）血流速率对静脉-静脉（VV） ECMO 患者应用盐水弹丸式电阻抗断层成像（EIT）技术评估肺灌注的影响。
这是一项单中心前瞻性生理研究，符合 ECMO 脱机标准的 VV ECMO 患者，在不同 ECMO 血流速率（逐渐从 4.5 L/min 降至 3.5 L/min、2.5 L/min、1.5 L/min，最后降至 0 L/min）下使用盐水弹丸式 EIT 评估肺灌注。比较不同流速下的肺灌注分布、死腔、分流、通气/灌注匹配和再循环分数。
共纳入 15 例患者。随着 ECMO 血流速率从 4.5 L/min 降至 0 L/min，再循环分数显著降低。主要的 EIT 发现如下。（1）感兴趣区域（ROI）2 和腹侧区域的中位肺灌注显著增加[38.21（34.93-42.16）%至 41.29（35.32-43.75）%，p=0.003；48.86（45.53-58.96）%至 54.12（45.07-61.16）%，p=0.037]，而 ROI 4 和背侧区域的肺灌注显著降低[7.87（5.42-9.78）%至 6.08（5.27-9.34）%，p=0.049；51.14（41.04-54.47）%至 45.88（38.84-54.93）%，p=0.037]。（2）死腔显著减少，腹侧和整体区域的通气/灌注匹配显著增加。（3）区域和整体分流无明显变化。
在 VV ECMO 中，与再循环分数密切相关的 ECMO 血流速率可能会影响高渗盐水弹丸式 EIT 评估肺灌注的准确性。
