Karagiannidis Christian, Kampe Kristin Aufm, Sipmann Fernando Suarez, Larsson Anders, Hedenstierna Goran, Windisch Wolfram, Mueller Thomas
Crit Care. 2014 Jun 17;18(3):R124. doi: 10.1186/cc13928.
While non-invasive ventilation aimed at avoiding intubation has become the modality of choice to treat mild to moderate acute respiratory acidosis, many severely acidotic patients (pH <7.20) still need intubation. Extracorporeal veno-venous CO2 removal (ECCO2R) could prove to be an alternative. The present animal study tested in a systematic fashion technical requirements for successful ECCO2R in terms of cannula size, blood and sweep gas flow.
ECCO2R with a 0.98 m(2) surface oxygenator was performed in six acidotic (pH <7.20) pigs using either a 14.5 French (Fr) or a 19Fr catheter, with sweep gas flow rates of 8 and 16 L/minute, respectively. During each experiment the blood flow was incrementally increased to a maximum of 400 mL/minute (14.5Fr catheter) and 1000 mL/minute (19Fr catheter).
Amelioration of severe respiratory acidosis was only feasible when blood flow rates of 750 to 1000 mL/minute (19Fr catheter) were used. Maximal CO2-elimination was 146.1 ± 22.6 mL/minute, while pH increased from 7.13 ± 0.08 to 7.41 ± 0.07 (blood flow of 1000 mL/minute; sweep gas flow 16 L/minute). Accordingly, a sweep gas flow of 8 L/minute resulted in a maximal CO2-elimination rate of 138.0 ± 16.9 mL/minute. The 14.5Fr catheter allowed a maximum CO2 elimination rate of 77.9 mL/minute, which did not result in the normalization of pH.
Veno-venous ECCO2R may serve as a treatment option for severe respiratory acidosis. In this porcine model, ECCO2R was most effective when using blood flow rates ranging between 750 and 1000 mL/minute, while an increase in sweep gas flow from 8 to 16 L/minute had less impact on ECCO2R in this setting.
虽然旨在避免插管的无创通气已成为治疗轻至中度急性呼吸性酸中毒的首选方式，但许多严重酸中毒患者（pH<7.20）仍需要插管。体外静脉-静脉二氧化碳清除（ECCO2R）可能是一种替代方法。本动物研究系统地测试了在插管尺寸、血液和吹扫气体流量方面成功进行ECCO2R的技术要求。
使用0.98平方米表面的氧合器对6只酸中毒（pH<7.20）猪进行ECCO2R，分别使用14.5法国（Fr）或19Fr导管，吹扫气体流速分别为8和16升/分钟。在每个实验过程中，血流逐渐增加至最大400毫升/分钟（14.5Fr导管）和1000毫升/分钟（19Fr导管）。
只有当使用750至1000毫升/分钟的血流速度（19Fr导管）时，严重呼吸性酸中毒的改善才可行。最大二氧化碳清除量为146.1±22.6毫升/分钟，而pH值从7.13±0.08升至7.41±0.07（血流速度1000毫升/分钟；吹扫气体流速16升/分钟）。相应地，8升/分钟的吹扫气体流速导致最大二氧化碳清除率为138.0±16.9毫升/分钟。14.5Fr导管的最大二氧化碳清除率为77.9毫升/分钟，这并未导致pH值正常化。
静脉-静脉ECCO2R可作为严重呼吸性酸中毒的一种治疗选择。在这个猪模型中，当血流速度在750至1000毫升/分钟之间时，ECCO2R最有效，而在这种情况下，吹扫气体流速从8升/分钟增加到16升/分钟对ECCO2R的影响较小。
