Background: This study aimed to determine the optimal position of venovenous extracorporeal membrane oxygenation (V-V ECMO) draining cannulas for refractory respiratory failure based on short-term clinical results.

Methods: In total, 278 patients underwent V-V ECMO at our hospital between 2012 and 2020. Those who underwent V-V ECMO with a femorojugular configuration were included. In the final cohort, 96 patients were divided into groups based on the draining cannula tip site: an inferior vena cava (IVC) group (n = 35) and a right atrium (RA) group (n = 61). The primary outcome was the change in fluid balance and ratio of awake ECMO 72 hours after V-V ECMO initiation.

Results: The only significant difference in baseline characteristics before V-V ECMO between the groups was a higher PaO₂/FiO₂ ratio in the RA group than in the IVC group (79.1 ± 26.21 vs 64.7 ± 14, P = .001). The degree of recirculation and arterial oxygenation, 90-day mortality, and clinical outcomes were similar between the groups. However, more patients achieved negative intake and output fluid balances (57.4% vs 31.4%, P = .01) and reductions in body weight (68.9% vs 40%, P = .006) in the RA group. At 72 hours after V_femoral-V_jugular ECMO initiation, more patients in the RA group than in the IVC group were managed under awake ECMO (42.6% vs 22.9%, P =.047).

Conclusions: Placement of a V-V ECMO draining cannula in the RA rather than the IVC is more effective for restricted fluid management and awake ECMO without significant recirculation.